The mosquito, a blood drinker in the pond

Frogs, garter snakes, turtles, none of the inhabitants of the pond escape the bites of adult mosquitoes. But they feast on their aquatic larvae, and few of them escape.

The world's ponds busy

Wetlands around the world are home to mosquitoes. Their eggs, and then their larvae, live in the water. The winged adults, while often foraging, are in search of blood, in all vertebrates. The inhabitants of the banks of the pond know them only too well.

In Europe, they are mainly solicited by Aedes, rather in temporary wetlands, Culex and some Anopheles in stagnant waters. In their family Culicidae we will also find the Coquillettidia, with a very original respiratory mode.

Aquatic larvae, air breathing

Mosquito larvae live in water but continue to breathe like terrestrial insects. They look for air on the surface of ponds, positioning themselves head down, vertically, for the Culex. A well known posture where we see the small silhouettes grouped, long and thin, as if hooked to the surface by their respiratory siphon. They stay there, breathing in and out. The Anopheles, without siphon, will lie under the surface allowing the air to circulate in their tracheas. And the Coquillettidia will never come to the surface. But then? From their pointed respiratory siphon they pierce the tissues of aquatic plants, and take the necessary air from them.

They feed on waste, nectar and a little blood

From the larva to the adult, from the male to the female, the feeding of mosquitoes differs completely. The adult female is well known for biting, injecting an anti-coagulant, and sucking blood from her prey. All this to bring to maturity her young, eggs that she will deposit delicately on the surface of the water.

Out of this period, the adults fly from flowers to flowers, feeding on their nectar and pollinating them. The larvae will spend their few weeks of aquatic life filtering and cleaning the water. They shake their mouth bristles, creating a water current, feeding on floating microparticles.

Larvae wriggle, adults fly

A mosquito larva has no legs, the observer approaching a tank of water will see them wriggling to disappear towards the bottom, helped by bristles arranged all along the body. The nymph, a strange silhouette with a large thorax floating in the middle of the larvae, is equipped with a swimming paddle at the end of its abdomen. The adult, better known, has a single pair of wings and two pendulums, like all members of its group Diptera.

Males and females, aquatic meetings

The females, with the hematophagous diet essential to the development of the eggs, lay eggs on the surface of the water. They float in small irregular groups in Anopheles, in rafts in Culex and Aedes. A first larva hatches, it will moult three times before turning into a nymph. With cycles of a few days to a few weeks, depending on the species and climatic conditions. Mobile, with a large dark thorax from which emerges a small breathing tube, the nymph will give birth to the winged adult at the surface.

Mosquitoes are not very popular, and often the idea of the pond, of the body of water, is associated with them, with the fear of seeing them invade our gardens. However, in the pond many predators devour them, and dragonflies spare few adults... They are thus essential to this ecosystem!

The grey heron, a fishing wader

The grey heron (Ardea cinerea) is a very shy fishing wader. It can be observed from a distance in the marshes and along the rivers of Europe. Protected since 1975, this majestic heron is the most common heron in Europe.

Nearly one meter high and weighing 2 kilos as an adult, the grey heron is the largest heron in Europe. This wading bird can be recognized by its size but also by its ashy gray plumage (hence its name), its white neck and its black spotted breast. Its white head is underlined by black lines starting from the back of the neck and stretching to the eye. The juveniles have the same physical characteristics as the adults but are more dull.

The grey heron has a long yellow beak which is a formidable weapon for its prey. A great hunter and fisherman, the grey heron feeds mainly on the product of its fishing in the river but also on frogs, reptiles and aquatic insects and small mammals such as mice, voles, field mice or moles. This wader, which is very common in Europe, is a partial migrant. Only in very cold weather does it move temporarily.

In some mild regions where food is abundant, the grey heron is a sedentary bird. Its heavy flight is graceful but slow (40 km / hour maximum). It can be found in some European countries such as the Netherlands, Scandinavia, England, Germany, but also further south in Portugal, Northern Italy and Greece. In France, it nests mainly in the North-East and in the vast marshy areas of the West (Poitou-Charente and Vendée).

The grey heron is a shy animal which does not let itself be easily observed up close. At the arrival of an intruder, it flies away to join a quieter corner. If this bird is generally a great loner, at the time of the mating, it joins its congeners within large colonies, the heronries, perched at the top of the trees. The nesting begins early in the season from February until July. It is the male who chooses the place where the eggs will be laid. The clutch consists of 4 to 5 light blue eggs. The two parents take turns during the 25 days of incubation. The first flight of the juveniles intervenes approximately 50 days after the hatching. The emancipation of the young is fast since in 3 weeks after the fledging, they must be able to manage alone.

The gyrin, a turnstile in the pond

Lively, light, the gyrins crisscross the surface of fresh water with their metallic shine, in a dizzying ballet of speed.

The speedboat of fresh water

They move at full speed on open waters, gather peacefully in the plants and dive to escape from predators. They live between air and water. Gyrins, small beetles of aquatic environments, hold the speed record of floating insects, with their 4 back legs they propel their 12 grams, in random but precise curves, avoiding for sure any collision. These insects of a few millimeters, 6 at most, with varied dark colors, have 3 genera and many species, all of the family Gyrinidae.

A life between air and water

Floating on water, Gyrinids breathe oxygen from the air, like any terrestrial insect. Their tracheas carry gases to all their organs. But at the slightest alert, they dive under water, take refuge in the grass beds, do not move any more. Do they hold their breath, do they have a snorkel like the nephrops or the eristalus? No, just before diving, with the tip of their abdomen, they capture a bubble of air, a precious reserve that ensures them to go back up when the danger has passed. Their daily activities, such as hunting, take place on the surface.

A predator on the water mirror

Untiring, the Gyrins watch and survey their territory, a vast and totally flat area. With their antennae on the surface of the water, they pick up the vibrations of insects, spiders, shipwrecked airborne creatures, desperately struggling to escape drowning. Spotted, they are seized by the front legs, ingested by a crushing mouth apparatus. And if no aerial prey presents itself, mosquito larvae, small crustaceans, will at some point pass near the surface, within reach of the paws of a hungry Gyrin.

Eyes for water, eyes for air

Between air and water, how can the Gyrin switch so quickly from an aerial hunt to an aquatic hunt? How does it spot a predator from the depths or diving from the sky? Its adaptation is simple, obvious: its eyes are divided into two parts, one for aerial vision, the other for underwater vision. To surprise him becomes a real challenge. And to escape him too. Especially since its adaptation to swimming is also remarkable.

Swimmers and trainers

The spectacle of the Gyrins spinning, twirling, so fast that the eyes cannot follow them, announces long afternoons of contemplation at the edge of the pond. Their back legs are said to be swimming, equipped with bristles they offer a powerful support on the water, activate vigorously several tens of times per second, and propel the Gyrin at high speed. The oars at rest are folded in a special box, so the small carinated and oiled body of the beetle finishes its slide with fluidity...

Males and females, aquatic meetings

Following a terrestrial hibernation, under the stones of the banks, the couples of Gyrins are formed, the females will lay about thirty eggs on the plants. These eggs will give birth to a larva which, as with all beetles, does not look like the adult. 15 mm long, whitish, thin, it crawls on the bottom or wriggles in the water, feeding on small animals. Its breathing is aquatic, abdominal feathery tracheal gills ensure the gas exchanges of its organism. After three larval stages a terrestrial nymph is formed, the metamorphosis will give birth to the Gyrins whirling on the water.

They float, spin on the water at full speed, they dive and swim, their young breathe under water... And moreover they can fly. Their wings spread, they leave to discover new environments, with calm waters, vegetated banks, with large areas to glide without hindrance.

The dytic, a ruthless hunter in the pond

An imposing shadow rises from the depths of the pond, with a supple and quick swim. A surprisingly large, dark-shelled Carabean pierces the surface of the water for a moment, then disappears. The Dytic is back on the hunt.

picture credit: dytic.over-blog

An aquatic beetle

Large family of beetles, the Dytiscidae have many genera in Europe, all well adapted to the aquatic environment. Eggs, larvae, adults, in their cycle everything happens under water. Only the nymphs make a brief excursion on the banks. Among more than a hundred species, the bordered dytic, Dytiscus marginalis, is one of the most common and most remarkable, by the size of the adult, 3 to 4 cm, its dark carapace, with elytra with metallic reflections, bordered of golden yellow. Its larva is no less astonishing, even larger than the adult, up to 6 cm, with a characteristic look, like an inverted question mark. Adults as well as larvae are merciless predators.

An aquatic life, an aerial breathing

If Dytics spend their life underwater, they have kept their aerial breathing, from the time of their distant terrestrial ancestors. Regularly, the adults go back to the surface, let emerge the end of their abdomen, capture air which they store between elytra and abdomen. Their reserve thus made, they spin in the vegetation. The larva has not adapted to aquatic breathing any more than the adult, no gills, no exchange membrane. It undulates towards the surface, head downwards, body arched, the end of its abdomen pierces the surface of the water, a drop of air is sucked in, feeding its network of tracheas.

The water tiger

The bordered Dytique has a reputation of voracious hunter. Deserved. Tadpoles, larvae, mud worms, fish, newts, no inhabitant of the pond is spared. And if the dytics regulate the inhabitants of the pond by cleaning up the populations, consuming the weakened and sick individuals, their pullulation can lead to the disappearance of all life in the pond. The adult, lying in wait in the vegetation, springs up with speed, following a lightning chase, the prey is captured, consumed with a crushing mouth apparatus.

Its larva is even more formidable. Thin, long, it carries a flattened head, provided with arched mandibles, spread out during the stalking. The prey passes, the mandibles close again. They have an action of claws, but also of syringes, instilling by two small channels of digestive juices which will liquefy the menu. Will not remain any more but to aspire it, by the mandibles also.

Just before becoming nymph, a larva can consume up to 30 preys per day.

Swimmer, diver, air sailor

The bordered dytic is a skilled swimmer, diver. Lively, fast, it has a body cut for swimming. Oval, flattened, carinated, bevelled, it splits the waters with ease. Its back legs equipped with natatory bristles row vigorously in a beautiful set. They handicap him however for the walk, of possible exits of water see him bumping painfully on the banks. On the other hand, if it walks badly, the Dytique can fly. The dark nights a light humming rises from the pond, the Dytics spread their elytra, spread their transparent wings, and fly away towards other spaces to live.

Males and females, aquatic meetings

The couples of Dytiques meet in spring, the males impregnate the females by maintaining themselves on their backs using the suction cups of their front legs. The eggs are aquatic, the larvae are born after 2 to 3 weeks, they will go through three stages before reaching the bank to become nymphs. Buried in the sand, in less than two weeks they will metamorphose into an adult still a little pale and soft, which will immediately return to the aquatic environment with its clumsy walk, where it can live for several years.

The bordered dytic is one of the most remarkable inhabitants of the pond, inviting itself according to its nocturnal flights, leaving without warning when the preys become scarce. A dense and varied vegetation, a diversified fauna, allow to perpetuate its presence, without excess however.

The common toad, a useful batrachian for your garden

Spring is approaching, slowly but surely, and for some, it will be tomorrow, the day after tomorrow; only the temperature, humidity and light will trigger the awakening after 3 to 4 months of winter rest of the most repulsive "monster", the most popular belief and always associated with witchcraft.

But, did you know that this host of the earth, of forests, gardens, swamps, ditches, ponds, of the plain as well as the mountains, of the city (it can be found in some parks in Geneva) as well as of the countryside, is the most useful for the protection of your salads?

Come on, the author is delirious; well, no, because this "residue of a disgusting elixir extract that everyone worships..." plays a crucial role in the destruction and regulation of all kinds of invertebrates such as earthworms, slugs, caterpillars, beetles, ants, and many more, whose existence you could not imagine.

It is the largest toad: the female can reach 12 cm (even 18 cm in the south of Europe), the male reaches quietly 8 to 9 cm and is provided with strong forearms whose three internal fingers are provided with rough and blackish pads named "callosities", in period of reproduction only. One can also recognize this one by seizing it, it will then emit some croaking while the female will remain mute.

35 years of existence, not without risk!

The life span of our "salad protector" can exceed 35 years unless, by mistake, it ventures to swallow a poisoned slug, hence the importance of using natural methods (saucers filled with beer) to eliminate gastropods if the damage done to the vegetable garden is major.

The natural predators of the common toad are mainly the garter snake, the hedgehog and certain birds such as the crow. Another factor that shortens the life of this amphibian is the high mortality during spring migration on our country roads crossing their territories. Indeed, as soon as the weather conditions become favorable for awakening and reproduction, thousands of toads move to their egg-laying site, which corresponds to their birthplace in general: they must then often cross busy roads. Hundreds of them will perish under the wheels of unconcerned motorists or even those who cannot do otherwise because there are so many of them. Remember, the road is not only slippery when it rains, it is doubly dangerous when it rains and when the amphibians are present.

Fortunately, there are now amphibian migration "tunnels" that are placed under the roadways that cross important migration routes, but there are still too few...

The reproduction of toads

After these asphalt considerations, let's get back to our toad. The males are so eager to find a mate that they can cling to a female for up to ten times, and she may drown under the burden. Females can sometimes be seen dead from disembowelment due to the power of the forearms of the first male clamped who was clutching harder and harder while other suitors were clutching in turn.

About reproduction, let us point out that the female is able to lay about 8000 eggs arranged in double gelatinous cords hung on aquatic plants. The tadpoles, which live in a gregarious way, are easily recognized by their modest size (3cm) and their black color; they gather in bands near the surface and at the edge of water points where the temperature is higher. Most of them will perish from predator attacks (aquatic insect larvae, newts, fish), or from unfavorable conditions (pollution, drying up) and only 1% of them will produce an adult capable of giving offspring. The obstacle course is particularly selective for all toads and frogs.

The "toad rains" as they were called in the past are due to the massive emergence of young after heavy rains. These, as soon as the metamorphosis takes place, which generally takes place at the end of June, take refuge in small crevices of the ground or under stones and plant debris. They will then lead all their life a terrestrial existence (except for the laying of eggs), crepuscular and nocturnal. The toad is a homebody, seems to know its hunting territory very well and always returns to the same refuge, year after year.

Reminder

The handling of the animal is not dangerous for humans. On the other hand, all amphibians and reptiles are strictly protected, as well as their biotopes. The taking of specimens in the wild is forbidden.

The salamander, a nocturnal amphibian

Legendary animal, symbol of passion, emblem of François 1er, the salamander has the reputation of being able to live in the middle of flames. But who is really this small amphibian?

The salamander, a discreet animal

Salamandra salamandra, more commonly known as 'Spotted Salamander' is an amphibian of 12 to 25 cm length living in humid forest environments. It is quite common in all deciduous and coniferous forests of medium altitude on the whole territory including Corsica. Easily recognizable by its shiny black body spotted with yellow, the salamander has webbed feet and a well-structured tail. Its big black eyes are arranged on both sides of its snout all in roundness. This rather terrestrial amphibian frequents streams and springs but does not live directly in water. Nocturnal, the salamander hides during the day under rocks, stumps, and can even invest the burrow of a rodent.

Carnivorous, it feeds on worms, small mollusks and insects.

In winter, salamanders enter into diapause and live in slow motion under the shelter of a stump or in a rock crevice until spring, when they will come out and frequent wetlands in order to reproduce. Ovoviviparous, the female deposits her larvae directly in a spring, a fountain or a small stream. The water must be well oxygenated and therefore in motion. Provided with external feathery gills, the larvae have the capacity to swim as soon as they are expelled and to devour mud worms, larvae of all kinds and even their fellow creatures! After 5 months of this diet, and a metamorphosis later, they will be transformed into salamanders and will be able to leave the water to begin their terrestrial life. The sexual maturity will be reached at the age of 4 years, but if the salamander escapes its predators (snakes, wild boars, hedgehogs, raptors...) it will be able to live more than 20 years.

The different species of salamanders

The spotted salamander (Salamandra salamandra) which we mentioned above is the most common and can be found in the whole country if the ecosystem is suitable. It can be recognized by its shiny black body with yellow/orange spots and its relatively large size compared to other species.

The Lanza's salamander (Salamandra lanzai) is very rare and exclusively represented in the High Alps between 1600 and 2200 m of altitude. It likes humid alpine grasslands and moves early in the morning. Its body is all black, shiny and does not exceed 15 cm in length. This salamander has an IUCN conservation status as it is considered a vulnerable species.

The black salamander (Salamandra atra) is less attached to the wetland than the other species. From 9 to 12 cm for the male and a maximum of 15 cm for the female, this salamander has a shiny black body marked by circular costal grooves. It is found only in the Alps. A subspecies Salamandra atra aurorae, dotted with large cream-colored spots lives in the southern Italian Alps.

The Corsican salamander (Salamandra corsica) is endemic to this island where it can be found up to 1800m altitude. It looks like the spotted salamander with its shiny black body dotted with yellow/orange spots. This protected species is listed in Annex III of the Bern Convention, Annex IV of the Habitat Directive and classified as a "species to watch" in the red list of amphibians and reptiles.

The spotted salamander, a dragon in the undergrowth

Legendary, known to all, the spotted salamander is found on rare occasions. On rainy evenings they come out, sometimes by the dozen, on the paths, at the edge of the fountains, in the garden. Then they return to their underground life, secret. Let's go and discover the unusual world of the Salamanders.

A miniature dragon in the undergrowth?

Its body of about fifteen centimeters rests on four short legs, and is extended by a round, tapered tail. Its colors, a shiny black dotted with yellow, allow to recognize it unequivocally. Its head has two large black eyes adapted to night and twilight vision, followed by two protuberances, the typical parotoid glands. Its appearance is almost reptilian, yet the Spotted Salamander, Salamandra salamandra, belongs to the class of Amphibians, vertebrates leading a double life, terrestrial for the adults, aquatic for the young. Alongside the Tritons, with a flat tail, it joins the order of the Urodeles, while Frogs and Toads are classified in the Anurans.

An adult life far from water

Surprisingly, for Amphibians, Salamanders spend their adult life far from the aquatic environment, but like humidity. They hibernate during the coldest months, under stones, old stumps, borrowing old rodent burrows. They rest during the summer heat, seeking coolness in their underground caches. They hunt at dusk, at night, snails, insects, earthworms, millipedes, spiders, caterpillars, sowbugs... Prey of all sizes, held in their powerful jaws before being swallowed.

And in their life cycle, even the mating season remains terrestrial.

Males and females, terrestrial meetings

As soon as they come out of hibernation, at the beginning of March, until September, the mating season will take place, entirely terrestrial. Preferring the month of July, the males from the age of 2, 3 years look for a female. They establish contact, with their head resting on her back. If the moment is favourable, the male slides under his partner, lifts her up slightly and holds her by a grip between her front legs. Fertilization is internal. Then follows for the female a long gestation, of several months. Eight in total. At the end of which she will finally return to the aquatic environment, so that her young develop there.

Small Salamanders long protected

The long gestation of the Salamander allows it to protect its eggs and to give birth to larvae already formed. After a migration towards a brook, a pond, a fountain, an active cave, it immerses itself partially... And releases about twenty larvae of 2 to 3 cm long; the most robust will go up to 60... Sharing the same habitat, Red Frogs, Common Toads, Alpine Tritons, have not adopted the same reproductive strategy, and to compensate for predation lay hundreds, thousands of eggs. In the case of the Salamander, the larvae are autonomous from birth.

Perennial larvae

Lively, the small larvae spin on their four legs, undulating with their long flat tail. They can be noticed by their finely branched external gills, the clear spot marking the base of their legs. Discreet, rather grayish, they hide in crevices, under stones, between roots, trying to dodge formidable predators, carnivorous insects, birds, aquatic shrews, trouts in deeper waters... And larvae of Salamanders bigger than them. Carnivorous, they hunt mosquito larvae, mayflies, gammarids, and become cannibals if needed. After 4 months of this diet, and several moults, the young Salamanders leave the water, for a long terrestrial life of several decades.

A long, long life

The longevity of Salamanders is exceptional, 30 years in the wild, up to 50 in captivity. Their absence of predators is one of the causes. Some have taken the risk, but they will not forget its yellow and black colors. Nor its toxic venom, secreted by the parotoid glands and the verrucous protuberances arranged in a line all along its body. This venom, dangerous alkaloid, is a neurotoxic aggressive for the mucous membranes, mouth and eyes. On the epidermis, the human skin, it can create irritations. For Salamanders, the protection is long-lasting, especially since it is completed with an anti-fungal and anti-bacterial action.

Many subspecies

If the spotted salamanders are distributed throughout Europe, we can not find 2 similar, their coloring varies considerably and is specific to each individual.

On the other hand, depending on the habitat, one can recognize about ten subspecies.

• Salamandra salamandra terrestris, widespread in France, has two parallel bands of yellow spots, sometimes in a continuous line;
• Salamandra salamandra salamandra, from the Alps, Carpathians, Balkans, has small spots;
• Salamandra salamandra fastuosa lives in the central Pyrenees, Cantabrian Mountains, with her the yellow predominates, in long and wide lines;
• Salamandra salamandra bechkovi will meet in Bulgaria;
• Salamandra salamandra crespoi, bejarae and almanzoris will be distributed in Spain. Among all these subspecies some have had to adapt to difficult climatic conditions.

The subspecies of Spain

Faced with heat and drought, the Salamanders of southern Europe no longer hibernate in winter, but in summer, burying themselves in cool, damp hiding places in the hottest months. Their adaptation also involves protecting their young.

The subspecies Salamandra salamandra bernardezi, in the North-West of Spain, will give birth to young Salamanders already formed, equipped with lungs, about twenty on average.

In Portugal and North-Western Spain, Salamandra salamandra gallaica, can return to the water to deposit its larvae, but also prolong its gestation, waiting for the larvae to finish their development internally, protecting them and freeing itself from the constraints of the aquatic environment.

Mountain species

The Spotted Salamander also has some European cousins adapted not to the heat, but to the cold. The Black Salamander, Salamandra atra, lives in the mountains of the Alps. Black, rarely spotted with yellow, thin, not very big, it lives in beech forests, seeks clearings and edges. It will be found in alpine meadows if scree slopes, hiding places, allow it to protect itself during the day and to hibernate in winter. Up in the mountains the good season is short, the Black Salamander has opted for maximum protection of its young. She will keep them inside her throughout their development, from the egg to the young Salamander. The gestation can last 2 to 3 years depending on the altitude, then only 2 young Salamanders will be born, already big, 4 to 5 cm, autonomous and resistant.

Human legends

Fascinating, mysterious, the Salamander is at the heart of many legends. It has a strange relationship with fire, able to cross it, to be reborn in it, even to extinguish it. Where does she get her magical powers? From its invincibility, from its venom, linked to its black and gold colors? From its habitat, when it emerges from under the stones of a fireplace, from a half-burned log? Or its appearance, closer to a dragon than a frog? And its ability to regenerate certain parts of its body, its exceptional longevity, do they also contribute to give it a special place in our imagination?

The Spotted Salamander and its numerous subspecies are widespread. They have adapted to a variety of habitats, even coming close to human dwellings offering suitable conditions.

The ranatre, a carnivorous bug in the pond

Concealed in the weed beds, the ranatre patiently awaits its prey. Under the frightened eyes of the children who observe the fascinating life of the aquatic world.

The "twig" bug of fresh water

It carefully moves its long body, 35 mm, on its 6 long legs, in the middle of aquatic plants. Water is its element. Like a twig, it remains motionless, observing its environment with its large round eyes. She captures her preys with her front legs transformed into ravenous claws, piercing them with her biting and sucking rostrum. The ranatre, Ranatra linearis, insect of the family Nepidae, is none other than an aquatic bug, known as heteropteran, a formidable predator of calm waters, common in the entire Palearctic zone.

It breathes oxygen from the air...under water

The ranatre lives, hunts, reproduces, under water. But it has neither gills nor breathing membranes. Then to find its oxygen it is equipped with a tuba. The end of its abdomen is extended by a long tube, made up of 2 half-stems with gutters, just as long as its body. This respiratory siphon links it to the air, allowing it to feed its tracheal system in air. It prefers to hunt close to the surface, in order to get regular supplies with less effort.

A carnivore on the lookout

At length of respiratory siphon of the surface, twig in the grasses, the ranatre settles and does not move any more. She waits. Aquatic insects, larvae, small crustaceans, tadpoles, and even small fish, are on its menu. If they pass within its reach, its legs fold up on the prey, hold it in a vice, hook and spine effectively close it. The continuation is terrible for the catch. And the observer. Seeing a small tadpole being pierced by the rostrum of the ranatre, being predigested, then absorbed by the hunter, is impressive, and not belonging to this small world is rather reassuring...

A clumsy swimmer

If the ranatre lives under water, swimming is not really her domain. It prefers to move at its own pace from plant to plant, hanging on with its long legs, which are not equipped with swimming bristles like its cousins the Notonectes and Naucores. And if it does not swim, or badly, it is able to leave water, to let itself dry, and... to take its flight. She spreads her wings, of a beautiful translucent blue, and leaves in search of new territories. Surprisingly, she reveals a red abdomen of the most beautiful effect, unexpected under her yellowish colors.

Males and females, aquatic meetings

The reproduction of ranatres takes place in spring. The female pierces the plants with her caudal auger and deposits eggs of about 2 mm, either scattered or in a line, depending on the plants chosen or available. 2 small air filaments are visible to the naked eye. At the hatching, the small ones resemble the adults, 5 larval stages will follow one another during 2 months to lead to the ranatre of final size. Which will live approximately 2 years.

If the ranatre is impressive when it captures its preys, to observe it cleaning itself delicately with its front legs, to stiffen like a twig, to deposit a line of eggs on a water lily, to fly away all colored, is a spectacle of which one does not get tired.

The notonect, a bee with its head upside down

A slender silhouette, the Notonecte criss-crosses the waters of the pond, spinning towards the surface, where it stops for a brief moment, legs and abdomen brushing the mirror. As if posed on the air, in an inverted world.

The freshwater "bee" bug

An essential inhabitant of ponds, the glaucous notonect cannot go unnoticed, a small insect of 15 mm, regularly emerging on the surface, to come and breathe. Always in a characteristic posture, the back downwards, its back legs allowing it to swim vigorously. Aquatic bug, it crosses its cousins, the Ranatre and the Nepe. And is just as carnivorous, consuming its prey with its stinging-sucking rostrum. Among half a dozen species of Notonectinae in Europe, Notonecta glauca is certainly the most common. Its life is entirely aquatic, from the egg to the adult.

It lives underwater but breathes oxygen from the air

Like many aquatic insects, the Notonecte has kept an air breathing mode. Only the larvae just out of the egg breathe under water, through the integuments. As soon as they grow, they must go up to the surface of water and constitute a reserve of air. This will be done at the level of the elytra, semi-membranous upper wings, and the silks of the abdomen. The network of tracheas will thus be able to be supplied with fresh air during the periods of immersion.

Effective hunting techniques

Patient, the Notonectes can hunt on the lookout, waiting for an unwary prey. An efficient swimmer, equipped with vibration detectors, it can also launch into fast, precise chases, where it leaves little chance for crustaceans, insects, worms, and even tadpoles or small fish. Its front legs hold its meal, pierced by the stinging-sucking rostrum. A first channel will allow him to inject a salivary juice paralyzing and digestive. By a second channel it will absorb its liquefied menu.

A powerful vision

The effectiveness of the hunting techniques of the Notonecte is reinforced by a highly sophisticated vision. Its two large black eyes defy the laws of optics and allow it to see under water, on water and above water.

At the same time. The adaptation to its living environment, to the interaction of the aquatic world and the aerial world, is optimal. Posed on the surface of the water, back downwards, tips of legs and abdomen maintained by the surface tension, it watches. Any prey coming from the sky, stranded on the water, or swimming quietly, will be spotted. And consumed.

The backstroke swimmer

Its name describes its appearance, "nocto" meaning back, "necte", swimming. The notonecte splits the water with its belly upwards, its elytra carinated downwards. With its long back legs covered with bristles it propels itself with efficiency, its swimming is fast, incisive, with a jerky rhythm. Placed on the surface of the water in an inverted position, it paddles gently, attentive to the slightest vibration, the slightest movement. Efficient to move in aquatic environment, the Notonecte is much more clumsy on the ground, encumbered by its two long back legs. It prefers to fly away, deploying its two pairs of wings, and in a soft roar leave towards new ponds or ponds to colonize.

Males and females, aquatic meetings

Pairs of Notonectes are formed at the end of winter, after fertilization the eggs are laid in the tissues of aquatic plants. Small larvae emerge, similar to adults, but clear, soft, without wings and reproductive organs. They will evolve to their adult form in five successive stages, and will be ready at the end of the summer to hibernate. The very first heat will see them come to the surface, ready for a new reproductive cycle.

The Notonecte is one of the most present insects of the ponds. A calm water, plants, abundant preys, it will not miss the call. Easy to observe, it is however better not to touch it, its rostrum then becoming defensive and provoking sharp pains similar to bee stings.

The aquatic shrew, a mouse in the pond

It comes out at sunset, scurries along the banks wriggling its long snout, dives into the pond to fish for small larvae. Discreet, the Crossope passes unnoticed.

The shrews, a large family

If we know the common shrew, small but great ally of the gardener, its semi-aquatic cousin, the Crossope, remains unknown. Frequent host of rivers, watercress beds, ponds and ditches, Neomys fodiens belongs to the same family, the Soricidae. It shows the same pointed, mobile snout, with long whiskers; its coat is rather grayish to black, with a well marked white belly. Of beautiful size, it measures up to 10 cm, without forgetting the tail, that is 8 cm more! This makes it the largest of the dozen shrews present in France.

An insatiable insectivore

The aquatic shrew comes out at sunset and is active all night long, looking for preys, mainly small invertebrates. On the menu: underwater, aquatic insect larvae, crustaceans, fry; on land, beetles, snails, worms, and even amphibians and small mammals. If its sight is weak, its sense of smell and hearing are excellent. Reinforced by mobile vibrissae, real underwater detectors. Its preys thus located, it seizes them with its small red and pointed teeth, poisons them by the toxic juices of its salivary glands. This is an efficient strategy, allowing this small mammal with high energy expenditure to be fed in abundance.

An accomplished swimmer

Water is its element, the aquatic shrew never goes too far from it. If it trots on the banks, it regularly dives with ease, swims between two waters, circulates on the bottom, goes up and floats like a cork.

It is nicknamed the "frame shrew". Its hind feet are lined with stiff hairs, reinforcing its support. Its tail is also equipped with two rows of the same hairs, and plays a powerful propelling role. Its coat is perfectly water repellent, and to complete the equipment, its auditory holes are obturable. An accomplished swimmer that will dig its burrow on the banks to house its young.

Many young

From April onwards, Crossopes are concerned about their offspring. Males and females meet each other, sometimes a little harshly. Through a small hole of 2 cm in diameter, the female will enter her carefully dug burrow. She will line it with plants rolled into a ball to accommodate 6 young on average. Her gestation will have lasted 2 weeks, 3 at the most. The reproduction will take place until September, the peak of the births being in May-June. The young will become adults after a few months and will reproduce in general the second year.

They will live at best 2 years. Mortality in the aquatic shrew is important, in the young as well as in the adults, especially during the breeding season.

Light traces

Discreet, nocturnal or crepuscular, the Crossope is difficult to see. Minute traces let us guess its passage. The fine and humid mud of the banks will be marked with light prints, with five fingers, without webbing. The posterior foot will measure hardly 1 to 1,5 cm, the anterior one will be even smaller. The droppings are almost invisible: 5 mm long, for 2 mm of diameter. Tiny droppings can be seen... Occasionally some remains of meals are observed, shells of snails, cases of caddisfly larvae, or better a larder supplied with preys half consumed. Other indication of presence, small acute nocturnal cries...

Small discreet mammal, the aquatic shrew plays an essential role in the aquatic ecosystems. But the degradation of its habitats is beginning to impact its populations, on the IUCN lists it is classified as a species of minor concern on the whole French territory, but in some departments the species is becoming almost threatened, vulnerable, even endangered.

The dragonfly, a useful insect in the garden

The dragonfly is an insect easily identifiable because of its large size, its translucent wings and its large faceted eyes. A carnivorous predator, the dragonfly is a useful insect in the garden.

The dragonfly is an animal that enjoys a good reputation among gardeners, and rightly so! This animal is indeed a formidable predator both when it is a larva and as an adult. Insect of the order Odonata, the dragonfly can be either of the suborder Zygoptera or of the suborder Anisoptera. The difference between the two suborders lies mainly in the shape of the eyes and the posture of the wings at rest (folded above the body in the zygoptera, or horizontal in the anisoptera).

Whatever the sub-order, the dragonfly is easily recognized by its large size (up to 110 mm wingspan). In adulthood, it has an elongated body with two pairs of wings generally transparent. It always lives near water (river, pond, basin...) for two essential reasons.

The first is that it lays its eggs in an aquatic environment. The second is that water attracts insects in number and it is thus there that it finds the best hunting ground. She enjoys flies and mosquitoes, which she hunts in full flight using a particularly well-honed technique. Its large faceted eyes allow it to count on a very piercing sight. The dragonfly in full hunting can easily make of the hover before melting on its prey. Fertilization in dragonflies is indirect.

The male will inject his spermatozoa in a special bag located on the abdomen of the female. The spermatozoa are thus stored without being fertilized. Fertilization is orchestrated by the female at the most opportune moment, generally during the month of May. Depending on the species, the female can lay up to 600 eggs. The eggs are deposited in the water where they will hatch releasing a prolarva. This one will know several stages of transformation.

The successive moults can last several months to several years depending on the species. During all its stay in water, the larva is a voracious predator. It eats in priority mud worms. The ultimate transformation is carried out out of water.

Unlike the butterfly, the larva does not go through a chrysalis stage. The passage between the stage of larva and that of the dragonfly corresponds to a final moult (known as imaginal moult).

The green frog, an attraction around the pond

The green frog or edible frog (Rana esculenta) is an amphibian that results from the hybridization between the Lessona frog (Rana lessonae) and the laughing frog (Rana ridibundus).

Of the Ranidae family, the green frog is green-brown and measures a good ten centimeters when adult. It populates our ponds, lakes, ponds and streams rich in vegetation that provides shelter. Its main predators are herons, pikes and snakes.

It comes out of its hibernation in March and resumes its place at the water's edge or on the water lilies. It is in summer, day and night, that we hear them the most. The males emit their songs especially at the end of the day or during the night to attract the females which will lay after the freshness of the gelatinous clusters composed of several thousands of eggs in the middle of the plants. After a few days, the tadpoles will appear and will remain in the water until the following spring when they will metamorphose into green frogs.

The green frog is a real attraction around the pond. Essentially an insectivore, it captures insects by leaping over 30 centimeters. It also feeds on earthworms, snails and slugs, and even other amphibians.

In November, with the return of the cold, the green frog will settle down to hibernate either in the mud or in a small gallery dug in the ground.

How to encourage the installation of frogs?

If your pond is colonized by frogs, the summers will be noisy! But what a show around the water. Children and adults alike will be delighted to watch them snatch up passing insects.

To help them settle in

• Install large rocks around your pond that will provide shelter for the winter but will also encourage the development of insects that will appreciate these shady and humid spots.
• Install a lot of vegetation on the edges of the pond.
• Install many flowers (lavender, perennial geranium, ...) that will bloom in a spread out manner from March to November. The flowers will attract foraging insects like bumblebees, bees and butterflies.
• Also install plenty of water plants to make them feel safe if the frogs need to hide from a predator.
• In winter, if you must handle the rocks, do so carefully, a toad or frog may be underneath.

The frog is protected

The handling of the animal is safe for humans. On the other hand all amphibians and reptiles are strictly protected, as well as their biotopes. The taking of samples in the wild is forbidden.

The great snail, a majestic snail in the pond

Of remarkable size, its elegant shell rolled up into a long point, the great snail crisscrosses the ponds with its quiet glide.

An aquatic snail

The great snail, Limnaea stagnalis, is a snail, with lungs, installed in quiet waters, with slow or non-existent currents. Imposing gastropod, its size can reach 5 to 6 cm, it remains elegant with its lengthened shell with the many spires. Accustomed to ponds, it is found throughout Europe, in the Northern hemisphere, Asia and America, alongside other limneas, all of the family Lymnaeidae.

A siphon to breathe oxygen from the air

If it lives in water, the Great Limnea cannot breathe oxygen. Its lungs need air. The attentive observer will have to wait long moments to see it finally going back to the surface, deploying a siphon, piercing the surface of the water and capturing the air necessary for long immersions. Immersions all the more long as the water will be well oxygenated, the gas exchanges taking place then also by the skin.

Its house on the back

Classic snail, the big Limnée carries its house. A "coat" on its back secretes a calcareous formation, of only one part it manufactures a twisted shell. In which she shelters her soft mollusc body, in case of predation and in times of drought. If its waiting in its shell must be prolonged, it will close the "door" using dried mucus, burying itself if possible in the mud.

A quiet path

On its muscular oval foot, the large Limnea surveys the bottom of the pond, its reliefs, slips from plants to plants. One can see it floating sometimes, between two waters, in ascending or descending movement. At the surface of the pond, between water and air, it is placed upside down and its mucus-covered foot is flush with the air. She glides slowly, feeding on the biofilm formed on the stagnant water.

She grazes, grazes

The great dabbler spends long moments grazing. Its two long triangular tentacles are surmounted by two eyes, below which is placed the mouth. In this mouth is the radula, which could resemble a rasping tongue, covered with asperities that allow it to scrape decomposing plants, to graze the aquatic bottom, to tear some particles from occasional decomposing corpses.

Males and females, aquatic meetings

The great snail, like many snails, is hermaphroditic, the same individual carrying, in a complex anatomy, the male and female sexes. After cross fertilization, sometimes with several individuals, the eggs are laid on the walls or on the plants in extremely adhesive elongated socks. After three weeks, more or less according to the temperature, the eggs hatch and come out tiny Limnea whose body and shell will grow in a few months.

Majestic, slow-moving, the great snail is one of the easiest to observe in the pond. Not very demanding, an abundant vegetation, a calm water and detritus will be enough to welcome it.

The gambusia, against mosquitoes

The Gambusia, from its small name Gambusia affinis, is a small freshwater fish native to the United States that likes to live in schools. It has been successfully introduced in several French regions, including the marshes of the Camargue and certain rivers in the southwest, in order to combat the proliferation of mosquitoes.

Presentation

The gambusia is part of the order Cyprinodontiformes. It is a cousin of the guppies that we commonly find in our aquariums, however its colors are less bright: they vary from gray to light green.

The head is large but ends in a point at the level of the mouth which is provided with many teeth.

The dorsal fin of the gambusia is positioned at the back of the body and is not very developed whereas the caudal fin is larger in the shape of a rounded fan. The ventral fin is located at the base of the tail, it is short and rounded in the female and is transformed in the male into a long pointed organ, the gonopod intended for the copulation.  The male is smaller than the female (3,5 cm against 6,5 cm for the female). In addition to their size, they are differentiated by the black spot that the female has on her abdomen.

Habitat and feeding

Native of the hot zones of the United States, the gambusia has incredible faculties of adaptation, what was worth to him to be introduced from share the world to fight against the plague of the malaria and other diseases carried by the mosquitos. Its preferred waters are fresh but it is not uncommon to find it in brackish waters or in saturated waters with very low oxygen content.

The gambusia is found in large numbers in Mexico, Cuba, Jamaica and Nicaragua. It can be described as robust and combative: it must often be isolated when it lives in an aquarium because it tends to attack the fins of other fish, it can even eat its own young.

Gambusia feed on mosquito larvae, bloodworms, water fleas or even tadpoles.

Life cycle

The reproduction period of the gambusir is from April to October. Males insert their gonopod into the genital opening of females and fertilize the eggs.

The fertilized females lay fry over a long period of time with intervals of a few weeks between each spawning.

The fry, less than 10 mm in size, are just born and disperse into the vegetation where they continue to develop until they reach sexual maturity six months later.

The life span of the Gambusia is approximately two years.

The craspedote, a freshwater jellyfish

They scare, fascinate: jellyfish populate the seas and oceans, and leave neither holidaymakers nor naturalists unmoved. And when we meet a small species in our lakes, ponds, canals, after a moment of surprise, we can only go to discover Craspedacusta sowerby, present in freshwater of all continents.

A small jellyfish in our water bodies

In 1880, London scientists discovered a jellyfish in a pond of exotic plants. Translucent, it is clearly visible to the naked eye with its 2 cm diameter. Named Craspedacusta sowerbyi, or freshwater Craspedote, it belongs to the Cnidaria, a cousin of the jellyfish of the seas and oceans, but also of anemones and corals. It is the only freshwater jellyfish that meets in its class of Hydrozoans only Hydras, polyps always fixed.

Since its first description in London, the Craspedote has been observed on all continents, in 1929 in the Garonne pond and then in all the rivers of France.

Fragile and elegant

The encounter is surprising: bending over the waters of a lake, a canal, an old gravel pit, or even a pond, one sees small translucent, parachute-shaped organisms the size of a 2 euro coin floating. The freshwater Craspedote is a typical Hydrozoan: its umbrella is lined with more or less long tentacles, up to 400, a velum closes the parachute on its lower face. Under the umbel, crossing the velum, a tube, the manubrium, springs out, equipped with an external orifice and connected to 4 radial channels in intern. All the anatomy of the medusa is visible by transparency.

It floats in the middle of its preys

The freshwater Craspedote can move by vigorous contractions of its umbrella, but lets itself float according to the movements of the water, among the zooplankton. It is thus within reach of its preys. Copepods, daphnids, all the small animals of the plankton will be captured by its tentacles, carried to the opening of the manubrium, the mouth, to be swallowed. Once the digestion is finished, the waste will be rejected by the same orifice, serving as anus this time.

In Craspedotes the tentacles are provided with cnidocytes, stinging cells provided with harpoons with paralyzing effects. Only on small preys, the man does not seem to have to worry about its presence, its epidermis cannot be crossed.

It appears and disappears suddenly

The Freshwater Craspedote can go unnoticed one year, as well as proliferate in abundant populations the following year. Then disappear again. Before being a floating jellyfish that can be observed with the naked eye, it takes the form of a tiny polyp of a few millimeters attached to the bottom, to vegetation, to rocks. Its small tentacles allow it to feed on animal micoplankton. This polyp will reproduce by asexual way, by budding, release of crawling "larvae" moving and forming a new polyp, and production of medusoid buds. Some will become medusas leading a sexual reproduction. The fertilized eggs will pass through the planula stage, a small floating ciliated larva that will settle and become a polyp.

Present on all continents and therefore considered as an invasive species, the freshwater Craspedote would not represent a threat to ecosystems. Its feeding in zooplankton remains limited, its presence remains discreet. The impact of climate change on the evolution of the populations of this species may however modify the current data in the coming years.

The koi carp

The Koi carp is a pond fish particularly appreciated by gardeners because of its large size, its colorful appearance and its proximity to humans.

The Koi carp, its origin

The Koi carp is, like the common carp of our rivers, a cold water fish particularly appreciated by gardeners with an outdoor pond. Originally, the Koi carp was Chinese. It is a descendant of the Magoi carp which was quite close to our European carps since they were essentially grey.

Introduced in Japan around the year 200, they became around the year 1000 ornamental carps raised exclusively by the Japanese nobility. Over the centuries, the Koi carp has been adorned with beautiful contrasting colors which makes it look today like very large goldfish that can reach 60 cm long.

Koi carp were introduced in Europe after the Second World War. These animals are distinguished from other species by their temperament and their peaceful and routine behavior, very close to humans. As long as the feeding is at regular time, the Koi carp comes easily to the contact of the hand that dispenses its food.

According to the habits, the gardener can thus perfectly caress his fish! The other great advantage of the Koi carp is that it is essentially herbivorous. It cohabits perfectly with all varieties of goldfish which is an important aesthetic argument since the pond can be adorned with a beautiful ballet of small and large fish.

There are several types of Koi, among which the scaly carp which meets the Japanese standard, the mirror carp of European origin, with large scales on the dorsal side and the attachment of the fins, the leather carp of German origin without scales or the carp with sail fins of American origin. In terms of color, if the red and white of the classic Kohaku carp dominate, many variants are possible such as the Sanshoku (red, white and some black scales), the Tancho (circular red spot on the head), the Shiro Itsuri (bicolor black and white), the Ki Utsuri (bicolor orange and black), the Shiro Muji (integrally white), the Ki-Goi (monocolored bright yellow), the Goshiki (5 colors: black, red, white and different shades of blue). ..

Did you know that ?

Koi carp is an imposing fish. For reasons of space, there are usually 10 to 12 carps of less than 15 cm for one cubic meter of water and only 1 to 2 of more than 45 cm for the same volume of water.

The Ide Melanote, a little known fish

Here is an animal that is not very common in our ponds and yet deserves to be better known! The Ide Melanote is a fish that is not afraid of the cold and that, by its mode of feeding, helps to regulate the ecosystem of the pond.

Presentation

The Melanote Ide (Leuciscus idus) is a member of the Cyprinidae family. This fish looks like a roach. Of gregarious nature, it likes to live in schools.

Its body is tapered and its color is mostly silver but can vary from blue-gray to a very dark green depending on the age and the period. The belly is whitish and the sides are always lighter and silvery. The fins are gray except for the pelvic and anal fins which are pink or red. Its head is narrow, with a mouth directed upwards.

The maximum adult size is 75 cm in length for a weight of 4 kg.

Habitat and feeding

This fish is found in the wild in rivers, ponds and lakes in Central and Eastern Europe, as far as the Ural plain. It is also very common in Great Britain. In France, it can be found in the Rhine, the Moselle or the Somme, more rarely in the Loire and the Sarthe. The Ide is not a difficult fish, it can live as well near the bottom as at a few centimeters of the surface and tolerates also brackish waters.

The Ide is a good ally in the pond because it feeds mainly on insects, small crustaceans, plant debris and algae, which allows to limit maintenance operations. Be careful though, because in very large ponds, where it can grow to its maximum size, it could feed on small fish.

Reproduction

The reproduction period of the Melanotus Ide is in spring, between April and June, depending on the weather conditions. A female can lay between 42,000 and 260,000 eggs in a shallow area with a gravelly bottom where the eggs can cling. Many will be destroyed before hatching or absorbed by predators in the first few hours of their life, thus limiting the number of individuals. The Ide can live more than 20 years.

Behavior in the tank

The Ide is a gregarious fish, it will be necessary to introduce several subjects of this same species (at least 5).

A pond of at least 25 m² is necessary for its lively movements under the surface. It is a hunter and spends its time cleaning the pond of insects that are on the surface or that have fallen into the water. It also appreciates aquatic insects, mosquito larvae and can also be very useful to rid the pond of green algae and other plant invasions.

The stickleback, a nesting fish

A superb fish the size of a small finger slips into the vegetation: blue eye, red belly, slate blue back. Exotic, installed in the living room aquarium? Not at all, the stickleback lives in our rivers, our ponds, busy building a comfortable nest for its young.

A small bony freshwater fish

The three-spined stickleback is a bony fish of the Gasterosteidae family. It lives in rivers with calm currents, but also in ponds, puddles and isolated waterholes, all over France. Common, ubiquitous, it walks its long body from 4 to 10 cm, with a greenish back, a silver belly, in the abundant vegetation, on muddy or sandy bottoms. On its sides, no scales, but bony plates; on its back a row of spines, three in Gasterosteus aculeatus; under its belly not fins but pelvic spines. And especially remarkable spring colors. In the male, only, which from March prepares for the mating rituals.

A colorful male

The arrival of spring announces for the male stickleback a new outfit, with bright colors. His throat, his flanks, will become orange-red, his back slate blue. And his eyes of dull gray become azure blue. The female doesn't change anything in her wardrobe, it is she who will choose the most attractive male, with the most attractive parade. The one who will fertilize the eggs. Prepared by dozens in the females, they are so numerous and so big that she grows spectacularly, up to 25% of her weight in addition. She will entrust them to the paternal care, particularly serious.

A safe and cozy nest

Not content with adorning himself with beautiful colors, the little male stickleback works for his offspring. He chooses a territory, in shallow fresh water, with dense vegetation. On the bottom, he builds a nest of intertwined plants, bound by a mucus of his own making. Until July he will watch for females. And will seduce them of a dance, parade of presentation of its body of male and its sure and cosy nest. The conquered female will then lay her eggs in the nest. And the male will chase her away immediately, to take care of his young. He watches over them, ventilates them by creating an oxygen-carrying current. 8 to 10 days later, when the young are born, he will still be there, ensuring their protection until they leave, carried away by the current to other territories.

Dreaded carnivores and sought-after prey

The young sticklebacks will disperse, forming small scattered groups from several nests. Carnivorous, they will feed on zooplankton, crustaceans, insects, larvae and adults, worms, fry... And will even practice cannibalism, devouring each other. Sometimes cited as harmful for their voracity, sticklebacks are themselves hunted. They seem to be formidable with their row of hard and sharp dorsal spines rising up during an attack, not to mention their lateral pelvic spines always ready to hurt. But some predators have been able to adapt: the kingfisher knocks it out before swallowing it, the spines at rest are always folded. The heron will prefer to crush it with its powerful beak. The egret gobbles it head on...

The stickleback is a common fish of our fresh waters, not well known despite its amazing habits. Often raised in aquariums, it offers a fascinating show, spring colors, nest building, ventilation of the young. But under the waters of our rivers, ponds, sticklebacks are in regression and are classified on the list of protected species in "minor concern".

The argyroneta, a diving spider

Discreet spider, the Argyronetus lives, hunts, feeds, reproduces, under water. Often unknown inhabitant of our ponds, it leads an original life, totally adapted to the aquatic environment.

An aquatic spider

It lives underwater in the middle of fish, frogs and dragonfly larvae. The Argyronet, Argyroneta aquatica, is the only spider known to lead its complete life cycle in an underwater habitat. Without gills, with its aerial respiratory system, it has managed to invest the third dimension of the aquatic world. And among spiders, it reigns as the uncontested master. Of small size, 8 to 15 mm, it knew how to adapt with ingenuity to an environment full of resources. The only one of its kind, of the family Dictynidae, it can be found in the whole Palearctic area.

It lives underwater but breathes oxygen from the air

The Argyronete has not developed an aquatic respiratory system, its adaptation is simple, ingenious and efficient. No need for tanks or scuba. It goes to the surface, captures air from its back legs which comes to be fixed solidly on its fine hydrophobic gray hairs and a bubble is then formed around its abdomen, conferring its silver aspect. This bubble supplies air to its respiratory trachea. This form of air storage having its limits, she has developed a custom-made habitat.

A self-breathing air bell

The Argyronet is the architect of the pond. It weaves its habitat, an inverted bell attached to the plants and impermeable to water. Its appearance has earned it its name, "Argyroneta" meaning "silver web". The properties of this cloth are amazing: it filters gases. The oxygen in the water diffuses into the bell filled with air by the Argyroneta, the carbon dioxide is rejected into the water. The web breathes. But these exchanges do not allow to keep a balance between the different gases, and regularly the Argyronetus must go back to the surface, recover air in the hairs of its abdomen and release it under its bell.

An accomplished swimmer

The powerful front legs of the Argyronetus allow it to unhook itself from the plants and swim with ease. The air bubble, depending on its size, more or less large in males or females, would encourage floating and would influence the agility and speed of each individual. The network of tracheas, extremely developed as in many insects, allows to diffuse the air in all the body, but would also play a hydrostatic role supporting the stability in water.

A hunter on the lookout

A predator, the Argyronetus hunts on the lookout, chasing its prey at full speed, scouring the waters in search of insects, small crustaceans, and even fish. It captures them with its powerful front legs, then neutralizes them definitively with its venom. She cannot consume them underwater, and must therefore bring them back under her bell, or to the surface. Encounters of the Argyronetus with humans, with very distinct habitats, are rare, but cause painful bites, although the venom is harmless.

Males and females, aquatic encounters

The male in the Argyronete is distinguished by its larger size, it joins the female in her bell where mating takes place. The eggs will be laid at the top of the lodge, surrounded by white silk, late spring and summer, the young are born and remain a long time in their shelter. The successive moults will take place in the air, under a bell or on the surface, the young will remain close by or will disperse along aerial threads to explore and colonize new aquatic spaces

Two cousins that walk on water

Large and powerful wetland spiders, Dolomedes live near ponds and calm waters. Powerful, the adults can capture large preys, like damselflies. But also small fish, their fishing technique is unstoppable: they vibrate the water with their front legs and wait for their meal. They make brief appearances underwater, clinging to plants, but generally remain on the surface, leaving the Argyronetus the exclusivity of the aquatic depths.

A pond, calm waters, plants to anchor its web, a little polluted water, some preys: the Argyronet can establish itself, live its adult life for two years, settle its young. And thus perpetuate its species with its so particular way of life. An unsuspected world to preserve.

Introducing fish into a pond

What could be more pleasant than watching the bright and colorful movements of fish in a pond? They help to control the growth of algae and mosquitoes and contribute to the balance of the ecosystem. Let's see when and how to introduce them into a pond so that they live happily.

A question of volume

Before thinking of introducing your fish, it is necessary to evaluate the volume of the pond in order not to overcrowd it and to install adapted species.

Another parameter to take into account is the depth, because in regions where it freezes in winter, the layer of ice can be thick, which does not pose a major problem for certain species as long as the depth is sufficient so that the fish are not caught in the ice. A minimum depth of 50 cm is required for small species in areas where freezing temperatures are prevalent.

When should I introduce fish into my pond?

The ideal time to introduce fish is during the summer months after the last frost. Spring and summer are good times to bring fish into the pond.

If you have just built your pond, wait at least 1 month after filling it before introducing your fish so that the water has acquired a good biological balance.

Planting aquatic plants beforehand is a plus because they oxygenate and purify the water, the fish will be able to hide there, lay eggs and enjoy their beneficial shade.

How do I get fish for my pond?

• Do not take fish from the natural biotope (lake, river, pond...) to introduce them into your pond.
• When buying fish, always check the sanitary conditions of the point of sale. The aquariums must be clean and no sick fish must be present at the risk of contaminating the others.
• Choose lively fish with well-developed fins and no suspicious blotches.
• The gills should not be red or excessively expanded.
• The fish should swim briskly between two waters. Avoid fish that are apathetic, stay on the surface or too deep (except for bottom cleaning species).

Which fish for my pond?

Depending on the volume of the pond and the climate, various species can be introduced, but make sure that they are compatible with each other because some fish are carnivorous and will not hesitate to attack others.

Let's start with the most common species and probably the easiest to raise at first: the goldfish.

The goldfish

Goldfish are gregarious animals that enjoy the company of others of their kind. Introduce at least 3 fish at a time to your pond. The classic species (Carassius auratus) has the advantage of being able to withstand the cold and adapt to the size of the pond by stopping its growth. A goldfish can live 25 to 30 years and reach 40 cm in length in large ponds. Whatever the size of the pond, provide at least 0.3 m³ of water per fish. Beware of ornamental varieties such as sail tails or fish with bulging eyes (Lorgnette de Ciel, Uranoscope, telescope...) which are much more fragile and require much more heat than the typical species.

The melanot fish

Melanotas are easy to live with and do not fear the cold. Silver in color, they move briskly creating reflections under the surface of the water.

The Ide is a gregarious fish that needs others of its kind to be happy, introduce 5 ides at a time to the pond.

The Ide can live more than 20 years and reach 75 cm in length. Allow 1 m³ of water per fish and a depth of at least 80 cm of water.

Koi carp

The legendary Koi carp need the same volume of water as the Ide per fish. Revered in Japan, these colorful carp can reach 80 cm in length and weigh 8 kg.

This fish can withstand cold weather and live up to 50 years without worry, but the pond must be deep enough (at least 1.20 m).

Sturgeon

The sturgeon is to be reserved for very large ponds because it can reach more than 3 meters in length for a weight of 300 kg. A total size of 25 m² and a depth of at least 1.20 m is required to accommodate this fish, which can withstand the cold very well in good conditions.

How do I introduce fish into my pond?

Introduce one species at a time, in small groups if the species is gregarious.

If there are already fish in the pond, make sure to choose a compatible species and introduce the new fish in small numbers.

Do not empty the bag of fish directly into the pond. Put it in the pond water for about half an hour to allow the temperature to adjust and the fish to get used to their new environment.

Then open the bag and add some water to the pond.

Wait another hour or so before releasing your fish.

Choosing the right fish for your pond

You have an ornamental pond and dream of putting fish in it. Questions then arise about the choice of species, their number and of course their possible agreement.

Fish in my pond

Subtle shimmering or brightly colored, fish complete the pond with their pleasant presence. The species chosen should be based on several criteria:

Cold resistance

In an outdoor pond, temperatures can sometimes drop to very low levels, so it is important to choose fish that are adapted to this situation. Avoid the original varieties of goldfish, such as the "Comêtes" with their beautiful sail-like fins, the black "Black Moor" with bulging eyes, or the "Tête de Lion". Choose hardy species such as the classic goldfish (Carassius auratus), Koi carp or sturgeon which are very resistant to cold.

The depth of the pond

If it freezes, the fish must be able to find refuge in the depths of a pond to avoid being caught in the ice. In cold regions the pond should be at least 80 cm deep to accommodate fish. Some species need depth throughout the year, such as the ide melanote or the sturgeon.

The agreement

Be careful, you should always ask before introducing a new species in a pond already inhabited. Some fish are very combative, others will have no qualms about eating other fish. So beware!

The volume of the pond

It is important to keep in mind that fish need space to live in harmony. For a small pond, prefer the classic goldfish which will be satisfied with 0.1 m³ per fish. This hardy fish has the ability to adapt its size to the space available. Koi carp will need much more space as three of them will need a volume of 5 m³. The ide melanote which is gregarious and needs other individuals of its species to survive as well as the sturgeon will only be introduced in very large ponds offering a surface of at least 20m² and a good depth.

Availability

The majority of the fishes require only limited care. Clean water and a well-maintained pond with a good ecological balance should be sufficient for their needs. Nevertheless, even if the fish feed on larvae, plants or algae, it will be necessary to distribute some food regularly. In winter, feeding will be much less restrictive or even non-existent except for sturgeon which must be fed all year long with special pellets. It is thus one of the most constraining fish.

Vegetating a pond

Whether it was created from scratch or is natural, a pond sometimes needs some small adjustments to accommodate both useful and ornamental plants.

What does revegetation consist of?

Revegetation is a term that designates the action of introducing non spontaneous plants into a specific environment. In the specific case of the pond, the plants used will be mainly aquatic. They will be chosen according to depth criteria, but also for their filtration and water purification properties in order to create a perfectly balanced biotope that will hardly need any maintenance. Let's not forget the ornamental side which should not be neglected to combine the useful with the pleasant!

A little help for nature

It is quite possible to let nature take over, but the result on an artificial pond is likely to be disappointing and very long to obtain.

A tarpaulin-covered soil does not allow for the immediate establishment of natural plants due to the lack of substrate. It will be necessary to integrate it beforehand to obtain a beautiful result quickly. Another parameter: the balance. It is much easier to balance the water by introducing cleaning, purifying and oxygenating plants. Some are spectacular or original and will add a touch of charm to the pond.

When and how to plant a pond?

The best time to plant is between March and June, depending on the hardiness of the species chosen. The plants then begin their growth period, and the temperature will soon allow for optimal development.

Always prefer to buy plants in containers rather than bare root plants which will have more difficulty to grow.

The ideal substrate should be composed of gravel, sand and good fertile soil. In the case of an artificial pond, it is preferable to prepare it before the water is put in to cover the walls. Don't forget to create "tiers" so that each plant can benefit from optimal growing conditions. Wait a couple of weeks before setting up the plants.

Start by installing the submerged plants, if necessary by emptying the pond a little. Plant according to the required depth directly in the substrate or in baskets weighted with stones. The baskets allow you to take out the most fragile plants during the bad season in order to protect them from freezing.

Then install border plants to create an attractive decor and maintain the banks. Wildlife will find it a peaceful refuge.

Then place floating plants on the surface of the pond, they will grow quickly.

What plants should be placed in a pond?

There is a wide choice, but we will only mention certain plants for their exceptional cleaning or ornamental qualities.

For the natural treatment of water, think of cattails, scirpus, phragmites or Phalaris but also Elodea and bladderworts.

For their outstanding ornamental qualities, pseudocarpus irises, water lilies, nelumbos and water hyacinths will have no equal.

Also consider decorating the banks with water marigolds (Caltha palustris), purple loosestrife, astilbe or even exuberant gunnere. The decor will be just as you expect!

A pond for what purpose?

A pond in a garden is much more than a simple ornamental piece. If you are lucky enough to have a place to build it, don't hesitate! It will contribute to the ecological balance of your garden.

Creating a pond

Formerly present only in the parks of castles, the pond becomes nowadays accessible to all. Garden centers, Internet sites and specialized stores offer a wide range of products allowing everyone to build a pond at home. Technically it is not very complicated, financially, a small pond is accessible to all. The interests are so numerous that it would be a shame not to be tempted!

A bewitching power

A pond in a garden is a window to the dream. The water reflects the sky and moves with the slightest breeze. With the gentle splashing of water jets or waterfalls, the soothing sounds and the serene vision of the ballet of fish, the pond is undoubtedly a place for contemplation. All that remains is to install a chaise-longue or a bench nearby to fully enjoy this soothing spectacle.

A piece of Nature

A pond makes it possible to recreate a part of nature in the closed space that constitutes the garden. Water is an essential element for life and a small pond will attract a number of animals that will settle in your home full time. Some of them are auxiliaries necessary to the good balance of the garden, others will constitute a source of food for them, others still will come to pollinate the surrounding plants.

Pond plants, in addition to their undeniable ornamental aspect, will serve as filters and natural purifiers for the pond water. If the pond is large enough, you can add fish that will be happy to eliminate mosquito larvae.

The pond will soon be full of life, ensuring the balance of the garden.

Fun and educational

Children are always amazed by the presence of a pond; what a pleasure to observe frogs basking in the sun on a water lily leaf, to contemplate the iridescent reflections of dragonflies, to be astonished by the slides of water spiders. A whole world opens up to them, provoking curiosity and questions. If the adults take the time to be interested in the life of the pond with them, it is then a joy to share and live together moments that will remain engraved in the head of the children for many years.

A pond with barrels

Why not use half barrels of recovery to realize an original set of ponds with a circulation between them by a system of overflow? It will be of the most beautiful effect near your terrace.

Preparation of the barrels

Take oak barrels cut in half in perfect condition (dimensions for the example of 70cm diameter by 45cm height, it is possible to find some in garden centers).

If the barrels have contained wine, it is necessary to proceed to a complete cleaning and rinsing stage. Then, to ensure a good watertightness of the interior, you can either place a pond liner cut to the right size and fixed around the perimeter or coat the interior with several layers of flexible resin. If there is aquatic life present, it is best to choose a food grade resin or a pond liner.

Installation of the barrels

Choose a shady spot in the garden during the hottest part of the summer. Sun in the morning and shade in the afternoon is preferable, it will limit evaporation and the development of green algae. Know that water lilies need a minimum of 6 hours of sunlight per day to bloom.

To create a water feature between the half barrels, place them with a height difference of about 10 cm. Then position the barrels with a spirit level.

The highest barrel has a hole in it to allow for drainage to the lower barrel. The hole corresponds to the outside diameter of a piece of bamboo for water circulation. The hole with the bamboo can be sealed with colorless putty.

To allow water to circulate, use a small pump submerged in the lower pond that returns the water to the upper barrel.

Placement of aquatic plants

Place the plants in 11 cm square plastic baskets with some heavy garden soil and then place pebbles or felt to prevent the soil from mixing with the water. This will also prevent the fish from digging into the contents.

Plants are arranged according to their height. For a graphic effect, the highest ones are towards the bottom.

Example of arrangement for the lower half of the barrel: Myosotis palustris, Iris versicolor, Myriophyllum Brasiliensis, Equisetum Japonicum, Nymphaea 'rose Nymphe'

Example of layout for the upper half of the barrel: Mentha aquatica, Lobelia Cardinalis, Acorus Gramineus 'Ogon', Nymphaea 'conqueror'

Installation of the aquatic fauna

Be careful with the stocking because depending on the exposure and your region, the barrels may freeze to their full depth. If you wish to put fish in them, it is necessary in this case to bring them in during the winter. When feeding them, limit their food so as not to pollute the tanks. The food must be eaten within 5 minutes.

Without fish, flying insects will most certainly come and reproduce there like dragonflies or mosquitoes. If you have an aquarium, they can be used as live food in summer.

Starting up

During the start-up period, green algae will develop while a general equilibrium is established. During this period of about one month, do not put any fish in the tank.

Maintenance of the pond

In the spring, clean your barrels of various plant debris that may have accumulated and control the growth of certain aquatic plants such as milfoil, which can become very invasive. Reassemble the filter. It should be cleaned regularly.

As winter approaches, turn off the filter, clean it completely and put it back in. Leave a few empty water bottles weighted down with pebbles floating on the surface to limit the pressure of ice on the walls. Protect the sides and top if necessary.

Making a garden pond in polyester resin

Building a pond is not something to be taken lightly. Indeed, there are all types of ponds with different techniques: clay, concrete, concreteity, preformed ponds or simply covered with a tarpaulin ... but the pond that holds our attention is made of polyester resin.

Why choose a polyester pond?

Creating a polyester pond is undoubtedly the best way to create a durable and solid piece of water. In addition to offering a long life to your pond, polyester requires little maintenance and offers great flexibility in the realization of shapes, only your imagination will be limited. It is also easy to repair and refurbish, and colorfast, all for a relatively low price.

Can I make a polyester pond myself?

Creating a polyester pond is not an easy task. Sometimes it's better to call in a professional than to go into a project head first. However, with a minimum of manual skills, it is possible to create your own water feature.

What are the different possibilities to create a pond?

First, you need to determine the shape of your pond and calculate its dimensions. The ideal is to have a deeper area at 1m20 so that in winter, your fish are safe.

There are 4 methods for preparing the soil:

1. The bitumen paper method: for walls with an angle of more than 45°.

• Less expensive and suitable for covering large areas.
• Place the paper at 20 - 30 cm on the edge and hold it with grass or stone clods.
• Glue the joints with insulating tape and apply the polyester coating starting with the sides and then the floor. Once the substrate is ready, start the polyester and glass mat coating.
• Place the glass mat strip over the resin layer and apply a new polyester layer.
• Remove air from the glass mat with an air roller. It is important to fray the edges of the glass mat to prevent the seams from showing when covering the 1st strip of glass mat with the 2nd layer of glass mat.
• Trim any protruding edges and sandpaper.
• Apply a layer of pre-coat. (10% polyester dye and 2% MEC hardener).
• Let dry for 3 to 7 days before filling the pond with water.

2. The concrete method: for round polyester ponds

• A layer of 2 - 3 cm is sufficient for the floor. Due to the alkaline nature of the cement, it should be allowed to dry for 8 days before applying the polyester liner.
• Apply a coat of PU primer, wait 1 to 4 hours maximum. Then apply the polyester coating.

3. The concrete block method for a polyester and fiberglass pond with vertical walls

• First pour a screed on the floor and mason the walls. For small areas: 5 cm screed and 12 cm walls. For large areas: 10 cm screed and 24 cm block walls.
• Cap the walls and round the corners to a radius of 2 cm. Due to the alkaline content of the concrete, a minimum of 28 days is required before applying the polyester coating.
• After 28 days, apply a coat of PU primer by brush or roller and wait a minimum of 1 hour and a maximum of 4 hours. Then apply the polyester coating.

4. The chipboard method: for walls with an angle of inclination of more than 45

This inexpensive method also allows for very large surface areas to be covered. Because of the counter pressure of the floor, the walls will have an angle of inclination of about 15°.

You will then have to nail boards to the joints.

• Round the corners with putty or with corner battens.
• Apply 2 coats of pu primer. Wait 1 hour minimum and 4 hours. Then apply the polyester coating.

What should I pay particular attention to?

• The application must be done at temperatures between 10 and 33°C. The higher the temperature, the shorter the application time. You can adjust the application time by adding more or less MEC hardener (1.5%).
• Please read the hazard warnings on the labels carefully.
• The hardener is a peroxide that can cause allergies.
• Check your local regulations for disposal of chemical waste.
• After curing, these products are neutral and therefore respect the fauna and flora.
• Cobalt is used to accelerate the resins, it should never be mixed directly with the MEC hardener: this causes a chemical reaction!

Your garden pond is now finished, all you have to do is place your selection of fauna and flora in it, and relax when the time comes!