Great Silver Water Beetle   (Hydrophilus piceus)

Britain's largest aquatic beetle, growing to a maximum length of up to 50mm, although 40mm is more common. The Great Silver Water Beetle numbers have declined recently. These beetles  are now one of Britain's rarest aquatic beetles. They can still be found across England in small numbers at ponds, lakes and slow moving water. They are now found mainly in the SE & SW of England. These impressive beetles are omnivorous but feed mainly on decaying plant matter at the bottom of ponds. The nymph can grow to 70mm in length and feeds largely on pond snails. The Great Silver Water Beetle lives at the bottom of ponds and can be seen as it takes to the water's surface head first. Oxygen is collected as a large bubble and stored in the beetle's wing-cases before the beetle quickly returns to the bottom of the pond. This trapped air bubble can give the beetle's underside a silvery appearance which is where they get their name. The similar Great Diving Beetle (Dysticus marginalis) comes to the water's surface rear end first. The Great Silver Water Beetle is largely a scavenger unlike the Great Diving Beetle (Dysticus marginalis) which is a ferocious predator.










Pond Snails
There are about 40 species of Pond Snail in the UK. Many feed primarily on decaying vegetation but others will readily feed on pond plants such as lillies.








Great Pond Snail   (Lymnaea stagnalis

The Great Pond Snail is Britain's largest aquatic snail and can grow to a maximum shell length of 70mm, although 50mm is more usual. These snails prefer stagnant water sources with plenty of vegetation. Their shell is long and pointed and when not covered in algae is a creamy-white colour. This species is found across much of Europe as well as other countries including North America and New Zealand. The Great Pond Snail needs to surface regularly to breathe but in the winter they will move to the bottom of the pond where they can take in just enough air through their skin to survive. They contain both male and female reproductive organs so can mate with any other Great Pond Snail or reproduce on their own if necessary. This would allow the introduction of just one specimen to populate a new pond with this species. Their eggs are laid in strings attached to the underside of leaves. They will feed on almost anything including all plants, algae and even their own excrement! 


A fairly small specimen at 40mm in length.















male Migrant Hawker nymph
Migrant Hawker Dragonfly Nymph   (Aeshna mixta)

Hawkers are the largest and fastest group of UK Dragonflies. The Migrant Hawker Dragonfly is one of the smaller hawkers, growing to around 63mm in length once they've metamorphosed from a nymph. They are not an aggressive species and will tolerate other dragonflies in their territory. They usually take to the wing in late summer - autumn and can be seen from July right up to November.




Unidentified Dragonfly Nymph





Migrant Hawker exuvia

Dragonflies spend the first part of their lives as water-dwelling insects feeding on smaller insects, small fish, tadpoles and newt efts. When ready to metamorphasise, the Dragonfly larvae climb up the stems of reeds and other water plants and leave the water. They bask in the sunlight and the exoskeleton begins to harden. Once fully transformed, the hardened case of the larvae cracks open at the back, and the newly formed dragonfly emerges. It will continue to bask in the sun until its new wings dry and harden, before taking to the sky for the first time. The empty exoskeleton or exuvia, is left behind still clinging to the plant stem.







Water Boatmen
Water Boatmen species are divided into two groups, Greater Water Boatmen (Notonecta Spand Lesser Water Boatmen (Corixa Sp). The Greater Water Boatmen are also known as Back-swimmers, obviously because they swim on their backs. Lesser Water Boatmen all swim on their fronts. All Back-swimmers are carnivorous and hunt down their prey at great speed. They can prey on small fish and tadpoles. Once prey is caught using their powerful front-legs, the Back-swimmer then stabs its prey using its sharp beak. The prey is then injected with saliva via the beak, and the Water Boatmen proceeds to suck out the insides. This beak can also be used as a form of defnce if handled as the effects are reported quite painful. Water Boatmen are competent fliers and may be seen leaving a pond on warm sunny days in search of other ponds. They are often the first species to inhabit newly made ponds. Lesser Water Boatmen are herbivores, feeding on plant debris and algae. 






Pond Skater - aka Water Striders
Pond Skaters are often seen in groups darting around on top of the water's surface on ponds, lakes, and slow-moving streams and rivers. There are nine species of Pond Skater in the UK and they range from 1-2cm in length. These delicate bugs are covered in tiny little hairs that trap air bubbles that make the Pond Skater waterproof and help them float on the water's surface. They are equipped with sharp pointed mouth-parts that they use to stab and piece their prey and suck out the internal fluids. Pond Skaters can move at a fantastic pace of over 1 metre per second in short bursts.




11cm juvenile European Eel
European Eel   (Anguilla anguilla)
Commonly known as Brown Eels, or Yellow Eels. These long slender fish are now considered to be critically endangered. They spend much of their lives at the bottom of rivers and streams. They can be found in most types of freshwater environments and may go undetected for many years. Eels have even been known to cross land during rainy periods, to find suitable habitat or prey. They don't feed frequently, but usually prey on insects and other invertebrates when small. As they grow they will take larger prey such as fish and frogs. They have an acute sense of smell and can easily locate dead and decaying fish. The European Eel usually grows to around 40-70cm, but specimens have been know to grow to 150cm!
Once sexually mature, the European Eel travels up streams and rivers and makes its way back to the sea. It will then head thousands of miles to the western Atlantic Sargasso Sea to breed.




Leeches
There are 37 different species of leech in the UK. The one pictured above is Glossiphonia complanata, one of the smaller and more common varieties. Glossiphonia complanata usually feeds off soft parts of the body of invertebrates such as snails.
Only the largest species of Leech, the Medicinal Leech is capable of piercing human skin and sucking blood. These Leeches have a relatively painless bite and often go undetected. Once they have secured a grip on their host they secrete an anticoagulant to prevent the blood from clotting. Many of the British species feed from amphibians and fish.




Damselfly Nymphs
Damselflies lay their eggs in little slits made in aquatic plants. These eggs eventually hatch into tiny Damselfly nymphs. As these nymphs grow they shed their skins several times, until the final slough, which is done out of water. At this stage the nymph climbs up the stem of an aquatic plant and begins its metamorphosis. It will emerge from the old dried skin into a damselfly. Here it will bask in the sun whilst the new exposed skin of the damselfly hardens. Then it will take to the air for the first time.







Soldier Fly Larvae

The Stratiomyidae family of Soldier Flies contains over 2700 species. The larvae are aquatic and can be found in many wetland habitats including garden ponds. They feed on algae and decaying organic matter. They can be seen slowly swimming at the surface of the water, breathing through their tail which breaks the water's surface. The tail is covered in tiny water-repellent hairs which allow it to break the surface of the water as well as trapping small air bubbles acting as a small air supply allowing the larvae to submerge and breath underwater. When fully developed the larvae will pupate by hardening its skin. These pupae are often in the mud surrounding a pond or lake, but sometimes they will be found floating on the waters surface or on vegetation in the pond.





Unidentified Water Beetle Nymph







Unidentified Water Beetle Nymph







Unidentified Water Beetle 







Unidentified Water Beetle 








Nine-Spined Stickleback   (Pungitius pungitius)

The Nine / Ten-Spined Stickleback is a small fish found in both freshwater and marine bodies of water. Adults grow to a length of 4-6cm although lengths of 9cm occur occasionally. Males usually live for around three years, and females five years. Despite their name, they can have between seven and twelve spines on their backs, which can be raised and used as a defence tactic to deter predators. These spines are smaller and not as effective as those found on the more common Three-Spined Stickleback (Gasterosteus aculeatus). These Sticklebacks don't have scales, but instead have bony side-plates as armour. The males can develop a black area around their groin in the breeding season. Males will guard fertilised eggs, and even teach their young to evade capture by chasing them around the water.


Three-Spined Stickleback (Gasterosteus aculeatus)
Britain's most common stickleback fish. These are often found living alongside the Nine-Spined Stickleback and are similar in behaviour. Adults usually grow to a length of 4-6cm although lengths of 10cm can occur with marine specimens.





Gasterosteus aculeatus  - Male top, female bottom







The Emperor Dragonfly Nymph

The Emperor Dragonfly is Britain's largest bodied dragonfly and grows to a length of 8cm. It is said to have been on the Earth for 230 million years. It is a very powerful flyer reaching speeds of up to 34mph and can detect prey from up to 40ft away. Most of the Emperor Dragonflies life is spent as a larvae / nymph for  2 - 5 years but once transformed into an adult it lives for just  4-12 weeks to breed.



Even as a nymph the Emperor Dragonfly is an aggressive hunter and will tackle prey as large as tadpoles, small fish, young newts and young frogs. When the nymph is ready to complete its metamorphosis it will climb up the stem of a reed or other aquatic plant and bask in the sun until its skin dries out and splits. It will then emerge from the old skin (exuvia) as a fully transformed dragonfly.












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