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POND SKATER Gerris
sp. 15mm long. Common bug on all the forest ponds. Feeds on dead
insects on the water surface. Bristles on the tips of legs prevent
it breaking through the surface film. Photo: July 1973 |
WATER SCORPION Nepa
cinerea. A leaf-like, flat bug 30mm long. Two front legs
adapted for grasping prey from which it sucks juices. The
"sting-like" appendage at the rear is in fact a breathing tube which
it uses like a snorkel. Photo: May 1971. Chigwell Row Pond. |
LDER FLY
Sialis sp. Lays eggs on plants overhanging water. The larvae
hatch and fall into the water and are carnivorous. when
developed crawl out of the water and pupate in the mud. Adult flies
hatch May-June. Photo: 11th May 2006. |
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A MAYFLY LARVA.
Ephemeroptera. The larvae have three long tail appendages, and
external gills on the abdominal segments, which are varied and used
in identification of species. 12mm long. Common in the forest ponds.
Photo: July 2004. Sheepwater. |
A MAYFLY.
Ephemeroptera. Wings held upright. Long tail filaments 2 or 3 in
number. Have a brief adult existence for mating and egg laying.
Photo: July 2000. |
POND SLATER or HOG LOUSE
Asellus.
A small crustacean 10mm
related to the woodlice. Common in all forest ponds. Withstands
pollution and low oxygen levels. Photo: July 2004
Sheepwater.
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BACKSWIMMER Notonecta
glauca. 15mm long. Common in all forest ponds and numerous in
Sheepwater. Often seen resting near the surface of the water
where they gather oxygen. Photo: July 2004. As its name suggests The
Backswimmer or Greater water boatman swims upside down The third pair
of legs, covered in hairs, are the longest and used to row through the
water. Far right: Microscope view of tip of third leg showing hairs
which help to propel it through the water. |
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Long bodied DRAGONFLY
LARVA, Anisopterid or Hawker type. Dragonflies occur in all
the forest ponds. They are carnivorous.
Photo: July 2004. Sheepwater.
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Short bodied DRAGONFLY
LARVA
Libellulid type. Photo:
May 1998 |
DAMSELFLY LARVA,
Zygoptera. Distinguished from all other aquatic larvae by the three
leaf-like tracheal appendages or "gills". Predatory, often lurking
among water plants awaiting prey. Photo: May 1998 Several
species of Damselfly occur in the forest ponds.
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GREAT DIVING BEETLE
LARVA.
Dytiscus marginalis.
Up to 50mm A voracious carnivore. The tail filaments are fringed
with hair and adhere to the surface film to obtain oxygen. Photo:
May 1998. |
GREAT DIVING BEETLE
LARVA hanging from the surface film. Note the two powerful mandibles
which are used hold the prey to enable it to suck out juices from
its prey and to dissolve the solid parts. Photo: July 1971. |
GREAT DIVING BEETLE
LARVA feeding on mayfly larva. Photo: May 1998. |
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WANDERING SNAIL
Lymnaea peregra.
20mm length. Plentiful
in Sheepwater. Like the other snails illustrated here they need to
rise to the surface to obtain oxygen.
Photo: July 2004
Sheepwater. |
GREAT
POND SNAIL Lymnaea stagnalis. A
large snail up to 55mm in length. Lays sausage-shaped gelatinous
masses of eggs on stems and under leaves of water plants.
Common in Roe's well.
Photo: July 2004
Feeds
on algae which it rasps from the surface of plants and rocks. It
will also eat animal matter. |
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RAMSHORN SNAIL
Planorbis sp.
20mm across. Common in Roe's well.
Photo: July 2004 |
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WOODLAND TRUST
CATTLE PONDS, LAMBOURNE
15th August 2017.
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Wandering snail Lymnaea sp |
Pond snail Physella sp. |
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Short, fat bodied, dragonfly
nymphs of the Libellulid type which include the Darters. |
Newtpole, feathery gills and
four limbs |
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Diving beetle Dytiscus sp. |
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During mid June Raymond
Small and myself visited all the ponds and streams in the forest, with a
net, to see what we could find there.
Raymond photographed all
of our finds and some are included here. We hope to do more as the
summer progresses.
At the end of June there
had begun a migration of toadlets and froglets from the Lake.
One of the best areas
was the small stream which starts at the second car park and originally
drained the Farm pond adjacent. |
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Tadpoles in various
stages of development (above and top) |
A newt
tadpole with four legs and feathery gills (above) |
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Water fleas Daphnia
pulex were found in the Lake in astronomical numbers during
June. Each dip of the net produced a large handful. These form the base of
a dynamic food web. |
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Damselfly
nymph. Spends a year in the water before becoming a damselfly |
Horse leech
Haemopsis sp. Not a blood sucker but feeds on small creatures and dead
fish. Head is the narrow end. |
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Water Hog louse aka Water
Slater Asellus sp. Abundant in stagnant ponds |
Freshwater shrimp
Gammarus sp. Abundant in stagnant ponds |
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Back swimmer or Water
Boatman Notonecta glauca. Third pair of legs have fringes of hairs
to aid swimming. Take air from the surface through their elytra or wing
cases which they push up through the meniscus. |
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| Blood worm larva of the
Chironomid midge Chironomus sp. Lives in polluted water and contains a
form of haemoglobin to help with oxygen transfer. |
Rat-tailed maggot, larva of a hoverfly Eristalis sp. Lives in murky
water.Its extendable "tail" is a breathing tube, used to reach to the
water surface to take in air. |
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Hainault Forest Website