Bugs
Although some people use the word "bug” to describe a variety
of small creatures, the name belongs properly to a group of insects whose
most important feature is a feeding tube with which they pierce and suck
the juices from animals or plants. Some of them look a little like beetles,
but they are distinguishable by the crossing of the wings which is visible
on their backs but not on those of beetles.
The various species of pond skater and water measurer are not truly aquatic.
Instead they operate on the water’s surface, skating over it by means
of feet equipped with water-repellent hairs and catching less fortunate
insects which have stuck to it. Some species of pond skater can fly. A
water measurer is smaller, wingless, and moves more slowly, usually staying
around the water's edge. It has one other method of predation, which involves
stabbing its feeding tube through the water surface to catch mosquito larvae
and other animals.
The other water bugs, and their larvae, live within the water. The Water
Scorpion crawls over the bottom mud and vegetation, seizing prey which
range from insect larvae to small fish. Its tail is not a sting but a breathing
tube which can be pushed out into the air. It can fly, but seldom does.
The Saucer Bug creeps among vegetation under the water, attacking insect
larvae, water lice and other small creatures. It is fierce enough to pierce
human skin when handled, inflicting a painful sting. This is the result
of toxic saliva which bugs inject to kill and digest their prey. The bug
carries air under its wings and in a layer on its under-surface. Although
it has wings it is flightless.
Two other types of bug commonly encountered when pond dipping appear similar
at first sight but perform very different roles within the freshwater community.
Water boatmen and lesser water boatmen both use an oaring motion of their
long legs to swim around. The former swim upside down, hence their alternative
name of backswimmers. A backswimmer has particularly long hind legs and
its back is keeled like a boat. The lesser water boatmen tend to be smaller,
and they swim the right way up. Water boatmen feed on creatures up to the
size of tadpoles and small fish, and are also capable of inflicting pain
on humans. By contrast, lesser water boatmen are harmless creatures whose
food is usually tiny pieces of plant remains and algae which are "hoovered" up
using their feeding tubes. A lesser water boatman carries air in a bubble
under its wings, while a water boatman holds a layer on its under-surface
(which is actually on top). Both types can fly.
Pond Skater |
Water Measurer |
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[Up to 17mm] |
[Up to 12mm] |
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Saucer Bug |
Water Scorpion |
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[Up to 16mm] |
[Up to 23mm, plus
10-12mm breathing tube] |
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Lesser Water Boatman |
Water Boatman
(Backswimmer) |
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 |
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[< 3-15mm] |
[Up to 16mm] |
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