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Family Notonectidae - Backswimmers
Classification · Other Common Names · Numbers · Size · Identification · Range · Habitat · Food · Life Cycle · Remarks · See Also · Internet References · Works Cited
Family Notonectidae (Backswimmers)
Other Common Names
Water Bees, Water Wasps
2 subfamilies, with 32 spp. in 3 genera in NA(1)(2) and 400 spp. in 11 genera worldwide(3)
Aquatic bugs that often swim upside-down. When resting at the surface, body is typically tilted with the head downward. Characteristics(4)(5):
hind legs modified for swimming, with long hairs
front legs not scoop-like (unlike in Corixidae)
dorsum convex, V-shaped when viewed from tip of abdomen
wings clear, tips without veins
eyes relatively close together--typically separated by less than the width of one eye
Accurate identification of species often requires examining stridulatory structures and male genitalia.
Keys to genera/species provided in(6)(1)(7)(8)(9)
Throughout North America
Ponds, freshwater pools, slow flowing streams
Prey on other aquatic insects and sometimes on small vertebrates; nymphs often cannibalistic
Elongated white eggs are cemented to underwater plant stems and hatch in a few weeks; first-generation adults appear in July; often 2 generations a year(10)
May bite if handled carelessly
Dive by holding air trapped in abdominal pockets; can remain submerged for up to 6 hrs
Come to lights; may invade swimming pools and become a nuisance
Males have a stridulatory apparatus probably used to attract females and communicate during courtship
Water Boatmen (Corixidae) have rather flat body (often cross-streaked with dark lines) and scoop-shaped front tarsi(11), and swim dorsal side up
|1.||Aquatic Insects of North America|
R. W. Merritt, K. W. Cummins, M.B. Berg. 2008. Kendall/Hunt.
|3.||Biodiversity of the Heteroptera|
Henry T.J. 2009. In: Foottit R.G., Adler P.H., eds. Insect biodiversity: Science and society. Oxford: Wiley-Blackwell: 223-263.
|5.||How to Know the Insects|
Roger G. Bland, H.E. Jaques. 1978. WCB/McGraw-Hill.
|6.||How to Know the True Bugs|
Slater, James A., and Baranowski, Richard M. 1978. Wm. C. Brown Company.
|11.||A Field Guide to Insects|
Richard E. White, Donald J. Borror, Roger Tory Peterson. 1998. Houghton Mifflin Co.
Contributed by Tony DiTerlizzi on 18 July, 2004 - 4:44pm
Additional contributions by cotinis, Robin McLeod, v belov
Last updated 12 December, 2011 - 7:05pm
Backswimmer, (family Notonectidae), any of a group of insects (order Heteroptera) that occur worldwide and are named for their ability to swim on their backs, which are shaped like the keel and sides of a boat. The backswimmer uses its long oarlike legs for propulsion and has an oval-shaped head and an elongated body, generally less than 15 mm (0.6 inch) in length. It is a good example of countershading, as its light-coloured back, seen from below, blends into the water surface and sky. The rest of the body is darker and, when seen from above, blends with the bottom of the body of water in which it lives.
Because the backswimmer is lighter than water, it rises to the surface after releasing its hold on the bottom vegetation. Once at the surface, it may either leap out of the water and fly or get a fresh supply of air, which is stored in a bubble under its wings and around its body, and dive again. The backswimmer is often seen floating on the water surface with its legs extended, ready to dart away if disturbed. It preys on insects, small tadpoles, and fishes, sucking their body fluids through its strong beak.
The genus Notonecta, distributed worldwide, may be quite destructive to fishes and tadpoles. It will bite humans when handled, the bite feeling somewhat like a bee sting. Its eggs are deposited either on or in the plant tissue of pond vegetation. The grousewinged backswimmer, N. undulata, found in North America, can often be seen swimming under the ice during the winter.
The genus Buenoa, which usually floats or swims some distance below the surface, appears reddish or pinkish in colour because of the pigment (hemoglobin) contained in certain cells.