Aquatic and Semiaquatic Hemiptera

hemiptera

Introduction

Aquatic and semiaquatic bugs (true bugs). A large order (or suborder Heteroptera) of over 50,000 species worldwide, but only 3200 species are aquatic or semiaquatic, about 400 of these occur in North America, north of Mexico. Closely related to the Homoptera (aphids, planthoppers, cicadas, etc.) with over 30,000 additional species. Neoptera- Exopterygota, paurometabolous.

Recognition

Mouthparts highly modified for piercing and sucking. The mandibles and maxillae form 4 piercing stylets within the beak (labium), which arises form the front of the head. The antennae are 4-5 segmented. Nymphs have external wingpads (sometimes absent) and unsegmented tarsi. Adults have the forewing (hemelytra) basally thickened and apically membranous. The hindwings are fully membranous. Some species may be brachypterous or apterous, if apterous the tarsi are 2-3 segmented.

Life Cycle

Adults breed mostly in the spring and early summer. Many species produce sound by stridulating to communicate between the sexes. Mating takes place in the normal habitat for the species. Eggs are normally attached to vegetation or other objects, some species guard the eggs. The eggs hatch quickly and the nymphs grow quickly through 5 (rarely 4) instars during the summer. The adults overwinter by hibernating or they may remain active. Most species are univoltine in our area.

Trophic Roles

The family Corixidae contains many species that feed on algae, or even as collectors as well as predators. All remaining aquatic and semiaquatic bugs are primarily predators as nymphs and adults. They use the piercing mouthparts to penetrate the prey, inject hydrolytic enzymes and suck out the juices. Many have raptorial forelegs to help handle the prey. Many are very fierce taking large prey and causing painful bites. Semiaquatic species feed from the surface or just below the surface. Purely terrestrial bugs may be predators, herbivores or even parasites.

Communities

Most diverse in warm, heavily vegetated, shallow, lentic or slow lotic waters. Corixids are most specious and show more pronounced habitat preferences. Most bugs come to the surface periodically for air. Some water striders live on the open oceans.

Economic Importance

Terrestrial species may be very important agricultural pests, pest controlling predators, or vectors of disease. Aquatic species help control nuisance insects, some are used for human or pet food, some are bitting nuisances, some may feed on hatchery fish, only corixids are normally fed upon by fish.

Zoogeography

The families and many species tend to be widely distributed due to long-lived adults with strong powers of flight. Some have migrations between summer and winter habitats.

Collecting

Aquatic and semiaquatic bugs are readily collecting in benthic or surface samples. They may be picked from thick debris by hand or extracted with a Berlese funnel. Many species are attracted to light during dispersal flights.

Rearing

Immature bugs are very similar to the adults in structure, habitat and habits, there is generally no need to rear them. They can be highly cannibalistic.

Preservation

Immature bugs are best fixed in Kahle's solution and stored in 70% ethanol. The adults may be treated similarly, or collected straight into 70-80% ethanol. The adults may be pinned or pointed latter. Adult specimens may also be killed in a killing jar and pinned or pointed directly.

Taxonomy

Most groups are pretty well known. Many faunas and revisions are available.

Synopsis Of Neartic Families

  1. Suborder Nepomorpha- antennae shorter than the head and usually hidden from above.
    1. fully aquatic underwater bugs, no ocelli.
      1. Corixidae- water boatmen, beak triangular, short, and unsegmented, front tarsi unsegmented and scoop-shaped, common is still water, many are plant feeders, non-biters.
      2. Belostomatidae- giant water bugs, apex of abdomen with retractile air straps, submerged debris of lentic and slow lotic waters.
      3. Nepidae- water scorpions, apex of abdomen with non-retractile siphon, tarsi one segmented, submerged debris of lentic and slow lotic waters.
      4. Naucoridae- creeping water bugs, flattened, raptorial front legs, membrane without veins, warm lotic and lentic waters, bite readily.
      5. Notonectidae- back swimmers, body elongate, over 4 mm long, hind tarsi without claws, common in still water.
      6. Pleidae- pygmy back swimmers, body ovoid and convex, less than 4 mm long, heavily vegetated lentic water, feed on zooplankton.
    2. semiaquatic bugs of shorelines, ocelli present.
      1. Gelastocoridae- toad bugs, front legs raptorial, antennae hidden, eyes protuberant.
      2. Ochteridae- front legs unmodified, antennae exposed.
  2. Suborder Gerromorpha (including Leptopodomorpha), semiaquatic bugs, antennae longer than the head.
      1. Gerridae- water striders, fore claws preapical, hind femur extends beyond abdomen, ocelli small, often apterous, gregarious, lentic and lotic pleuston.
      2. Veliidae- broad-shouldered water striders, fore claws preapical, hind femur not so long, ocelli absent, often apterous, gregarious, lentic and lotic pleuston.
      3. Hydrometridae- water measurers, body very slender and elongate, 8-10 mm long, often apterous, shorelines and lentic floating debris.
      4. Hebridae- velvet water bugs, body stout, tarsi 2 segmented, 1.5-2.5 mm long, on the water surface, floating debris or shorelines.
      5. Mesoveliidae- water treaders, tarsi 3 segmented, inner margin of eyes converging anteriorly, 2-5 mm long, often apterous, shorelines and floating debris.
      6. Macroveliidae- tarsi 3 segmented, inner margin of eyes arcuate, lotic margins.
      7. Saldidae- shore bugs, membrane of wing with 4 or 5 large similar cells, shorelines and floating debris.

Montana Species list

Reference update

  • Spence, J.R. and N.M. Andersen. 1994. Biology of water striders - interactions between systematics and ecology. Ann. Rev. Ent. 39:101-128.
  • Andersen, N.M. and J.R. Spence. 1992. Classification and phylogeny of the holarctic water strider genus Limnoporus Stal (Hemiptera, Gerridae). Can. J. Zool. 70:753-785.
  • Henry, T.J. and R.C. Froeschner. 1992. Corrections and additions to the catalog of the Heteroptera or true bugs, of Canada and the continental United States. Proc. Ent. Soc. Wash. 94:263-272.
  • Henry, T.J. and R.C. Froeschner, eds. 1988. Catalog of the Heteroptera or true bugs, of Canada and the continental United States. E.J. Brill, Leiden, 958pp.
  • Hilsenhoff, W.L. 1986. Semiaquatic Hemiptera of Wisconsin. Great Lakes Ent. 19:7-19.
  • McKinnon, C.N. and J.T. Polhemus. 1986. Notes on the genus Isocytus with the description of a new species and key to species (Hemiptera: Heteroptera: Saldidae) J. N.Y. Ent Soc. 434-441.
  • Polhemus, J.T. 1985. Shore bugs (Heteroptera, Hemiptera; Saldidae) a world overview and taxonomy of middle American forms. The Different Drummer, Englewood, Colorado, 252pp.
  • Hilsenhoff, W.L. 1984. Aquatic Hemiptera of Wisconsin. Great Lakes Ent. 17:29-50.
  • Roemhild, G. 1976. Aquatic Heteroptera (True bugs) of Montana. Montana State Univ. Ag. Exp. Sta. Res. Rep. 102:1-70.

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Updated on 20 NOV 1995 D.L. Gustafson
AIM home page
dlg@rivers.oscs.montana.edu