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 Major Groups | Insecta (insects) | Hemiptera (bugs) | Aphelocheiridae

Aphelocheirus australicus

Major Group: Insecta
Order: Hemiptera
Family: Aphelocheiridae
Genus: Aphelocheirus
Species: australicus
This family is represented in Australia by a single species, Aphelocheirus australicus.

Descriptive Features:

  • body sub oval and strongly flattened
  • head produced anteriorly
  • antennae 4-segmented, elongate and slender
  • rostrum relatively long, reaching well onto metasternum
  • forelegs not raptorial, fore femur only slightly thickened
  • hindlegs not oar-like, but fringed with swimming hairs
  • all tarsi 3-segmented, but basal segment very small
  • 1 pair of equally and well developed claws on all tarsi
  • macropterous and micropterous adult forms, micropterous form with small but distinct wing rudiments
  • posterior, lateral angles of connexiva often spine-like, produced
  • venter of thorax and abdomen with a dense layer of microhairs (plastron)
  • abdominal sternum 2 with a pair of sub lateral, plate-shaped sense organs
  • Total length: 6.5 - 8.8 mm

      Aphelocheirus australicus micropterous adult

      Taxonomic Checklist:
      Aphelocheirus australicus Usinger

      Distribution: N Qld, N NT. This species is endemic.

      Sensitivity Rating: none

      Functional Feeding Group: predators


      South Alligator River, Kakadu NP NT

      Ecology: Instream habitat: Aphelocheirus australicus generally occurs in well aerated streams but may also occur in areas of low flow and riverine pools with larger populations occurring in unshaded areas. These bugs are benthic living under pebbles or in the sandy substrata. They are best collected by disturbing the bottom sediments and allowing the bugs to drift into a downstream net
      Feeding ecology:Aphelocheirus australicus feeds on the young of other aquatic insects, such as mayflies (Ephemeroptera), caddisflies (Trichoptera) and black flies (Diptera: Simuliidae). They occasionally pierce human skin resulting in a painful “sting”.
      Habit: Aphelocheirid bugs hide during the day and then becoming more active at night, crawling over the stream bed. Aphelocheirus species have the unique ability to stay submerged indefinitely. The body surface is covered by a dense pile of minute microhairs. The tip of each hair is bent approximately at a right angle to its base and this hair pile is able to resist wetting and mechanical breakdown. The thin layer of air held by the pile of microhairs (plastron) is continually in contact with ventral spiracles. The spiracular openings are expanded to form a flat bag with numerous outgrowths (rosette) and perforations through which oxygen reaches the tracheae. In addition there are many small holes on the abdomen and head which lead to narrow channels through the cuticle ending in air sacs. Tracheoles connect these air sacs with the rest of the tracheal system. The plastron of Aphelocheirus species can be considered an external physical gill as it is self renewing; oxygen continually diffuses in and nitrogen out. In nymphs, respiration takes place directly through the cuticle.
      Life history: Eggs are nearly cylindrical with broadly rounded ends and a distinct hexagonal sculpture. They are deposited singly, in clusters or in strings and are glued to larger substrates, such as stones or mollusc shells. The life span of Australian Aphelocheirus is not known, however the Northern Hemisphere Aphelocheirus eggs hatch after nine to ten weeks and development from nymph to adult takes at least two years in colder climates.


      Information Sources: Andersen & Weir 2004