Print This Page

 Major Groups | Insecta (insects) | Trichoptera (caddisflies) | Hydrobiosidae


Major Group: Insecta
Order: Trichoptera
Family: Hydrobiosidae

Descriptive Features:

  • head prognathous, rounded, upper surface convex, without ridges or carinae
  • secondary setae absent
  • pronotum sclerotised
  • most species with some sclerotization of the prosternum, usually with a moderate to large medial sclerite
  • mesonotum and metanotum membranous
  • legs subequal in size
  • foreleg modified for grasping, differs from mid- and hindlegs in either being chelate or having the femur broadened and bearing a field of stout spines
  • abdomen smooth, without gills, usually with tergite on segment 9
  • abdominal prolegs strongly developed, anal claws robust
  • Total length: 8 - 15 mm
  • Taxonomic Checklist: Genera
    Allobiosis (larva unknown)
    Allochorema (larva unknown)
    (larva unknown) 
     (larva unknown)
    (3 undescribed genera)

    Distribution: N Qld, SE Qld, NSW, Vic, Tas, SA, S WA

    Sensitivity Rating: SIGNAL grade 8

    Functional Feeding Group: predators

    Ecology: Instream habitat: Hydrobiosid larvae are generally found on stony substrata in cool flowing streams but also occur in warmer lowland streams.
    Feeding ecology: Larvae are predatory, feeding on other aquatic invertebrates including midge larvae (Diptera: Chironomidae), worms (Oligochaeta), blackfly larvae (Diptera: Simuliidae), mayfly nymphs (Ephemeroptera) and riffle beetle larvae (Coleoptera: Elmidae).
    Habit: Larvae are active and free swimming, not constructing a case or retreat. Some species may trail a silken thread that attaches to substrata. They have a foreleg modified for grasping and tearing prey, giving larvae the common name of 'pincer-clawed caddis'.
    Life history: Larvae undergo five instars. Final instar females are considerably larger than males. The pupal chamber is made of small stones or gravel and attached to the underside of larger rocks or submerged logs. Inside the pupal chamber, the animal spins a semi-permeable silk cocoon with a smooth outer surface. Synchronisation of the life cycle may be poor, with larvae and adults being present together through much of the year, but extensive Australian studies have not been conducted.
    Information Sources: Dean 1997, Dean et al 2004, Dean & Bunn 1989
     More ›››  key to genera