Caddisflies

Code QL999999

See Key to Families of Australian Trichoptera Larvae

The Trichoptera is an order of over 7,000 species worldwide. Holometabolous, with adult moth-like, usually covered in hairs; setal warts (setose protuberances) often on dorsum of head and thorax; head with reduced mouthparts, but with 3- to 5-segmented maxillary and 3-segmented labial palps (cf. proboscis of most Lepidoptera), antennae multisegmented, filiform, often as long or longer than wings, large compound eyes and 2-3 ocelli; prothorax smaller than meso- or metathorax; wings haired or sometimes scaled, distinguished from Lepidoptera by different wing venation; abdomen typically 10-segmented.

Larva with 5-7 aquatic instars, with fully developed mouthparts; 3 pairs of thoracic legs with at least five segments, without the ventral prolegs characteristic of lepidopteran larvae; abdomen terminating in hook-bearing prolegs; closed tracheal system, with tracheal gills often on most or all 9 abdominal segments, sometimes associated with thorax or anus; gas exchange also cuticular, enhanced by ventilatory undulation in tubular case. Pupa aquatic, in silken retreat or case, with large functional mandibles to chew free from pupal case or cocoon; free legs with setose mid tarsi to swim to water surface; gills coincide with larval gills; eclosion through pharate adult swimming to water surface where pupal cuticle splits and exuviae used as floating platform.

Predominantly univoltine, with development longer than one year at high latitudes and elevations. Larva free-living, net-spinning, or saddle-, purse- or tube-case making; diverse feeding habits, including predators, filterers and/or shredders of organic matter, and some grazers on macrophytes. Net spinners restricted to flowing waters, with case-makers frequent also in standing waters. Adults may ingest nectar or water, but often do not feed.