Family GLOSSOSOMATIDAE

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Family GLOSSOSOMATIDAE

Compiler and date details

29 June 2010 - ABRS

Arturs Neboiss, Department of Entomology, National Museum of Victoria, Abbotsford, Victoria; updated (2002) by Alice Wells, Australian Biological Resources Study, Canberra, Australia

Introduction

Small (wing span 8–12 mm), dull, blackish caddis-flies, all rather uniform in appearance.

The family, which was regarded as a subfamily within the family Rhyacophilidae, occurs in all faunal regions and there are about 20 genera and 400 species. In Australia it is represented by 23 described species (Neboiss 1986a; Wells 2010), all of which are referred to the genus Agapetus. It is interesting to note that the family is well represented in New Guinea and on other SW Pacific Islands, but it does not occur in New Zealand or New Caledonia. Neboiss (1986b) discussed the distribution and taxonomy of glossosomatids in the SW Pacific region, and described two new Agapetus species. Cartwright (1997) provided a guide to late instar larvae. Wells (2010) reviewed the genus in Australia, and added 13 new species.

Agapetus species have been the subject of ecological studies and these include work by Gawne (1995, 1997) and Gawne & Lake (1995, 1996).

Diagnosis

Adult: ocelli present. Maxillary palpi 5-segmented in both sexes, the first two segments short, subequal, second with globular mesolateral projection, third segment the longest. Antennae stout, shorter than forewing. Mesoscutum and scutellum each with a pair of setal warts. Forewings elongate, ovate, discoidal cell of forewing closed. In females the midtibia and tarsus more or less dilated, abdominal segments 8 and 9 each with a long internal apodeme on each side.

Tibial spurs 2: 4: 4.

Larva: inhabit cool, fast flowing streams and construct dome-shaped cases of small stones; the ventral side of the case is flattened and made of smaller grains. Larvae are usually referred to as saddle-case makers. They feed on algae and fine organic particles. Shortly before pupation the larva removes the flattened ventral part of the case and fastens the dorsal section to the substrate. The pupa is enclosed within a greyish or brownish silk cocoon, similar to that found in Hydrobiosidae.