Hydrobiosidae

Abstract: Analysis of modes of pupation in Trichoptera reveals two fundamental types of pupal enclosures and concomitant systems for water circulation. In one (Rhyacophilidae, Hydrobiosidae, Glossosomatidae, Hydroptilidae-infraorder Spicipalpia Weaver), pupating larvae construct a closed cocoon of parchment-like silk, usually discrete from the pupal enclosure of small stones; water currents bathe the external surface of the cocoon during metamorphosis. In the other type (most families in the suborders Annulipalpia Martynov s.s. and Integripalpia Martynov s.s.), larvae con- struct a pupal cell with open meshes or holes at each end, permitting water currents to bathe the surface of the pupa directly during metamorphosis. Exceptions in the Philopotamidae, Stenopsy- chidae, Ecnomidae, and Phryganopsychidae are considered. The function of trichopteran cocoons during metamorphosis is considered, indicating that osmotic relations in closed cocoons of parchment-like silk in the Rhyacophilidae and allied families impede the efficiency of respiration mediated solely by diffusion of oxygen across the semipermeable wall of the cocoon. Because ovoid, closed cocoons of parchment-like silk also occur in primitive Lepidoptera, the sister group of Trichoptera, cocoons of this type are proposed as part of the groundplan of Tri- choptera. Consequently, the open pupal cells of Annulipalpia (retreat-makers) and Integripalpia (case-makers) are interpreted as derived. It follows that the habitat common to the families con- structing closed cocoons-cool, flowing waters-would likely have been the habitat in which Tri- choptera originated. The hypothesis proposed for the phylogeny of pupation in Trichoptera is that the closed cocoon of semipermeable silk in the ordinal groundplan required Trichoptera to become aquatic in cool, lotic waters; and that evolutionary innovation through subsequent derivation of cocoons of perme- able silk with ventilatory openings enhanced the efficiency of respiration, enabling Trichoptera to invade warmer waters of reduced current, and opening the way for radiation of the major lineages now extant-the retreat-making (Annulipalpia s.s.) and the case-making (Integripalpia s.s.) families. An alternative form of the higher classification of Trichoptera is proposed and discussed, elevating the Spicipalpia, termed the cocoon-making Trichoptera, to the rank of a third suborder, co-ordinate with the Annulipalpia and Integripalpia.

Abstract: The vitality of the phylogenetic dialogue in trichopterology, especially since 1967, is evidenced by the high quality and large number of published phylogenetic inferences concerning caddisflies and the continuing spirited exchange of opinions about some differences among those ideas. Monophyly for Trichoptera seems well argued. Monophyly for suborder Annulipalpia sensu stricto also is widely acknowledged, as is monophyly for suborder Integripalpia sensu stricto. Various postulated relationships of Hydrobiosidae, Rhyacophilidae, Glossosomatidae, and Hydroptilidae (="Spicipalpia") are less convincing. Phylogenies for several groups of families within Annulipalpia and Integripalpia have been proposed and relationships within at least 126 intrafamilial taxa also have been inferred.

Abstract: A phylogeny of the families of Trichoptera is reviewed to provide a basis for understanding the probable evolution of feeding tactics and case or retreat constructions by larvae. At least 48 hierarchically inclusive homologues are known, mostly from larval, pupal, and adult morphology. Their resulting phylogeny indicates that Rhyacophilidae, Hydrobiosidae, Glossosomatidae, and Hydroptilidae are more closely related to Philopotamidae, Hydropsychidae, and their allies than to Limnephilidae, Leptoceridae, and their allies. This phylogeny implies that the ancestral caddisfly larva was probably a tube-dwelling detritivore, inhabiting humus and detrital mats near the shores of lentic or lotic-depositional habitats. This ancestor evolved into a tube-case-making detritivore and scraper in the ancestor of Integripalpia and into a retreat-making collector-gatherer in the ancestor of Annulipalpia. All other larval feeding and case-making tactics evolved from these ancestral habits.