A systematic study of the nearctic larvae of the Hydropsyche morosa group (Trichoptera : Hydropsychidae) /

Abstract

A system of taxonomic characters based on primary and secondary setae is developed and applied to identification of larvae of the Hydropsyche Mosely. Of the Nearctic species known in the morosa group. H. abella Denning, andersoni Denning, cora Denning, dorata Denning, intrica Denning, protis Ross, and vanaca Denning remain unassociated in the larval stage, although diagnoses for three unnamed species known only as larvae are also provided. Secondary setal types are defined and illustrated, and a key is provided to the Nearctic larvae now known; distribution of each species is summarized. Characters based on setae appear to be less variable over the entire range of each species than the traditional characters of colour, and for the most part they are concordant with genitalic characters, suggesting that larval chaetotaxy is likely to provide useful data for classification and phylogeny in the Hydropsychidae.Hydropsyche larvae attach fine-meshed silken nets to permanent substrates in moving water. Oriented in the current to filter suspended organic particles, the nets of different species vary in mesh size or location within the stream. At the edge of the net is a silken retreat, covered with sand grains or organic material, in which the larva lies concealed. Hydropsyche larvae are generally omnivorous, feeding on a variety of suspended organic materials including detritus, various invertebrates, algae, and diatoms, the latter also being scraped from algal mats which may accumulate near the opening of the larval retreat (Fuller and Mackay, 1980).

DNA barcoding facilitates associations and diagnoses for Trichoptera larvae of the Churchill (Manitoba, Canada) area

“…However, these larval characters have been shown to be highly variable within Hydropsyche species [22,23]. This is also evident in Churchill specimens (Figure 3B-C).…”

Trophic ecology of the Lake Superior wave zone: a stable isotope approach

“…Invertebrate identifications followed keys in Ross (1944), Burks (1953), Flowers & Hilsenhoff (1975), Pescador & Berner (1981), Schefter & Wiggins (1986), Merritt & Cummins (1996), Wiggins (2000), Smith (2001), and Thorp & Covich (2001). Diet records used to generate a priori predictions of trophic status were published by Merritt & Cummins (1996), Benke & Wallace (1997), Wiggins (2000), Smith (2001), and Thorp & Covich (2001).…”

Net-Building Behaviour of Six Hydropsyche species (Trichoptera) in Relation to Current Velocity and Distribution along the Rhône River

“…The Hydropsyche species are divided into groups according to the authors' indications on their longitudinal distribution. HW: maximum head-width of larvae of fifth instar, from data of Schuster and Etnier (1978) and Schefter and Wiggins (1986) for A, and Edington and Hildrew (1981) No field study appears to have examined the microdistribution of large-river species in Europe in relation to current velocity. In North America, two species, abundant in large rivers, have been studied: H. incommoda Hagen (as H. orris) abundant in the Upper Mississippi near Keokuk (Fremling 1960) and in the lower reach of the Savannah River (Gordon andWallace 1975, Cudney andWallace 1980), and H. rossi Cudney and Wallace (1980) reported that the biomass of H. incommoda was greatest at 25-50 cm/s over a range of 10-75 cm/s.…”

“…Velocity was measured 2 mm above the rock surface, beside each retreat. Maximum density was at 20.6 cm/s for H. cockerelli Banks, a species living in the middle reaches of western montane streams (Schefter and Wiggins 1986), 16 cm/s for H. oslari Banks, which occurs mostly in the middle reaches of streams and small rivers (Schefter and Wiggins 1986) and 8.3 cm/s for H. occidentalis Banks. However, when velocity was measured 10 mm above the substrate, specific preferences were less distinct (28, 23, 22 cm/s, respectively) although they showed the same trend.…”