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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Life Histories
LIFE-CYCLE AND FEEDING HABITS OF LEPIDOSTOMA PLUVIALE (MILNE) IN STREAMS AND RIVERS OF NORTHEASTERN OREGON.
W.J. Gerth and J.L. Li. Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR, USA 97331
Lepidostoma pluviale (Milne) is a common caddisfly in many larger streams of northeastern Oregon and is the dominant Lepidostoma species in many montane areas of the western U.S (Ross, 1946). Larvae of this species construct tubular cases of sand grains. Larval, pupal, and adult specimens were collected or reared during a variety of studies our laboratory conducted in four river basins of the Blue Mountain region of Oregon. From these collections we infer that L. pluviale has a slow-seasonal life-cycle. There is likely some minor year-to-year and site-to-site variation, but in general, eggs hatch in July and August. Larvae grow throughout the fall, winter, and spring and pupation occurs in late spring. Adult flight occurs in June and July. Based on the habitats where L. pluviale larvae were collected and preliminary examination of the gut contents of larvae collected in late summer, we hypothesized that this species, in contrast to other species of Lepidostoma, was a scraper. Subsequently, we have found that L. pluviale is an avid colonist of leaf-packs in fall, and may switch to shredding coarser organic material later in its life-cycle.
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