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Presented at the NABS Annual meeting, Anchorage, Alaska, 2006
in Life Histories
Life history of Neophylax rickeri (Trichoptera: Uenoidae) in coastal California streams
P.K. Mendez1, J.R. Wood2, A.H. Purcell1, and V.H. Resh1.1Department of Environmental Science, Policy, and Management, University of California, Berkeley, 2Department of Biology and Environmental Studies, The King's University College, Alberta, Canada
We have examined the life history of the grazing caddisfly Neophylax rickeri (Trichoptera: Uenoidae) over nearly three decades in four, coastal California streams in Marin Co., CA from 1977–1982, 1993, and 2001–2006. Head and pronotal measurements identified five larval instars and a relatively synchronous, univoltine life cycle. N. rickeri oviposits egg masses containing ∼580 eggs/mass underwater on emergent rocks in riffles. Egg masses often occur in aggregations on the downstream-facing side, or on undersides of rocks. Larvae are present and active in three of the streams from January–September, but are active in Webb Creek year-round. Early instar larvae use silk threads as a safety lines in shallows and quiet areas. Prepupae and pupae occur in large aggregations and have an extended prepupal diapause from April until October. Both laboratory and field emergence studies, and pupal surveys, demonstrate protandry whereby males preceded females; thus determination of sex ratios of adults are time dependent. Adults are present from late September until mid-November in all streams. Measurements of the forewing discoidal cell revealed that females are on average 1.1x larger than males. Adults live ∼8 days.
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