20 KB916 KB15 KB200520192010Anderson, Norman H.Stewart, Kenneth W.številka:6letnik:6str. 52-57ISSN:1854-0392ISSN:1855-5810COBISSID:864245URN:URN:NBN:SI:doc-YHAOI4CEenMississipi College, Dept. of BiologyPrirodoslovni muzej SlovenijeIlliesiaentomologylife historyNemouridaeOregonOstrocercaPlecopteraThe life history of Ostrocerca dimicki (Frison) in a short-flow, summer-dry Oregon stream|The voltinism and life history of Ostrocerca dimicki (Frison) were determined from monthly benthic collections of larvae, and adults from an emergence trap,from a short-flow, intermittent stream. Collections were from four water years, 1996-97, 1997-98, 1998-99, and 2002-03, selected from 17 years of samples. Determination of emergence timing was supplemented by collections of adults in 2008, from 10 emergence traps set to include a range of habitat types on the receiving seasonal stream. Growth was assessed by increase of head- capsule width of 667 larvae. A total of 202 males and 261 females were taken in the 4-year and 2008 emergence trap samples. Emergence in late February- April, first appearance of early- instar larvae the following December or January about a month after typical resumption of water flow, and rapid growth in 3-4 months, indicated a straightforward univoltine, fast cycle, with a probable over-summer egg diapause. Population levels fluctuated substantially over the 17-year period, depending on rainfall and duration of flow. Drought periods reduced the population, leading to low or no emergence and subsequent slow recovery, presumably from long-term diapausing eggsTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaPrirodoslovni muzej Slovenije