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Sieve Efficiency in Benthic Sampling as Related to Chironomid Head Capsule Width
Patrick L. Hudson and Jean V. Adams
Journal of the Kansas Entomological Society
Vol. 71, No. 4, Special Publication Number 3: A Festschrift Honoring Mary and Jim Sublette. Part 2: Biology, Ecology and Natural History of Chironomidae (Oct., 1998), pp. 456-468
Published by: Kansas (Central States) Entomological Society
Stable URL: http://www.jstor.org/stable/25085862
Page Count: 13
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The width of the head capsule in chironomid larvae is the most important morphometric character controlling retention of specimens in sieving devices. Knowledge of the range in size of these widths within any chironomid community is fundamental to sampling and interpreting the resulting data. We present the head capsule widths of 30 species of chironomids and relate their size distribution to loss or retention in several experiments using graded sieve sizes. Based on our measurements and those found in the literature we found the head capsule width of fourth instars in half the chironomids species to be less than 350 μm. Many species may never be collected with the commonly used U.S. Standard No. 30 sieve (589 μm), and the No. 60 (246 μm) screen appears to retain most species only qualitatively. We found 70 to 90% of the chironomid larvae and 19 to 34% of their biomass can pass through a No. 80 sieve (177 μm). The implications of sieve loss and other factors affecting sieving efficiency are discussed.
Journal of the Kansas Entomological Society © 1998 Kansas (Central States) Entomological Society