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The drift of some chironomid egg masses (Diptera: Chironomidae)
Author(s) -
WILLIAMS C. J.
Publication year - 1982
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1982.tb00649.x
Subject(s) - chironomidae , biology , larva , darkness , ecology , botany
SUMMARY. The drift of chironomid egg masses was investigated in the River Mole (Devon) and the River Wye (Powys) in 1981. Large numbers of egg masses were found in the drift just after dusk; on one occasion an estimated 50,000 egg masses passed a sampling point in 5 h. Oviposition of free‐floating egg masses appeared to be initiated and synchronized by the onset of darkness. Egg masses of some Pentaneurini (Tanypodinae), Tanytarsini and Chironomini (Chironominae) were found in the drift and adhering to submerged stones. Flotation by means of a gas vacuole within the egg mass was observed in the Polypedilum ‘convictum’ group. The gas vacuole decreased in size over 8–11 h and the egg masses sank after 2–3h. Some chironomid egg masses are capable of drifting large distances after oviposition. The implications of sueh drift are briefly discussed in relation to the distribution of chironomid larvae.