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The downstream drifting of larvae of Dixa (Diptera: Dixidae) in two stony streams
Author(s) -
ELLIOTT J. M.,
TULLETT P. A.
Publication year - 1977
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.1365-2427.1977.tb01688.x
Subject(s) - pupa , larva , diel vertical migration , instar , streams , aquatic insect , invertebrate , ecology , biology , hydrology (agriculture) , geology , computer network , geotechnical engineering , computer science
SUMMARY. Larvae of Dixa , especially D. puberula Loew., were a significant component of the invertebrate drift in the Walla Brook in southwest England, the Wilfin Beck and the River Duddon in the English Lake District, and the River Estibère in the French Pyrenees. The drifting of the larvae increased markedly at night and showed a definite diel periodicity with maximum numbers usually in the early hours of the night. Seasonal peaks in the density of larvae in the drift frequently occurred in months when adults and especially pupae were present. Most drifting larvae were in the fourth and final instar, and their drift rate usually increased when they were searching for suitable pupation sites.