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Adaptive head coloration in case‐making caddis larvae
Author(s) -
OTTO C.
Publication year - 1984
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.1365-2427.1984.tb00044.x
Subject(s) - crypsis , predation , biology , river ecosystem , ecology , intraspecific competition , lake ecosystem , larva , habitat
SUMMARY. 1. In daylight conditions brown trout preferably attacked head capsules with a contrasting colour pattern compared to those which were more uniformly coloured. This preference was reversed under reduced illumination. It is argued that striped head capsules are cryptic to predators at low light intensities. 2. In caddis larvae contrasting head patterns are found mainly in lentic species, whilst the heads of lotic larvae are usually more uniformly coloured. Lentic species dwell in conditions of more diffuse illumination than lotic one, and each category thus achieves high crypsis with respect to head capsule coloration. 3. Lentic molannid and phryganeid larvae often dwell at considerable depths, and these species also have the most sharply defined head patterns. These species are predatory and, besides being cryptic to larger predators, may also be cryptic to their prey. 4. Intraspecific variation in head capsule coloration in relation to habitat type is also discussed.