LIFESCI 2D03 Lecture 22: Lecture 22
12 Jan 2018
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Document Summary
Cryptic colouration morphological colouration that matches the colour of the environment to reduce detection by predators. Crabs live + feed on benthic substrate (bottom of marine coastal habitats) Juveniles colour variation ranges from brown tan white with many spots/stirpes: adults light purple colour. Larger crabs had no preference for either background in the control, but strongly preferred shell-hash in the predator treatment. Juvenile crabs can select an appropriate cryptic background when given a choice, and complex colour of juvenile crabs is an adaptation to minimize detection by predators. Lower mean movement rate + mean time moving. Prey take evasive or aggressive action when detected. Startle display abrupt changes in behaviour, often involving sudden exposure of conspicuous colours that may be accompanied by a sound: can discourage a predator. Many behaviours represent adaptive trade-offs involving predation risk. Vigilance behaviour individual scans the environment for predators. When animals search for food or feed, they tend to lower their head.
