Role of different colours of aposematic insects in learning, memory and generalization of naïve bird predators

Abstract

Juvenile great tits (Parus major) were trained to avoid several colour forms of the firebug Pyrrhocoris apterus. Particular colour of the prey did not influence the rate of avoidance learning.

However, the generalization among different colour forms was asymmetric, the birds birds that learned to avoid red firebugs did not generalize their experience to yellow or white mutants whereas birds that learned to avoid yellow mutants generalized their experience to red firebugs. The red colour thus represents a more effective signal than the yellow; predation by birds could have played a crucial role in selectively favoured evolutionary transitions from yellow to red coloration in pyrrhocorids.

Keywords

• asymmetric generalization
• avoidance learning
• firebug
• great tit
• peak shift
• Parus major
• Pyrrhocoris apterus
• signal memorability
• warning signal