| Popis: |
Avian brood parasitism is an ideal system for the study of coevolution. Brood parasites and their hosts have developed interesting adaptations during co-evolution allowing them to maximize their fitness. The evolution of these adaptations has a character of an "arms race" where the evolution of one trait in the host is tied with the evolution of another trait in the parasite. In my doctoral thesis, I deal with two of these adaptations: recognition of parasitic eggs by hosts and mimicry of eggs in parasites. Since both these adaptations are influenced by birds' visual system, in all my studies I used an objective method to measure the colour and the modelling of avian visual system that is quite different from the human visual system. For instance, humans in contrast to birds cannot perceive ultraviolet (UV) light. However, this part of spectrum influences behaviour of birds substantially (e.g. courtship or foraging). We found that the hosts of brood parasites can use UV light when recognizing parasitic eggs. However, it seems that this part of spectrum is not the main cue in egg recognition (manuscript 1). Ambient light has also an important impact on colour perception. We determined whether the light conditions in nests influence host responses to alien eggs. The Red Bishop (Euplectes orix) was an ideal... |
