Colour characteristics of the blunt egg pole: cues for recognition of parasitic eggs as revealed by reflectance spectrophotometry
Authors | |
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Year of publication | 2007 |
Type | Article in Periodical |
Magazine / Source | Animal Behaviour |
MU Faculty or unit | |
Citation | |
Field | Ecology |
Keywords | blackcap; brood parasitism; recognition cues; reflectance spectrophotometry; rejection behaviour |
Description | We examined the role of colour characteristics in the egg recognition in blackcaps (Sylvia atricapilla). Multivariate analyses of spectrophotometric data revealed that the likelihood of egg rejection significantly increased with decreasing intraclutch variation in blue chroma. Furthermore, probability of egg rejection significantly increased with decreasing contrast between parasitic and host eggs in UV wavelengths and with decreasing brightness of host eggs at the blunt egg pole. Accepted foreign eggs were significantly darker at the blunt pole than acceptors’ own eggs. The paradox that rejected eggs had lower contrast could be explained by the fact that the contrast in UV spectrum is associated with brightness of the blunt egg part. Our data suggest that colour characteristics of the blunt egg part may play a major role in the recognition of parasitic eggs in the blackcaps. |
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