|MadSci Network: Zoology|
In the essay on brood parasitism in The Birder's Handbook (also available on-line at http://www.stanford.edu/group/stanfordbirds/text/essays/Brood_Parasitism.html) the authors state that some cuckoos specialize in parasitizing specific host species and that this specificity may differ for females within the same brood. The ability of females to mimic their host's eggs appears to reside genetically in the females, as females parasitizing a specific species will mate with random males. Recent research (Aviles, et al. 2006) indicates that females to some degree choose eggs which will more closely match their own. This matching seems to incorporate both cues we humans can see as well as elements visible in the ultraviolet end of the spectrum. These findings argue that there is some cognizance on the part of the female European cuckoo for visual elements of the hosts eggs which lead to her laying in that specific nest. For a good overview of cuckoo nest parasitism see Brooker and Brooker (1990) which is also available on-line. In this article the authors raise the question of whether the females imprint on their hosts and possibly the other eggs in the nest to guide them when it comes time to dump their own broods. Aviles JM, BG Stokke, A Moksnes, E Roskaft, M Asmul, AP Moller. Rapid increase in cuckoo egg matching in a recently parasitized reed warbler population. 2006. Journal of Evolutionary Biology 19:1901-1910(10) Brooker, LC and MG Brooker. 1990. Why are cuckoos host specific? Oikos 57:301-309. Ehrlich P, DS Dobkin and D Wheye. 1988. The Birder's HandbookŁ. Fireside.
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