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Coevolution of brood parasites and their hosts : a case of the great spotted cuckoo and its corvid hosts


We propose a study of the coevolution between an obligate brood parasite (the great spotted cuckoo (Clamator glandarius)) and its major corvid host, the magpie (pica pica). The great spotted cuckoo has coexisted with its magpie host for variable periods of time in different areas in Spain. Magpie
populations therefore vary in their duration of sympatry with the parasite from a few decades to probably thousands of years, while other magpie populations are allopatric. We intend to utilize this ideal natural setting for a number of field studies by establishing three transects across the distributional boundary of the great spotted cuckoo in Spain, and combine
the results from these areas with results from two long-term study areas with different durations of sympatry in S Spain. The project consists of three main parts: (1) Micro-evolutionary changes in host-parasite relationships. We intend to determine whether gene flow from allopatric magpie populations can explain rates of magpie ejection of cuckoo eggs in areas of
recent sympatry. Alternatively, ejection behaviour by magpies may be the result of a recent increase in the frequency of ejector genes among hosts. (2) Host responses to the parasite across the distributional boundary of the the parasite. The following host responses will be studied: (i) Egg discrimination by hosts and the effects of intra-clutch variability among
hosts on discrimination. (ii) Learning of anti-parasite behaviour by hosts. (iii) Magpie aggression towards parasites as a means of reducing parasitism. (iv) Effects of magpie nest dispersion and breeding synchrony on risks of
parasitism,and the intraspecific costs of breeding dispersion and synchrony. (3) parasite responses to the host across the distributional boundary. The following parasite responses will be studied: (i) Effects of cooperation cooperation between parasites and the role of males in successful parasitism. (ii) A test of the mafia hypothesis which suggests that magpies may be forced to accept the parasite egg because the cuckoo otherwise may
destroy the magpie nest. (iii) Effects of morphological and vocal mimicry by cuckoo nestlings on the success of parasitism.

Funding Scheme

CSC - Cost-sharing contracts


Universidad de Granada
Campus Fuente Nueva S/n
18071 Granada

Participants (2)

United Kingdom
Western Bank
S10 2TN Sheffield
Uppsala University

751 22 Uppsala