Meadow pipit (Anthus pratensis) egg appearance C. Moskát et al. / Animal Be1288in cuckoo (Cuculus canorus) sympatric and allopatric populations

• Main Authors: J M Aviles, A P Møller, Jesus M Aviles, Anders P Møller
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1041.2948; http://iis1.eeza.csic.es/eeza/documentos/Aviles_Moller_BJLS_2003.pdf

Host populations tend to show less ability to discriminate against parasites when living in their absence. However, comparison of rejection rates among sympatric and allopatric host populations does not allow determination of whether the greater tolerance in allopatric populations reflects a genetic change or phenotypic plasticity. Here we test the existence of changes in a host's adaptation to brood parasitism in the absence of parasitism by studying intraclutch variation in egg appearance, which is a genetically determined component of host defence favouring discrimination of parasitic eggs. We investigated egg phenotypes of a common host of the European cuckoo, Cuculus canorus , in the presence and in the absence of cuckoos. By using objective spectroradiometry techniques of colour assessment we compared intraclutch variation between populations of meadow pipit, Anthus pratensis , sympatric (England) and allopatric (Iceland and Faeroe Islands) with C. canorus . Allopatric populations of A. pratensis showed greater intraclutch variation in egg appearance in the ultraviolet part of the spectrum than did a population sympatric with C. canorus . Two possible alternative mechanisms explaining these findings are discussed.