1990/04/01 by Lesley Brooker, Michael Brooker · 3 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Environmental Science · #Plant Parasitism and Resistance #Plant and Fungal Species Descriptions #Animal Ecology and Behavior Studies
paper · doi:10.2307/3565958
openalex publication_date 1990/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/11
Evidence suggests that each cuckoo species is specific to a discrete group of primary hosts, although there is often considerable overlap in the use of secondary hosts. Presumably therefore, the host segregation of cuckoo species has evolved as a result of interspecific competition, in line with Gause's hypothesis. Teleological evidence of host specificity on cuckoos is their diverse egg morphology, which could have arisen either in response to varying degrees of tolerance shown by different host species or as the result of interspecific and intraspecific egg replacement by female cuckoos. We suggest (a) that the second alternative provides the more convincing explanation with regard to host specialization in cuckoos and (b) that host defences in these essentially one-on-one host/parasite systems may operate as a density-dependent control on cuckoo numbers rather than as a continuing influence on the morphology of the cuckoo egg.