Host-Race Formation in the Common Cuckoo
Karen Marchetti,
*
Hiroshi Nakamura,
H.
Lisle Gibbs
The exploitation of a new host by a parasite may result in
host-race formation or speciation. A brood parasitic bird, the common
cuckoo, is divided into host races, each characterized by egg mimicry
of different host species. Microsatellite DNA markers were used to
examine cuckoo mating patterns and host usage in an area where a new
host has been recently colonized. Female cuckoos show strong host
preferences, but individual males mate with females that lay in the
nests of different hosts. Female host specialization may lead to the
evolution of sex-linked traits such as egg mimicry, even though gene
flow through the male line prevents completion of the speciation
process.
K. Marchetti and H. L. Gibbs, Department of Biology, McMaster
University, 1280 West Main Street, Hamilton, L8S 4K1 Ontario, Canada.
H. Nakamura, Department of Biology, Faculty of Education, Shinshu
University, Nishinagano, Nagano, 380, Japan.
*
To whom correspondence should be addressed at Department of Biology
0116, University of California, San Diego, La Jolla, CA 92093, USA.
E-mail: Marchet{at}biomail.ucsd.edu
