PLANT AND ANIMAL SCIENCES
BY FRANCISCO J. AYALA
Department of Ecology and Evolutionary Biology
University of California, Irvine
" The cuckoo Cuculus canorus parasitizes a variety of hosts, but particular strains favor just one species and lay eggs colored to match those of their particular host. Host discrimination against badly matching eggs is the selective force. Cuckoos lay a better mimetic egg whenever the host species is more discriminating.
M. de L Brooke, N.B. Davies, Egg mimicry by cuckoos Cuculus canorus in relation to discrimination by hosts,” Nature, 335 (6191), 630-2, 13 October 1988.
" Large Drosophila subobscura males carry bigger drops of regurgitated food during courtship and have greater courtship success with starved females than do small males. However, if males are prevented from producing a drop, small males have greater success because they are better at tracking the female during the courtship dance: They take...