TAXONOMIC SIGNIFICANCE OF HOST-EGG MIMICRY BY FACULTATIVE BROOD PARASITES OF THE AVIAN GENUS COCCYZUS (CUCULIDAE)

Authors
Citation
Jm. Hughes, TAXONOMIC SIGNIFICANCE OF HOST-EGG MIMICRY BY FACULTATIVE BROOD PARASITES OF THE AVIAN GENUS COCCYZUS (CUCULIDAE), Canadian journal of zoology, 75(9), 1997, pp. 1380-1386
Citations number
83
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Zoology
Journal title
ISSN journal
0008-4301
Volume
75
Issue
9
Year of publication
1997
Pages
1380 - 1386
Database
ISI
SICI code
0008-4301(1997)75:9<1380:TSOHMB>2.0.ZU;2-4
Abstract
Black-billed (Coccyzus erythropthalmus) and Yellow-billed (C. american us) cuckoos are facultative brood parasites that occasionally lay thei r eggs in the nests of 10 and 11 other bird species, respectively. Thi s study demonstrates that both cuckoo species produce blue-green eggs that fully or nearly match the eggs of over 70% of their reported host species, a proportion significantly greater than if hosts were being selected at random from the potential host pool. These results suggest that the cuckoos may be selecting hosts on the basis of their egg col our, and support a hypothesis of egg mimicry. Since egg mimicry is unl ikely to evolve in a facultative parasite, its existence in Coccyzus w ould imply a historically intense relationship between these birds and their hosts. This hypothesis is corroborated by recent phylogenetic a nalyses which suggest that the ancestral Coccyzus was an obligate para site. Factors responsible for the loss of obligate parasitism in this genus may also have contributed to the general paucity of obligate par asitism in New World cuckoos. Competitive exclusion or resistance to i nvasion by parasitic cowbirds (Molothrus spp.) should be considered.