Brood parasitism and egg recognition in three bunting hosts of the cuckoos.

ABSTRACT

Comparative studies of egg recognition and rejection between various sympatric hosts provide insight into the coevolutionary history of the hosts and parasites, as well as the degree of antagonism between the species. Although buntings are widely considered to be a suitable host taxon for cuckoos, there has been relatively little research on this example of parasitism and host antiparasitic behaviour. Here we provided the first report on brood parasitism and egg recognition in three sympatric ground-nesting bunting hosts of the common cuckoo (Cuculus canorus), namely the yellow-throated bunting (Emberiza elegans), south rock bunting (E. yunnanensis), and crested bunting (E. lathami). The results show that for the five breeding seasons during 2018-2022, the parasitism rate by common cuckoos was 0.87% and 0.45% in yellow-throated buntings and south rock buntings, respectively, whereas the parasitism rate by an unidentified parasite was 4% during 2018-2023 in the crested bunting. The rejection rates of the three bunting hosts for blue non-mimetic eggs were 89.3%, 88.9%, and 100% for yellow-throated buntings, south rock buntings, and crested buntings, respectively. The rejection rates for red non-mimetic eggs by yellow-throated buntings and south rock buntings were lower at 76.9% and 82.4%, respectively. All three sympatric bunting hosts examined had high levels of egg recognition and egg rejection, suggesting that it may have been subjected to high parasitic history and that egg recognition ability was retained after the loss of parasitism, which needs to be further verified by future experiments.