When perfection isn’t enough
How fork-tailed drongo egg signatures defend against near-perfect African cuckoo mimicry
Parental care is costly, but avian brood parasites get around this by laying their eggs in the nests of a different bird species – their ‘host’. The host then bears the burden of raising the parasitic chick, often to the detriment of its own offspring. But hosts can fight back by rejecting (i.e. removing from their nests) cuckoo eggs that look dissimilar to their own eggs. This behaviour leads to cuckoos evolving eggs that mimic host eggs in colour and pattern. But what happens when a cuckoo’s egg evolves to be a perfect match for the host eggs?
The African Cuckoo is a brood parasite that mimics the eggs of its host, the Fork-tailed Drongo, with remarkable accuracy. In her talk, Jess will explore the concept of perfect mimicry, focussing on the evidence for perfect mimicry in the African Cuckoo and Fork-tailed Drongo system, how drongos can fight back against a perfect mimic, and what this means for the future of the system. She will also compare the African Cuckoo and Fork-tailed Drongo system to other brood parasites and their hosts, and discuss the role that genetics play in restricting or facilitating perfect mimicry.