Brood parasitism: Langmore et al 2003 Flashcards
paper:
escalation of a coevolutionary arms race through host rejection of brood parasitic young
cuckoo nestling thats evict all other young form the nest soon after hatching impose a high
reproductive cost on their hosts
defences used by fairy wrens are easily evaded by
Horsfields bronze cuckoo
results:
hosts never deserted their own broods, they later deserted 40% of nests containing a lone Horsfields bronze cuckoo nestling and 100% of nests with a lone shining bronze cuckoo nestling
horsfields bronze cuckoo
- australian brood parasite
- lays a white egg covered with fine red-brown speckling (mimic fairy wren)
- cuckoo evicts host young once hatched
fairy wrens response to egg depended on time of laying
- cuckoo eggs laid before host laid = sewn into nest lining
- those laid during host laying period = accepted
- egg added after host began incubation = accepted
desertion was more likely when
cuckoo spotted at nest during incubation, egg itself didn’t facility desertion
fairy wrens discriminated against foreign eggs only in relation to their
size (larger)
- dim environment promoted tactile over visual identification
point reached in this coevolutionary arms race between host and parasite
- discrimination against cuckoo eggs
- fairy wrens found deserting nests of hors fields bronze cuckoos but never their own young
- 3-6 days old female desert
- male may continue to feed but eventually young dies
- recognise simply because hteyre alone in the nest
shining bronze cuckoo >/< desertion than horsifeld bronze cuckoo
MORE different begging call
Great reed warbler different to fairy wrens how
GRW imprint on first clutch, FW don’t
desertion for fairy wren all bad?
no as 3 broods per year, can go on to breed again that year, smaller costs
