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THE EVOLUTION OF SPERM SIZE IN BIRDS
TLDR
It is suggested that future models of sperm‐size evolution consider not only the role of sperm competition, but also how female control and manipulation of ejaculates after insemination selects for different sperm morphologies.
BEHAVIORAL DEFENSES AGAINST AVIAN BROOD PARASITISM IN SYMPATRIC AND ALLOPATRIC HOST POPULATIONS
TLDR
Results support the hypothesis that recognition of cowbirds and their eggs evolved as adaptations to counter cowbird parasitism and not some other selection pressure, and the expression of anti‐parasite defenses by some individuals within allopatric populations further suggests these traits may be controlled genetically but persist in such areas.
Begging intensity of nestling birds varies with sibling relatedness
TLDR
It is shown that the loudness of nestling begging calls increases as the relatedness amongst the members of a brood declines, suggesting that increased intensity of begging can evolve whenever female promiscuity or brood parasitism lowers the coefficient of relatedness among nestmates.
Male sperm reserves and copulation frequency in birds
TLDR
Results suggest that where sperm competition is intense, a large cloacal protuberance is required to maintain a large sperm reserve for a high copulation rate.
Sexual selection and the intromittent organ of birds
TLDR
It is suggested that male IOs may have largely disappeared in birds because of female preference for males without IOs (Female Choice Hypothesis), thereby allowing females more control over fertilisation and the small number of independent evolutionary losses of IOs in birds precludes rigorous statistical tests of these hypotheses.
Sperm size and sperm competition in birds
TLDR
It is concluded that sperm competition influences sperm size in birds and detailed study of this interaction will provide a new dimension to the study of avian mating systems.
Inbreeding and endangered species management: is New Zealand out of step with the rest of the world?
TLDR
Results from recent field studies in New Zealand indicate that, despite the opportunity for purging, inbreeding depression is evident in many threatened species, and it is advocated that genetic considerations be better integrated into recovery plans.
Extra-pair paternity, sperm competition and the evolution of testis size in birds
TLDR
It is demonstrated that testis mass is related positively to the level of extra-pair paternity, after controlling for body size and phylogeny, and it is argued that selection has favoured increased testismass in situations of more intense sperm competition in order to retaliate against copulations by rival males.
Nest predation and the evolution of nestling begging calls
TLDR
The relationship between call structure and the risk of predation supports the hypothesis that attracting predators is a direct cost of begging and that such costs can constrain any evolutionary escalation in the intensity of nestling begging.
Introduced Mammalian Predators Induce Behavioural Changes in Parental Care in an Endemic New Zealand Bird
TLDR
Parents of endemic New Zealand bellbirds found that females spent more time on the nest per incubating bout with increased risk of predation, a strategy that minimised activity at the nest during incubation, and parental activity during the nestling period decreased.
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