SR 6/7: Pryke 2010- female multiple mating and sperm competition Flashcards
what did the study show that female participation in extra pair copulations and sperm competition enables?
enables female finches to target genes that are optimally compatible with their own to ensure fertility and optimise offspring viability
what did the study show about the function of female infidelity?
adaptive
in socially monogamous systems what is optimal female choice limited by?
the number of high quality compatible partners available
what do extra pair copulations allow females to avoid?
fitness costs of genetically incompatible partners
what was the study species?
Gouldian finch (E.gouldiae)
where does genetic incompatibility occur, what is it controlled by and what % greater offspring mortality rates does it result in
- interbreeding between different head colour morphs/genotypes
- head colour determined by Z-linked gene
- 60%
what genetic makeup can M and F have?
M: homozygous ZrZr=black or heterozygous ZRZr=red
F: hemizygous Zr=black
who do the finches prefer to breed with?
their own morph type
what % of wild bird breeding pairs are mixed morph?
30%
how long was the virgin male placed with female?
60 min
what were the 3 situations/contexts?
- adaptive context
- maladaptive context
- neutral
what was the adaptive context?
incompatible partner, compatible extra pair partner
what was the maladaptive context?
compatible partner, incompatible extra pair partner
what was the neutral situation?
both partners either compatible or incompatible
which females were likely to engage in extra pair behaviour?
females across all contexts despite head colour or compatibility
what % females copulated with an extra pair male
77.5%
what is considered copulation?
cloacal contact
in what situations did females never copulate?
when forced
how may females be bearing a cost from the investment into extra pair copulations?
mate with incompatible males as cant distinguish homozygous compatible red males from heterozygous incompatible ones
in the adaptive context which males fathered more offspring per brood?
extra pair males
what can bias the outcome of fertilisation?
genetic compatibility
when are offspring more likely to survive?
when both parents are compatible
what is needed to account for to understand the evolution of female polyandry?
account for both pre and post copulatory processes
what cant the extra pair male fertilise?
the first and second egg that is fertilised by the social male partner
what is sperm competition limited to between social and extra pair males?
1-7 potential eggs
which males had more fertilisation success?
extra pair males
did males discriminate between incompatible and compatible males?
no
why may extra pair males have greater post copulatory success?
different ejaculate size to social males
what % increase in offspring survival did extra pair copulations result in?
38.9%
what did females do in incompatible social pairings after participating in extra pair copulations?
copulated with their partner less
what does female participation in extra pair copulation increase and what is a disadvantage?
the number of eggs she produces
- bears the cost of the investment
in what context were there significantly more extra pair offspring?
adaptive
