Flashcards in special reading - post copulation sexual selection - 1 - multiple mating and genetically loaded sperm competition in gouldian finch Deck (7)
what is the question of the experiment?
what is the benefit of extra pair copulation to gouldian finches
what is the hypothesis?
females take part in EPCs to ensure comparable mates therefore increasing chance of offspring reaching adulthood
what is the aim?
to understand pre and post copulatory selection for extra pair mates in gouldian finches
what are the methods?
- had a population of gouldian finches - half compatible and half incompatible - then separated the pairs and placed a virgin male either incompatible or compatible with the female for 60 mins
- wanted to see if females in an incompatible pair were more likely to engage in EPCs with compatible mates - used the other treatments as controls
- experimental design provided a predicted adaptive context, a maladaptive context, and two selectively neutral situations
what were the results?
despite morph mate preferences in selection against mix morph mating females across all experimental contexts were equally likely to engage in EPCs - 31/40
all successful copulations were preceded by active female solicitation
new males sexually displayed to females in 95% of trials - indiscriminate of colour morphs
what was the outcome of sperm competition?
- the females can store sperm from the males for a while so postcopulatory sexual selection Is important
- as predicted the 31 successful EPCs resulted in a disproportionate number of fertilised offspring among broods
- furthermore more offspring per brood were fathered by the Extra pair male in the adaptive context i.e compatible
- females in incompatible pairs that partook in EPCs with compatible pairs had a 40% increase in offspring