L13 - Intersexual selection Flashcards
(13 cards)
what is a male ornament
any display or trait has affects probability of mating successfully
what is female mating preference
behaviour, physiology, morphology that interacts with ornament and affects reproductive success
what is a nuptial gift and how does it affect reproductive success
for example spermatophylax which contains nutritions/food items, thus as long as female is “distracted” by gift, the male can transfer more sperm during longer copulation
why does cannibalism (post and pre copulation) occur
nutrition increases chance of offspring survival, males may avoid through being large or having eg larger tufts (jumping spider)
how can parental behaviour increase offspring survival
finches example shows that compatible parents who work better togeher have more offspring that survive
what is the Fisherian runway selection model
females mate with preferred males to produce attractive sons, as they will have a higher reproductive success rate, ornament may or may not be linked to fitness, there is a heritable female preference for said ornament
what is the good genes model
femaes mate with males who have genes that give both daughters and sons a viability advantage
how is exaggeration linked to the Fisherian runway model and how is it regulated
links preferences and the characteristic
genetic correlation produced by linkage desequilibrium, moves ornament over optimal for survival as daughters preference for tail length increases with sons tail, however when survivorship costs turn to be equal to mating benefit, exaggeration halts
what is an example which provides evidence for the fisherian runway model
stalk eyed flies where long eyed females prefer long eyed males, but if “fake” evolution occurs and short females bred out, they will prefer short males
also sandflies where survival is not correlated to attractiveness of father however mating success is
how can good genes be reflected and how is variation maintained
eg long tail costly to produce and may negatively impact survival theso reflects the male has good genes to maintain it, female choice for indicator trait may vary over time and fitness determining trait likely polygenic, mutation also increases variance, host parasite arms race
explain the host parasite arms race
environment where green parasite is most common, being green host (resistant) or female with preference for green host is advantegous, yellow parasite increase inf requency as it spreads to non resistant greens, which increases its frequency - unstable equilibrium
what are the predictions by hamilton and Zuk
parasites decrease fitness, resistance is genetic, resistance may be associated with sexy ornament and females choose males for resistance
what is an example of an indicator for good genes
carotenoids, therefore red and orange colour, show that in fish if female unable to see colour, there is no difference in choice however if able to see, then bright male are preferred, is a idrect benefit
