Mating systems II Sexual conflict Leks –Hotspot –Female preference Male aggregations Hotshots –Kin selection

Sexual conflict expectations Environment quality alters relative and absolute ranking of each mating system for each sex

Sexual conflict in marmots

Sexual conflicts in dunnock

Females solicit male dunnocks to keep them on territories

Resource addition alters mating system of dunnock

Swedish for mating arena No male parental care No resource on territory Males aggregate and display at traditional sites Male mating success is highly skewed Leks

Males defend tiny territories on a lek

Male mating success on leks is skewed

Leks occur when females are not defensible Leks ->

Lekking is often associated with frugivory in birds Lek Exploded lek Territory

New World lekking birds ManakinsBell birds Cock-of-the-rock

Hypotheses for male clustering Hotspot –males aggregate to maximize female encounter rate Female preference –females prefer to select mates in aggregations –males aggregate around most attractive male (hotshot) Expect center male to have highest mating success Kin selection –Males aggregate around relatives

The hotspot model

Leks of leks suggest hotspots Ochre-bellied flycatcher Red-capped manakin Blue-crowned manakin Hermit hummingbird

Sage grouse leks are at hotspots Lek location Female nest density

Possible reasons for female preference to mate at a lek Reduce predation –No evidence in sage grouse Reduce mate searching costs More efficient comparison of males –But largest gain occurs at small n –Can copy choice of others

Do leks recruit more females/male in kob? No!

Do leks recruit more females/male in ruff? Sometimes!

Are black grouse hotshots? Yearly shift suggests male attractiveness, not position, is important

Related manakins on leks Shorey et al Nature 408: Also in peacock, black grouse, satin bowerbirds, wild turkeys

The lek paradox If intense selection depletes genetic variation, what will females gain by choosing? Genetic variation must persist for traits Condition dependent traits differentially advertise genetic variation for condition, which is likely to be influenced by many genes