Leks
• Hotspot
• Female preference
– Male aggregations
– Hotshots
• Kin selection
• The lek paradox
Leks
•
•
•
•
Swedish for mating arena
No male parental care
No resource on territory
Males aggregate and
display at traditional sites
Leks occur when females are not defensible
Leks ->
antelope
grouse & ptarmigan
Males defend tiny territories on a lek
Bat video
Male mating success on leks
Sage grouse video
Lekking and frugivory in birds
Lek
Exploded lek
Territory
New World
lekking birds
QuickTime™ and a
H.263 decom pressor
are needed to see this picture.
Cock-of-the-rock
Manakins
Bell birds
Hypotheses for male clustering
• Hotspot
– males aggregate to maximize female encounter rate
• Female preference
– Females prefer to select mates in aggregations
– Females prefer central male
– Females prefer attractive male (hotshot) and other
males aggregate around him
• Kin selection
– Males aggregate around relatives
The hotspot model
Leks of leks suggest hotspots
Hermit hummingbird
Ochre-bellied flycatcher
Red-capped manakin
Blue-crowned manakin
Sage grouse leks and
hotspots
Lek location
Female nest density
Possible reasons for female preference to
mate at a lek
• Reduce predation
Best-of-n
expectation
– No evidence in sage grouse
– Reduce mate searching costs
– But, assuming male quality is
normally distributed, advantage of
choosing best male is greatest in
small, not large, leks
– Can copy choice of others
Std dev units
• More efficient comparison of
males
Number of males
Mate choice copying in sage grouse
Green = observed, orange = predicted w/out copying
Mate choice copying simulations
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. 2000 Nature 408:352-353
Also in peacock, black grouse, satin
bowerbirds, wild turkeys
The lek paradox
• In lekking species, males only pass sperm.
Therefore, only indirect benefits are possible.
• If males differ in genetic quality, then females
should always prefer the male of highest
quality.
• Over time, such intense selection will deplete
and possibly eliminate genetic variation.
• What then do females gain by choosing?
Solution to the lek paradox
• Genetic variation must persist for
ornamental traits and genetic quality
• Ornament expression depends on condition.
– Only males in good condition are able to fully
express ornament
– Condition is likely influenced by many genes.
Consequently, deleterious mutations constantly
replenish genetic variation.
Sage grouse condition and display