Transcript Mating Systems powerpoint

Avian Mating Systems
Table 13-1
Monogamy 90%
Polygamy
Polygyny 2%
Resource defense
Female defense
Male-dominance
Polyandry 1%
Polygynandry 1%
Promiscuity 6%
Behavioral Monogamy - most prevalent
What leads to different strategies?
Why Monogamy?
But extra pair copulations common in many behavioral monogamous birds
EPC’s vs EPF’s
Why?
Direct
Genetic
Polygyny – Resource –defense
-
Redwinged blackbirds
Inter vs. intra sexual selection
Nice territory!
Look at those
epaulets!
Orians’ Polygyny Threshold Model
Polygyny –
Female defense (Harem) – Grackles
Wild Turkeys – winter flock
-sibling males and
harems of 4 -7 females
Polygyny – Male hierarchy
“lekking”
Open area grouse - Sage grouse,
prairie chickens , manakins
Polyandry
Sequential – phalaropes
Simultaneous – spotted sandpiper and jacanas
Promiscuity
Forest grouse are solitary
Ruffed Grouse, Blue grouse
Hummingbirds
The Ruff and multiple mating male strategies
Satellite:
Heterozygous
Non territorial
Longer lived
11% copulations
Territorial
Homozygous recessive
Territorial
Shorter-lived
89% of copulations if with a sattellite
What leads to different strategies?
Polygyny / Promiscuity and lekking?
OSR
Hot spots
Hot shots
Female preference
Polyandry?
OSR
Clutch Size Limitations?
Increasing variance in reproductive success
leads to increased sexual selection
Promiscuity > Polygyny = Polyandry (reversed SD) > Monogamy
100
% of males
contributing
genes
0
Species
Convergence (sort of) in African widowbirds
Shabby epaulets!
Run-away selection –
Based on female preference
linked to male trait
What a tail!!
Sexual selection can lead to ever more elaborate displays
in plumage
Hummingbirds Neotropical and Nearctic
Birds of Paradise - Australasia
In some cases, both sexes display ornament, though males’ may be larger
Black-billed
Magpie
Scissor-tailed Flycatcher
Hypotheses about sexual selection for these traits?