Transcript Chapter 12 Mating systems and parental care

• Today
– Review paper
assignment
– Web of Science
tutorial
– Meeting signup
sheet
– Quiz
– Mating systems
• Thursday
– Louise Barrett leads
discussion on Engh et
al. 2002
• Friday
– No office hours
• Next Tuesday
– Lecture on chapter 14
– Quiz on chapter 12,
reading
• “Unrestricted”
– No enduring relationship
– Female biased investment
• Evolves when mates are
highly dispersed…
– Gastropods
• … in explosive mating
systems
– Horseshoe crabs
• …and in some social
animals
– Pseudo-promiscuous primates
http://www.lanting.com/images/prod
ucts/fineprints_lrg/DP-213.jpg
• The system
• Females choose
• High mating skew
– 6% of male hammerheaded bats get 80%
of matings
• Birds, bats and
antelope
– Females / resources
are indefensible
• Insect mating swarms
http://www.animalpicturesarchive.com/ArchOLD3/1112851279.jpg
• Benefits to males
– Antipredation
– More females
• Benefits to females
– Mate copying
– Comparisons
• Where to lek?
– Hotspots
– Hotshots
• In marine iguanas
– Black holes
From Partecke et al. 2001 BES 51:579-587
• Some males
breeds with
several females,
each of which
breeds with only
one male
– Simultaneous
– Sequential
• High reproductive
variance for males
http://z.about.com/d/animals/1/0/l/
W/RW-BB-4917_2.jpg
• Concentrated resources
draw females
– In Uta palmeri
http://isu.indstate.edu/~dhews/Utapalmeri.gif
From Hews 1993 Anim. Behav. 46:279-291
Harem defense
polygyny
• Females gather
for protection,
hunting, etc.
• Males monopolize
females
– Lions
• Female groups,
male coalitions
• Infanticide
• Reverse polygyny
– Some insects fish
and birds
• When males are
the limiting sex?
• In jaçana
– Dimorphism
– Infanticide
• In seahorses
Cooperative polyandry
• Multiple males mate w/ one female
• Coalitions defend a rare resource
• In Galapagos hawks
Monogamy
• One male
bonded to one
female
• Rare, but widely
distributed
– 90% of birds
• Social / genetic
• Default below the polygyny
threshold
• Necessity of paternal care
• Defendable, distributed
resources
• Synchronous breeding
• Female-female aggression
• PC increases
offspring fitness
• Depreciative
• Non-depreciative
• Parental
investment
benefits offspring
at parent’s
expense
http://www.pbase.com/jlima/imag
e/60123030
• Tradeoffs
• Investment
• Predation risk
– In tropical and
temperate birds
• Parent’s age
– In Mongolian
gerbils
From Ghalambor & Martin 2001 Science 292:494-497
• Internally fertilizing ectotherms
– Single parents are usually female
• Externally fertilizing ectotherms
– Single parents are usually male
• Homeotherms
• Allocating care in biparental species
– Compensation
– In response to mate’s attractiveness
• Trivers’
model
• Honest
begging?
• Siblicide
– In herons