Behavioral Ecology Exam #3

Intrasexual Selection?
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Terms in this set (180)
Intrasexual Selection?
Competition among members of one sex for the opportunity to mate with members of the other sex
Evolutionary psychology?
Theoretical approach to psychology that attempts to explain useful mental and psychological traits, such as memory and perception
Intersexual Selection? Who usually chooses? What helps choose?
Selection by members of one sex of which members of the other sex with whome to mate ("female choice", "mate choice,").
What type of selection best explains the evolution of certain traits? Can both types favor the same raits? Example of traits that come about through intra-sexual selection?
Intra-sexual selection explains better, as traits that develop through intersexual selection are tougher to distinguish. Yes. Example: Long tailed widowbird. - long tail is attractive to females but impractical.
Who do females often preferentially mate with? Why does intersexual selection get more attention than intrasexual selection?
Males with strange exaggerated traits. Essentially showy traits. Intersexual selection results in the evolution of strange traits, leading to the question, "What are females thinking?". It is more complicated. Females often show preference for show males with bright colors and enlarged ornamented traits, like peacock tails. They show preference for vocalizations. These traits may not be good for survival and may not be practical.
Parrot example? WHat does this lead to?
parrots females often mate with males with showy colors, enlarged ornamented traits, coloration, vocalization, other behavior. Like intrasexual selection, leads to evolution of sexual dimporphism.
Can traits favored by mate choice compromise a male's viability? Example?
Vocalizations in tungara frogs, they make calls to attract females, a whirr and a chuck to them. The females really like the chucks, the problem is they are preyed upon bats, who are really good at picking up the chucks. You can whirr all you want, wont get many females, chuck really gets the females going, but chuck gets the bats too.
What is the relationship between intersexual selection and speciation? Example?
- leads to trait divergence among isolated populations, which plays a role in reproductive isolation, ultimately speciation. Noles example with a changing dulap color which separates populations.
What is the direct benefit explanation of female preferences? Examples of direct benefits? How are choices made? Example?
Providing food, nest sites, protection from predators, offspring care - males provide some type of direct benefit to female, whether it be survival or reproduction. She chooses males based on the quality of that service. Female hangingflies prefer males who provide larger prey during mating - Females wont let males mate with them for very long if food item is small, the larger the food item the longer the mating. The duration of copulation correlates linearly with sperm transger, at about 20 minute mark that's maximum sperm transfer, no point in mating any longer, Therefore there is a standard prey size that you want that alows this 20 minute copulation.Lady beetle is best gift for copulation. Male catches fly and uses it as bait for female, advertising it by fanning its wings and releasing perfume from the abdomen.
What are the 2 problems with the direct benefit model?
1. Only works if the male provides a direct benefit, which is not the majority of cases, the males usually just mate and go away.
2. Direct benefits cannot explain the evolution of showy male characteristics. (maybe females choose showy males because they'll be eaten first by predators, but not sound logic, b/c females male children will also be subjected to this fate.)