Mate Choice, sexual selection (Was breasts)

Sun, 24 Sep 1995 13:48:00 CDT

There have been some important developments in theory and experiment on mate
choice, secondary sexual characters, etc. Most of the theory that we have had
on this from Darwin through the Emlen and Oring cited earlier on this list are
based on observations of species (especially mammals) with greatly skewed sex
ratios, intense and focused male-male competition, a winner-take-all paradigm,
with essentially unlimited choices to the winners and little or no choice to the
loosers. Typically, this was based on "lekking" species -- those in which the
males (usually) gather consipucuously in one location (the lek) during mating
season and display or fight or compete somehow for the right to mate with

One of the important things that this leaves out for many species that spend the
whole year in cohesive social groups and with a much more attenuated breeding
season is that various behaviors that occur throughout the year contribute to
the ultimate action that we call "mate choice." In addition, in species (such
as humans and Canada gesse, for example) that tend to form medium-to-long-term
pair bonds, the social structure of the breeding pool limits the available
candidates for a variety of reasons -- including the fact that someone who is
desirable to you has already paired off with someone else and is not about to
switch (at least not yet). And in these pair-bonding species, there tends to be
relatively little sexual dimorphism, so, perhaps the secondary sexual (aka
epigamic) traits receive a lot more attention than they might warrant.

Then, there is a whole literature on deceptive signalling -- how to manipulate
epigamic signals to potential mates that fool them into mating with you when the
might not otherwise.

For more current thinking on these issues, I can recommend the following...

Gomulkiewicz, R. Limited female choice and the evolution of secondary sexual
characters. American Naturalist, 1991; 136(6):1396-1407. For an interesting
discussion of the mechanics of "preference" vs. "choice" as an operator in
situations in which choice was limited in various ways.

Choudhury S, Black JM. Mate-selection behaviour and sampling strategies in
geese. Animal Behaviour 1993; 46(4):747-757. Discussion of various models of
choice (and how females compare male quality) and how quality in potential mates
is measured (BTW 60% of geese paired with the first mate they sampled).

Moller AP. Frequency of female copulations with multiple males and sexual
selection. AMerican Naturalist 1992; 139(5):1089-1101. Discusses mate choice
within the context of "what's left" after another someone choices a mate out of
the pool and how extrinsic conditions may affect choice, despite existing (and
maybe genetically programmed) preferences.

Sullivan MS. Mate choice as an information gathering process under time
constraint: Implications for behaviour and signal design. Animal Behaviour
1994; 47(1):141-151. Also discusses mate choice strategies and talks about the
costs involved in assessing complex signals about mate quality -- especially in
social groups in which taking too long to decide can cost you your preferred
mate (and also how easy it is to fake it when you only have to do it for a short


That's just a beginning, but this is a very active field in animal behavior
right now with interesting research going on in many species. There is a high
concentration of such articles in Animal Behaviour, American Naturalist,
Behavioral Ecology and Sociobiology, to name a few.

Andrew Petto
Dept Anthropology, UWisc
1180 Observatory Dr.
Madison 53706-1393