Meeting Abstract

40.1  Sunday, Jan. 5 08:00  When is sexual selection not sexual selection? Surprisingly often … PADIAN, K.; Univ. of California, Berkeley kpadian@berkeley.edu

Darwin invented the concept of sexual selection in order to explain sexual dimorphism, notably those unusual structures (usually in males) that did not conceivably contribute to the individual’s success in its environment, but were used to attract mates or repel rivals for mates. Therefore sexual dimorphism was at the heart of Darwin’s concept, which he documented fulsomely in The Descent of Man, and Selection in Relation to Sex. This concept has been bowdlerized in recent years because biologists have mistakenly thought that sexual selection, like (also incorrectly) natural selection, is just a matter of leaving more offspring in the next generation. This neo-Darwinian concept of fitness has made us look the wrong way at different types of selection. Focusing only on number of offspring, many biologists have come to think that sexual dimorphism (in structure, function, or behavior) is not necessary for sexual selection. Some have even maintained that sexual selection is “a form of” natural selection, but Darwin wrote two large books to distinguish them, and the two types of selection often work in opposition. A hierarchy of concepts related to intraspecific interactions, comprising (successively) species recognition, social selection, mate recognition, mate choice and preference, mate competition, and sexual selection better explains how animals interact. It also relieves much of the confusion in the current literature regarding the terminology and definitions of social interactions and mechanisms. Many very interesting studies that claim to be investigating sexual selection are really investigating other intraspecific interactions. The term “mutual sexual selection” is an oxymoron; “mutual mate choice” is more apt. Species recognition is often a more likely explanation for “bizarre structures” (and others) that do not differ between males and females, and it is probably more important in evolution than usually thought.