Some recent issues
In this chapter I discuss five miscellaneous issues on which I believe my opinions to be a minority view among contemporary biologists: the lek paradox, the female pheromone fallacy, Schreckstoff, the helpful stress effect, and abuses of the species concept. My model for this and the final two chapters is Darwin's ( 1859) Chapter 6 (' Difficulties of the Theory') and Chapter 7 (' Miscellaneous Objections to the Theory of Natural Selection'). With hindsight we can see that Darwin's chapters successfully surmounted most of the difficulties and answered most of the objections. I expect no comparable success, but hope that I can at least convince some others that evolutionary biology today, no less than in Darwin's time, faces some serious anomalies and conceptual challenges.
Discussions of sexual selection have proliferated in recent years, along with a growth of awareness of its importance. A useful review and initiation into the spirit of current debates is found in Bradbury and Andersson ( 1987). One of the controversies is on the evolutionary basis of mate choice by females in species with males that make no contribution to the rearing of offspring. A clear example is seen in birds in which males form leks, localized groups where they compete with each other for positions of dominance. Females arrive singly at leks and are courted by the males, with highly variable success. Often one of the males of a dozen or more will win the acceptance of most of the females, and one or two other males will get almost all the rest ( Bradbury et al. 1985). For most males the mating effort will be entirely fruitless. Females once mated return to their own individual nesting sites. There are good recent reviews of the lek phenomenon by Bradbury and Gibson ( 1983), Gibson and Bradbury ( 1986), and McDonald ( 1989).
The most challenging aspect of lek mating systems is female behavior,