The theory of sexual selection

The inheritance of pheromone production in the sulphur butterflies Colias eurytheme and C. Philodice

“…Behavioral evidence that intraspecific pheromone variation is great enough to make possible individual recognition exists for several species (Barrows et al, 1975;Leonard and Ehrman, 1976). The results presented here support conclusions reached by theoretical analyses (Alexander, 1962;O'Donald, 1962) that species-specific (and presumably invariable) features of communication systems should be inherited as blocks of co-adapted gene complexes or supergenes. Conversely, the results of Averhoff and Richardson (1976) indicate that the loci affecting intraspecific variation in these systems are distributed throughout the genome and inherited independently.…”

Mate selection—A selection for a handicap

“…The conservation of food supply for the population may be a side effect rather than the causal mechanism which selects for territory size. O'Donald (1963) already suggested that sexual selection may be involved in territorial behaviour but he understood somewhat differently the selective mechanism involved.…”

“…As a consequence (if natural selection allows) one would expect also the evolution of markers for the differentiation of quality in individuals. O'Donald (1963) suggested that altruistic behaviour may function as a marker for quality and that it is selected for through mate preference. Unfortunately that idea has not been followed, perhaps because it was believed that the evolution of exaggerations (handicaps), through mate preference, is only a by-product of a "run-away" process (Fisher, 1930;O'Donald, 1962).…”

“…O'Donald (1963) suggested that altruistic behaviour may function as a marker for quality and that it is selected for through mate preference. Unfortunately that idea has not been followed, perhaps because it was believed that the evolution of exaggerations (handicaps), through mate preference, is only a by-product of a "run-away" process (Fisher, 1930;O'Donald, 1962). When the handicap caused by mate preference is considered as the key to the selection process rather than its byproduct (Fig.…”

Sexual selection and the evolution of preferential mating in ladybirds I. Selection for high and low lines of female preference

“…But as the preference becomes more common, it may become the main selective force. The dynamics of the process of the joint selection of preferred character and preference are very complex (O'Donald, 1962;1980;Lande, 1981;Kirkpatrick 1982), particularly when females have preferences for more than one male phenotype (O'Donald, 1980). Kirkpatrick has suggested that the initial preference might be the incidental effect of some other aspect of behaviour.…”