Male courtship vigour: a cause or consequence of female receptivity?

There are many published studies in which females show greater receptivity in the presence of males having vigorous courtship. Such studies typically take this as evidence of female preference for vigorous males and speculate about benefits accruing to females with such preferences. However, an obvious and equally parsimonious alternative has received little attention. Perhaps males are all similar to each other in capacity for vigorous courtship but simply tailor their courtship vigour to match the apparent receptivity of each female encountered. In trials with each male and each female used only once, it is not possible to discriminate between these possibilities. We here report on trials in which each male and female wolf spider was used in multiple trials to determine whether males vary in characteristic courtship vigour, whether females vary in characteristic receptivity, whether male courtship vigour varies with female encountered and whether female receptivity varies with male encountered. Such an approach allows us to derive evidentiary correlation that help to elucidate whether male courtship vigour is a cause or consequence of female receptivity.