Monopolization in a resource queue: water striders competing for food and mates.

摘要

Twelve groups of male Aquarius remigis were used to: (1) test the general prediction that monopolization of both food and mates decreases as the temporal clumping of resources increases, (2) compare the efficiency of two indices of resource monopolization, coefficient of variation and Q (Ruzzante et al. 1996), and (3) quantitatively assess the resource queue model of Blanckenhorn and Caraco (1992). Each group of 6 males competed for both food items and mates released from the upstream end of a laboratory stream. The mean inter-arrival time for resource units (food or females) was 10 min, with 4 levels of temporal clumping (variance in inter-arrival time: 0, 25, 50 or 320 min2). As predicted, the monopolization of both food and mates decreased as the temporal clumping of resource arrival increased, although monopolization was greater for food than for mates. Q detected the difference in monopolization of food and mates, whereas the coefficient of variation did not, because Q is independent of meanresource abundance. The resource queue model successfully predicted monopolization of both resource types, explaining 89% and 76% of variation in the proportion of food and mates acquired by the 6 males. The success of the model suggests that the scaling of handling time to the variance in resource inter-arrival time should play an important role in any general theory of resource monopolization.