Territoriality and Reproductive Tradeoffs in the Threespine Stickleback, Gasterosteus Aculeatus

Abstract

To examine the reproductive costs of territoriality, male threespine sticklebacks were divided into two treatments: competitive and solitary. Relative to solitary males, competitive males had longer and fewer brood cycles, higher rates of energy expenditure per brood cycle, higher motivation to court additional females in the first brood cycle, and lower amounts of parental care during the first brood cycle. Thus territoriality in this species seems to effect the tradeoff between present versus future reproduction, and within present reproduction, the tradeoff between quantity versus quality of offspring.