Abstract
A progressive decline in a male's propensity to mate with the same female, combined with a heightened sexual interest in new females, is known as the Coolidge effect. The Coolidge effect has been reported in a number of taxa and is thought to be adaptive, as males distribute sperm evenly across multiple females thereby maximising fitness. Here we looked for the Coolidge effect in the Australian field cricket, Teleogryllus oceanicus (Le Guillou). We found that males did not show greater sexual interest in novel females compared with their previous mates. Moreover, we did not find any decline in the quality of ejaculates transferred by males when mating sequentially with the same female, or an increase in ejaculate quality when males were presented with novel females. Our results are in contrast with findings investigating the Coolidge effect in other insects, which may reflect differences among species in the fitness benefits associated with mating repeatedly with the same female. We argue that examinations of the Coolidge effect need to be incorporated routinely into studies that examine the benefits of polyandry for females, because of the potential impact of reduced ejaculate expenditure by males in monandrous treatments.
