Predator-naïve fall field crickets respond to the chemical cues of wolf spiders

Few studies have addressed whether terrestrial insects assess predation risk via chemical cues. We exposed predator-naïve fall field crickets ( Gryllus pennsylvanicus Burmeister, 1838) to filter paper containing the chemical cues of three wolf spiders ( Hogna helluo (Walckenaer, 1837), Rabidosa rabida (Walckenaer, 1837), Rabidosa punctulata (Hentz, 1844)), the house cricket ( Acheta domesticus L., 1758,) and blank filter paper. Crickets exhibited greater immobility and reduced speed of movement when exposed to chemical cues of all three spider species. Crickets exhibited reduced speed with increasing mass of R. punctulata, suggesting that larger spiders may pose a greater risk. Cricket response did not differ between cues of H. helluo fed conspecific crickets versus H. helluo fed house crickets, suggesting that crickets cannot distinguish between cues from H. helluo fed phylogenetically similar crickets. Our work nevertheless demonstrates that naïve field crickets respond to chemical cues of several species of wolf spiders.

Male control of copulation duration in a wolf spider (Araneae, Lycosidae)

While a great deal of research has examined mate choice, variation in behavior during copulation can also have important consequences for the fitness of males and females. We examined the relationships between male and female characteristics (age, size and condition) and copulation duration in the wolf spider Hogna helluo (Araneae, Lycosidae). In addition, we used these relationships to test if males control copulation duration. In this species, males mount the dorsal surface of females and females make no visible attempts to terminate mating. Male age was positively related to the duration of copulation. In addition, male condition was negatively related to the duration of copulation such that poor condition males mated for longer durations. If a group of outlier copulations are removed from the analysis, then male age is no longer a predictor of mating duration but male condition becomes an even stronger predictor of mating duration. Males that engaged in long copulations were more likely to be cannibalized following mating. Our data provide support for the hypothesis that males exert the primary influence on copulation duration in H. helluo . Older and poor condition males may engage in longer copulations to increase their paternity with the current female because they may have a lower chance of escaping postcopulatory sexual cannibalism or surviving to find another female.