Monday, December 10, 2007 - 10:41 AM

Male cricket aggression and diet-based spider cues: Crickets fight over black widow silk (Latrodectus hesperus)

Leslie J. Buena, and Sean E. Walker, California State University, Fullerton, Department of Biological Science, 800 N. State College Blvd, Fullerton, CA

Male crickets defend or obtain resources by engaging in aggression that may cause males to be conspicuous and vulnerable to predators. Crickets may reduce aggression amounts to limit predation risk. We hypothesized that perceived risk will influence male aggression in house crickets, Acheta domesticus. Paired males were observed under varied degrees of perceived risk and potential benefit. Risk was manipulated by adding spider silk from Agelenopsis aperta or Latrodectus hesperus fed crickets. Benefits were manipulated by adding cues from three virgin, female crickets. There were significantly less encounters in the A. aperta than the no spider cue treatments, with intermediate amounts in the L. hesperus treatment. Resident males showed no difference in response when presented female cues, no cues, or A. aperta silk. However, residents showed significantly more aggression and won more in the presence of L. hesperus silk than any other treatment. Additional observations were made using silk from L. hesperus fed mealworms (Tenebrio molitor) to test if silk cues may be diet based. Crickets showed significantly less aggression and won fewer contests in this treatment than treatments of cricket-diet-L. hesperus silk. Aggression results suggest that crickets do not use these spider cues for predation warnings, but silk may have an effect on movement activity. It appears that black widows may embed cues from their prey into the silk. This result suggests a novel diet-based mechanism by which certain web-building spiders might increase the attractiveness of their webs and have higher prey capture.

Species 1: Orthoptera Gryllidae Acheta domesticus (house cricket)
Species 2: Araneae Theridiidae Latrodectus hesperus (western black widow)
Species 3: Araneae Agelenidae Agelenopsis aperta (funnel web spider)