Patterns of Silk and Excreta Deposition in the Wolf Spider Hogna helluo
We measured the context and pattern of silk and excreta deposition in the wolf spider Hogna helluo. Hogna were allowed to move freely for four hours on individual grid-bearing 80 mm dia. paper disks. We then quantified dragline silk coverage, attachment disks and excreta deposited on each sheet. We compared differences in silk and excreta deposition as a function of time, sex, developmental status, clutch, female reproductive status (virgin and mated), female diet (cannibalistic/not), and the presence or absence of chemical cues from crickets (Acheta domesticus). Silk deposition (both dragline and attachment disks) was highly variable and did not differ significantly by clutch among juvenile spiders. Dragline silk production increased significantly among mature females compared to various juvenile stages (early, mid and penultimate instars) and adult males. Surprisingly, we found no significant reduction in dragline deposition among females after mating suggesting either another function independent of mating, or that female Hogna may continue to advertise to acquire multiple mates. We found no significant difference in dragline or attachment disk deposition among cannibals and non-cannibals. Excreta deposition was highly controlled and context specific, significantly increasing in the presence of chemical cues from house crickets. Attachment disks were produced similarly by all developmental stages and both sexes. Adult females significantly decreased attachment disk production in the presence of prey cues. Since prey of wolf spiders use silk information as an early warning for the presence of predators, reduced silk production may increase foraging effectiveness and mitigate antipredator responses in prey.
SILK DRAGLINE DEPOSITION AND CONSPECIFIC COMMUNICATION IN THE WOLF SPIDER HOGNA HELLUO.
Spiders produce silk threads (draglines) as they move through the environment. Adult female draglines are known to convey information to adult male spiders about the maturity and mating status of females, but whether or not females vary the quantity or quality of the draglines in the presence of males remains unknown. Furthermore the dragline function among males remains unknown. We tested the function of dragline silk in intersexual communication among adult males and adult females of the wolf spider, Hogna helluo. We placed adult male and female H. helluo on grid-bearing 80 mm dia. paper disks for four hours within transparent plastic containers. Spiders were then allowed to observe a conspecific adult female, adult male, juvenile, or no spider through the transparent container. We then quantified the amount, type, and pattern of silk and excreta deposition for each spider on the grids. Preliminary results suggest that male silk deposition patterns remained unchanged in the presence of conspecific spiders, however there was a non-significant trend toward increased deposition of attachment disk silk in the presence of mature females and mature males compared to juveniles and the blank control. Fine gauge silk deposition occurs almost exclusively among mature females suggesting a sex-specific function of this silk type.
