Persons, Kelsey, Ecology Program, Susquehanna University, 514 University Avenue, Selinsgrove, PA, 17870, 26personskelsey@seal-pa.org; Persons, Matthew, H., Ecology Program, Susquehanna University, 514 University Avenue, Selinsgrove, PA, 17870, persons@susqu.edu.
Dolomedes triton is a semi-aquatic spider that deposits hydrophobic silk across the water surface. Female silk attracts males but could also act as a trip-line to increase prey detection or function as an aquatic web. Alternatively, neustonic silk may alert prey to the predator’s presence. The whirligig beetle, Dineutus assimilis, swims across surface water and may encounter fishing spider silk. We measured space use of beetle pairs in the presence or absence of male or female silk. We also compared silk quantity deposited by male vs. female spiders. In a second experiment, we measured beetle pair survival with live male or female spiders with or without their silk. Females deposited significantly more silk on the water surface and showed significantly higher predation than males. Female silk also decreased prey capture time by female spiders. Beetles avoided silk-laden areas and showed no avoidance difference between male and female silk, but their silk-mediated behaviors only increased spider predation. Our results suggest a trip-line function for silk that enhances prey detection, but mostly with female spiders. Fishing spider silk may mediate neustonic arthropod trophic interactions.
enemy-avoidance kairomone, neustonic, spider, beetle