Abstract:

Female Pardosa milvina wolf spiders carry large eggsacs. We quantified the effects of carrying eggsacs on foraging success and susceptibility to predation. In addition to monitoring individuals carrying natural eggsacs, we induced females to carry artificial eggsacs of varying mass. We determined the propensity of females to attach eggsacs or plastic beads of various sizes. We then quantified prey capture success and the avoidance of the predatory wolf spider, Hogna helluo, for Pardosa with and without eggsacs or plastic beads attached. Females attached their own eggsacs significantly more than plastic beads of equal mass and attached artificial eggsacs 10 times larger than natural eggsacs significantly less often than smaller plastic beads (ones equal to or 2.7 times the size of natural eggsacs). Females carrying real or artificial eggsacs of any mass captured fewer prey, but prey capture success did not vary among females with different-sized eggsacs. Except females of the 10 × eggsac treatment, individuals carrying an eggsac suffered significantly greater predation compared to females without eggsacs. Eggsac transport carries significant predation and foraging costs, but we found little evidence that carrying heavier eggsacs incur incrementally greater increases in predation risk or decreased foraging efficiency than carrying lighter eggsacs.

Keywords: REPRODUCTIVE COSTS; FORAGE; PREY; LYCOSIDAE; EGG CASE

Document Type: Research article

DOI: 10.1163/156853907781871888

Affiliations: 1: Biology Department, Susquehanna University, Selinsgrove, PA 17870, USA 2: Department of Zoology, Miami University, Hamilton, OH 45011, USA