The effect of predation risk on male courtship and copulatory behavior in the wolf spider Pardosa milvina
The wolf spider, Pardosa milvina, displays a variety of antipredator responses in the presence of chemical cues (silk and excreta) from a larger wolf spider, Hogna helluo. We examined the influence of substratum-borne predator chemical cues on male P. milvina courtship and copulatory behavior. Forty-one pairs of adult virgin male and female P. milvina experienced one of two substrates: 1) a sheet of filter paper previously occupied by an adult female P. milvina for 24 h followed by an adult female H. helluo for 24 h or 2) a control sheet of paper occupied by only an adult female P. milvina for 24 h. Using behavioral observation software (Observer), we recorded courtship latency, duration, and intensity. We also measured the total number of matings, the duration of each mating, and the number and rate of successful and failed palpal insertions. While we found no difference in mating success across treatments, there were significant increases in courtship latency and latency to mate when Pardosa was in the presence of predator cues. There were also significant decreases in courtship and copulation intensity under predation risk. Males under predation risk had a significantly lower palpal insertion rate and had significantly more missed insertions than individuals not on predator substrates. Results suggest that increased predation risk has the potential to negatively impact sperm transfer efficiency as well as copulatory courtship.