Document Type
Presentation - Oral - to academic peers, less than or equal to 1 hour
Behavioral Use and Physical Characteristics of Defensive Silk in the Western Black Widow Spider (Latrodectus hesperus)
Department
Biology
Date of Activity
7-13-2017
Recommended Citation
American Arachnological Society, Queretaro, MX 2017 Nelsen, D. R., Bonney, D., Delote, I., Young, W., Min, J., Lopez M., Wilson M., Corbit, A. G., Behavioral Use and Physical Characteristics of Defensive Silk in the Western Black Widow Spider (Latrodectus hesperus). July 24-28 Behaviors associated with defense against predation are under high selective pressure. Because of this, judicious use of defensive behaviors associated with a high, or potentially high, metabolic cost should be favored. Animals that exhibit behaviors that are both defensive and have high metabolic cost offer an excellent opportunity to study an animals ability to make decisions and possible cognitive capabilities. Spiders in the genus Latrodectus are unique in their active use of silk during defense. This silk has several unique physical attributes including the presence of very large viscous globules, which are potentially metabolically costly to produce and are structurally distinct from gum-footed lines. In this study, we investigated the ability of L. hesperus to control the quantity of silk and the volume of viscous globules used during defensive events and its physical appearance. We use a repeated measures design and tested each spider under three threat conditions: low (prods to legs IV) and medium (pinch and hold of leg IV) and high (pinch abdomen). We found that spiders were significantly more quick to engage in the behavior and had larger viscous globules in the medium threat condition. Additionally, defensive silk was structurally distinct from gum-footed lines. These results suggest that the defensive use of silk is metabolically costly and is possibly under cognitive control.