Exploring the Links Between Seasonal Variation and Spider Foraging

• Main Author: Dantas Whitney, Thomas Edward
• Format: Others
• Published: UKnowledge 2014
• Subjects: Generalist predators; Schizocosa ocreata; Schizocosa stridulans; molecular gut-content analysis; supercooling point; Entomology; Terrestrial and Aquatic Ecology
• Online Access: http://uknowledge.uky.edu/entomology_etds/9; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1009&context=entomology_etds

According to optimal foraging theory, generalist predators, such as spiders, are thought to feed indiscriminately on prey according to its availability, especially when food is scarce. In contrast, generalists can display selective feeding decisions under regimes of high prey abundance, but few studies have tracked changes in prey choice on a seasonal basis under open field conditions. Additionally, adaptations to surviving winter have been largely ignored in the research of foraging behavior. To elucidate this, I monitored prey availability and collected common forest-dwelling wolf spiders for molecular gut-content analysis, in parallel for 18 months, to assess the temporal changes occurring in spider preferences of common leaf litter prey. In addition, to determine if any physiological improvements to resisting low temperature mortality were affecting spider foraging, I also collected spiders monthly to track changes in spider supercooling points. The results revealed that spiders do exhibit selective feeding throughout the year, and appear to do so in a way that diversifies their diets. Also, despite low litter temperatures putting them in severe freezing risk, cold tolerance in these spiders remained unchanged throughout the winter, which suggests opportunity for growth during this uncompetitive period is paramount to accumulating survivorship-increasing, but also mobility-decreasing, cryoprotectants.