Haixin Zhang, He Zhang, Lang Hu, Lelei Wen, Changchun Li
Phenotypic plasticity in extended phenotypes has been proposed as a mechanism by which animals modify their phenotypes in response to changing environmental conditions. This phenomenon is exemplified by certain spiders that construct bell-shaped cobwebs using sand grains, soil particles, prey remains, and plant debris. The retreat and gumfooted lines in these cobwebs are believed to serve defensive and foraging functions. This study aimed to test both the phenotypic plasticity and the tradeoff hypotheses by examining whether the common cobweb spider Campanicola campanulata alters web architecture and behavioral investments in response to variations in prey availability. When prey availability increases, spiders build webs higher, construct smaller and lighter retreats, and produce cobwebs with fewer gumfooted lines and smaller capture areas. Results indicated that, in the presence of abundant ant-prey, spiders reduced their investment in both foraging and defense. These findings suggest that the web architecture of C. campanulata exhibits a high degree of plasticity in response to variation in prey availability, but investment in web architectures does not involve tradeoffs between foraging and defense.