When disturbed, the spider might first vibrate the web to try to make its body look bigger, but if that fails to deter a predator she will drop to the ground and hide (Faulkner 1999). Adults may be captured by wasps such as the Blue Mud Dauber, Chalybion californicum (Landes et al. 1987). They are also eaten by birds, lizards, and shrews.
Overwintering egg cases protect spiderlings from predation. Suspending the cocoon from the web is particularly effective against ant predation. The vast majority, however, are eventually damaged by birds. Cocoons wall layers provide barriers against burrowing larvae of insect predators and ovipositors of parasitic insects, but ichneumonid wasps such as Tromatopia rufopectus and chloropid flies such as Pseudogaurax signatus lay their eggs in Argiope aurantia egg cases. In fact, one study found that in addition to A. aurantia, nineteen species of insects and eleven species of spiders emerged from A. aurantia egg cases. (Hieber 1993, Lockley and Young 1993).
Anti-predator Adaptations: aposematic
- Landes, D., M. Obin, A. Cady, J. Hunt. 1987. Seasonal and latitudinal variation in spider prey of the mud dauber Chalybion californicum (Hymenoptera:Sphecidae). Journal of Arachnology, 15: 249-256.
- Lockley, T., O. Young. 1993. Survivability of overwintering Argiope aurantia (Araneidae) egg cases, with an annotated list of associated arthropods. Journal of Arachnology, 21(1): 50-54.
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