Substitution of silk stabilimenta for egg sacs by Allocyclosa bifurca (Araneae: Araneidae) suggests that silk stabilimenta function as camouflage devices

The matching form and orientation of egg sacs and spiders, the match between egg sac color and that of the spider, ontogenetic changes in spider coloration that occur when egg sacs begin to be produced, differences in the positions of the spiders' legs during the day and at night, and coordinated changes in spider and egg sac colors in different populations all indicated that the egg sac and detritus stabilimenta near the hub function as camouflage in Allocyclosa bifurca. Silk stabilimentum construction was induced by experimental removal of egg sac stabilimenta, and was inhibited by addition of egg sacs. This implies that silk stabilimenta also function as camouflage devices.