Seta-Spigot Homology and Silk Production in First Instar Antrodiaetus unicolor Spiderlings (Araneae: Antrodiaetidae)
Jason E. Bond: Department of Biology,
ABSTRACT: A scanning electron microscope study of the silk spigots of the first free postembryonic instar of Antrodiaetus unicolor shows that their spigots and setae are more similar in early instar spiderlings than in the adult spiders. This ontogenetic evidence supports the hypothesis that the silk spigots of spiders evolved from setae. These observations also suggest that spigots with a deep articulation between the base and shaft are more primitive than the non-articulated spigots.