Journal of Insect Behavior, Vol. 15, No. 2, March 2002 ( C  2002) Silk Spinning Behavior and Domicile Construction in Webspinners J. S. Edgerly, 1,2 J. A. Davilla, 1 and N. Schoenfeld 1 Accepted October 29, 2001; revised December 26, 2001 Analysis of spinning and of silk domiciles revealed similarities and differences for three species of embiids: Antipaluria urichi (Saussure), Pararhagadochir trinitatis (Saussure), and Oligotoma saundersii (Westwood). Each exhibited similar routines while spinning; they positioned the silk by touching the sub- strate with either front tarsus and by moving the leg to the next position, with many silk strands issuing forth at each step. Reinforced pathways developed as they spun while traveling from diurnal retreats and nocturnal foraging zones. Frass from the interior of their domiciles was spun into the silk. O. saundersii was unique in that it plastered its silk with gathered materials. Analysis of field colonies of P. trinitatis and O. saundersii showed that, like A. urichi, adult females share their silk with offspring and, often, with other females. KEY WORDS: Embiidina; Embioptera; webspinners; arthropod silk; silk spinning. INTRODUCTION Embiids (Order Embiidina or Embioptera) live within the confines of spun silk except during brief dispersal flights by winged males or walks by wingless females. Dwelling within these narrow silk domiciles has apparently con- strained their body form, as vividly reflected in the form of females, which are wingless, streamlined, and very flexible (Ross, 2000). Their tarsal silk glands (Mukerji, 1927; Barth, 1954; Alberti and Storch, 1976; Nagashima et al., 1991; Dubitzky and Melzer, 1999) are unique for hexapods (Craig, 1 Department of Biology, Santa Clara University, Santa Clara, California 95053. 2 To whom correspondence should be addressed. E-mail: jedgerlyrooks@scu.edu. 219 0892-7553/02/0300-0219/0 C  2002 Plenum Publishing Corporation