Molting Process in the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)

Abstract This study describes the behavioral and histological changes that take place during ecdysis in the Formosan subterranean termite. The molting process was described in four distinct phases, starting with the peristaltic contraction of the abdomen to the complete shedding of the exuvium. Although individual termites still managed to go through the molting process when isolated from their nestmates, it required more time for the molting individual to complete the process than when aided by its nestmates. Histological observations were made on termites during the intermolt period, the premolting or fasting period, the pre-ecdysis and the ecdysis periods, and on newly molted individuals. Symbiotic protozoans were voided at the beginning of the premolting/fasting period. The detachment and reattachment of the muscles of the abdominal segments occurred during pre-ecdysis, and the leg muscle detachment and reattachment occurred during ecdysis. During pre-ecdysis, the abdominal cuticle had a wrinkled texture and two layers of cuticles were observed, one of which was the newly formed cuticle underneath the old one. Finally, the old tracheae were shed from the tracheal system and were pulled out from the spiracular openings of the mesothorax with the help of the nestmates. We concluded that, as social insects, the presence of nestmates during the molting of individual termites reduced the time necessary to complete the ecdysis, and the histological description of the molting process provides a template for further studies on the effect of chitin synthesis inhibitors on ecdysis in termites.