Physiology of Insect Rhythms
Open Access
- 1 April 1974
- journal article
- Published by The Company of Biologists in Journal of Experimental Biology
- Vol. 60 (2), 371-382
- https://doi.org/10.1242/jeb.60.2.371
Abstract
1. Late in the fifth instar, Manduca sexta larvae cease feeding and become ‘wandering larvae’ which are morphologically characterized by an ‘exposed heart’ and the appearance of a pink pigment along the dorsal midline. Two days later ocellar retraction signals the beginning of the prepupal period and 3 days thereafter the pupal ecdysis occurs. 2. The timing of the endocrine events which are responsible for these changes was determined by ligaturing animals of the appropriate developmental stage at various times of day. The times of prothoracicotropic hormone (PTTH) release by the brain were determined by neck ligations. Estimates of the times of prothoracic gland activity were obtained through the isolation of abdomens. 3. It was found that the fifth stage larva releases PTTH on two occasions. The first release lasts approximately 3.5 h and triggers the transformation to the wandering stage. The second release occurs two days later, lasts at least 7 h, and provokes the onset of the pupal moult. 4. The prothoracic glands are involved in triggering the same two changes. In the first instance the glands apparently require the continuing influence of the brain and consequently secrete for about 3.5 h. During the stimulation of the pupal moult the prothoracic glands become ‘turned-on’ and continue to secrete for at least 10 h after the time when the brain is no longer required. In this latter instance the total time of prothoracic gland activity may be as long as 17 h.This publication has 13 references indexed in Scilit:
- Diapause termination and metamorphosis in brainless tobacco hornworms (Lepidoptera)Life Sciences, 1972
- JUVENILE HORMONE IN RELATION TO THE LARVAL-PUPAL TRANSFORMATION OF THE CECROPIA SILKWORMThe Biological Bulletin, 1972
- Insect HormonesPublished by Elsevier ,1972
- The molt/intermolt cycle in the epidermis and other tissues of an insect Calpodes ethlius(Lepidoptera, hesperiidae)Tissue and Cell, 1970
- ECDYSONE AND ECDYSONE-ANALOGUES: THEIR ASSAY AND ACTION ON DIAPAUSING PUPAE OF THE CYNTHIA SILKWORMThe Biological Bulletin, 1968
- A study of the structure and activity of the endocrine organs in Cerura vinula L. (Lepidoptera) during the pupationWilhelm Roux' Archiv für Entwicklungsmechanik der Organismen, 1968
- Der Ecdysontiter während der InsektenentwicklungDevelopmental Biology, 1965
- Die Auslösung der Umfärbung durch das Häutungshormon bei Cerura vinula L. (Lepidoptera, Notodontidae)Journal of Insect Physiology, 1959
- PHYSIOLOGY OF INSECT DIAPAUSE. IV. THE BRAIN AND PROTHORACIC GLANDS AS AN ENDOCRINE SYSTEM IN THE CECROPIA SILKWORMThe Biological Bulletin, 1952
- THE “GIN‐TRAPS” OF SOME BEETLE PUPAE; A PROTECTIVE DEVICE WHICH APPEARS TO BE UNKNOWNEcological Entomology, 1946