EFFECTS OF OVARIECTOMY AND ALLATECTOMY ON ECDYSTEROID SYNTHESIS AND ECDYSTEROID TITERS DURING LARVAL-ADULT DEVELOPMENT OF GRYLLUS-BIMACULATUS DE GEER (ENSIFERA, GRYLLIDAE)

In last instar larvae of Gryllus bimaculatus, the prothoracic glands a s well as the ovary and the abdominal integument synthesize and releas e ecdysteroids. Ovariectomy of day (d) 1 penultimate instar larvae ext ended the last larval stadium from 8 to 12 days (at 27 degrees C). Ecd ysteroid liters in haemolymph and abdominal integument of ovariectomiz ed d 6/7 last instar larvae were similar to those of d 4 intact larvae and of d 6/7 sham-operated animals. Net release of ecdysteroids (in v itro) by the abdominal integument from ovariectomized and sham-operate d d 6 last instar larvae was twice that for intact d 4 specimens. Ovar iectomy of d 1 last instar larvae strongly reduced levels of ecdystero ids in haemolymph and integument as well as release of ecdysteroids by the abdominal integument in 4-day-old adults. Allatectomy of d 1 last instar larvae also markedly reduced ecdysteroid titers as well as rat es of ecdysteroid release by the abdominal integument and by the ovary of young female crickets. The results suggest a prominent role of the ovary in ecdysteroid synthesis of adult females and indicate a juveni le hormone-dependent control of ecdysteroid biosynthesis during vitell ogenesis. (C) 1997 Wiley-Liss, Inc.