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Analysis of precocious metamorphosis induced by application of an imidazole derivative to early third instar larvae of the silkworm, Bombyx mori
Author(s) -
Gu ShiHong,
Chow YienShing
Publication year - 1997
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/(sici)1520-6327(1997)36:4<349::aid-arch7>3.0.co;2-m
Subject(s) - metamorphosis , instar , biology , ecdysteroid , larva , bombyx mori , endocrinology , medicine , botany , biochemistry , gene
When an imidazole derivative (KK‐42) was applied to day 1 third instar larvae of the silkworm, Bombyx mori , 100% underwent precocious metamorphosis at the end of the fourth instar. Thus, the fourth instar becomes the last instar in these KK‐42–treated larvae. The endocrine systems underlying the precocious metamorphosis were analyzed in the present study. Hydroprene application during the prolonged third instar after KK‐42 treatment can prevent precocious metamorphosis, and the results showed dose‐dependent and stage‐specific effects. From analysis of the developmental changes in ecdysteroid levels in both KK‐42–treated larvae and KK‐42– and hydroprene‐treated larvae, we conclude that changes in JH levels during the third larval instar can modify the secretion pattern of prothoracic glands and that during the next larval instar, very low ecdysteroid levels during the early stages of the presumptive last (fourth) larval instar are directly related to precocious metamorphosis. Arch. Insect Biochem. Physiol. 36:349–361, 1997. © 1997 Wiley‐Liss, Inc.