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Morphogenetic and gonadotrophic effects of a juvenile hormone analogue ((7 S )‐hydroprene) in last instar female larvae of Diploptera punctata
Author(s) -
KIKUKAWA S.,
SMITH C.L.,
TOBE S.S.
Publication year - 1989
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1989.tb00948.x
Subject(s) - juvenile hormone , biology , ecdysteroid , medicine , endocrinology , ecdysis , corpus allatum , metamorphosis , instar , basal (medicine) , larva , hormone , botany , insulin
. The effect of treatment of last instar female larvae of Diploptera punctata with a Juvenile Hormone (JH) analogue, (7 S )‐hydroprene, has been determined with respect to the ability of the analogue to alter the duration of the stadium and the nature of the ensuing ecdysis. We have also investigated the effects of the analogue on JH release, the growth of the basal oocytes, as well as ecdysteroid titres during the fourth stadium. Analogue treatment prior to day 10 of the stadium results in prolongation of the stadium and desynchronization of ecdysteroid release. Thereafter, treatment with the analogue has little effect. Analogue treatment results also in the formation of supernumerary larvae and intermediates, in a dose‐dependent fashion, provided that animals are treated on day 10 or earlier. Thus, the ‘critical’ period for metamorphosis in last instar D. punctata is between days 0 and 10. Treatment with (7 S )‐hydroprene produces profound effects also on both JH release, and basal oocyte growth. At a dose of 500μg administered on day 1, JH release is stimulated significantly at a time when JH release is normally undetectable. Significant growth of basal oocytes is observed in such treated animals, and appears to precede the peak in JH release. We suggest that the growth of the basal oocytes, as a result of analogue treatment, stimulates the production of JH by CA in these last instar larvae.