Effects of certain juvenoids on growth and morphogenesis in Spodoptera littoralis (Boisduval)

El-Ibrashy M.T., . and Aref N.B.E., . Effects of certain juvenoids on growth and morphogenesis in Spodoptera littoralis (Boisduval). pp. 105-116. ISSN 0127-6883

When topically applied to allatectomised Spodoptera littoralis larvae of the penultimate instar certain juvenoids known to have good stability under a variety of practical field situations were revealed to have some inherent morphogenetic activities equivalent to or even surpassing those displayed by the natural juvenile hormones (JHs) of the insect. Further when assays were made on intact last instar larvae such activities might substantially be modified as a function both of the juvenoid nature and of the physiological age of the test animals. Surprisingly a restoration of larval programming occurred when intact wandering larvae were treated with juvenoids especially when high dose was used. This was manifested in resumption of feeding activity and in supernumerary ecdysis into superlarvae some of which were viable enough to proceed development till imaginal completion. Induction of either type of the morpho-genetic responses was found to be causally connected with the changes elicited in the growth rate of the juvenoid-treated animals. Highly effective in our bioassays were the juvenoids containing a phenoxy or pyridyloxy functionality in place of the methyl ester moiety of the JH molecules as well as those in which phenyl rings interbridged with oxygen atoms substitute for two or all the three isoprene units

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Abstract

When topically applied to allatectomised Spodoptera littoralis larvae of the penultimate instar certain juvenoids known to have good stability under a variety of practical field situations were revealed to have some inherent morphogenetic activities equivalent to or even surpassing those displayed by the natural juvenile hormones (JHs) of the insect. Further when assays were made on intact last instar larvae such activities might substantially be modified as a function both of the juvenoid nature and of the physiological age of the test animals. Surprisingly a restoration of larval programming occurred when intact wandering larvae were treated with juvenoids especially when high dose was used. This was manifested in resumption of feeding activity and in supernumerary ecdysis into superlarvae some of which were viable enough to proceed development till imaginal completion. Induction of either type of the morpho-genetic responses was found to be causally connected with the changes elicited in the growth rate of the juvenoid-treated animals. Highly effective in our bioassays were the juvenoids containing a phenoxy or pyridyloxy functionality in place of the methyl ester moiety of the JH molecules as well as those in which phenyl rings interbridged with oxygen atoms substitute for two or all the three isoprene units

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Item Type:	Article
Additional Information:	5 tables; 23 ref. Summaries (En Malay)
AGROVOC Term:	SPODOPTERA
AGROVOC Term:	HORMONAS JUVENILES
AGROVOC Term:	MORFOGENESIS
AGROVOC Term:	TERAPEUTICA MEDICAMENTOSA/ PLAGAS DE PLANTAS
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:53
URI:	http://webagris.upm.edu.my/id/eprint/18625

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