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Phase variation and ‘off-season’ survival of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae)

Published online by Cambridge University Press:  19 September 2011

Syed Khasimuddin
Syed Khasimuddin
Affiliation:
International Centre of Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi, Kenya
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Abstract

The existence of phase variation in S. exempta has long been known and the possible significance of the phenomenon in terms of the insect's life-system has been discussed previously (Rose, 1979). Present studies carried out on a comparative basis have shown meaningful differences in many attributes of solitary- and gregarious-phase caterpillars.

The solitary-phase caterpillars take longer to develop, possess more protein fractions and higher levels of juvenile hormone in the haemolymph of sixth instars, and their pupae consume more oxygen compared to the gregarious ones. It is suggested that the solitary form of larvae is the normal type for the species, while the gregarious form is able to make maximum use of resources during some parts of the year.

Type
Research Article
Information
International Journal of Tropical Insect Science , Volume 1 , Issue 4 , December 1981 , pp. 357 - 360
Copyright
Copyright © ICIPE 1981

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References

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