Nocturnal behaviour of adults of Heliothis armigera (Hübner) (Lepidoptera: Noctuidae) in the Sudan Gezira and pest control implications

Abstract

AbstractField and cage observations were made on Heliothis armigera (Hübner) in the Sudan Gezira to quantify nocturnal patterns of moth emergence, copulation and oviposition and the ages at which copulation and egg-laying occur. The flight activity pattern of males, virgins and inseminated females was assessed for crops with scarce or abundant sources of honeydew or nectar. A pronounced redistribution of moths between crops during the peak flight activity period (18.15-19.30 h) was demonstrated and measured, with the net exchange being approximately balanced. The direction of this movement was dependent upon the attractiveness of crops for feeding or oviposition. Male and female moths developing from larvae reared on groundnuts had significantly shorter lifespans when fed only water and less fat-body at emergence than moths developing from larvae reared on sorghum. When offered sugar solution, lifespans were significantly greater and differences in the lifespan of moths from groundnuts or sorghum were no longer evident. Adult feeding appears to compensate for any deficiencies associated with a larval diet of groundnut. Feeding was important for adult survival; there was a strong attraction of moths to crops with plentiful honeydew or nectar. A descriptive behavioural model is presented for the first half of adult life, until peak oviposition, and the uses of this model for pest management are discussed.