Seasonal Population Fluctuations in the Black Cowpea Moth Cydia Ptychora (Meyrick) (Lepidoptera:Tortricidae)
Investigations were carried out on the seasonal population fluctuations of the moth Cydia ptychora. The population increased from May to September and declined from November to April. Increasing temperatures and decreasing r.h. appeared to be associated with population decline, while the reverse seemed to favour population increase.
From light trap catches, sex ratios of adults showed considerable variation from month to month. The overall ratio was 2:1, in favour of the males, but there was a tendency for adjustment towards an apparently female-biased ratio from March to August.
Bracon (?) hancocki was found to be a major parasite. Other biotic factors contributing to population regulation included 13 hymenopterous parasites and three predators (Philodicus temerarius, Bactria sp. nr. guineensis and Chrysopa sp.)
Key WordsAsilid flies Bracon hancocki cowpea ectoparasitism endoparasitism homodynamic lace wing lindane population sex ratio
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