Aspects of the Biology of the Seed Beetle, Bruchidius atrolineatus (Pic.) (Coleoptera: Bruchidae) on Stored Seeds of Cowpea, Vigna unguiculata (l.) Walp

OFUYA, T.I.

ABSTRACT: Observations were made on the biology of the seed beetle. Bruchidius atrolineatus (Pic.) which attacks seeds of cowpea, Vigna unguiculata (L.) Walp. in the West African Sahel. The egg laying pattern and realized fecundity of females, effect of host availability on egg laying, effect of seed size on seed choice for oviposition and beetle population fluctuation, were examined. The number of eggs laid by females reached a peak in the first day after emergence and decreased with age. The realized fecundity of females was 56.73 ± 1.37 eggs. Female fecundity and fertility were not influenced by duplicate mating. Female fecundity and development period were independent of seed population and size. B. atrolineatus‘ preferred large seeds to smaller ones for oviposition. Larvae consumed more seed material (18.8 ± 0.72) mg) from larger seeds and thus produced bigger adults (5’:1± 0.62 mg). There were more survivors from larger seeds at infestation level of four or more larvae per seed. These observations are discussed in relation to the population dynamics of the species.

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