SOME FACTORS AFFECTING OVIPOSITION AND DEVELOPMENT OF CALLOSOBRUCHUS-SUBINNOTATUS (PIC) (COLEOPTERA, BRUCHIDAE)

Some factors affecting oviposition and development of Callosobruchus s ubinnotatus were investigated. Females were found to prefer healthy se eds to infested bambarra seeds for egg-laying. When offered only infes ted seeds, the number of eggs laid did not differ from that laid when only healthy seeds were offered. Females were able to distinguish seed s having lower numbers of emergence holes and preferred these to seeds with many emergence holes for egg deposition. Offering egg-laden seed s to females inhibited oviposition and this inhibition progressively i ncreased as the egg density of seeds increased. The number of seeds of fered the gravid female for oviposition affected the number of eggs la id. Offering few seeds inhibited oviposition and up to 20 seeds were r equired for a female to achieve its optimal egg production. Delays up to 3 days in offering mated females seeds for oviposition inhibited ov iposition and reduced the egg output of the female. Development was fa ster and heavier offspring were produced when larvae were reared on he althy seeds than on infested seeds. There was high mortality of develo ping larvae when the bruchids were bred on previously infested seeds. High larval density of up to five larvae per seed prolonged developmen tal period and caused the production of miniature individuals which la id very few eggs. These miniature individuals were not 'active' or 'fl ight' forms.