Oviposition of Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae) on Arachis hypogaea (L.) (Papilionaceae), Citrullus lanatus (Thunb.) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae)

Studies on the oviposition of Oryzaephilus mercator on three commodities ( Irvingia gabonensis var. excelsa, Citrullus lanatus and Arachis hypogaea) were conducted under fluctuating conditions (20–30 °C and 70%–85% r.h.). The length of the pre-oviposition period was not affected by the type of commodity; however, it was significantly shorter on the milled form than on the whole form of the commodities. Preference for specific oviposition sites on seeds to containers was demonstrated only on I. gabonensis and C. lanatus. The total numbers of eggs and the duration of the oviposition period were significantly higher on I. gabonensis and A. hypogaea than on C. lanatus. The rate of oviposition was higher on milled A. hypogaea than on I. gabonensis and C. lanatus. Unmated females did not lay eggs. The mean oviposition period was significantly longer and the egg numbers were higher in undisturbed mated pairs than in interrupted mated pairs. A variation in sex ratio did not significantly affect the number of eggs laid per female.