The development and oviposition of Oryzaephilus spp. on unrefined sugars

Abstract

Experiments were conducted with Trinidad strains of Oryzaephilus surinamensis (L.) and O. mercator (Fauv.), the average sizes of which were smaller than those given in the literature. Limited observations on their biology on cereal products showed that whereas the egg-production of O. mercator was comparable with that recorded by other workers under similar conditions, that of O. surinamensis was much lower.Larvae of both species were able to complete their development on raw and yellow-crystal sugar, but there was a high mortality among those of O. surinamensis. Both species showed very low oviposition rates on sugar and this, together with a high larval mortality, would indicate that infestations of O. surinamensis on these products would die out. O. mercator, on the other hand, could multiply very slowly. Oviposition rates rise rapidly when females return from sugar to cereal products.Unrefined sugars should accordingly not be disregarded as sources of Oryzaephilus infestation, especially in the humid tropics.