Lentil seeds infested with Callosobruchus chinensis (Linnaeus) for 12–15 days were exposed to Dinarmus basalis (Rondani) alone, Anisopteromalus calandrae (Howard) alone, or to both species, at densities of 2, 4, 8, 16 and 32 insects. Intra-specific competition and host emergence decreased with increasing parasitoid density in both D. basalis and A. calandrae, but progeny production of the parasitoids and parasitoid-induced mortality (PIM) increased with increasing parasitoid density. Dinarmus basalis was much more efficient in parasitizing C. chinensis than A. calandrae. Emergence of D. basalis and A. calandrae, and the PIM were highest at a parasitoid density of 32. Parasitoid density and a combination of parasitoids significantly (P<0.01) affected the number and progeny sex ratio of emerged parasitoids. There were significant (P<0.01) effects of inter- and intra-specific competition on host mortality. Host mortality increased with increasing parasitoid density. Parasitoid combination and parasitoid density also significantly affected PIM.

The age-dependent fecundity and offspring production of females of a solitary ectoparasitoid Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) were determined on its host Callosobruchus maculatus F. (Coleoptera: Bruchidae). The resulting data were used to determine the longevity and reproductive potential of the species, by establishing its life and fertility tables. In the presence of 16 hosts renewed every 48 hours, D. basalis females had a mean longevity of 32.6 ± 1.6 days. They laid an average of 136.5 ± 55.2 eggs, parasitised 132.7 ± 53.9 hosts, and produced 111.8 ± 3 offspring, consisting of 58.3 % of males and 41.7 for females. The total mean development time was 14.0 ± 0.7 days for females and 11.8 ± 0.8 days for males. The net reproductive rate (Ro) was 38.9 females progeny per adult female, and the intrinsic rate of population increase (rm) 0 16 per day. The generation time (G) was 22.5 days and the doubling time (DT) 4.3 days. These parameters permitted to determine the reproductive potential of D. basalis as a biological control agent against the bruchid in West Africa.