Tropicultura (Jan 2006)
Comparaison de quelques caractéristiques biologiques entre Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) élevé soit sur son hôte habituel Callosobruchus maculatus F. (Coleoptera: Bruchidae) soit sur Acanthoscelides macrophthalmus Schaef. ou Bruchidius lineatopygus Pic. identifiés comme hôtes de substitution
Abstract
Comparison of some Biological Characteristics between Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) Reared either on his Habitual Host Callosobruchus maculatus F. (Coleoptera: Bruchidae) or on Acanthoscelides macrophthalmus Schaef. and Bruchidius lineatopygus Pic. Identified as Substitution Hosts. In this study, we have measured some biological parameters of Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) when this parasitoid grows on three hosts: Callosobruchus maculatus F. (usual host), Acanthoscelides macrophthalma Schaef. and Bruchidius lineatopygus Pic. (substitution hosts). The results of this comparative study in no choice situation show that, life duration and development duration of this parasitoid are identical in laboratory conditions. By contrast, the female fecundity, the sexual rate and the parasitism rate of D. basalis are different according to the hosts presented. Although such differences appear to be small between C. maculatus and A. macrophthalmus. In presence of these two species, the number of eggs laid by the female of D. basalis is respectively 61 ± 5.24 and 54 ± 5.60, the sexual rate 37.63 ± 2.13% and 41.73 ± 3.69% and the parasitism rate 85.46 ± 2.61% and 76.48 ± 5.90%. This indicates that these two Bruchids can be used as hosts to D. basalis for a mass production. In presence of B. lineatopygus, the fecundity and the parasitism rate of D. basalis female are very low and the sexual rate more favourable of the males. This situation is unfavourable for a parasitoid production. When D. basalis females are placed in choice situation with equal number of the hosts nowely C. maculatus and A. macrophthalmus, the parasitism rate obtained, is higher for C. maculatus that of A. macrophthalmus. This parasitism rate remains high for C. maculatus even when the other host A. macrophthalmus is twice the number of C. maculatus. Thus the parasitoid seems to have a preference for his natural host. However, A. macrophthalmus can still be used in production unit of D. basalis.
