The competition between populations of the parasitoids C. grandis and B. vulgaris was studied using larvae of Euscepes postfasciatus (Fairmaire) as an alternative host. A series of biological parameters was observed and related to the competitive abilities of both parasitoid species. They were capable of colonizing and maintaining their populations regardless of host location. The population growth of C. grandis and B. vulgaris, based on fecundity was not affected by the competition. The parasitism and survivorship to the adult stage were affected by competition, except when the host was located at the bottom of the rearing cage. C. grandis performed better than B. vulgaris independently of the competition and host location, but it did not exclude the other species.
Biological control; Anthonomus grandis; competition between parasitoids
