Abstract

RIOS R., Angélica V. et al. Life cycle and exploration of parasitism in Specularius impressithorax (Pic) 1932 (Coleoptera: Bruchidae) from Mexico. Acta Zool. Mex [online]. 2015, vol.31, n.1, pp.27-35. ISSN 2448-8445.

Specularius impressithorax is a bruchid of African origin whose displacement has been worldwide, it has been found in India, United States (Hawaii, California), and currently in Mexico. In the latter country, it has moved to several states because of its food source, that is the Erythrina's seeds, which are found abundantly in climatic zones that goes from semiarid to dry or temperate; the climate and the Erythrina species diversity found in Mexico are favorable for its establishment and the attack to new hosts. For the study of the insect life cycle, breeding was done, the number of eggs laid was recorded, as well as the time required for each developmental stage; also the polyphagy was measured by offering to it new hosts, and an exploration of parasitism in S. impressithorax, all of this at environmental temperature (18 - 22 °C) and controlled temperature of 25 °C ± 2 °C. The results showed that S. impressithorax in the laboratory with controlled conditions undergo a decrease in the oviposition of fertile eggs in comparison to the environmental temperature where most of the eggs become fertile and reached the adult stage. Virgin insects of S. impressithorax were placed in containers where they were fed with different species of Erythrina native to Mexico and the food preferences was evaluated. It was observed that they were capable to invade new hosts, from which adults emerged. The collects were carried out where seeds infested by S. impressithorax were present, eggs of the bruchid attacked by a parasite was observed, this was identified as Uscana sp. (Hymenoptera: Trichogrammatidae); however, free adult forms could not be obtained for corroboration of the species. A second natural enemy was determined as Entedeon erythrinae Gumovsky & Ramadan (Hymenoptera: Eulophidae) that is an egg-larvae parasitoid of bruchids. Previous data show that infestation to new Erythrina hosts and the increase of its dispersion will be imminent, and that it is necessary to implement control strategies for the bruchid; biological control can be included in its management and thus prevent the deterioration of the host germplasm, which play important functions in the ecology, the ethnobotany, and science.

Keywords : Seed beetle; natural enemies; exotic pests.