Encapsulation of Metaphycus sp. (Hymenoptera: Encyrtidae) by its host, Capulinia sp. (Hemiptera: Eriococcidae)

Resumen

Encapsulation of Metaphycus sp. eggs by its host, Capulinia sp. was assessed during March-December 2002 on laboratory colonies at Maracaibo and field populations at two localities of Maracaibo lake basin, on Psidium guajava. In the laboratory and southern lake zone host colonies were artificially initiated by egg inoculations, while natural infestations were evaluated at the north west. Percentage of encapsulated eggs (%EEg) out of total laid and percentage of encapsulation efficiency (%EEf) were estimated. Additionally, Capulinia individuals of six ages (young N2, advanced N2, adult females of 1-5, 6-10, 11-15, 16-20 days from molting) were separately exposed to Metaphycus in the laboratory. By localities %EEg was 19.79 and 12.81 and %EEf 15.77 and 8.77, at the southem lake zone and the north west zone, respectively. The %EEg increased with host age (14.29-24.44%), but %EEf varied less (14.29-17.39%). The results suggest that when host generations overlap (natural infestations) encapsulation (%EEg) and its interference with natural control (%EEf) are lower compared to more uniform generations (artificial egg inoculations). Although encapsulation is greater in preferred host ages for parasitoid attack (adult females 1-20 days) the preference for this ages could overwhelmingly compensate for the interference with the population regulation due to encapsulation.