Técnica de criação e bioecologia do parasitoide larval Aganaspis pelleranoi (Brèthes, 1924) (Hymenoptera: Figitidae) em duas espécies de moscas-das-frutas

Abstract

Aganaspis pelleranoi (Brèthes, 1924) (Hymenoptera: Figitidae) is a koinobiont endoparasitoid of fruit-fly larvae, and is a candidate for the establishment of applied biological control. The objective of this study was to develop a technique for rearing A. pelleranoi and to study its biology in different hosts and temperatures. The study was carried out in three stages. In the first stage, experiments performed with the aim of developing a rearing technique determined that third-instar larvae of Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae) are preferred for parasitism over the first and second instars, both in a free-choice test and in confinement. The 4-hour period of exposure of the larvae of A. fraterculus led to the production of the largest number of parasitoids, the highest percentages of parasitism and emergence, and a higher proportion of females in the offspring. The number of four larvae of A. fraterculus per female of A. pelleranoi, offered for a period of 4 hours, led to the highest production of parasitoids. Provision of a 30% honey-water solution for the parasitoids is essential to extend their life span and enable them to produce more offspring. In the second stage, study of the biology of A. peleranoi in larvae of A. fraterculus and Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) revealed that the parasitoids multiplied in larvae of A. fraterculus produced more offspring, had a shorter egg-adult period, a higher sex ratio, greater longevity, and higher percentages of parasitism and emergence than those reared on larvae of C. capitata. Also, A. pelleranoi reared in A. fraterculus were heavier and had a longer tibia than those reared in C. capitata. Based on the fertility life table, it was determined that the population doubling time (Td) was about 3.4-fold shorter for the insects obtained from larvae of A. fraterculus. Therefore, A. pelleranoi develops better in larvae of A. fraterculus. In the third stage, females maintained at different temperatures produced the largest number of parasitoids in the temperature range of 18 to 20 °C, and parasitism ranged from 21.7 to 34.4 in the temperature range studied. The longevity of males and females was inversely proportional to temperature, ranging from 49.1 to 3.73 days for females and from 32.1 to 3.8 days for males, in the temperature range of 18 to 30 °C, respectively. The duration of the biological cycle (egg to adult) ranged from 69.1 days at 18 °C to 30 days at 25 °C. At temperatures of 28 and 30 °C there was no development of pre-imaginal A. pelleranoi. The lowest temperature limit for development (Tb) and the thermal constant (K) were 11.69 °C and 391.70 degree-days respectively. Therefore, in this paper it was demonstrated that A. pelleranoi prefers warmer temperatures.