Host-specific demography of Utetes anastrephae (Hymenoptera, Braconidae), a native parasitoid of Anastrepha spp. fruit flies (Diptera, Tephritidae)

Abstract

The braconid Utetes anastrephae (Viereck, 1913) (Hymenoptera: Braconidae) is a larva-pupal parasitoid of fruit flies of the genus Anastrepha Schiner, commonly associated with Anastrepha obliqua (Macquart, 1835) (Diptera: Tephritidae), the most important pest of mango (Mangifera indica L., 1753) in Mexico. This parasitoid was established in a laboratory colony using larvae of Anastrepha ludens (Loew, 1873) as host. Here we describe a demographic study to compare the reproductive and population parameters of this parasitoid reared on A. obliqua and A. ludens under laboratory conditions. Two U. anastrephae cohorts of 30 individual pairs each were set up, one was reared on A. obliqua larvae and the other one on A. ludens. Every day, 30 third instar larvae of each host species were exposed to an adult pair through the lifespan of the female. Daily mortality and fecundity were recorded. Life tables were constructed and sex ratios, parasitism rates, survival, reproductive and population parameters were estimated. Higher survival of U. anastrephae females was observed in females from A. obliqua (mean live expectancy of 22.4 days), but higher fecundity and parasitism occurred in females from A. ludens (net fecundity of 62.61 daughters/ female and 16.72% parasitism rate). The intrinsic rate of increase (r = 0.128 and r = 0.134 for A. obliqua and A. ludens respectively), mean generation time (27.88 and 28.30 days) and population doubling time (5.42 and 5.16 days) were similar in both cohorts, as well as the sex ratio (73 and 69% of females). These results suggest that A. ludens as host increase the production rates; however, any one of these two species could be used as host for mass rearing purposes.