Egg Allocation on Anastrepha ludens Larvae by Mass-Reared Diachasmimorpha longicaudata Females

Abstract

The age-dependent reproductive behavior of parasitoid females under mass-rearing conditions may influence the quality of the biocontrol agents produced. Therefore, this study assessed the egg allocation behavior of Diachasmimorpha longicaudata (Ashmead) females at different ages under mass-rearing conditions. This parasitoid native to Southeast Asia is mass-reared on irradiated Anastrepha ludens (Loew) larvae at the Moscafrut Program facility in Mexico and is released in crop areas to suppress fruit fly pest species. Parasitoid females aged 5-10 days were used to assess quality control parameters, such as parasitized host mortality, parasitoid emergence, offspring sex ratio, and superparasitism. Anastrepha ludens puparia were checked and dissected 72 h after being exposed to female parasitoids to determine the number of scars on the puparium of first-instar parasitoids, respectively. Parasitized puparia were kept under lab conditions to assess adult emergence and offspring sex ratio. Host mortality, superparasitism, and parasitoid offspring sex ratio were affected by female age. The highest host mortality and superparasitism were caused by 5-7-day-old females, which also produced a significantly higher female-to-male offspring ratio with improved fitness-related parameters. The use of cages with females of these ages may improve the quality parameters of parasitoids and result in higher female-to-male offspring sex ratios. Furthermore, production costs could be lowered by reducing the quantity of hosts and rearing commodities. These findings are a useful contribution to improving the current method used for the mass rearing of D. longicaudata at the Moscafrut Program facility.

Keywords: female allocation; fruit fly parasitoid; offspring fitness; parasitoid mass production; quality control parameters; reproductive strategy.

Figure 1

Mean (±SEM) percentage of parasitoid F1 adult emergence recorded from Anastrepha ludens larvae exposed to Diachasmimorpha longicaudata females of different ages under mass-rearing conditions. Different letters above bars indicate significant differences (Tukey’s HSD test, p = 0.05).

Figure 2

Mean (±SEM) parasitoid F1 offspring sex ratio recorded from Anastrepha ludens larvae exposed to Diachasmimorpha longicaudata females of different ages under mass-rearing conditions. Different letters above bars indicate significant differences (Tukey’s HSD test, p = 0.05).

Figure 3

Cumulative survival curves of F1 parasitoid female (A) and male (B) offspring produced by Diachasmimorpha longicaudata maternal females of different ages.

Figure 4

Mean (±SEM) number of F2 parasitoid female and male offspring (fecundity) produced by Diachasmimorpha longicaudata F1 maternal females of different ages. Different letters above bars indicate significant differences (Tukey’s HSD test, p = 0.05).