# Evaluating Field-Collected Populations of Cotesia flavipes (Hymenoptera: Braconidae): Enhancing Biological Traits and Flight Activity for Improved Laboratory Mass Rearing

## TL;DR

This study compares wild and lab-reared populations of Cotesia flavipes wasps to see if introducing wild wasps improves mass rearing quality.

## Contribution

The study shows that field-collected Cotesia flavipes populations can improve offspring production in early generations of lab rearing.

## Key findings

- Field-collected C. flavipes developed faster and produced more offspring per host by the twentieth generation.
- Both populations showed similar flight activity, with most wasps walking rather than flying.
- After ten generations, the field population stabilized and matched the lab population in quality.

## Abstract

Many insect production facilities raise the parasitoid wasp Cotesia flavipes to help control agricultural pests. To improve the quality of these wasps, some facilities introduce new populations collected from the wild, even without knowing if they will perform better. This study compared a field-collected population of C. flavipes from Brazil with a population that has been reared in the laboratory for over 40 years. The goal was to determine if the field population had better biological traits and flight ability, making it a good candidate for mass production. Over 20 generations, researchers observed that the field population developed slightly faster and, by the twentieth generation, produced more offspring per parasitized host. However, both populations showed similar movement ability, with more wasps walking rather than flying. By the tenth generation, the field population had stabilized in the laboratory, and overall quality became similar to the long-term lab population. These findings suggest that introducing field-collected wasps into mass production can be beneficial, but the differences in performance diminish after several generations in captivity.

Due to the biofactories’ concern for the quality of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae), a common practice is to introduce a population collected from the field into the laboratory mass rearing, even without prior information about the introduced population’s quality or potential positive outcomes. Thus, the objective of this study was to determine whether populations of the C. flavipes parasitoid collected from the field exhibit better biological characteristics and flight activity, with the aim of incorporating them into laboratory mass rearing to enhance the quality of the parasitoids. To achieve this, a population of C. flavipes collected from the field (Pradópolis, SP, Brazil) was studied for twenty generations and compared with a population maintained in the laboratory for 42 years. The egg-to-pupa period in the field population was shorter across generations, particularly in the twentieth generation (11.0 days). Although the field population exhibited a lower number of adults that emerged per host in the fifth and tenth generations, by the twentieth generation, it showed higher offspring production per parasitized host (56.5 parasitoids/host). The results of the flight activity test revealed that both the laboratory-maintained population and the field-collected population exhibited higher percentages of insects classified as walkers compared to flyers (25.7% to 32.3% flying). The field-collected population stabilized in the laboratory by the tenth generation. Moreover, the results of the biological characteristics, longevity, and flight activity of the parasitoids indicate similar quality between the two populations studied after stabilization of the field-collected population.