Ecology and host manipulation by an egg‐larva parasitoid of Chrysodeixis includens (Lepidoptera: Noctuidae)

Abstract

AbstractParasitoids are among the main natural enemies of crop pests. Copidosoma truncatellum (Hymenoptera: Encyrtidae) is a parasitoid of Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae: Plusiinae), which is an important pest of soybean, bean, cotton, sunflower, tomato and potato. Copidosoma are parasitoids of lepidopteran egg‐larva, especially those of the subfamily Plusiinae. The embryonic development of the Copidosoma parasitoid begins in the lepidopteran egg, and this development extends to the beginning of the host larval stage of the parasitized lepidopteran. However, the rate of parasitism is a complex ecological relationship affected by climatic elements and age of the host. Thus, the present study aimed to investigate the ecology and host manipulation exerted by the C. truncatellum parasitoid on C. includens. The research was conducted in bean crops (Phaseolus vulgaris) over 2 years. The highest rates of parasitism were observed in crops in March in both years, when it was observed that about 40% of the individuals of C. includens were parasitized by C. truncatellum. In hot seasons and with less rainfall, parasitism is greater. The age of C. includens eggs (up to 3 days) did not affect C. truncatellum parasitism. The parasitized C. includens egg and caterpillar stages, which had their durations extended, showed the parasitized C. includens caterpillars presented higher leaf consumption. Additionally, this study was conducted in the field, which makes its results representative of natural conditions. Therefore, in warm and dry seasons, more significant parasitism of C. includens by C. truncatellum is expected. Parasitism increases the duration of the stages of lepidopterans and increases food consumption by its larvae.