Development and sex ratio of the parasitoid Chrysocharis pentheus (Hymenoptera: Eulophidae) on the leaf miner Liriomyza trifoli (Diptera: Agromyzidae)

Leafmining flies such as Liriomyza trifolii and L. sativae are serious invasive pests of many agricultural sind ornamental crops. Biological control with native parasitoids can be a promising approach to manage the leafminers. The larval parasitoid Chrysocharis pentheus is a common and widespread native natural enemy of Liriomyza spp. in Asia but many aspects of its biology remain unclear. Here, the laboratory culture of C. pentheus with L. trifolii was established and its development on the host was investigated. The percentage of parasitized hosts producing the parasitoid offspring was nearly 90% at 25°C. Under low temperature/short day conditions, C. pentheus developed normally though the offspring survival was lower than that under 25°C conditions. Host 3^rd and 2^nd instars produced the parasitoid offspring with an equal proportion. However, the percentages of female parasitoids emerging from host 3rd instars were much higher than 2nd instars. Curiously, the offspring sex ratio (% females) was low at 15°C. The female offspring took longer time to finish development than males did. The offspring parasitoids were larger when emerged from host third instars than second instars. Overall, the biology of C. pentheus is similar to other eulophid parasitoids attacking dipteran lesifminers but our results suggest that C. pentheus is useful as a biocontrol agent during low temperature conditions.