Liotryphon caudatus, an ichneumonid parasitoid of codling moth (Cydia pomonella), is known to perform host-feeding on late-instar host larvae. In this study, we examine the relationship between host-feeding, parasitisation behaviour and nutritional requirements of L. caudatus females and the impact on oogenesis and parasitism success. Using a series of laboratory experiments, we demonstrate that female L. caudatus lacking access to hosts for host-feeding were not able to develop mature eggs. Females successfully attacked only the immobile stages of codling moth to either host-feed or parasitise. No major differences in host attack behaviour were observed between naïve and experienced females, as both performed host-feeding similarly. However, experienced females exhibited significantly greater parasitisation success. We also found that when fed honey, female longevity increased up to fivefold compared to having only host-feeding opportunities or to a pure water control. Additionally, success in killing host larvae through host-feeding or parasitism was significantly enhanced with the access to honey. Overall, our findings emphasize that the presence of a carbohydrate source (honey) and a suitable host for host-feeding (immobile larval stages) are essential for the effective parasitisation and host-feeding performance of L. caudatus, as well as for the prolonged survival of females. This study provides new insights into the nutritional requirements, host preferences, and behavioural strategies of L. caudatus and underscores the importance of host-feeding for the reproductive success and survival of this parasitoid.

Apple orchard, Cydia pomonella, destructive host-feeding, nutrition ecology, synovigenic parasitoid