Developmental synchrony between Spodoptera littoralis (Boisd.) and its parasite Microplitis rufiventris Kok

The developmental interaction between Spodoptera littoralis (Boisd.) and its endoparasite, Microplitis rufiventris Kok. were studied under controlled conditions of short (6 h light–18 h dark) and long (18 h light–6 h dark) photoperiods, 20 ± 1°C and 60 ± 5% r.h. The developmental times of both species were reduced under short-day photoperiod conditions. Photoperiod as well as parasitism markedly affected the number of moults of the host larvae and the developmental time of the parasite was correlated with its sex, the host's age and photoperiod. Juvenile hormone titres in the haemolymph of parasitized and unparasitized larvae were determined using the Galleria bioassay. The haemolymph juvenile hormone titres of parasitized larvae were significantly higher than those of unparasitized larvae. The high levels of juvenile hormone were recorded prior and subsequent to parasite emergence. Importantly, parasitism interferes with the normal development of the host larvae.