The family Bombycidae (sensu Minet, 1994) is a diverse group of species belonging to the superfamily Bombycoidea. It is an economically important group of moth species, containing well-known silk-producing insects, as well as many pests of agriculture and forestry. The morphology-based hypothesis of Minet (1994) on the composition of Bombycidae is in conflict with subsequent phylogenetic hypotheses for the superfamily based on nuclear genes. In this paper, the complete mitochondrial genomes of nine species of Bombycidae are presented for the first time. Based on these genomes, four dataset partitions and three gblocks parameter settings, phylogenetic relationships among Bombycidae were reconstructed using maximum likelihood and Bayesian inference methods. Bombycidae was confirmed as a polyphyletic group, with the traditional subfamilies Prismostictinae and Oberthueriinae forming a single well-supported clade that is distant to Bombycinae. The phylogenetic relationships within Bombycoidea were supported as ((((Bombycinae, Sphingidae), Saturniidae), (Prismostictinae, Oberthueriinae)), Eupterotidae).

Microplitis similis (Hymenoptera: Braconidae) is a solitary endoparasitoid of Spodoptera litura larvae (Lepidoptera: Noctuidae). Here, the effects of constant temperature (18, 21, 24, 27, 30, 33 and 36 °C) on the development and fecundity of M. similis developing in S. litura were studied in the laboratory to clarify the range of its potential distribution and better understand its potential as a biological control agent. The developmental duration of M. similis varied from 10.6 (33 °C) to 27.9 days (18 °C). The developmental threshold temperature and effective accumulative temperature of M. similis were 9.96 °C and 231.14 Degree-days, respectively. The average adult longevity of M. similis ranged from 5.1 (33 °C) to 26.8 days (18 °C). The maximum fecundity of the parasitoid was observed at 27 and 30 °C, which were 43.07 and 39.73 eggs, respectively. The minimum fecundity of the parasitoid was observed at 18 °C, which was 8.27 eggs. The intrinsic rate of increase (rm) and finite rate of increase (λ) of M. similis were the highest at 30 °C. The net reproduction rate (R0) was the highest at 27 °C and 30 °C, which were 44.34 and 40.39, respectively. We concluded that temperatures in the range 27-30 °C are the most suitable for development and reproduction of M. similis. Our study provides detailed basic information for development and reproduction of M. similis under different temperature conditions.

Identifying novel biocontrol agents and developing new strategies are urgent goals in insect pest biocontrol. Ascoviruses are potential competent insect viruses that may be developed into bioinsecticides, but this aim is impeded by their poor oral infectivity. To improve the per os infectivity of ascovirus, Bacillus thuringiensis kurstaki (Btk) was employed as a helper to damage the midgut of lepidopteran larvae (Helicoverpa armigera, Mythimna separata, Spodoptera frugiperda, and S. litura) in formulations with Heliothis virescens ascovirus isolates (HvAV-3h and HvAV-3j). Btk and ascovirus mixtures (Btk/HvAV-3h and Btk/HvAV-3j) were fed to insect larvae (3rd instar). With the exception of S. frugiperda larvae, which exhibited low mortality after ingesting Btk, the larvae of the other tested species showed three types of response to feeding on the formulas: type I, the tested larvae (H. armigera) were killed by Btk infection so quickly that insufficient time and resources remained for ascoviral invasion; type II, both Btk and the ascovirus were depleted by their competition, such that neither was successfully released or colonized the tissue; type III, Btk was eliminated by the ascovirus, and the ascovirus achieved systemic infection in the tested larvae. The feeding of Btk/ascovirus formulas led to a great reduction in larval diet consumption and resulted in a significant decrease in the emergence rate of H. armigera, M. separata, and S. litura larvae, which suggested that the formulas exerted marked oral control effects on both the contemporary individuals and the next generation of these tested pest species.