Factors Affecting the Reproduction and Mass-Rearing of Sclerodermus brevicornis (Hymenoptera: Bethylidae), a Natural Enemy of Exotic Flat-Faced Longhorn Beetles (Coleoptera: Cerambycidae: Lamiinae).

Abstract

Simple SummaryNatural enemies play a fundamental role in the control of invasive insects and may be particularly important in controlling Xylopagous beetle, which are difficult to contain with traditional chemicals as they are usually concealed within wood. Among the natural enemies that have proven effective against these beetles are parasitoid species in the genus Sclerodermus. The present article furthers knowledge of Sclerodermus brevicornis performance, focusing on the survival capability under different thermal conditions and the longer-term influences of these conditions.Many species of long-horned beetles are invasive pests causing significant economic damage in agro-forestry systems. They spend the majority of their life-cycle concealed inside natural wood or wooden packaging materials and are largely protected from adverse environmental conditions and pesticide sprays. Biological control via parasitoid natural enemies including members of the bethylid genus Sclerodermus, has proven effective against some long-horned beetles that are invasive in China. In Europe, the biocontrol potential of native Sclerodermus species is being evaluated with a view to developing efficient mass-rearing techniques and then actively deploying them against invasive Asian beetles. Here, we continue evaluations of S. brevicornis by establishing that groups of females that have already reared offspring to emergence are capable of reproducing subsequent hosts and by evaluating the lifetime reproductive capacity of individual females provided with successive hosts. Additionally, we assess the laboratory shelf-life of adult females stored for different times at different temperatures including cold storage, and then assess the post-storage reproductive performance of groups of females provided with a single host. We found that adult female longevity declines with increasing storage temperature and that most aspects of subsequent performance are negatively affected by high temperatures. The adaptability to low temperature storage enhances the suitability of S. brevicornis to mass-rearing programs and thus biocontrol deployment.