Host adaptation of a gregarious parasitoid Sclerodermus harmandi in artificial rearing

Abstract

Adaptations of a parasitoid, Sclerodermus harmandi (Buysson 1903) (Hymenoptera: Bethylidae) to a target host, Monochamus alternatus Hope (Coleoptera: Cerambycidae), were investigated in laboratory colonies. We quantified the physiological and behavioral flexibility of the parasitoid reared on M. alternatus compared to the parasitoid reared on a common host, Saperda populnea (Coleoptera: Cerambycidae). Adult performance (fecundity and pre-oviposition period) and offspring physiological responses (mortality and sex ratio) of S. harmandi reared on M. alternatus improved over multiple generations. S. harmandi females of the 12th generation on the target host showed better performance, i.e., shorter time for searching and handling, higher oviposition preference, and, subsequently, lower offspring mortality and proportion of male emergence on the host than those from the base stock. Our work demonstrated that these traits in S. harmandi were influenced by the integration of cultured generations and host quality, which implies that the potential effectiveness of S. harmandi as a biological control agent can be further improved.

Determination of the optimal parasitoid‐to‐host ratio for efficient mass‐rearing of the parasitoid, Sclerodermus pupariae (Hymenoptera: Bethylidae)

“…One of the costs of biological control is the massive production of useless males during the mass‐rearing of parasitoids on substitute hosts (Li et al. ). In all our experiments, sex ratios of S. pupariae were always female‐biased.…”

“…Unlike S. harmandi Buysson (Hymenoptera: Bethylidae), one of the most common biological control agents attacking young larvae of several long‐horned beetles in China (Li et al. ), many S. pupariae females can develop into winged morphs (Figure S1). Winged individuals can better disperse to colonize habitats beyond the release site and thus reduce the overall pest management costs in biological control programmes.…”

“…Parasitoids are often used as biological control agents because of their efficient host searching ability, and they can occasionally be generalists. Parasitoid wasps of the genus Sclerodermus (Hymenoptera: Bethylidae), a category of generalists, are widely used in the biological control of some wood borers in Asia (Hong et al 2008;Shimazu 2008;Li et al 2010;Wei et al 2013Wei et al , 2014Yang et al 2014). The efficiency of biological control can be enhanced by developing an effective parasitoid mass-rearing system to produce large numbers of high-quality parasitoids (Chambers 1977).…”

The developmental strategies and related profitability of an idiobiont ectoparasitoid Sclerodermus pupariae vary with host size

“…Of the factors (e.g. favourable species, size, stage) (Li et al, 2010;Lauzière et al, 2011;Liu et al, 2011). For insect parasitoids, a single host represents the entire quantity of resources and physiological environment available during immature development.…”

Host Suitability of a Gregarious Parasitoid on Beetle Hosts: Flexibility between Fitness of Adult and Offspring

“…S. harmandi is a synovigenic anautogenous species in which oogenesis takes place after females feed on hosts and is stimulated by direct access to suitable hosts for oviposition [8], [15]. Because host meals are essential for oogenesis throughout the reproductive lifetime, parasitoids are often considered to have inherent parental conflicts of interest vis-à-vis their progeny [16]–[17].…”