Effects of host stage and number of feeding larvae on parasitism success and fitness in the coleopteran parasitoid, Dastarcus longulus Sharp (Coleoptera: Bothrideridae)

Abstract

Fitness elements (number and weight of emerging adults) and the success of parasitism (host mortality) in Dastarcus longulus were compared among three host stages (Monochamus alternatus larvae, pupae and adults). Different numbers of first-instar larvae were released onto single host individuals to determine the optimal host quality and rearing conditions needed to obtain large numbers of high-fitness individuals and to maximize the rearing efficiency of the parasitoid. Host mortality after the release of a single parasitoid larva was 88% on pupal hosts but Ͻ50% on larval and adult hosts. The numbers and weights of emerging adults per host were highest on pupal hosts. The estimated number of ovarioles in emerging adults was also the highest on pupal hosts. Pupae of M. alternatus thus provided the best host quality for rearing D. longulus. High host mortality was caused mainly by pupal immobility. A high feeding rate was associated with high parasitoid reproductive potential on pupal hosts. Although the release of 10 larvae onto a single pupal host resulted in the highest overall fitness of the rearing population of D. longulus, the release of two larvae onto each pupal host was the optimal procedure for maximizing the weight of individuals.

Factors Influencing Copulation Duration in Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae)

“…The gregarious ectoparasitic beetle, Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae), is considered a primary biocontrol agent for controlling several cerambycid pest species [28,29]. This beetle is widely distributed in East Asian countries, including China, Korea, and Japan [28,30,31]. In the field, female D. helophoroides usually lay egg clutches near the elliptical holes and on the frass of cerambycid larvae [28].…”

New method for rapidly estimating population densities of the concealed wood‐borer Monochamus alternatus (Coleoptera: Cerambycidae) in the field

“…The M. alternatus larvae only inhabit dead or dying pine trees, and dissections of logs are typically used to assess the vector populations in forests (Kang et al . ; Urano ; Zhang et al . ), which is very labor‐intensive.…”

“…However, the number of natural enemies to be released in forests needs to be calculated according to the host densities of M. alternatus larvae. The M. alternatus larvae only inhabit dead or dying pine trees, and dissections of logs are typically used to assess the vector populations in forests (Kang et al 2008;Urano 2010;Zhang et al 2012), which is very labor-intensive. In some previous studies, the larval population densities of some cerambycid beetles were related to the number of oviposition sites (Kondo & Yukimasa 1983;Nakamura et al 1995a,b;Ohta et al 2012).…”

Fecundity and egg hatchability of Dastarcus helophoroides adults fed on different types of artificial diets

“…helophoroides larvae can be reared on a substitute host (pupae of carabid beetles, the species are patented) (Yang 2004), live M. alternatus larvae or pupae, and artificial diet (full-grown larvae of Galleria mellonella Linnaeus are needed) Urano 2010). Adults could be reared in the laboratory using different types of artificial diets Ogura et al 1999;Yang 2004;Lei et al 2005).…”