Assessment of Zophobas morio (Coleoptera: Tenebrionidae) pupae in cold storage for mass rearing of the ectoparasitoid Dastarcus helophoroides (Coleoptera: Bothrideridae)
摘要
Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important biocontrol agent against longhorned beetles, and could be successfully reared on the factitious host Zophobas morio Fabricius (Coleoptera: Tenebrionidae). To improve the production quality of this parasitoid and enhance the utilization efficiency as well as available periods of the host, the life history parameters (parasitism rate, cocooning rate, emergence rate, larval duration, cocoon duration, and adult weight) of D. helophoroides were examined using Z. morio pupae stored at 0 °C, 5 °C, 10 °C, and 15 °C for 6‒84 days at 6-day intervals (0 day as the control) as the factitious host. The results showed that the parasitism rates of this parasitoid gradually decreased with increasing host storage period at a given temperature, while the larval durations were prolonged. The cocooning and emergence rates initially increased but then declined at 0 °C, 5 °C and 10 °C, whereas these parameters remained statistically stable throughout the storage periods at 15 °C. Adult weight did not significantly differ from or even exceed that of the control in any of the treatments. We suggest that ≤ six days at 0 °C and 5 °C, ≤ 24 days at 10 °C, and ≤ 18 days at 15 °C represent the optimum storage conditions for Z. morio pupae. These findings should be helpful for efficient utilization of factitious hosts while reducing the rearing costs of parasitoids, thereby improving the mass production efficiency of D. helophoroides and making more cost-effective use of resources in biological control programs.