Induction, Maintenance, And Termination Of Diapause In Mylabris Phalerata Pallas

Blister beetle, Mylabris phalerata Pallas (Coleoptera: Meloidae), natural enemy of Chondracris rosea rosea De Geer (Orthoptera: Acridiidae) and important Chinese medicine material, has important economic significance. Facing the fact of shortened resources of the blister beetles, artificial mass rearing becomes one of the effective approaches to obtain large numbers blister beetles. But documents about the blister beetles are not available for people to progress a feasible protocol. The major reason is that few studies are found about the diapause in the fifth instar larvae of M. phalerata. In the field, the blister beetle undergoes larval diapause in the ground, which lasts for more than five months. This makes it be appropriate for researching diapause in soil-inhabiting insects. In addition, more attentions are paid on synchronized development between parasite and host, synchronized development between predators and preys are neglected. In the present study, the relationship of the development of M. phalerata and C. rosea rosea was determined and the effect of the larvae diapause in M. phalerata on the synchronized development between M. phalerata and C. rosea rosea was discussed. The main results of these researches were as follows:The morphology and life history of M. phalerata were observed. The effect of temperature on the duration of immature stages of M. phalerata reared at 18, 22, 25, 28, 31, and 34 °C was determined. The adaptable temperature for artificial mass rearing was ≥ 28°C. Lower developmental thresholds were estimated to be 7.59, 8.28, 8.28, -2.12, 6.63, and 6.29°C for egg, larval instars L1, L2, L3, L4 and pupa, respectively, and the thermal constant was 1839.87 degree-days for total immature stages, using the linear model. Based on the developmental cycle of M. phalerata, its known geographic distribution, and temperature data, diapause is attributed to the overwintering fifth-instar larva.In the field, the blister beetle M. phalerata undergoes larval diapause in the ground, which lasts for nearly six months. The effect of the soil environment on this diapause was examined. Final instar larvae kept at temperatures of ≥ 26 °C do not enter diapause and continued to develop regardless of the soil water content and photoperiod. Below 25 °C the final instar larvae entered diapause regardless of soil water content and photoperiod. The early stages, particularly L2, appeared to be more important for...