Study on the biological characteristics of Ephedrus plagiator

The objective of this study is to investigate the biological characteristics of Ephedrus plagiator, an important endoparasitoid of Hyaloptera arundinis, as studies on its biological characteristics are scarce both domestically and internationally. This study can provide a theoretical basis for the biological control of H. arundinis.

In this paper, we adopted a combination of field investigations and laboratory experiments to examine the parasitic characteristics, emergence, occurrence patterns, mating behavior, and oviposition behavior of E. plagiator.

The results showed that E. plagiator completed 6~8 generations per year in the Baoding area, and the occurrence period was from April to November; it overwintered mostly as mature larvae inside the mummies of H. arundinis. After being parasitized, H. arundinis continued feedinh for 1~2 days, ceased movement and feeding after 3 days, and gradually swelled and died within 4~8 days, E. plagiator adults emerged from the host on days 10~12. Three instars were initially observed in the larval stage, and four developmental stages were observed in the pupal stage, with distinct morphological characteristics at each stage. Adults mainly emerged during daylight, peaking between 6:00-8:00, accounting for 28% of the daily total emergence. The parasitism rate of E. plagiator against H. arundinis was the highest in mid-June, reaching 53%; the female-to-male ratio was 3∶1. Compared with the control group (without sugar feeding), 15% honey water or 15% sucrose solution significantly increased the parasitism rate and prolong E. plagiator's lifespan. The 15% honey water yielded the best results, with the parasitism rate and lifespan reaching 59% and 11.17 days, respectively. The mating process of E. plagiator was divided into four stages: courtship, pre-copulation, copulation, and post-copulation; the female wasps mated only once in their lifetime, while the male wasps mate multiple times. Oviposition process was divided into three stages: pre-oviposition host location and inspection, oviposition, and post-oviposition grooming.

This study clarifies the key biological characteristics of E. plagiator, which provides an important theoretical basis for the application of E. plagiator to the biological control of H. arundinis.