Novel insights into courtship and mating behavior of Anastatus japonicus enhance pest control and mass-rearing efficiency

The solitary egg endoparasitoid, Anastatus japonicus (Hymenoptera: Eupelmidae), holds substantial potential for effectively controlling hemipterous and lepidopterous pests. The present study endeavors to elucidate the courtship and mating behavior of this parasitoid, as a comprehensive understanding of female and male mating status and its implications on offspring production remains inadequately documented. Courtship and mating behavior process impacted by food, age, host, body size, virgin and mated both sexes were monitored by direct observation, while fecundity and female proportion of virgin and mated females were tested in Petri dishes. During courtship, only males make physical contact with the antennae and thorax-abdomen regions of females. Mating success was quicker at younger age of both sexes (i.e. < 24 h old), and higher when A. japonicus males approached the female from the left side (right biased) and preferential turning on the right (left biased) to attempt copula resulting in monandry and polygyny behavior in female and male, respectively. Females prefer to mate with virgin males over mated, and honey fed males were preferred over starved ones. Anastatus japonicus unmated females are haploid and produced only males, however mated females are diploid and produced both progenies. Furthermore, females showed synovigenic strategy and produce more offspring numbers (11-14) and females' proportion (83-92%) at older age (10-30 d old) rather than younger aged (0-5 d, offspring number: 5-10; female proportion: 62-72%). Female wasps that mated with already mated males produce a smaller proportion of females (with virgin male: 61.88%, mated male: 37.17%), exhibiting possible sperm depletion effect. It is highly expected that a tailor-made large-scale rearing system of A. japonicus will be developed to optimize mating success and female-biased progeny production to fully utilize its reproduction potential and to ultimately improve mass-rearing efficiency.