Morphological Anatomy, Developmental Characteristics of the Reproductive System in Arhopalus rusticus (Coleoptera: Cerambycidae) and Their Impacts on the Transmission Potential of Bursaphelenchus xylophilus (Aphelenchida: Parasitaphelenchidae)

In recent years, opinions have diverged on whether the oviposition pathway of Arhopalus rusticus (Linnaeus, 1758) (Coleoptera: Cerambycidae) can transmit Bursaphelenchus xylophilus (Steiner & Buhrer, 1934) (Aphelenchidae: Nematoda). Based on biological observations and biochemical index calculations, this study assessed the development degree of the internal reproductive system (morphological soluble total sugar and protein content) and external genital morphology of A. rusticus before and after gnawing pine needles. The study results indicate that A. rusticus developed and matured immediately after eclosion in natural conditions, and it could mate and spawn directly. However, gnawing on pine needles has no significant impact on the development of the reproductive system of both male and female A. rusticus, indicating that this behavior is not a prerequisite for reproductive maturity. Furthermore, through dissection and behavioral observations, it has been determined that the degree of ossification in the ovipositor of A. rusticus is lower than that in the ovipositor of Monochamus alternatus (Hope, 1843) (Coleoptera: Cerambycidae), and its egg-laying method involves only depositing eggs on the surface of a bark, thus confirming that the reproductive behavior of A. rusticus does not facilitate the transmission of B. xylophilus.