Species Diversity, Parasitism Rates, Longevity, and Population Dynamics of the Parasitoid Complex Attacking Ophelimus...

The fast-growing Eucalyptus is often subjected to significant threats from the invasive gall wasp Ophelimus bipolaris Chen & Yao. This study represents the first report of the parasitoid complex associated with O. bipolaris in China. Seven parasitoid species were identified, including three known species, Closterocerus pulcherrimus (Kerrich), C. chamaeleon (Girault), and Eurytoma spinipes Kalina, and four recently described species, Aprostocetus bipolaris Zheng & Yefremova, Aprostocetus eucalyptus Zheng & Yefremova, Chrysonotomyia ophelimi Zheng & Yefremova, and Megastigmus bipolaris Zheng & Yefremova. While several of these parasitoid species (e.g., A. bipolaris, A. eucalyptus, C. ophelimi, and M. bipolaris) have recently been described as parasitoids of O. bipolaris, this study provides the first concurrent evaluation of their relative abundance and parasitism performance under field conditions. Their parasitism rates varied, with C. ophelimi being the most effective (33.85%). In laboratory experiments, access to a honey solution significantly increased the adult longevity of these parasitoids. Field monitoring revealed that the population dynamics of C. ophelimi and O. bipolaris exhibited three synchronized peaks in April, July, and October. These findings identify C. ophelimi as a promising native biocontrol agent and highlight the importance of adult nutrition in enhancing the efficacy of parasitoids for the management of O. bipolaris.