Interactions between migration and immunity among oriental armyworm populations infected with the insect pathogenic fungus, Beauveria bassiana

Authors: LV, WEIXIANG - Chinese Academy Of Agricultural Sciences; JIANG, XINGFU - Chinese Academy Of Agricultural Sciences; LI, PING - Chinese Academy Of Agricultural Sciences; XIE, DIANJIE - Chinese Academy Of Agricultural Sciences; Stanley, David; HU, GAO - Chinese Academy Of Agricultural Sciences; ZHANG, LEI - Chinese Academy Of Agricultural Sciences

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2024
Publication Date: 8/9/2024
Citation: Lv, W., Jiang, X., Li, P., Xie, D., Stanley, D.W., Hu, G., Zhang, L. 2024. Interactions between migration and immunity among oriental armyworm populations infected with the insect pathogenic fungus, Beauveria bassiana. Journal of Pest Science. https://doi.org/10.1002/ps.8345.
DOI: https://doi.org/10.1002/ps.8345

Interpretive Summary: Many pest insect species undergo seasonal migrations. The oriental armyworm is a serious long-distance migratory pest insect. It migrates from southern China to northern China and other Asian countries in spring and returns as winter approaches. A problem is that environmental changes are driving a shift from migration to residency in pest insect some populations. There is very little information on the interactions between migratory and resident populations, particularly with respect to key aspects of pest insect biology, such as immune reactions to infections. Here, we investigated migration-immunity interactions between migrant and resident populations infected with a pathogenic fungus. Compared to resident populations, we found the migrants had stronger pathogen resistance and faster development. However, large infections led to decreased reproduction in migrants and residents. Smaller infections led to increased flight capacity, yet long-distance flights (5 consecutive 10 hour night flights) inhibited reproductions in infected males and led to serious transgenerational impairments in off spring larval development and immune capacities. This study generated new, necessary knowledge on interactions between migration and immunity in a migratory pest insect. This new knowledge will be used by scientists at the global level to expand research beyond a single pest to greater understanding of migratory pests generally. It will also contribute to developing new migratory pest insect monitoring and management. In the longer term, it will lead to sustainable production of agricultural products for a growing human population.

Technical Abstract: Migration and immunity are behavioral and physiological traits that protect organisms from environmental stressors or pathogen infection. Shifting from migration to residency has become more common in some wildlife populations due to environmental changes. However, other biological shifts, such as interactions between migration and immunity among populations within a species are largely unexplored for many agricultural migratory pests. Here, we investigated migration-immunity interactions between migrant and resident populations infected with Beauveria bassiana (the sole fungus used in this work) in the oriental armyworm, Mythimna separata, a long-distance migratory pest. We found that M. separata migrants exerted stronger pathogen resistance, faster development and lower pupal weight than residents. High-concentration infections (5.0×105 and 5.0×106 conidia/mL) led to seriously decreased reproductive capacity in migrants and residents. Low-concentration infections (1.0×104 and 5.0×104 conidia/mL) led to significantly increased host flight capacities. Consecutive flight tests showed that 5 flight nights inhibited the reproduction of paternal infected M. separata populations. The flights also led to serious transgenerational impairment to larval development and immune defense of offspring populations. In contrast, two flight nights enhanced the reproductive capacities of M. separata populations and did not exert negative transgenerational effects on offspring populations. This may facilitate migration. This study provides insights into interactions between migration and immunity among M. separata populations. These insights may guide development of future monitoring and management technologies of this pest.