Jasmonic Acid and Salicylic Acid Crosstalk Mediates Asymmetric Interactions Between Aphis gossypii and Lema decempunctata in Lycium barbarum

The aphid, Aphis gossypii Glover, and the leaf beetle, Lema decempunctata Gebler, are two catastrophic pests affecting the production of the organic goji berry, Lycium barbarum L. Our previous studies have demonstrated that the defense responses of goji berry induced by aphid infestations can facilitate the growth and development of beetles. However, the reciprocal effects of these two insect infestations on aphids remained unclear. In this study, the impacts of these two pest infestations on the development, survival, and reproduction of aphids were examined. Additionally, the levels of plant defense-related hormones, salicylic acid (SA) and jasmonic acid (JA), were measured. Subsequently, host plants were treated with two hormone analogues, 2, 1, 3-benzothiadiazole (BTH) and methyl jasmonate (Me-JA), to identify their effects on aphid development, survival, and reproduction. The results showed that the total developmental duration was accelerated by 33.60%, and the total reproduction of aphids was increased by 82.98% compared to the control after aphid infestation, without influencing survival. In contrast, the beetle infestation did not significantly influence any aspect of the aphid population. The content of SA in plants after the aphid infestation and JA after the beetle infestation increased 19.42 times and 400.50 times, respectively, compared with the control. The total developmental duration of aphids treated with BTH was reduced by 13.44%, while their reproduction increased by 60.52% compared with the control. The total developmental duration of aphids treated with Me-JA was prolonged by 23.51% compared to the control, while survival rates and reproduction were unchanged. Our research elucidates the intricate interspecific relationship between A. gossypii and L. decempunctata, providing valuable insights into the complex interspecific relationship between the two pests and informing effective strategies for their scientific prevention and control.