Chen Yao, Cui Hejun, Xu Tian, Chen Li
College of Life Sciences, Hebei Basic Science Center for Biotic Interactions, Hebei University, Baoding 071002, China.
Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
Insects. 2025 Mar 4;16(3):271. doi: 10.3390/insects16030271.
Cotton aphids, , are an important pest worldwide and have evolved mutualistic relationships with the invasive fire ant . Their body color varies from pale yellow to dark green, with an increase in body size and fecundity. The body color composition in a cotton aphid colony can be influenced by biotic interactions with mutualistic ants and predatory ladybugs. However, since the distribution of nutrients varies across host plant organs, there may exist special effects of biotic interactions on the body color composition of the aphids on different plant parts. In the present study, we found that, under constant laboratory conditions, the proportions of dark green morphs varied among the cotton aphids distributed on different parts of a cotton seedling, with significantly higher proportions on the stems, petioles, and sprouts (SPSs) than on leaves. The presence of mutualistic fire ants significantly increased the proportion of dark green morphs in the cotton aphid colony, but with a reduction in aphid body size, compared to the untended individuals. In contrast, the introduction of a predatory seven-spotted ladybug, , dramatically decreased the proportion of dark green morphs on SPSs, but not on leaves, leading to a reduction in the proportion of the whole colony. These results illustrate a spatial variation in the proportions of dark green morphs on host plants in cotton aphids, which may be an adaptive strategy used by the aphids to gain benefits and/or minimize costs in the interactions with mutualistic ants and predatory ladybugs.
棉蚜是全球重要害虫，已与入侵红火蚁形成互利共生关系。其体色从浅黄色到深绿色不等，且体型和繁殖力会增加。棉蚜群体中的体色组成会受到与互利共生蚂蚁和捕食性瓢虫的生物相互作用影响。然而，由于宿主植物器官中养分分布不同，生物相互作用可能对不同植物部位上蚜虫的体色组成存在特殊影响。在本研究中，我们发现，在恒定实验室条件下，分布在棉苗不同部位的棉蚜中深绿色形态的比例不同，茎、叶柄和嫩梢（SPSs）上的比例显著高于叶片。与未受照顾的个体相比，互利共生的红火蚁的存在显著增加了棉蚜群体中深绿色形态的比例，但蚜虫体型减小。相反，引入捕食性七星瓢虫显著降低了SPSs上深绿色形态的比例，但对叶片上的比例没有影响，导致整个群体的比例下降。这些结果表明棉蚜在宿主植物上深绿色形态比例存在空间差异，这可能是蚜虫在与互利共生蚂蚁和捕食性瓢虫相互作用中获取利益和/或最小化成本的一种适应性策略。
