Adaptive divergence of three Aphis gossypii haplotypes on leguminous hosts.

BACKGROUND As a polyphagous agricultural pest of global significance, Aphis gossypii exhibits substantial population differentiation and inflicts damage across a broad host range, including economically important leguminous crops. This study aimed to clarify the adaptation of three A. gossypii haplotypes (Hap1, Hap3, Hap4) to four legume hosts: cowpea (Vigna unguiculata) varieties Zhongshouluchangfeng (ZLC) and Zhongshoucuichangfeng (ZCC), hyacinth bean (Lablab purpureus) and winged bean (Psophocarpus tetragonolobus). RESULTS Results showed Hap1 and Hap4 on cowpeas had higher net reproductive rate (R0 > 25) and intrinsic rate of increase (r > 0.36) than on hyacinth bean and winged bean (R0 < 6, r < 0.27). Meanwhile, Hap3 exhibited poor life-table parameters on all legumes. Among legumes, all haplotypes preferred hyacinth bean and refused to feed on winged bean. EPG analysis showed that Hap1 and Hap4 had longer nonprobing time on winged bean, and prolonged xylem ingestion on hyacinth bean. All haplotypes fed longer on cowpea phloem than on hyacinth bean and winged bean. Notably, the proportion of saliva secretion time in the phloem feeding duration of A. gossypii feeding on winged bean exceeded 75%. A. gossypii that fed on cowpeas secreted the highest amount of honeydew CONCLUSION: Different haplotypes of cotton aphids show differentiated adaptability to legumes, and there also is differentiation in the aphid resistance among legumes. These findings can be applied to the formulation of aphid control technologies for legumes and lay a foundation for studying the co-evolution between A. gossypii and their hosts. © 2025 Society of Chemical Industry.