From flower buds to bolls: how cotton reproductive structures shape boll weevil development, reproduction and...

The cotton boll weevil Anthonomus grandis grandis is a major pest in tropical and subtropical cotton crops, where its management relies heavily on insecticide applications. Despite that, the physiological mechanisms enabling survival and reproduction in the tropical off-season remain poorly understood. This study examined host usage, and physiological pathways linking nutrition and reproduction in boll weevils, and how larval and adult food sources affect development, survival and reproduction.

Larvae fed bolls extended developmental time, produced larger adults, accumulated greater lipid reserves and survived longer, particularly if fed pollen when adult, but females exhibited significantly reduced fecundity compared with those developing in flower buds. By contrast, flower bud-fed adults displayed enhanced ovariole development, higher protein content and markedly increased daily egg production. Molecular analysis revealed that vitellogenin (Vg) expression was reduced in females fed on bolls or cotyledons, suggesting nutritional constraints impairing reproductive capacity. Vg expression was 2.5-fold higher in bud-fed females relative to boll-fed counterparts, whereas FOXO expression remained unaffected. These results demonstrate a reproduction-longevity trade-off driven by adult diet quality: flower buds promoted reproductive output, whereas bolls favored lipid storage and extended survival.

Feeding on cotton flower buds sustains continuous reproduction in A. grandis grandis, whereas boll-based diets reduce vitellogenesis and favor survival through lipid accumulation. This nutritional shift explains how tropical populations persist during host-free periods but resume reproduction once they return to flower bud feeding. The findings highlight the need for strict crop-free intervals and provide a physiological basis for refining integrated management strategies. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.