Bean-weevil
Guides
Bruchini
seed beetles, bean weevils
Bruchini is a tribe of small beetles within the subfamily Bruchinae, commonly known as seed beetles or bean weevils. Despite their common name, they are true beetles (Coleoptera), not weevils (Curculionidae). Members of this tribe are characterized by their compact, oval bodies and association with legume and other plant seeds. The tribe contains numerous genera, including Bruchus and Acanthoscelides, many of which are significant agricultural pests.
Zabrotes subfasciatus
Mexican bean weevil
Zabrotes subfasciatus, commonly known as the Mexican bean weevil, is a small bruchine beetle that infests stored legume seeds, particularly common bean (Phaseolus vulgaris). Females deposit eggs on seed coats; larvae develop endophytically within the cotyledons, consuming the seed from the inside. A single seed can support up to 20 emerging adults. The species has demonstrated capacity to utilize alternative hosts including cowpea (Vigna unguiculata), lentil, chickpea, and soybean, with populations showing plasticity in host preference through artificial selection. Development from egg to adult takes approximately 34 days at 27°C and 70% relative humidity. Maximum female fecundity is around 55 eggs. The species is a significant post-harvest pest in tropical regions, with reported production losses up to 35%.