Bean Weevils

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Bean Weevil Facts

  • Bean weevils range in size from 3.5 to 5 mm.
  • Bean weevils cause extensive damage to live bean plants, dry stored beans and other grains.

What Are Bean Weevils?

Bean weevils are actually beetles, lacking the snouts of true weevils
Infesting a variety of seeds and beans, bean weevils, or seed beetles, actually belong to the family Chrysomelidae, which includes leaf beetles. Granivores, bean weevils can live out their entire lives inside a single seed. Ranging in size from 3.5 to 5 mm, bean weevils, or bean beetles, are relatively small and compact oval-shaped black or brown insects, often with mottling or striped patterns. With over 1,350 species globally, including cowpea weevils, bean weevils lack the long snouts characteristic of true weevils.

Bean weevils thrive on all continents in the world with the exception of Antarctica. Probably originating in West Africa, according to historians, the majority of bean weevil populations spread throughout the world in legume shipments, while some were distributed by people moving dry stores of beans from place to place.

Bean weevils make excellent research subjects
Considered model organisms, because of their quick generation times, low maintenance, bean weevils are commonly used in research and education. Several species, considered agricultural pests in the US, destroy bean crops and some species infest warehouse bean stores, making their way into household cupboards.

Adult female bean weevils do not feed on beans but deposit their eggs on WHOLE beans or seeds. Beans provide nutrition for developing larvae that eat their way into beans. When bean larvae pupate, they emerge through exit holes as adults.

Additional Information

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