User:Vircum/Bean weevil

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Bean weevils
Starr 040201 3575 acanthoscelides obtectus.jpg
Acanthoscelides obtectus
Scientific classification

Latreille, 1802 [1]

About 1,350 species; see text.

58 genera
Damage to beans by larvae of the common bean weevil, Acanthoscelides obtectus

The bean weevils or seed beetles are a subfamily (Bruchinae) of beetles, now placed in the family Chrysomelidae, though they have historically been treated as a separate family. They are granivores, and typically infest various kinds of seeds or beans, living for most of their lives inside a single seed. The family includes about 1,350 species found worldwide.

Bean weevils are generally compact and oval in shape, with small heads somewhat bent under. Sizes range to 1 mm, up to 22 mm for some tropical species. Colors are usually black or brown, often with mottled patterns. Although their mandibles may be elongate, they do not have the long snouts characteristic of true weevils.

Adults deposit eggs on seeds, then the larvae chew their way into the seed. When ready to pupate, the larvae typically cut an exit hole, then return to their feeding chamber. Adult weevils have a habit of feigning death and dropping from a plant when disturbed.

Host plants tend to be legumes, but species will also be found in Convolvulaceae, Arecaceae, and Malvaceae, and several species are considered pests.

One characteristic of the beetles which can be seen in the photo is that the elytra are short, not quite reaching the tip of the abdomen.

The adult beetles are occasionally found in the United Kingdom when they emerge out of stored products in warehouses & dwellings, but they cannot proliferate in unheated buildings in that climate.

Notable species[edit]


This list of genera follows the old systematics, when the family Bruchidae was still valid.[1]


  1. ^ "Bruchinae". Integrated Taxonomic Information System.