| image_caption = ''[[Lixus angustatus]]''

Many weevils are damaging to crops. The grain or [[wheat weevil]] (''Sitophilus granarius'') damages stored [[cereal|grain]]. The [[boll weevil]] (''Anthonomus grandis'') attacks [[cotton]] crops. It lays its eggs inside cotton bolls, and the young weevils eat their way out.

Weevils are often found in dry foods including nuts and seeds, cereal and grain products, such as pancake mix. In the domestic setting, they are most likely to be observed when a bag of flour is opened. Their presence is often indicated by the granules of the infested item sticking together in strings, as if caught in a cobweb.

Because there are so many species and such diversity, the higher classification of weevils is in a state of flux. Weevils are generally divided into two major divisions, the Orthoceri or primitive weevils, and the Gonatoceri or true weevils ([[Curculionidae]]). [[Elwood Zimmerman|E. C. Zimmerman]] proposed a third division, the Heteromorphi, for several intermediate forms.<ref>{{cite book |author=E. C. Zimmerman |year=1994 |title=Australian weevils (Coleoptera: Curculionidae). Volume 1. Orthoceri: Anthribidae to Attelabidae: the primitive weevils |publisher=[[Commonwealth Scientific and Industrial Research Organisation|CSIRO]] |location=[[East Melbourne, Victoria|East Melbourne]] |pages=741 pp}}</ref> Primitive weevils are distinguished by having straight antennae, while true weevils have elbowed (geniculate) antennae. The elbow occurs at the end of the [[antenna (biology)|scape]] (first antennal segment) in true weevils, and the scape is usually much longer than the other antennal segments. Some exceptions occur. [[Nanophyini]] are primitive weevils (with very long [[arthropod leg|trochanters]]) but have long scapes and geniculate antennae. From the true weevils, [[Gonipterinae]] and ''[[Ramphus]]'' have short scapes and little or no elbow.

The most recent classification system to family level was provided by Kuschel,<ref>{{cite journal |author=G. Kuschel |year=1995 |title=A phylogenetic classification of Curculionoidea to families and subfamilies |journal=[[Memoirs of the Entomological Society of Washington]] |volume=14 |pages=5–33}}</ref> with updates from Marvaldi ''et al.'',<ref name="Marvaldi">{{cite journal |author=A. E. Marvaldi, A. S. Sequeira, C. W. O'Brien & B. D. Farrell |year=2002 |title=Molecular and morphological phylogenetics of weevils (Coleoptera, Curculionidae): do niche shifts accompany diversification? |journal=[[Systematic Biology]] |volume=51 |issue=5 |pages=761–785 |url=http://taylorandfrancis.metapress.com/openurl.asp?genre=article&doi=10.1080/10635150290102465 |doi=10.1080/10635150290102465 |pmid=12396590}}</ref> and was achieved using [[phylogenetic]] analyses. The accepted families are the primitive weevils, [[Anthribidae]], [[Attelabidae]], [[Belidae]], [[Brentidae]], [[Caridae]] and [[Nemonychidae]], and the true weevils [[Curculionidae]]. Most other weevil families were demoted to subfamilies or tribes. Weevil species radiation was shown to follow steps in plant evolution upon which the weevils feed. Weevils can vary in color from black to light brown.