It also includes the bark beetles as subfamilyScolytinae, which are modified[unreliable source?] in shape in accordance with their wood-boring lifestyle. They do not much resemble other weevils, so they were traditionally considered a distinct family, Scolytidae. The family also includes the ambrosia beetles, of which the present-day subfamily Platypodinae was formerly considered the distinct family Platypodidae.
They are recognized by their distinctive long snout and geniculate antennae with small clubs; beyond that, curculionids have considerable diversity of form and size, with adult lengths ranging from 1 to 40 millimetres (0.04 to 1.57 in).
Weevils are almost entirely plant feeders, and most species are associated with a narrow range of hosts, in many cases only living on a single species. With so many species to classify and over 400 genera, the taxonomy of this family is quite complicated, and authors disagree on the number and placement of various subfamilies, tribes and subtribes.
The phylogeny of the group is complex; with 40 000 species there is a spirited debate about the relationships between subfamilies and genera. A 1997 analysis attempted to construct a phylogeny based mainly on larval characteristics.
Almost two dozen subfamilies are recognized by some authors even when merging those that are certainly invalid. Others, however, recognize a lesser number – the only subfamilies that are almost universally considered valid are the Baridinae, Cossoninae, Curculioninae, Cyclominae, Entiminae, Molytinae, Platypodinae and Scolytinae. The various proposed taxonomic schemes typically each usually recognize again as many additional subfamilies, but there is little agreement between authorities about which ones of those below these are. In particular the delimitation of the Molytinae has proven difficult.
The subfamilies considered valid by at least some authors today:
Curculionidae (Weevils, Snout Beetles) This is a very large family of beetles. The adults range in size from small to large; they have stout bodies and a hard carapace. Weevils have a long narrow snout projecting from the head, with a pair of short, jointed antennae toward the middle of this snout. This provides them with a distinctive appearance. Weevils are generally dull tannish brown or grey, but sometimes have carapace that is red, green, or shiny black. Both adults and larvae feed on various parts of many kinds of plants, and can be very destructive. However, adults sometimes visit flowers to feed on pollen or nectar. Insect activities: sn = sucks nectar
Barcode of Life Data Systems (BOLD) Stats Specimen Records:32423 Specimens with Sequences:22749 Specimens with Barcodes:18089 Species:4019 Species With Barcodes:3019 Public Records:8312 Public Species:1845 Public BINs:1788