The Curculionoidea (weevils) are a hyperdiverse group of beetles with between 60,000 and 70,000 described species. They can be distinguished from most other beetles by their possession of a tubular extension to the front of the head - the rostrum - on which the mouthparts are borne. Some weevils apparently lack a rostrum, in particular the bark beetles and powder post beetles (Scolytinae and Platypodinae), and a very few other beetles have a similar structure, but in the majority of cases the structure is diagnostic
Most weevils are plant-feeding both as larvae and adults, although there are a number of fungus-feeders. The adults mainly feed externally, as do some larvae. Most species, however, have internally-feeding larvae, these gaining protection against predators, parasitoids and desiccation by this means. The adult female will use her rostrum to drill a hole in the plant into which she deposits one or more eggs. Weevil larvae can be found on or in all plant parts: boring in roots, stems and leaves, feeding in buds, fruit or seeds, creating galls, and utilising both dead and living plants. Some weevil species are agricultural, forestry or horticultural pests, while others are immensely economically valuable in biocontrol or as pollinators
Weevil classification is problematic, and there is still great disagreement on the phylogenetic relationships or even validity of most groups within the superfamily. On this site two classifications are given, so that users can see how different taxonomists are today using the names.