Weevil snouts chew—they do not pierce like a mosquito
Curculionoidea beetles, usually under 6 mm and plant-eating, brandish elongated rostra that carry chewing jaws at the tip. About 97,000 species make them one of beetle-dom's mega-clades. Grain, maize, and rice weevils wreck stored harvests; many still fly, while Otiorhynchus species often cannot.
About 97,000 known species make the superfamily Curculionoidea one of the great beetle radiations, most of them in Curculionidae, the true weevils. Bark beetles, despite lacking the trademark snout, sit inside that family, while "bean weevils" and the biscuit weevil wear the name without being close kin. Typical weevils are small plant-eaters under 6 mm long.
The rostrum is a drill, not a straw. Chewing jaws sit at its tip, and its main job is egg-laying: a female bores a deep hole into plant tissue and then slips her ovipositor in. In the hollyhock-feeding Rhopalapion longirostre, the female's snout is twice the male's length, a difference driven by that boring work rather than mate choice. New Zealand's giraffe weevil shows the opposite skew, with males reaching 90 mm against 50 mm for females. Advanced weevils fold the base of the antenna into a groove along the snout, and true weevils have elbowed antennae where primitive ones have straight.
Larvae are soft, nearly legless grubs that mostly live inside dying or stressed plants, though Tentegia larvae eat dung. The most primitive living weevils feed on conifers, hinting that conifers were the original host, and fossils reach back to the boundary between the Middle and Late Jurassic, from Kazakhstan, Mongolia, China and Australia. Austroplatypus incompertus is eusocial, a rarity among insects outside ants, bees, wasps and termites.
People meet weevils mainly as pests. Sitophilus granarius and the maize weevil hollow out stored grain, and the boll weevil lays eggs in cotton bolls that its larvae eat their way out of. Most weevils, rice weevils included, can fly, though Otiorhynchus is often grounded and some species jump. Other species earn their keep as biological controls on invasive plants.
Source: Weevil
