BRENTIDAE

Common names

straight-snouted weevils, pear-shaped weevils, primitive weevils, timberworms

General distribution

Global

Component taxa

There continues to be much controversy in the higher level classification of this and closely related taxa. We follow Lawrence and Newton (1995) and Lawrence (1982) in our assessment of ~350 genera and ~2500 species.

Description

Adult: Overall shape variable from elongate, narrow and parallel-sided to pear-shaped and greatly convex. Length ranging from 2-80mm, typically between 4-20mm. Head with prominent straight rostrum, elongate and typically narrow and cylindrical. Antenna 11-segmented, typically straight (geniculate in Nanophyinae taxa), funicle narrow and slender, terminal two or three antennomeres comprising a loose club or rarely a compact club (some Apioninae and Cyladinae). Elytra typically entire and covering all of abdomen. Hindwing with reduced anal venation. First two abdominal segments connate and longer than following segments. Sexual dimorphism evident in overall body length and shape, length of rostrum.

Larva: Body lightly to moderately sclerotized, white to yellowish in color, typically elongate and subcylindrical, averaging between 2-20mm in length. Vestiture typically short and fine. Legs absent or rudimentary (2 segmented and short). Head typically exserted and hypognathous. Hypopharyngeal bracon present, gular sutures absent, mandible without mola. Antennae reduced to a single segment. Stemmata absent. Pronotal plate on prothorax distinct. Meso- and metathorax subdivided by pro- and postdorsal folds. Abdominal segments subdivided by 3-4 dorsal folds. Urogomphi and terminal appendages absent.

Pest information

Brentid weevils are known to bore into the sapwood of various trees, especially as larvae. The genus Cylas is known to be a pest of sweet potatoes and other crops. Ischnopterapion species have recently been reported as a pest of clover. Some Nanophyinae genera may cause gall formation. Some wood boring pestiferous genera include Orfilaia and Podapion. Some species also have been imported as biocontrol agents for various adventive or noxious plants.