in 2002, and was achieved using phylogenetic analyses. Some exceptions occur, such as Nanophyini, primitive weevils with long scapes and geniculate antennae, while among the true weevils, Gonipterinae and Ramphus have short scapes and little or no "elbow".Ī 1995 classification system to family level was provided by Kuschel, with updates from Marvaldi et al. The elbow occurs at the end of the scape (first antennal segment) in true weevils, and the scape is usually much longer than the other antennal segments. Primitive weevils are distinguished by having straight antennae, while true weevils have elbowed (geniculate) antennae. Zimmerman proposed a third division, the Heteromorphi, for several intermediate forms. ![]() They are generally divided into two major divisions, the Orthoceri or primitive weevils, and the Gonatoceri or true weevils ( Curculionidae). One species of weevil, Austroplatypus incompertus, exhibits eusociality, one of the few insects outside the Hymenoptera and the Isoptera to do so.Ĭurculio nucum Taxonomy and phylogeny īecause so many species exist in such diversity, the higher classification of weevils is in a state of flux. Most weevils have the ability to fly (including pest species such as the rice weevil ), though a significant number are flightless, such as the genus Otiorhynchus. In more derived weevils, the rostrum has a groove in which the weevil can fold the first segment of its antennae. The mouthparts are often used to excavate tunnels into grains. Other weevils are used for biological control of invasive plants.Ī weevil's rostrum, or elongated snout, hosts chewing mouthparts instead of the piercing mouthparts that proboscis-possessing insects are known for. The boll weevil ( Anthonomus grandis) attacks cotton crops it lays its eggs inside cotton bolls and the larvae eat their way out. The grain or wheat weevil ( Sitophilus granarius) damages stored grain, as does the maize weevil ( Sitophilus zeamais) among others. Many weevils are considered pests because of their ability to damage and kill crops. Some other beetles, although not closely related, bear the name "weevil", such as the biscuit weevil ( Stegobium paniceum), which belongs to the family Ptinidae. It also includes bark beetles, which while morphologically dissimilar to other weevils in lacking the distinctive snout, is a subfamily of Curculionidae. They belong to several families, with most of them in the family Curculionidae (the true weevils). Approximately 97,000 species of weevils are known. They are usually small – less than 6 mm ( 1⁄ 4 in) in length – and herbivorous. Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts.
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