![]() Rhopalapion longirostre exhibits an extreme case of sexual dimorphism. Ī phylogeny of the Curculionoidea based on 18S ribosomal DNA comparison and morphological data conducted by Marvaldi et al in 2002 is suggested below: ![]() However, their phylogenetic position is contested, with others considering it part of Archostemata. Genera of the family have been only found in three formations in Kazakhstan, with most named in 1993. The extinct family Obrieniidae, with species dating from the Ladinian stage of the Triassic through to tentatively the Oxfordian, have sometimes been considered weevils. The oldest weevils date to the Middle-Late Jurassic boundary, found in the Karabastau Formation of Kazakhstan, the Shar-Teg locality of Mongolia, the Daohugou locality in Inner Mongolia, China, and the Talbragar site in Australia. Further work resulted in the elevation of Cimberididae to family from placement as a subfamily of Nemonychidae in 2017 and the recognition of the Cretaceous age family Mesophyletidae in 2018 from Burmese amber. Most other weevil families were demoted to subfamilies or tribes. The accepted families were the primitive weevils, Anthribidae, Attelabidae, Belidae, Brentidae, Caridae, and Nemonychidae, and the true weevils Curculionidae. 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.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. Eastern Pine Weevil ( Pissodes nemorensis)
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |