Weevil

Weevils Temporal range: Recent PreꞒ Ꞓ O S D C P T J K Pg N
Lixus pulverulentus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Suborder:	Polyphaga
Infraorder:	Cucujiformia
Clade:	Phytophaga
Superfamily:	Curculionoidea Latreille, 1802
Families
Anthribidae Attelabidae Belidae Brentidae Caridae Cimberididae Curculionidae †Mesophyletidae Nemonychidae †?Obrieniidae

Weevils are

Many weevils are considered pests because of their ability to damage and kill crops. The grain or wheat weevil (Sitophilus granarius) damages stored grain, as does the maize weevil (Sitophilus zeamais) among others. The boll weevil (Anthonomus grandis) attacks cotton crops; it lays its eggs inside cotton bolls and the larvae eat their way out. Other weevils are used for biological control of invasive plants.

A weevil's rostrum, or elongated snout, hosts chewing mouthparts instead of the piercing mouthparts that proboscis-possessing insects are known for. The mouthparts are often used to excavate tunnels into grains.^[1] In more derived weevils, the rostrum has a groove in which the weevil can fold the first segment of its antennae.

Most weevils have the ability to fly (including pest species such as the rice weevil^[2][3]), though a significant number are flightless, such as the genus Otiorhynchus.

One species of weevil, Austroplatypus incompertus, exhibits eusociality, one of the few insects outside the Hymenoptera and the Isoptera to do so.

Taxonomy and phylogeny

Because so many species exist in such diversity, the higher classification of weevils is in a state of flux. They are generally divided into two major divisions, the Orthoceri or primitive weevils, and the Gonatoceri or true weevils (

• Anthribidae—fungus weevils
• Attelabidae—leaf rolling weevils
• Belidae—primitive weevils
• Brentidae—straight snout weevils
• Caridae
• Cimberididae
• Curculionidae—true weevils
• †Mesophyletidae
• Nemonychidae—pine flower weevils
• †?Obrieniidae

Sexual dimorphism

Rhopalapion longirostre exhibits an extreme case of sexual dimorphism. The female rostrum is twice as long and its surface is smoother than in the male. The female bores egg channels into the buds of Alcea rosea. Thus, the dimorphism is not attributed to sexual selection. It is a response to ecological demands of egg deposition.^[15]

Another example of extreme dimorphism in weevils is that of the New Zealand giraffe weevil, males measure up to 90 mm (3.5 in), and females 50 mm (2.0 in), although there is an extreme range of body sizes in both sexes.

References