Anthribidae

Oberprieler, Rolf G., Marvaldi, Adriana E. & Anderson, Robert S., 2007, Weevils, weevils, weevils everywhere *, Zootaxa 1668, pp. 491-520 : 499

Anthribidae

This is a much larger family of weevils, with 371 genera and 3860 species described ( Rheinheimer 2004) and occurring throughout the world, mostly in tropical regions. Anthribid success in diversity is seemingly linked to mycetophagy, their adults and larvae developing predominantly on wood-decaying ascomycete fungi ( Holloway 1982). Some species, however, feed on pollen, lichens, wood, seeds and even scale insects. The anthribid rostrum is short and broad (fig. 2), seemingly adapted to grazing fungal mycelia and not used in preparing oviposition sites ( Howden 1995), but the larvae lead a truly endophytic life inside fungus-infested wood of mainly angiosperms, the eggs being inserted into the plant tissues by means of a specialised, dentate ovipositor. Mycetophagy appears to be the ancestral life style of anthribids and the development in angiosperm seeds and stems by the specialised Choraginae and Urodontinae a derived trait, although the latter group was thought to have retained the phytophagous habits of ancestral weevils ( Crowson 1984). The cycad-associated genus Apinotropis in southern Africa suggests that mycetophagy may have evolved from a phytophagous larval development in decaying gymnosperm sporophylls (Oberprieler 1999).

Several questions remain about the classification of the Anthribidae . The weevil phylogeny of Kuschel (1995) shows them as the sister-group of all other weevil families except Nemonychidae , but subsequent analyses of expanded character sets ( Marvaldi & Morrone 2000, Marvaldi et al. 2002) indicate them as being adelphic to Nemonychidae . Although most character agreements between these two families are based on plesiomorphic conditions and few synapomorphies are in evidence in support of this relationship, it is also readily recovered in recent molecular analyses (Marvaldi et al. in prep.). Within Anthribidae , uncertainties exist about the status of the three subfamilies Anthribinae , Choraginae and Urodontinae , in that the monophyly of Anthribinae with respect to Choraginae is not established and in that Urodontinae differ from the other two groups in numerous features, prompting several authors (e.g., Crowson 1984, Thompson 1992, Louw 1993) to treat them as a distinct family. They share a few apomorphic features with Anthribinae / Choraginae , notably the long but faint, transverse notosternal sutures, a grooved pygidium (tergites 6/7) and the absence of tibial spurs, but their male genitalia are quite different ( Lyal & Barclay 2001, Wanat 2007) and their larvae have dorsal ambulatory papillae and purple Malpighian tubules ( May 1993) like those of Nemonychidae . The tubules may be involved in silk production, as at least some urodontine larvae spin cocoons for pupation in the soil ( Scott 1930, Oberprieler pers. obs.). Further studies and especially analyses of molecular characters are needed to establish the true relationships and taxonomic status of the urodontines. Relationships within Anthribinae are still unclear, no phylogeny being available yet and no proper concepts existing for the 28 tribes generally recognised.