The larvae of the weevil tribe Eurhynchini and the phylogeny of the Brentidae (Coleoptera : Curculionoidea)

Abstract

The larvae of Eurhynchus laevior (Kirby) and Aporhina australis (Heller) are described, representing two of the three extant genera of the small Australian–New Guinean weevil group Eurhynchini. The description of the E. laevior larva verifies the limited account of eurhynchine biology available so far. The patchy knowledge of the biology of these two species is summarised. The larva of E. laevior tunnels in woody branches of Persoonia (Proteaceae), and that of A. australis develops in slightly swollen twigs of Litsea (Lauraceae). An undescribed species of Xanthocryptus Cameron (Ichneumonidae) is recorded from the larval chamber of A. australis. The eurhynchine larvae display the greatest similarity to brentine larvae, but exhibit several less derived character states. A phylogenetic analysis of 33 larval characters is conducted for 20 brentid species spanning Eurhynchini, Brentini, Cyladini, Antliarhinini, Tanaini, Apionini, Nanophyini, Ithycerini and Microcerini, with Curculionidae added as the indicated adelphotaxon of brentids and Caridae as the outgroup. Microcerini are excluded from Curculionidae: Brachycerinae, and included in Brentidae because of numerous character state agreements with the latter. The results suggest a monophyletic family Brentidae with three to four major clades: Ithycerinae, Brentinae and Apioninae, and Microcerinae either as a fourth or included in Brentinae. Eurhynchini consistently cluster as adelphon of Brentini, while Antliarhinini group in Apioninae. Larval characters can be problematic in phylogenetic analyses because of parallel reductions, but they can also show relationships more clearly than imaginal features, which are often adaptive and convergently evolved.