Subfamily Bruchinae Latreille, 1802

Bruchinae

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Subfamily Bruchinae Latreille, 1802

Compiler and date details

January 2013 - ABRS

March 2012 - Chris Reid, Australian Museum, Sydney

Bruchinae Latreille, P.A. 1802. Histoire Naturelle, Générale et Particulière des Crustacés et des Insectes. Ouvrage faisant suite à l’histoire naturelle générale et particulière, composée par Leclerc de Buffon, et rédigée par C.S. Sonnini, membre de plusieurs sociétés savantes. Familles naturelles des genres. Tome troisième. Paris : F. Dufart xii + 13–467 + [1] pp. [An "X" (title page = 1802)] [192].

Introduction

The Bruchinae, traditionally called pea-weevils but better named seed-beetles, have traditionally been considered a separate family, intermediate between leaf-beetles and weevils. That view prevails in almost all popular books on insects, and amongst applied entomologists and bruchine specialists (for example, Kingsolver 2003). Nevertheless, Bruchinae are clearly most closely related to Sagrinae (Crowson 1955, 1994; Monros 1960; Mann & Crowson 1981; Borowiec 1987; Reid 1995, 2000; Gomez-Zurita et al. 2008) and recognition of this relationship requires either that nomenclature does not reflect relationships, or Sagrinae also be given family rank, or that the traditional Bruchidae be demoted to Bruchinae. Since Bruchinae appear to be Chrysomelidae, with morphological novelties for seed predation (Crowson 1955, 1981; Reid 1995), the latter option is preferred and has been applied in most recent Australian literature (Lawrence & Britton 1994; Matthews & Reid 2002). The nomenclatural politics of this issue were debated in the mid 1990s, particularly in the journal Chrysomela (Schmitt 1989, 1998; Kingsolver 1995; Reid 1996; Verma & Saxena 1996; Duckett 1997; Lingafelter & Pakaluk 1997). The most recent systematics studies of Bruchinae reflect the revised status of the group (Kergoat et al. 2008; Kergoat et al. 2011). Reid and Beatson (2013) list a number of genera that have been intercepted by Australian quarantine, but have not established, including Amblycerus Thunberg, 1815, Caryedes Hummel, 1827, Caryobruchus Bridwell, 1929, Megabruchidius Borowiec, 1984, Pachymerus Thunberg, 1805, Specularius Bridwell, 1938, Stator Bridwell, 1946, and Zabrotes Horn, 1885, and note a failed introduction, Meibomeus Bridwell, 1946. They also include a key to genera that occur in Australia.

Bruchinae are like miniature Sagrinae, as both adults and larvae. Adults share elongate head, narrow prothorax and swollen hind femora, usually toothed; larvae share scarabaeiform shape, elongate head capsule embedded in prothorax, thoracic eggbursters absent.

In Australia there are 13 described native species, in the genera Bruchidius (Kingsolver 1971; Matthews & Reid 2002), Callosobruchus, Parasulcobruchus and Spermophagus. At least some of the Bruchidius species are likely to be misplaced in that genus. There is currently considerable research on the composition of genera in the Bruchidius group (for example Kergoat et al. 2008, 2011), which may resolve some of the problems in the Australian fauna. In addition, there are at least three introduced pests of stored seeds (Matthews & Reid 2002), plus 6 accidentally and 8 deliberately introduced established species, the latter introduced as biological control agents for leguminous weeds (Julien & Griffiths 1998). There is a huge literature worldwide concerning Bruchinae [mostly as Bruchidae], as many species are important crop pests (Southgate 1979; Labeyrie 1981; Jackai & Daoust 1986; Kingsolver 2003; Tuda 2007) and many are significant biological control agents of weeds (Julien & Griffiths 1998).

Larvae of most species of Bruchinae feed on seeds of Fabales, but some species of Spermophagus, including the Australian one, feed on seeds of Convolvulaceae (Borowiec 1991). Adult Bruchinae feed on a wide variety of pollens, often unrelated to the larval host. Pupation takes place in the host seed capsule, in a smooth-walled coccoon.

Diagnosis

After Reid (2000). Adult: head strongly reflexed, without deep facial grooves; hind femora enlarged; tarsi with bifid setae; pygidium elongate-triangular; tegmen with sclerotised dorsal cap.
Larva: white, inhabiting seedpods; head elongate, basal half inserted into thorax; labial palpi 1-segmented or absent; first instar with median prothoracic ridge-like eggburster.