Subfamily Chrysomelinae Latreille, 1802

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Subfamily Chrysomelinae Latreille, 1802

Chrysomelinae 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)] [220].

Introduction

The subfamily Chrysomelinae is large, with approximately 150 genera and 3000 species worldwide. The Australian fauna is disproportionately large, with 47 genera, 762 valid species and many undescribed species (Reid 2006; Reid, Jurado-Rivera & Beatson 2009). Chrysomelinae occur throughout Australia.

The subfamily Chrysomelinae is monophyletic and is probably sister to subfamily Galerucinae (Reid 1995, 2000). The internal classification is untested and has remained largely unchanged for more than 90 years, but a system with two tribes seems most stable (Daccordi 1982, 1994; Gomez-Zurita et al. 2008; Bouchard et al. 2011). Timarchini is monotypic and absent from Australia. Within Chrysomelini there are three easily recognised groups or subtribes: Chrysomelina is probably monophyletic if defined by its distinctive larva with prominent lateral glands (Kimoto 1962; Takizawa 1989; Reid 1991) and, if so, is represented in Australia by a single genus, Plagiodera (Biondi & Daccordi 1998; Reid 2006). Gonioctenina is possibly monophyletic if defined by the pair of dorsal glands on most larvae (Kimoto 1962) and Phyllocharitina is possibly monophyletic on the basis of the larval pre-apical pseudopoda (Kimoto 1962; Reid 1991), but many larvae of these subtribes are unknown.

The Australian fauna includes many large and conspicuously coloured species. Keys and descriptions are available for identification of the genera (Reid, Smith & Beatson 2004; Reid 2006) and the biology of several species has been described. The largest genera, with approximate numbers of species, are Trachymela (120), Paropsisterna (110), Peltoschema (100), Paropsis (70) and Calomela (55). Few species feed on herbs and the huge diversity of Australian Chrysomelinae is primarily associated with two host genera which are also diverse, Eucalyptus s. lat. and Acacia s. lat. (Orchard 1999). Several species of the same genus can co-exist on the same host, along with their larvae (Hunt, Gullan & Reid 1996). This associated diversity has led to speculation of co-speciation between the insects and plants (Selman 1985), but host-specificity is rare and preferred hosts vary according to location (Edwards & Wanjura 1991; Ohmart 1996). Individuals have been found with more than one plant genus in the gut (Jurado-Rivera et al. 2009). Nevertheless, there is evidence that generic relationships of the beetles match planthost family relationships, giving some support to co-evolution having occurred in the past (Jurado-Rivera et al. 2009).

Several species are forestry pests in Australia, notably Paropsisterna bimaculata and Peltoschema orphana in Tasmania.

Chrysomelinae adults and larvae use chemical-secreting glands for defence against predators — the secretions produced by paropsines kill ants (Moore 1967). Such chemicals are generally synthesised by the beetle or larva. Most Chrysomelinae are fully winged, but a substantial number of Australian species are flightless. The latter tend to be small, dark and nocturnal, for example Canobolas species (Reid, Jurado-Rivera, & Beatson 2009).

Almost all Australian chrysomeline species follow a simple life-history pattern: eggs laid on host plant, larvae feeding on host leaves, pupation in soil, adults feeding on host leaves. Some species drop their eggs from the host and many feed on flowers as adults and larvae. Many species are ovoviviparous, larvae emerging from eggs as they are laid. Pupation rarely occurs on the host (Plagiodera). In Pterodunga the female parents show brood care (Reid, Beatson & Hasenpusch 2009).

Four genera and several species of Chrysomelinae have been introduced deliberately into Australia as biocontrol agents of weeds, with some success (Julien & Griffiths 1998; Reid 2006).

Diagnosis

From Reid (2000, 2006).
Adult: without stridulatory mechanism; antennae inserted on or adjacent to anterior edge of head; inner face of mandible with large membranous prostheca; wing with only one anal cell, or wing reduced in size or absent; metendosternite lateral arms without lobes; femora without internal spring sclerite; tibial spurs absent; tarsi without bifid setae; aedeagus without tegminal ring; testes not fused within a common membrane; female kotpresse absent.
Larva: not in a transportable case; 6 pairs of stemmata; labial palpi 2-segmented; mandibles palmate; labrum freely articulated; annular spiracles; legs present, with paronychial appendix and pretarsus.