Family BERYTIDAE

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Family BERYTIDAE

Compiler and date details

15 February 2002

Introduction

The Berytidae or stilt bugs are a cosmopolitan family of lygaeoid bugs comprising three subfamilies, six tribes, 36 genera and 172 species (Henry 1997a, 1997b; Henry & Froeschner 1998; Zoological Record 1999–2001).

Fieber (1851) first recognised the group at suprageneric level. In the modern literature it is treated largely as a distinct family. Alternative arrangements include placement of berytids in a subfamily within the Coreidae (Costa 1853; Uhler 1876; Banks 1910) and the Lygaeidae (Stål 1874), and as a tribe within the Lygaeidae: Cyminae (Southwood & Leston 1959). Other workers, such as Hamid (1975) and Péricart (1984), argued against the latter arrangement. Henry (1997a, 1997b, 1997c) in the most comprehensive treatment of stilt bugs and an analysis of lygaeoid relationships, established them as a distinct family with phylogenetic links to the Cymidae, Ninidae, Colobathristidae and Malcidae. Henry & Froeschner (1998) catalogued the world fauna.

Henry (1997a) provided a major rearrangement of the intrafamilial classification of stilt bugs, recognising three subfamilies and six tribes, all of which are monophyletic, based on an analysis of 82 morphological characters. The proposed phylogenetic arrangement of subfamilies is as follows: Berytinae + (Gampsocorinae + Metacanthinae). In this work he also transferred a number of genera between suprageneric groups. His suprageneric classification is used in the Catalogue, and is as follows: Berytinae (Berytini and Berytinini), Gampsocorinae (Gampsocorini and Hoplinini) and Metacanthinae (Metacanthini and Metatropini).

The Berytinae are primarily an Eastern Hemisphere subfamily (Neoneides Stusak occurs in the United States), with the Berytini comprising 11 genera and 24 species, and the Berytinini, a monogeneric tribe of 12 species, confined to the Palaearctic Region. The Berytini includes five monotypic genera, and nearly all genera are confined to one zoogeographic region. The Berytini are currently represented in Australia by two genera, Bezu Stusak and Chinoneides Stusak, that Henry (1997a) established as sister-taxa. Bezu occurs in Australia and New Zealand, with B. maiponga distributed in South Australia and Tasmania. Chinoneides is known from China and Australia, and this disjunct distribution may indicate that the placement of the Australian species, C. tasmaniensis (Gross), within this genus is doubtful, as intimated by Henry (1997a). This species exhibits a Bassian distribution, being known from coastal districts of New South Wales, Victoria, South Australia and Tasmania.

The Gampsocorinae include the Eastern Hemisphere tribe Gampsocorini, which contains four genera and 21 species, and the Western Hemisphere tribe Hoplinini, with eight genera and 33 species. Henry (1997a) established the monotypic genus Australacanthus Henry, for A. halei (Gross), which is largely confined to the semi-arid areas of the Murray-Darling and Lake Eyre drainage basins of New South Wales and South Australia. Henry (1997a) postulated that Australacanthus is the sister-genus to the remainder of the Gampsocorini, which are predominantly Afrotropical in distribution.

The Metacanthinae are the most speciose stilt bug subfamily. They include the nominotypical tribe, Metacanthini, with 11 genera and 70 species, and the Metatropini. The Metatropini, found in China and Korea, is a monogeneric tribe of 12 species. The Metacanthini, aside from the distinct genera Jalysus Stål and Metacanthus Costa, is confined to the Eastern Hemisphere. The tribe is represented in Australia by four species. The only Australian representative of the genus, Capyella lobulata Bergroth, is restricted to the Northern Territory; elsewhere the genus Capyella is broadly distributed in the tropical parts of the Afrotropical, Oriental and Australian Regions. Two species in the cosmopolitan genus Metacanthus Costa occur in tropical and subtropical Australia. Henry (1997a) in accepting the subgeneric arrangement of Metacanthus by Kerzhner (1964), placed M. pulchellus (Dallas), in the subgenus M. (Cardopostethus) Fieber. This species is broadly distributed in the Oriental Region, and occurs in tropical areas of the Northern Territory. Metacanthus (Metacanthus) pertenerus vittatus Gross is also known from tropical Australia, with the nominotypical subspecies found in the Oriental Region. The fourth Australian species, Pneustocerus pluto (Gross), is found in the tropical and subtropical areas of Queensland and New South Wales; elsewhere Pneustocerus is known in New Guinea and Borneo.

Gross (1950) revised the Australian Berytidae, describing five of the seven known species. He placed most of the species in Neides and Metacanthus, and figured all species. The Berytidae are likely to be represented in Australia by additional species, and the family has yet to be recorded from Western Australia.

Extralimital regional works of significance include Kerzhner's (1964) and Péricart's (1984) treatment of the eastern Palaearctic fauna; Hsiao's (1974) review of the Chinese fauna; a series of papers by Stusák (1964, 1965a, 1965b, 1967a, 1967b, 1971, 1989, 1992) on the Afrotropical and Oriental faunas; Gross' (1963) review of Micronesian stilt-bugs; Woodward's (1961) treatment of the New Zealand berytids; and Henry's (1997b) review of the Western Hemisphere berytid fauna.

Henry (1997b, 2000) also reviewed berytid biology. Berytids are found primarily on plants and most species are phytophagous. Occasional feeding habits include omnivory and facultative carnivory or saprophagy. Wheeler & Schaefer (1982) provided a list of host plant associations for the family, which suggests that many stilt bugs may be host plant specific. They concluded that stilt bugs feed on a wide variety of hosts, most of which are eudicotyledonous angiosperms. Henry (1997b) reported that Jalysus, Gampsocoris Fuss and Metacanthus feed on grasses.

Berytids are often associated with species with glandular trichomes in the plant families Geraniaceae, Onagraceae, Scrophulariaceae and Solanaceae. The Australian species have been recorded from the plant families Amaranthaceae, Cucurbitaceae, Poaceae, Geraniaceae, Fabaceae and Solanaceae. Pneustocerus pluto is associated with the underside of leaves of the Stinging Tree, Dendrocnide, a much-avoided urticaceous tree common to rainforest edges.

Hickman (1976) described the biology of Chinoneides tasmaniensis in detail. He reported that adults occurred year-round in Tasmania, feeding on geraniums and pelargoniums, as well as on aphids associated with these plants. Aphid-feeding also occurs in other parts of the world (Froeschner 1942), which suggests that some species of stilt-bugs may have evolved to feed on host-specific phytophagous insects as well as their host plants. Ground-dwelling behaviour has also been recorded for berytids. Hickman (1976) reported that C. tasmaniensis is commonly found on the ground.

Records of berytids as economic pests are few (Henry 2000). In North America Jalysus wickhami Van Duzee sometimes causes damage to crops (Wheeler & Henry 1981).

Diagnosis

Berytids are slender, delicate, elongate insects. The body is often cylindrical with very long, thin appendages. The body sometimes has sericeous setae (Berytinae). The head is declivent and bilobed. The vertex has a transverse sulcus and the frons sometimes has a spine (Berytinae). Ocelli are present. The antennae are 4-segmented, with the first segment extremely long and the fourth segment often fusiform and swollen. The labium is 4-segmented. The pronotum is densely punctate and sometimes has spines on the margins. The scutellum is triangular and the apex is sometimes elongate and pointed. The scutellum often has tubercles or spines. The hemelytra are almost always uniformly membranous. Wing polymorphism is very rare and nearly all species are macropterous. The coxae are directed posteriorly. The apex of the femora are sometimes incrassate. The claws are dentate. The external efferent system of the metathoracic glands is prominent, often with a strongly auriculate peritreme, sometimes spout-like (Metacanthinae). In the Hoplinini the peritreme is absent. The evaporative areas are extensive and often cover the metapleuron. The abdominal spiracles are dorsal between the inner and outer laterotergites. The abdominal trichobothria are not significantly specialised, with the following pattern on segments III to VII: 3:3:2:2:2. The ovipositor is reduced. (Henry 1997a, 1997b, 1997c)