Family ARADIDAE

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Family ARADIDAE

Compiler and date details

15 February 2002

Introduction

The Aradidae, commonly called flat (or bark) bugs, are a cosmopolitan family of pentatomomorphan bugs comprising eight subfamilies, about 233 genera and 1931 species (Kormilev & Froeschner 1987; Zoological Record 1987–2001; Henry 2009). Eight subfamilies, 38 genera and 143 species are listed for the Australian fauna.

Stål (1873) established the first synthetic classification of the aradids, recognising three suprageneric groups: Aradina, Isodermina and Calisiaria. Reuter (1910, 1912) also recognised the aradids as a higher-taxon, including two families: Aradidae and Dysodiidae (= Aradidae: Mezirinae sensu stricto). Modern interpretations of the suprageneric classification of the family are largely derived from the seminal work of Usinger & Matsuda (1959). Their classification includes eight subfamilies as follows: Aneurinae, Aradinae, Calisiinae, Carventinae, Chinamyersiinae, Isoderminae, Mezirinae and Prosympiestinae. Kormilev & Froeschner (1987) erected tribes within the Chinamyersiinae (Chinamyersiini and Tretocorini) and Prosympiestinae (Llaimocorini and Prosympiestini). The tribal classification within the Chinamyersiinae is based on generic groupings identified by Monteith (1966, 1980). This suprageneric classification was used by Cassis & Gross (1995).

Usinger & Matsuda (1959) first established a phylogenetic arrangement of the subfamilies, recognising two major clades, Aneurinae + (Mezirinae + Carventinae) and Isoderminae + ((Calisiinae + Aradinae) + (Chinamyersiinae + Prosympiestinae)). This phylogeny was based entirely on external morphological characters (mouthparts, adult metathoracic glands, scutellum and connexiva). Vasárhelyi (1987) evaluated this arrangement and proposed a significantly different hypothesis, that the Chinamyersiinae are the most basal subfamily, and the Prosympiestinae are the sister-group to the Aneurinae + (Mezirinae + Carventinae). This arrangement was based on re-interpretations of character states of the pretarsus and larval dorsal abdominal glands. Grozeva & Kerzhner (1992) gave an alternative phylogeny, re-analysing Vasárhelyi's characters, and proposed the following relationships: Isoderminae and Prosympiestinae as sister-groups, and the Tretocorini as the sister-group to the Calisiinae + Aradinae.

The Australian Region is the only zoogeographic region where all eight aradid subfamilies are represented. About a tenth of the world aradid fauna is found in Australia, mostly in the tropical rainforests of Queensland. The Mezirinae and Carventinae are the most diverse subfamilies. The plesiomorphic subfamilies Chinamyersiinae and Prosympiestinae are both found in temperate Australia. Monteith & Gross (1991) reviewed the Australian aradid fauna.

The Aneurinae are found in all zoogeographic regions and comprise seven genera and 139 species. Most of the genera are endemic to one zoogeographic region, aside from the nominotypical genus, Aneurus Curtis, which is the most speciose aneurine and has a cosmopolitan distribution, and Aneurillus Kormilev which is largely circumtropical in distribution. The Aneurinae are represented in Australia by five endemic species of Aneurus, which are restricted to the temperate and subtropical regions of eastern Australia. Kormilev (1957b, 1965, 1966) described three of the species and provided a key to all the known species.

The Aradinae comprise four genera and 207 species. Only the nominotypical genus Aradus Fabricius is broadly distributed, found in all parts of the world. This genus contains over 90% of the aradine species and is most diverse in the Northern Hemisphere. Aradus is represented in Australia by five species, most of which are very broadly distributed across eastern Australia. A. albicornis (Walker) and A. australis (Erichson) range from Cape York Peninsula (Queensland) to Tasmania, with the latter species also known from New Caledonia and New Zealand (Myers & China 1928; Usinger & Matsuda 1959). Kormilev (1957b, 1965, 1966) described two of the species and addressed aspects of the taxonomy of all the species.

Worldwide there are six genera and 100 species of Calisiinae. The subfamily is cosmopolitan in distribution but the majority of species occur in New Guinea and continental Australia, and on the island archipelagos of Melanesia and Micronesia. Most species belong to the nominotypical genus, Calisius Stål, which has a largely circumtropical distribution. There are 13 species of Calisius in Australia, all of which are endemic, and six of which are restricted to Queensland. Kormilev (1958b, 1963, 1966, 1967a) reviewed the Australian fauna.

The Carventinae are represented by 61 genera and 251 species worldwide. They are the most diverse aradid subfamily aside from the Mezirinae. The tropical regions of the world contain the highest species richness of carventines. Aside from the nominotypical genus, Carventus Stål (44 species), most genera contain only a few species, with 29 genera being monotypic. The Australasian Region has almost 100 species. The Australian fauna is represented by nine genera and 18 species. Five of the genera (Aellocoris Kormilev, Glyptoaptera Kormilev, Paracarventus Kormilev, Probatoceps Kormilev and Rhombocoris Kormilev) and all the species are endemic. Lord Howe Island has three endemic carventine species, belonging to Acaraptera Usinger & Matsuda and Lissaptera Usinger & Matsuda, both of which also have species in New Zealand. The majority of Australian carventine species occur in the coastal regions of Queensland, with a few also occurring in New South Wales. Carventus brachypterus Kormilev is the only species represented in Western Australia, which is also broadly distributed across Australia. Kormilev (1958a, 1964, 1965, 1966, 1969, 1972) described the majority of Australian Carventinae. Monteith (1967) reviewed Glyptoaptera and hypothesised that speciation within the genus was facilitated by changing climatic conditions and contraction of rainforest cover during the Pleistocene.

The Chinamyersiinae comprise two tribes, four genera and seven species. The subfamily is restricted to the Australian Region (Australia, New Zealand, New Caledonia and Vanuatu). The Tretocorini contains two genera: Tretocoris Usinger & Matsuda, a monotypic genus endemic to New Zealand, and Kumaressa Monteith (3 species) which is restricted to eastern Australia. Monteith (1966, 1969, 1980) described all the Kumaressa species, and gave detailed discussions on their morphology, relationships, and relictual distribution patterns.

The Isoderminae comprise six species belonging to the eastern Gondwanan genus Isodermus Erichson. The genus is found in Chile (1 species), New Zealand (3 species), and Australia (2 species). Isodermus dimorphus Heiss is known from Tasmania and Victoria, and I. planus Erichson is known from these States, as well as South Australia and New South Wales. The most significant works on the subfamily are Wygodzinsky (1946), Usinger & Matsuda (1959) and Heiss (1982).

The Mezirinae are the most diverse aradid subfamily and currently comprise 124 genera and 1121 described species. They are most diverse in the tropical regions of the Southern Hemisphere, with only a few taxa occurring in the Holarctic. At least 300 species occur in each of the Neotropical, Oriental and Australian Regions, with the Afrotropical fauna less diverse, about half the size of the former regions. Most of the genera are small in size and almost half are monotypic. Only the speciose genera, Mezira (160 species) and Neuroctenus Fieber (175 species) are cosmopolitan in distribution. A few genera (Ctenoneurus and Brachyrhynchus Laporte) have an Indo-Pacific distribution pattern. The Australian mezirine fauna exhibits considerable generic overlap with the Oriental Region, whereas the Afrotropical mezirines are highly insular.

The Australian Mezirinae comprise 23 genera and 93 species, of which 10 genera and 75 species are endemic. The most speciose genera in Australia are: Neuroctenus (13 species), Arictus Stål (7 species), Drakiessa Usinger & Matsuda (13 species), Neophloeobia Usinger & Matsuda (8 species), and Granulaptera Monteith (7 species). Monteith (1997) monographed the Australian mezirine fauna, describing three new genera and 46 new species. He also analysed their biogeography and documented their close association with rainforest blocks in coastal regions of eastern Australia, recognising area relationships with New Guinea, other parts of Melanesia (e.g. New Caledonia) and New Zealand. Other significant works on the Australian Mezirinae include Usinger & Matsuda (1959) and Kormilev (1953, 1955, 1957a, 1958a, 1964, 1965, 1967b, 1971).

The Prosympiestinae comprises two tribes, four genera and 13 species. The Llaimocorini is monotypic, there being a single species in Chile. The Prosympiestini has three genera, two of which are endemic to New Zealand (Adenocoris Usinger & Matsuda and Neadenocoris Usinger & Matsuda), and Prosympiestus Bergroth with four endemic species confined to temperate eastern Australia. Usinger & Matsuda (1959) described the Australian species.

The biology of Aradidae has been reviewed by Usinger & Matsuda (1959), Kormilev & Froeschner (1987), Monteith & Gross (1991) and Heliövaara (2000). Aradids are generally associated with bark, either under loose bark or bark scales, or on the outer surface of fallen branches or logs. Atypical habitats include foliage, bird and rodent nests, and termite nests (inquilines). Most species are cryptozoic, being dark-coloured and mottled, and often apterous with dorsal ornamentations. Many bark-dwelling species are gregarious. The majority of species are thought to be mycetophagous, feeding on the mycelia or fruiting bodies of wood-rotting fungi (Monteith & Gross 1991).

Monteith (1997) reviewed the biology of Australian Mezirinae. Most species occupy open forest and rainforest habitat types. Within rainforests, mezirines appear to favour timber in various degrees of decay, including newly fallen timber, intermediate aged timber and old rotten timber. Mezirines do not appear to be associated with particular tree species. In Western Australia, the mezirine species, Aspisocoris termitophilous Kormilev is found in the nests of termites.

Diagnosis

Aradids are usually reddish-brown, strongly dorsoventrally flattened, medium to large sized bugs, often with a granular, robust appearance. The antennae are 4-segmented and robust. The labium is 4-segmented and has elongate stylets which are coiled and retracted into the clypeal region of the head. The ocelli are absent. The wings are often absent, and when present the hind wings lack a hamus. Abdominal trichobothria are lacking. The tarsi are 2-segmented. The ovipositor is laciniate. The male aedeagus is divided into a phallosoma, conjunctiva and vesica. (Usinger & Matsuda 1959; Slater 1982; Monteith & Gross 1991; Schuh & Slater 1995)