The Platystomatidae (signal flies) are a distinctive family of

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...

(Diptera) in the superfamily

Tephritoidea The Tephritoidea are a superfamily of flies. It has over 7,800 species, the majority of them in family Tephritidae. The following families are included: * Ctenostylidae * Eurygnathomyiidae * Lonchaeidae - lance flies * Pallopteridae — flutter ...

. Signal flies are worldwide in distribution, found in all the

biogeographic realm A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. ...

s, but predominate in the tropics. It is one of the larger families of acalyptrate Diptera with around 1200

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

in 127

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

Biology

Adults are found on tree trunks and foliage and are attracted to flowers, decaying fruit, excrement, sweat, and decomposing snails. Larvae are found on fresh and decaying vegetation, carrion, human corpses, and root nodules, particularly in the genus ''Rivellia'', which has economic implications for legume crops. Larvae from the remaining genera are either phytophagous (eating plant material) or saprophagous (eating decomposing organic matter). Some are predatory on other insects and others have been found in human lesions, while others are of minor agricultural significance.

Family description

For terms see Morphology of Diptera
Signal flies are very variable in external appearance, ranging from small (2.5 mm), slender species to large (20 mm), robust individuals, often with body colours having a distinctive metallic lustre and with face and wings usually patterned with dark spots or bands. The head is large. Frontal bristles on head are absent. Two orbital bristles are on the head. The frontal stripe is pubescent and the arista is more or less long and pubescent. The antennal grooves are deep and divided by a median keel. Radial vein 4+5 bears bristles. The costa is without interruptions and the anal cell is elongated, bordered on outer side by an arcuate or straight vein. The abdomen of male has five visible segments and the female has six. Boatman fly

Many bizarre forms of morphology and behaviour occur in this family. Heads and legs (fore legs especially) may be oddly shaped, extended in various ways or with adornments, all of which serve to supplement agonistic behaviour. Such behaviour underlies social and sexual interaction between individuals of the same species of signal flies, first researched in Australian species of the genera ''Euprosopia'
image
and ''Pogonortalis'' In males of ''Pogonortalis'', the length and degree of development of hairs (setae) on the lower facial area, together with widening of the head, facilitates territorial dominance by head-butting and rearing-up behaviours. Head-butting is taken to the extreme in the Australasian genus ''Achias'', in which species have the fronto-orbital plates expanded laterally to produce eyestalks. Development of body structures is prevalent in the Afrotropical and Oriental subfamily Plastotephritinae, including 9 different types of modification in 16 genera. Novitates Zoologicae1910PlateXV

Some species have prominent eyestalks also found in the family Diopsidae. In the Diopsidae, eyestalks develop through lateral development of the frontal plate, with the result that the antennae are situated on the stalk near the compound eye. The process of development in signal flies is different in that the fronto-orbital plates expanded laterally to produce eyestalks and consequently the antennae remain in a central position. This is an example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

. The development of eyestalks reaches its extreme in the platystomatid species ''Achias rothschildi'' Austen, 1910 from New Guinea
pictured here
in which males have an eye-span up to 55 mm. Families of acalyptrate flies exhibiting morphological development associated with agonistic behaviour include: Clusiidae, Diopsidae,

Drosophilidae The Drosophilidae are a diverse, cosmopolitan family of flies, which includes species called fruit flies, although they are more accurately referred to as vinegar or pomace flies. Another distantly related family of flies, Tephritidae, are true ...

, Platystomatidae,

Tephritidae The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), ...

, and

Ulidiidae The Ulidiidae (formerly Otitidae) or picture-winged flies are a large and diverse cosmopolitan family of flies (Diptera), and as in related families, most species are herbivorous or detritivorous. They are often known as picture-winged flies, alo ...

. See als

Biogeography

The largest concentration of Platystomatidae undoubtedly occurs in the Australasian region, followed closely by the Afrotropical region. The number of genera and species in the Oriental, European, Nearctic and Neotropical faunas are much more restricted and are summarised in the Regional Catalogues. Some genera are widely distributed over more than one region. For example, ''Plagiostenopterina'' Hendel, 1912, is widely distributed in the Old World tropics (Australasian, Oriental and Afrotropical regions) and ''Rivellia'' Robineau-Desvoidy, 1830 is almost cosmopolitan, although numbers of species in Europe are very restricted in number. Taxonomic revisions of such genera need to examine the wider implications of these broad distributions. Other genera are known from just a single location. ''Bama'' McAlpine, 2001, for example, is known only from New Guinea.

Taxonomic history

As is the case with the taxonomy many flies, the first described species of Platystomatidae were placed in the large family Muscidae, because in the 19th century, the Muscidae formed a portmanteau group for the higher Diptera. It was only after many species were accumulated into larger collections and numerous names proposed, that taxonomists began to realise that the Diptera consisted of several distinct families. The oldest family-group name for the Platystomatidae is in fact Achiasidae Fleming, 1821, based on the genus ''Achias'' Fabricius, 1805. There has, however, been an overwhelming predominance of the usage of names based on the genus ''Platystoma'' Meigen, 1803. After petition by Steyskal & McAlpine (1974), the International Commission on Zoological Nomenclature (1979) ruled under plenary power that family-group names based on ''Achias'' should be suppressed, giving those based on ''Platystoma'' precedence. Initially, subfamilies within the Muscidae were recognised; the early Platystomatidae belonging to the Ortalides, but toward the end of the 19th century, many of these subfamilies were raised to family status, at which point the Ortalides became the Ortalidae. The name Otitidae became a replacement name for Ortalides, until Hendel's significant contribution and re-organisation of the genera of the World firmly placed the Platystomatidae as a subfamily of Muscaridae, divided into several tribes. Furthermore, he recognised the broad divisions Acalyptrae and Calyptrae, placing Platystomatinae correctly in the former. Enderlein, who proposed more new plastotephritine (subfamily) names than Hendel, still preferred Ortalidae to Muscaridae, but adopted the Platystomatinae subfamily status that Hendel had proposed.Enderlein, G (1922) Die Platystominentribus Plastotephritini. ''Stettiner Entomologische Zeitung'' 83: 3–16.

References

External links

Species lists

West Palaearctic including RussiaJapanWorld list

Picture story about the biology of ''Platystoma seminationis''EOL
images
Images representing Platystomatidae
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