Beris is a genus of flies in the family Stratiomyidae. They are also referred to as the false soldier fly. As described by Latreille in 1802, these are small to medium sized flies with metallic colors.
Description These are flies with elongated bodies and reduced palpi. The scutellum typically features spines and the abdomen has seven visible segments. They are characterized as having black or metallic green thorax, black or orange abdomen and darkened wings in some species.
Habitat and behavior Soldier flies are primarily found in tropical regions but are widespread globally. The larvae are scavengers, inhabiting decaying organic matter, wet moss, compost, and aquatic environments. Adults are typically found near larval habitats, frequenting flowers and forming swarms.Woodley, N. E. 2009. Family Stratiomyidae, pp. 100-106. In, J. Gerlach (Ed.). The Diptera of the Seychelles islands. Pensoft Publishers, Sofia and Moscow. 431 pp. Published February 2009 These swarms are normally observed around foliage near mountain valleys, marshes, and damp places.Rozkosný R (1973) The Stratiomyioidea (Diptera) of Fennoscandia and Denmark. Vol. 1. Fanua Entomologica Scandinavia. Scandinavian Science Press, Gadstrup, 151 pp.
Morphology Bright, metallic colored species sometimes resemble wasps or bees. The wing venation is a strongly specific characteristic of the family, with interior veins and a small discal cell in the anterior half of the wing. The antennae show structural variations, and the scutellum is equipped with spines.
The larval body is flat with a strongly sclerotized head capsule, three thoracic and about 8 abdominal body segments. The cuticle has a honeycomb-like appearance due to calcium carbonate secretions. The mandibles and maxillae are fused together, forming two distinct mandibular-maxillary complexes. These complexed move alternately in a vertical plain. Terrestrial larvae are elongated and oval with a rounded abdominal end, while aquatic or semi-aquatic larvae have a tapering posterior end with a crown of hydrofuge hair.Kovac, D., & Rozkošný, R. (2004). Insecta: Diptera, Stratiomyidae. Freshwater Invertebrates of the Malaysian Region; Yule, CM, Yong, HS, Eds, 798.
The larvae are not predatory or parasitic. They feed on detritus, while their specialized mouthparts serve as sweeping apparatus. Aquatic larvae feed on decaying leaves, micro-organisms and detritus, while the Oxycera larvae feed on algae on moist rocks.Kovac, D., & Rozkošný, R. (2004). Insecta: Diptera, Stratiomyidae. Freshwater Invertebrates of the Malaysian Region; Yule, CM, Yong, HS, Eds, 800. Some adults are nectar feeders, indicated by an elongated proboscis and narrow labella, however, most of the species have a relatively short proboscis with a large fleshy labella which consume pollen grains and honeydew.Olroyd H. (1969) Diptera Brachycera. Section (a) Tabanoidea and Asiloidea. Handbook for Identification of British Insects 9: 1–132.Beuk P.L.T. (1990) Honeydew as food source for insects in particular for soldier flies (Diptera: Stratiomyidae). Phegea 18: 137–140.
In general, male flies in the genus Beris tend to be slightly smaller in size compared to females. Their eyes are contiguous in the male. The coloration of the body and wings can vary between species and exhibit sexual dimorphism
Life cycle In temperate regions, the life cycle is annual. The larvae may hibernate several times. The eggs are usually pale yellow and elongated. The female is capable of laying 600 or more eggs per batch. Pupation takes place within the final larval skin, or puparium. The pupa is much smaller than puparium since the remaining space is filled with air to allow floatation upon the water's surface.Kovac, D., & Rozkošný, R. (2004). Insecta: Diptera, Stratiomyidae. Freshwater Invertebrates of the Malaysian Region; Yule, CM, Yong, HS, Eds, 802.
Species Beris alamaculata Yang & Nagatomi, 1992 Beris ancistra Cui, Li & Yang, 2010 Beris annulifera var. luteipes Johnson, 1926 Beris annulipes Brunetti, 1912 Beris basiflava Yang & Nagatomi, 1992 Beris burmanica Frey, 1960 Beris chalybata (Forster, 1771) Beris clavipes (Linnaeus, 1767) Beris concava Li, Zhang & Yang, 2009 Beris cypria James, 1970 Beris digitata Li, Zhang & Yang, 2009 Beris dolichocera Frey, 1960 Beris emeishana Yang & Nagatomi, 1992 Beris excellens Frey, 1960 Beris flava Li, Zhang & Yang, 2011 Beris furcata Cui, Li & Yang, 2010 Beris fuscipes Meigen, 1820 Beris gansuensis Yang & Nagatomi, 1992 Beris geniculata Curtis, 1830 Beris hauseri Stuke, 2004 Beris heptapotamica Pleske, 1926 Beris hildebrandtae Pleske, 1930 Beris hirotui Ôuchi, 1943 Beris huanglianshana Li, Zhang & Yang, 2009 Beris kovalevi Rozkošný & Nartshuk, 1980 Beris latifacies Nagatomi & Tanaka, 1972 Beris luteistigma Frey, 1960 Beris malaisei Frey, 1960 Beris miocenica James, 1937 Beris morrisii Dale, 1841 Beris nebulosa Nagatomi & Tanaka, 1972 Beris potanini Pleske, 1926 Beris pulchripennis Frey, 1960 Beris rozkosnyi Kassebeer, 1996 Beris schaposchnikowi Pleske, 1926 Beris shennongana Li, Luo & Yang, 2009 Beris spinosa Li, Zhang & Yang, 2009 Beris strobli Dušek & Rozkošný, 1968 Beris trilobata Li, Zhang & Yang, 2009 Beris vallata (Forster, 1771) Beris yangxiana Cui, Li & Yang, 2010 Beris zhouae Qi, Zhang & Yang, 2011 Beris zhouquensis Li, Zhang & Yang, 2011 Beris ziminae Rozkošný & Nartshuk, 1980
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