Decomposer
Guides
Scatopse notata
Black Compost Fly
Scatopse notata is a minute dipteran in the family Scatopsidae, commonly known as the Black Compost Fly. The species occurs across the Palearctic region and has been recorded from isolated subantarctic islands including South Georgia and Amsterdam Island. Larvae develop in decomposing organic matter and serve as hosts for the microsporidian parasite Plistophora scatopsi, which infects the mid-gut epithelium across all life stages.
Scatopsidae
Minute Black Scavenger Flies, Dung Midges
Scatopsidae, commonly known as minute black scavenger flies or "dung midges," is a small family of nematoceran flies in the order Diptera. The family contains approximately 250 described species across 27 genera, though many species remain undescribed. Members are typically small to minute (0.6–5 mm), dark-colored flies that bear superficial resemblance to black flies (Simuliidae) but generally lack the characteristic humped thorax of that family. They have a worldwide distribution.
Sceptonia
Sceptonia is a genus of fungus gnats in the family Mycetophilidae, established by Winnertz in 1863. Species in this genus are small, delicate flies associated with forest habitats. The genus occurs across northern Europe and has been documented in Denmark, Norway, and Sweden. As with other Mycetophilidae, larvae are presumed to develop in fungal substrates, though specific life history details for most Sceptonia species remain poorly documented.
Scheloribatidae
Scheloribatidae is a family of oribatid mites in the order Sarcoptiformes, established by Grandjean in 1933. The family comprises at least 20 genera and approximately 320 described species. Members of this family are part of the diverse soil mite fauna and contribute to decomposition processes in terrestrial ecosystems.
Sciaridae
dark-winged fungus gnats, black fungus gnats
Sciaridae are a family of small, dark-colored flies commonly known as dark-winged fungus gnats. Adults range from 1–11 mm in length, typically under 5 mm. The family is among the least studied of the large Diptera families due to small size and taxonomic difficulty. Approximately 1,700 species are described globally, with an estimated 20,000 species awaiting discovery, primarily in tropical regions. Larvae develop in moist, decaying organic matter and play significant roles in decomposition and nutrient cycling.
Sciodrepoides latinotum
Sciodrepoides latinotum is a small carrion beetle in the family Leiodidae, described by Peck & Cook in 2002. It belongs to the subfamily Cholevinae, a group commonly associated with decomposing organic matter and subterranean habitats. The species is known from the eastern and central United States, with records spanning from the Mid-Atlantic to the Great Plains and Gulf Coast.
Scytonotus
Scytonotus is a genus of flat-backed millipedes in the family Polydesmidae, containing approximately 17 described species. The genus was established by C.L. Koch in 1847. Members of this genus are part of the diverse order Polydesmida, which includes millipedes with flattened bodies and lateral extensions of their dorsal plates (paranota). Species in this genus are poorly documented in scientific literature, with limited ecological and behavioral data available.
Seioptera vibrans
Dark-tipped Wingwaver
Seioptera vibrans is a small ulidiid fly, 5–6 mm in length, recognized by its habit of constantly waving its wings while at rest. Adults are active from May to September in vegetated habitats and feed on flower pollen and small insects including aphids. Larvae develop in leaf litter where they contribute to decomposition.
Seira
slender springtails
Seira is a genus of slender springtails in the family Entomobryidae, first described by Lubbock in 1870. The genus contains approximately 17 described species. These springtails are characterized by their elongated body form and are distributed across multiple biogeographic regions including tropical and subtropical areas.
Seira brasiliana
Seira brasiliana is a species of elongate-bodied springtail in the family Entomobryidae. It is a Neotropical species originally described from Brazil, with subsequent records from multiple Brazilian states including Mato Grosso do Sul, Paraíba, Rio de Janeiro, Santa Catarina, and São Paulo. As a member of the genus Seira, it possesses the characteristic scaled body covering typical of this group. The species remains poorly studied, with limited published information on its biology and ecology.
Sepsidae
black scavenger flies, ensign flies
Sepsidae is a family of small, slender flies in the order Diptera, commonly known as black scavenger flies or ensign flies. The family contains over 300 described species worldwide. Adults are typically found on mammal excrement, decaying animal and plant material, and carrion, where they feed and oviposit. Many species exhibit a distinctive wing-waving behavior while walking. The family plays a significant ecological role as decomposers and has forensic and hygienic relevance due to their association with feces and decaying matter.
Sepsis
black scavenger flies, ensign flies
Sepsis is a genus of small flies in the family Sepsidae, commonly known as black scavenger flies or ensign flies. These flies are characterized by their distinctive wing-waving behavior and association with decaying organic matter. The genus contains numerous species distributed across temperate and tropical regions worldwide. Adults are typically black with silvery or metallic markings and possess a characteristic humpbacked appearance.
Sericomyia slossonae
Slosson's Pond Fly
Sericomyia slossonae is a species of hoverfly (family Syrphidae) in the tribe Milesiini. The genus Sericomyia is part of the group commonly known as "rat-tailed maggots" due to their larvae possessing an extensible posterior breathing siphon. Larvae of Sericomyia species are known to inhabit bog mat pools. Adults are pollinators that visit flowers for nectar and pollen. The species was described by Curran in 1934 and is accepted as valid.
Sigmoria ainsliei
Sigmoria ainsliei is a large flat-backed millipede in the family Xystodesmidae, endemic to a narrow region of eastern Tennessee. First described in 1921, it is one of the largest xystodesmid millipedes in North America, with adults exceeding 50 mm in length. The species has a highly restricted distribution spanning approximately 50 km from the Great Smoky Mountains National Park to Knoxville.
Sigmoria plancus
Sigmoria plancus is a species of flat-backed millipede in the family Xystodesmidae, first described by Loomis in 1944. It belongs to a genus of eastern North American polydesmid millipedes characterized by distinctive color patterns and defensive chemical secretions. The species is part of a taxonomically complex group where species boundaries and distributions remain incompletely documented.
Silvaninae
silvanid flat bark beetles
Silvaninae is a subfamily of silvanid flat bark beetles (family Silvanidae) comprising approximately 11 genera and at least 30 described species. The subfamily includes several economically significant stored product pests, most notably species in the genera *Oryzaephilus* and *Cathartus*. Members are characterized by their dorsoventrally flattened bodies adapted for living under bark or in similar confined spaces. The group has a cosmopolitan distribution with species found across multiple continents.
Sinella
slender springtails
Sinella is a genus of slender springtails in the family Entomobryidae, containing at least 20 described species. Members of this genus are characterized by elongated bodies and are part of the diverse soil and litter microarthropod fauna. Several species, including Sinella curviseta and Sinella coeca, have been subjects of ecological and toxicological research. The genus has a broad geographic distribution spanning multiple continents.
Sinella sexoculata
slender springtail
Sinella sexoculata is a species of slender springtail in the family Entomobryidae, described by Schött in 1896. As an entomobryomorph collembolan, it possesses the characteristic elongated body form and well-developed antennae typical of this group. The species has been documented in the Caribbean mainland and Pacific North American regions based on GBIF distribution records. Like other members of the genus Sinella, it inhabits soil and leaf litter environments where it contributes to decomposition processes.
Siricidae
horntails, wood wasps
Siricidae is a family of approximately 150 species of non-social wasps commonly known as horntails or woodwasps. These insects are characterized by their cylindrical, cigar-shaped bodies and the prominent spine or "cornus" at the tip of the abdomen that gives the family its common name. Females possess a long, drill-like ovipositor used to bore into wood and deposit eggs. Siricidae are xylophagous, with larvae developing inside dead, dying, or weakened trees, where they feed on wood colonized by symbiotic fungi that females introduce during oviposition. The family is economically significant: most native species are not pests and target already-compromised trees, but introduced species such as Sirex noctilio have become major forest pests in pine plantations worldwide.
Sminthurinus henshawi
Henshaw's globular springtail
Sminthurinus henshawi is a species of globular springtail in the family Katiannidae. It is a small, soil-dwelling hexapod with a characteristic rounded body shape. The species has been recorded across multiple continents including North America and Eurasia. It is one of the more frequently observed springtail species, with over 1,400 citizen science records.
Sminthurus sp-nr-variegatus
variegated globular springtail
Sminthurus sp-nr-variegatus is a globular springtail in the family Sminthuridae, characterized by its distinctive variegated color pattern. This species exhibits the rounded body form typical of the order Symphypleona, with a furcula (springing organ) folded beneath the abdomen. It inhabits surface vegetation and soil litter in various terrestrial environments. The 'sp-nr-variegatus' designation indicates a species near or related to Sminthurus variegatus, pending formal taxonomic resolution.
Solva
wood soldier flies
Solva is a genus of soldier flies in the family Xylomyidae, commonly known as wood soldier flies. These Diptera are characterized by their association with decaying wood habitats. The genus is distributed across northern Europe and North America, with documented records from Denmark, Norway, Sweden, and the northeastern United States including Vermont. Solva species are part of the understudied but ecologically significant group of xylophagous insects that contribute to wood decomposition processes.
Sphaeridium lunatum
Crescent Water Scavenger Beetle
Sphaeridium lunatum is a small water scavenger beetle in the family Hydrophilidae, commonly known as the Crescent Water Scavenger Beetle. The species is native to the Palearctic region, with established introduced populations in North America. It inhabits moist organic substrates, particularly dung and decaying plant matter. The specific epithet 'lunatum' refers to the crescent-shaped markings on the elytra.
Sphaeridium marginatum
Sphaeridium marginatum is a species of water scavenger beetle in the family Hydrophilidae, first described by Fabricius in 1787. It belongs to the subfamily Sphaeridiinae, a group commonly known as dung beetles within the Hydrophilidae. The species has a broad Palearctic distribution across Europe, North Africa, and parts of Asia, with introduced populations reported in North America. It is associated with decaying organic matter and moist habitats.
Sphaerocera curvipes
lesser dung fly
Sphaerocera curvipes is a species of small dung fly in the family Sphaeroceridae, commonly known as lesser dung flies. The species was described by Latreille in 1805 and is one of the more frequently observed members of its genus, with over 260 documented observations on iNaturalist. It belongs to a family specialized in exploiting decaying organic matter, particularly dung.
Sphaeroceridae
lesser dung flies, small dung flies, lesser corpse flies
Sphaeroceridae is a family of true flies (Diptera) in the section Schizophora, subsection Acalyptratae. The family contains over 1,300 species in approximately 125 genera, making it a diverse group of small to minute flies. Members are characterized by saprophagous habits, typically associated with decomposing organic matter including dung, carrion, and decaying plant material. They occur worldwide except in regions with permanent ice cover.
Sphaeroceroidea
Sphaeroceroidea is a superfamily of small flies (Diptera) comprising approximately 2,600 species across several families, most notably Sphaeroceridae (small dung flies), Heleomyzidae, and Chyromyidae. These flies are generally a few millimetres in length and are associated with decaying organic matter. The superfamily is confirmed as monophyletic and represents the sister group to all other Schizophora. Taxonomic composition has been historically disputed, with proposals to merge families that remain controversial.
Sphaeropsocus
Sphaeropsocus is a genus of small psocopterans in the family Sphaeropsocidae, first described by Hagen in 1882. It belongs to the suborder Troctomorpha, a group of barklice and booklice characterized by specialized mouthpart structures. The genus is part of a small family containing few described species, most of which are rarely encountered. Members of this genus are minute insects associated with dead plant material and organic debris.
Sphegina campanulata
Orange-horned Hammertail, Orange-horned Pufftail
Sphegina campanulata is a syrphid fly (hoverfly) species described by Robertson in 1901. It is fairly common in the northeastern United States. The species is known for its distinctive orange-horned appearance and is one of approximately 45 observations documented on iNaturalist. Like other members of the genus Sphegina, it exhibits the characteristic hovering flight ability common to syrphid flies.
Spilomyia alcimus
Broad-banded Hornet Fly
Spilomyia alcimus is a syrphid fly first described by Walker in 1849. It exhibits wasp mimicry, resembling yellowjackets in appearance, sound, and behavior. Adults visit flowers for nectar and pollen. The species is uncommon and distributed across Canada and the United States.
Spilomyia citima
Western Hornet Fly
Spilomyia citima, commonly known as the Western Hornet Fly, is a rare species of syrphid hoverfly first described by Vockeroth in 1958. It belongs to a genus renowned for exceptional mimicry of yellowjacket wasps, employing visual, behavioral, and acoustic deception. The species has been documented in Canada and the United States, though records remain sparse.
Spilomyia crandalli
Crandall's Hornet Fly
Spilomyia crandalli is a rare species of syrphid fly described by Curran in 1951. Adults are known as flower flies and are commonly found on flowers, where they feed on nectar and pollen. The species belongs to a genus renowned for exceptional wasp mimicry, including visual, behavioral, and acoustic deception of yellowjackets. Larvae are adapted to moist environments such as tree rot holes.
Spilomyia fusca
Bald-faced Hornet Fly
Spilomyia fusca, the Bald-faced Hornet Fly, is a syrphid fly first described by Loew in 1864. This species is a notable wasp mimic, resembling yellowjackets in both appearance and sound. Adults are pollinators that frequent flowers, while larvae develop in moist tree rot holes where they feed on decaying organic matter. The species is relatively common in eastern North America.
Spilomyia interrupta
Interrupted Hornet Fly
Spilomyia interrupta, commonly known as the Interrupted Hornet Fly, is a species of hoverfly in the family Syrphidae. First described by Williston in 1882, this uncommon species is native to western North America, particularly along the California coast. Like other members of the genus Spilomyia, it exhibits remarkable mimicry of yellowjacket wasps, including similar coloration, body shape, and even wingbeat frequency. Adults visit flowers for nectar and pollen, while larvae develop in moist tree rot holes.
Spilomyia liturata
Rocky Mountain Hornet Fly
Spilomyia liturata, commonly known as the Rocky Mountain Hornet Fly, is an uncommon species of hoverfly (Syrphidae) found in western North America. Adults are notable mimics of yellowjacket wasps, exhibiting sophisticated visual and auditory deception. The species is associated with montane habitats along the Rocky Mountains, where larvae develop in water-filled tree holes.
Spilomyia sayi
Four-lined Hornet Fly
Spilomyia sayi is a common North American hoverfly and wasp mimic, ranging from western Canada to the northeastern United States. Adults are active from June to October and are frequently found on flowers where they feed on nectar and pollen. The species exhibits remarkable mimicry of yellowjacket wasps, including visual, behavioral, and acoustic deception. Larvae develop in decaying heartwood of deciduous trees and in rot holes.
Spiniphora
Spiniphora is a genus of scuttle flies (Phoridae) established by Malloch in 1909. The genus includes saprophagous species, with Spiniphora genitalis documented as a decomposer of mollusc carrion and vertebrate remains. Species in this genus complete development on decaying organic matter and have been recorded from the Oriental region, parts of the Australian region, and introduced populations in Hawaii. Larvae exhibit distinct morphological features including ventral flattening, segmented bodies with tubercles and spinulose formations, and respiratory transitions between instars.
Stelidota coenosa
Stelidota coenosa is a small beetle in the family Nitidulidae, commonly known as sap beetles. It feeds on fermenting plant sap, overripe fruit, and other decaying organic matter. The species occurs across North America and is frequently encountered in agricultural settings, particularly where fruit crops are present. It is one of several Stelidota species that can be challenging to distinguish without close examination.
Stephostethus lardarius
minute brown scavenger beetle
Stephostethus lardarius is a species of minute brown scavenger beetle in the family Latridiidae. It is a small beetle that feeds on fungal spores and decaying organic matter. The species has been recorded in parts of Europe and North America. It is one of many small beetles in this family that inhabit moist, moldy environments.
Stictomyia
Stictomyia is a small genus of picture-winged flies (family Ulidiidae) containing two described species. The genus is notable for its highly unusual morphology and ecology, particularly in Stictomyia longicornis, which exhibits beetle-like appearance and strong association with cacti. These flies are among the more aberrant members of the Ulidiidae, departing significantly from the typical wing-patterned, active-flying form of most picture-winged flies.
Striaria
Striaria is a genus of millipedes in the family Striariidae, order Chordeumatida. The genus was established by Bollman in 1888. These small, eyeless millipedes are part of the diverse soil-dwelling fauna of temperate forests. The name Striaria is also used for a genus of brown algae (Phaeophyceae), but this represents a separate taxonomic entity in a different kingdom.
Styletoentomon
Styletoentomon is a genus of minute, soil-dwelling proturans in the family Eosentomidae. The genus was established by Copeland in 1978 and contains two described species: S. rostratum and S. styletum. Proturans in this genus lack antennae and eyes, and possess distinctive mouthparts adapted for feeding on fungal hyphae and decaying organic matter in soil and leaf litter habitats.
Sylvicola notialis
Sylvicola notialis is a species of wood gnat in the family Anisopodidae, described by Stone in 1965. Wood gnats in this genus are associated with decaying wood and moist forest habitats. The species is part of a group of Diptera commonly found in woodland environments where larvae develop in rotting wood or other decomposing plant material.
Symphora flavicollis
Red-necked False Darkling Beetle
Symphora flavicollis, commonly known as the Red-necked False Darkling Beetle, is a species of false darkling beetle in the family Melandryidae. The species was described by Haldeman in 1848 and is distinguished by its characteristic yellowish or reddish pronotum that contrasts with the darker body. It belongs to a small genus of beetles that are often associated with decaying wood and fungal habitats.
Syritta flaviventris
Peg-legged Compost Fly
Syritta flaviventris is a syrphid fly species known from Madagascar, southern Europe, and introduced populations in the Americas (Chile, Brazil, United States, Mexico). Larvae develop in decaying platyclades of Opuntia maxima, with immature stages described from Spanish Mediterranean populations. Adults have been reared from larvae collected in this cactus substrate.
Tachinus fumipennis
Tachinus fumipennis is a rove beetle (family Staphylinidae) found across much of North America. The species belongs to the genus Tachinus, a group of moderately sized rove beetles often associated with decaying organic matter and fungi. As with many staphylinids, it likely plays a role in nutrient cycling through its feeding habits, though specific biological details for this species remain poorly documented in published literature. The species is distinguished from congeners by subtle morphological features of the elytra and antennae.
Tachinus rufipes
Tachinus rufipes is a rove beetle in the family Staphylinidae, characterized by reddish legs that give the species its name. Originally described by Linnaeus in 1758 from European material, it has since been introduced to North America where it is now established in eastern Canada and the northeastern United States. The species belongs to the subfamily Tachyporinae, a group known for rapid movements and association with decaying organic matter.
Tachinusini
Tachinusini is a tribe of rove beetles within the subfamily Tachyporinae. Members are small to medium-sized beetles characterized by compact bodies and relatively short elytra that leave several abdominal segments exposed. The tribe includes the genus Tachinus, which is among the more frequently observed tachyporine groups. Tachinusini species are found primarily in the Northern Hemisphere, with many species adapted to cool, moist microhabitats.
Telephanus atricapillus
Black-headed Silvanid Beetle
Telephanus atricapillus is a small beetle in the family Silvanidae, commonly known as the Black-headed Silvanid Beetle. It is primarily known from northeastern North America, with records from Ontario, Québec, and Vermont. The species was described by Erichson in 1846 and is currently treated as a synonym of Telephanus velox in some taxonomic databases, though this synonymy may not be universally accepted. Like other silvanids, it is associated with stored products and forest floor habitats.
Telomerina flavipes
lesser dung fly
Telomerina flavipes is a species of lesser dung fly in the family Sphaeroceridae, a group of small Diptera commonly associated with decomposing organic matter. The species was first described by Johann Wilhelm Meigen in 1830 under the name Borborus flavipes. It is currently known from scattered records in northern Europe including Denmark, Norway, and Sweden. As a member of Sphaeroceridae, it likely inhabits environments rich in decaying plant or animal material, though specific ecological details remain poorly documented.