Themira

Themira species are distinguished from other sepsid genera by male genitalic structures, particularly the form and coloration of the 4th sternites and the mobile surstyli. Males possess ornate forelegs used during courtship to grasp the base of the female's wing. Species-level identification requires examination of male terminalia and sternal lobe morphology. DNA barcoding of the COI mitochondrial gene has been used to confirm species identity in taxonomic studies.

Species occur in diverse environments including urban parks, forested areas, and open landscapes. Specific documented habitats include urban settings with arboreal vegetation and rich ground cover of small plants and shrubs. Some species have been collected from experimental carrion placements on soil ground surrounded by vegetation.

Primarily Holarctic distribution with records across Europe, Asia, and North America. European records include Austria, Great Britain, Czech Republic, Denmark, Finland, France, Germany, Hungary, Latvia, Lithuania, Norway, Poland, Russia, Slovakia, Sweden, Switzerland, Netherlands, Ukraine, Italy, and Romania. Nearctic distribution includes USA (Alaska, Connecticut, Illinois, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania) and Canada (Newfoundland). Palaearctic Asia includes Kazakhstan, Korea, Kyrgyzstan, Pakistan, Turkmenistan, South Korea, and Japan. Disjunct Neotropical record in Cuba documented for T. leachi.

Adults active during warm season, with main occurrence from late March through August. T. nigricornis has been collected in the second half of April at temperatures around 20°C.

Necrophagous; feeds on decomposing animal material. T. nigricornis has been observed on pig carcass in advanced decomposition stage. Family Sepsidae is known as black scavenger flies with coprophagous preference, found on dung, animal and plant decaying material, and predominantly on human and animal excrements.

Males exhibit elaborate courtship behavior involving at least five distinct patterns, with at least three shared with more derived sepsid groups. During copulation, male sternal lobes twist and separate to fan out combs of long setae that tap the female. Male genitalic surstyli are mobile and likely serve to clasp the female. Males use ornate forelegs to hold onto the base of the female wing during mounting. Some species show relatively low abundance, with only occasional population peaks.

Contributes to decomposition of faeces and carrion. Necrophagous species aid in carcass decomposition processes. Frequently occurs simultaneously with other necrophagous taxa including Calliphoridae, Muscidae, Cleridae, and Silphidae.

Occurs in urban park environments. Used as indicator species in forensic entomology due to association with carrion. Subject of behavioral and evolutionary studies examining the origin of complex courtship in sepsid flies.

• Other Sepsidae generaThemira is distinguished by relatively basal phylogenetic position and presence of mobile genitalic surstyli and elaborate sternal lobe courtship structures that differ from derived sepsid genera

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• First Record of Themira Nigricornis (Meigen, 1826) (Sepsidae: Diptera) in Romania/ Prima semnalare a speciei Themira Nigricornis (Meigen, 1826) (Sepsidae: Diptera) în România
• Morphology and DNA sequences confirm the first Neotropical record for the Holarctic sepsid species Themira leachi (Meigen) (Diptera: Sepsidae)
• Sexual behavior and morphology of Themira minor (Diptera: Sepsidae) males and the evolution of male sternal lobes and genitalic surstyli
• Hidden in the urban parks of New York City: Themira lohmanus, a new species of Sepsidae described based on morphology, DNA sequences, mating behavior, and reproductive isolation (Sepsidae, Diptera)
• Figure 3 from: Ang Y, Rajaratnam G, Su KFY, Meier R (2017) Hidden in the urban parks of New York City: Themira lohmanus, a new species of Sepsidae described based on morphology, DNA sequences, mating behavior, and reproductive isolation (Sepsidae, Diptera). ZooKeys 698: 95-111. https://doi.org/10.3897/zookeys.698.13411
• Supplementary material 1 from: Ang Y, Rajaratnam G, Su KFY, Meier R (2017) Hidden in the urban parks of New York City: Themira lohmanus, a new species of Sepsidae described based on morphology, DNA sequences, mating behavior, and reproductive isolation (Sepsidae, Diptera). ZooKeys 698: 95-111. https://doi.org/10.3897/zookeys.698.13411
• Figure 1 from: Ang Y, Rajaratnam G, Su KFY, Meier R (2017) Hidden in the urban parks of New York City: Themira lohmanus, a new species of Sepsidae described based on morphology, DNA sequences, mating behavior, and reproductive isolation (Sepsidae, Diptera). ZooKeys 698: 95-111. https://doi.org/10.3897/zookeys.698.13411
• Figure 2 from: Ang Y, Rajaratnam G, Su KFY, Meier R (2017) Hidden in the urban parks of New York City: Themira lohmanus, a new species of Sepsidae described based on morphology, DNA sequences, mating behavior, and reproductive isolation (Sepsidae, Diptera). ZooKeys 698: 95-111. https://doi.org/10.3897/zookeys.698.13411