Exoristini

Exoristini can be distinguished from other Tachinidae tribes by examining male genitalia: the surstyli are typically fused or closely approximated basally, and the cerci are often slender and curved. The tribe differs from Blondeliini in having a more reduced larval mouthhook structure. Exorista species, the most diverse genus, are recognized by their striped thorax and relatively robust body form. Separation from Tachinini requires examination of the abdominal sternite 6 in males, which is typically broader in Exoristini. Identification to species level often requires dissection and examination of internal genitalic structures.

Habitats vary by genus and species, encompassing forests, grasslands, agricultural areas, and urban environments. Larval habitats are determined by host availability rather than specific environmental conditions. Adults are frequently found in open, sunny areas where they actively search for hosts or nectar at flowers.

Cosmopolitan distribution. Documented from North America, Europe, Asia, Africa, Australia, and South America. Individual genera show varying geographic ranges: Exorista is widespread across the Holarctic and Oriental regions; Tachinomyia occurs in North America; Chaetogena and Phorocera are primarily Palearctic.

Adult activity varies by latitude and species. In temperate regions, most species are active from late spring through autumn (May–October in the Northern Hemisphere). Some species exhibit bivoltine or multivoltine life cycles with overlapping generations. Tropical species may be active year-round.

All members are parasitoids. Females deposit eggs or larvae on or near hosts, or oviposit directly into host bodies. Larvae develop internally within the host (endoparasitism), typically consuming the host before pupating. Hosts include Lepidoptera (primarily), Hymenoptera, and occasionally other insects. Development time varies with temperature and host species, typically ranging from 1–4 weeks for larval development.

Adults are diurnal and active fliers. Females exhibit host-searching behavior, often visually locating hosts on vegetation. Some species are attracted to flowers for nectar feeding. Males patrol territories or aggregate at lekking sites. Defensive behaviors include rapid escape flight and, in some species, thanatosis (death feigning) when disturbed.

Significant biological control agents, regulating populations of herbivorous insects, particularly Lepidoptera. Exorista species are among the most important parasitoids of pest caterpillars globally. The tribe contributes to top-down population regulation in natural and agricultural ecosystems, with some species used in classical biological control programs.

Several species are commercially produced and released for biological control of agricultural pests, particularly Exorista larvarum and related species against noctuid moth pests. Some species have been introduced outside native ranges for classical biological control, with documented cases of successful establishment. No species are known to be of medical or veterinary importance.

• TachininiSimilar overall morphology and parasitoid biology, but differs in male abdominal sternite 6 structure and larval cephalopharyngeal skeleton morphology. Tachinini typically have more robust body forms and different wing venation patterns.
• BlondeliiniShares parasitoid lifestyle but differs in male terminalia structure, particularly the separation and shape of surstyli. Blondeliini larvae possess more developed accessory sclerites in the cephalopharyngeal skeleton.
• EryciiniClosely related tribe with similar host associations, but distinguished by differences in the structure of the male aedeagus and the arrangement of abdominal sternites.

• parasitoid
• tachinid
• biological control
• Diptera
• insect parasitoid
• endoparasite

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• T.G.I.Flyday: Tachinomyia sp. | Beetles In The Bush
• Diptera | Beetles In The Bush | Page 4
• Tachinidae | Beetles In The Bush