Stylogaster

Macquart, 1835

thick-headed fly, needle-tailed fly

Stylogaster is a of distinguished by extreme morphological and biological specializations. possess an elongated exceeding body length when extended, and females have a dramatically elongated folded beneath the body—the 'needle tail' referenced in the generic name. The genus is the sole member of Stylogastrinae and comprises approximately 92 with predominant Neotropical distribution. Unlike other conopids that parasitize , Stylogaster species are of orthopteroid (, ) with documented associations also including various calyptrate .

Stylogaster neglecta by (c) skitterbug, some rights reserved (CC BY), uploaded by skitterbug. Used under a CC-BY license.

Stylogaster neglecta (Michael Hodge) by Michael Hodge. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Stylogaster: /ˌstaɪloʊˈɡæstər/

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Identification

Distinguished from all other by the combination of: extremely elongated longer than body when fully extended; reduced in ; and in females, the greatly elongated folded ventrally beneath the body. Antennal proportions differ between —S. neglecta has short 2nd and highly elongate 3rd antennomere, while S. biannulata has 2nd and 3rd antennomeres nearly equal in length. are uniquely morphologized with rigid barbed tips, unlike the smooth eggs of other conopids.

Images

Habitat

Associated with supporting (Ecitoninae, Dorylinae) raiding columns in Neotropics and Old World tropics, where females exploit -driven disturbance. occasionally found at flowers. habitats include ground-dwelling and environments.

Distribution

Widespread across tropical and subtropical regions: Neotropics (69 , predominant center of diversity), Afrotropical region including Madagascar (14 species, with 5 to Madagascar), Australian region (5 species), Oriental region (2 species), and Nearctic region (2 species: S. neglecta and S. biannulata). Absent from Palaearctic region. In North America, recorded from southern Ontario and northeastern United States southward.

Diet

feed on nectar using the elongated . are developing within .

Host Associations

Oecanthus nigricornis - confirmed black-horned ; first confirmed of S. neglecta with successful larval
Muscidae (various genera) - or including Dichaetomyia, Helina, Phaonia, Stomoxys; attached to but definitive status unconfirmed
Calliphoridae - or including Bengalia, Tricyclea, Hemigymnochaeta; 24% of Tricyclea specimens in one study bore Stylogaster
Cockroaches - reported historical records, specific not consistently documented
Army ants (Ecitoninae, Dorylinae) - ecological associatefemales exploit raiding columns to access flushed ; not obligate for all as occurs in Madagascar where are absent

Life Cycle

are forcibly jabbed into using the female's elongated ; barbed egg tips anchor in host tissue. approximately 30 days based on S. neglecta rearing data. develop as , eventually emerging to pupate; host death follows larval . Multiple has been documented.

Behavior

Females exhibit specialized : hovering over raiding columns, then diving to jab into flushed by activity. This high-risk strategy results in significant egg loss when ants capture post-oviposition. Oviposition involves a stabbing motion with the thrust forward between the legs. Some may operate independently of army ants.

Ecological Role

of orthopteroid and potentially other . May function as agent through of calyptrate . Association with represents a complex three- interaction exploiting -driven disturbance.

Similar Taxa

Other ConopidaeOther parasitize (, , ) rather than orthopteroids; lack the elongated and needle-like female ; have smooth without barbed tips
Mydidae (mydas flies)Large size and - in some may cause confusion; distinguished by elongate clubbed versus short antennae of Stylogaster