Cephenemyia phobifer

Larvae develop internally in the retropharyngeal pouch of deer and are not externally visible until potentially emerging; puparia are dark, hardened, and barrel-shaped with a distinct posterior respiratory plate. Adults are short-lived and rarely observed. Distinguished from other Cephenemyia species by host specificity (primarily Odocoileus virginianus, with occasional records in Alces americana) and northeastern distribution; C. apicata and C. jellisoni occur in western and northwestern regions respectively, while C. pratti is southwestern and C. trompe is northern.

The internal pharyngeal region, specifically the retropharyngeal pouch, of white-tailed deer. Free-living stages occur in environments where deer are present; puparia may be found on soil surface near deer activity. Deer from second-growth forest habitats show higher infestation rates than those from mature deciduous forests.

Northeastern Nearctic region. Documented in Ontario (Algonquin Park), Vermont, and southeastern Missouri. GBIF records indicate presence in Vermont and broader United States.

Two generations per year: winter cycle requiring approximately 6 months, summer cycle approximately 3 months. Adults are short-lived. Larval presence in deer documented year-round with seasonal variation in instar occurrence.

Larvae feed on deer blood and tissue, specifically within the pharyngeal region; deer blood has been documented in larval alimentary tracts. Adults do not feed.

• Odocoileus virginianus - primary hostwhite-tailed deer; 62% infestation rate documented in Algonquin Park population, highest in deer 6 months to 2 years of age
• Alces americana - secondary hostmoose; occasional records

Probable larviparous reproduction; females deposit first-instar larvae directly onto or near hosts. Three larval instars develop within the pharyngeal pouch of deer. Pupation occurs in soil; puparia metamorphose in 23±1 days at 63±5°F or 15 days at 77±2°F. Two generations annually with overlapping cohorts.

Females exhibit probable larviposition behavior, approaching deer to deposit larvae. Larvae remain within host pharyngeal tissue until mature, then exit through host nostrils or mouth to pupate in soil.

Parasite of cervid hosts; causes pathological changes including enlargement of retropharyngeal pouch and destruction of epithelial layers. Population dynamics influenced by deer herd behavior and forest habitat type.

No direct human health significance; of interest to wildlife biologists and veterinarians managing deer populations. Infestation prevalence used as indicator of deer population health and habitat quality.

• Cephenemyia apicatawestern distribution; parasitizes Odocoileus hemionus
• Cephenemyia jellisoninorthwestern distribution; broader host range including multiple cervid species
• Cephenemyia prattisouthwestern distribution
• Cephenemyia trompenorthern distribution; primarily parasitizes Rangifer spp. (reindeer/caribou)
• Gasterophilus intestinalishorse bot fly; similar puparium morphology but different host and anatomical location

• parasite
• bot fly
• cervid parasite
• larviparous
• pharyngeal parasite
• wildlife disease
• Oestridae

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Wednesday “What the heck?” | Beetles In The Bush
• Probable larviposition by Cephenemyia phobifer (Clark) (Diptera: Oestridae)
• THE NEARCTIC SPECIES OF THE GENUS CEPHENEMYIA (DIPTERA, OESTRIDAE)
• ON THE BIOLOGY OF CEPHENEMYIA PHOBIFERA (DIPTERA : OESTRIDAE), THE PHARYNGEAL BOT OF THE WHITE-TAILED DEER, ODOCOILEUS VIRGINIANUS