Cuterebra

Large, stout-bodied flies with bumble bee-like appearance. Adults lack functional mouthparts. Rabbit-infesting species (including C. abdominalis, C. buccata, and related species) possess distinctive red bands in the eyes—a diagnostic feature not present in rodent-infesting species. Adults rarely encountered; identification often confirmed by association with host warbles or puparia. Larvae develop as large subcutaneous bots, creating conspicuous warbles with respiratory openings.

Adults frequent dark situations near host activity: rodent and lagomorph burrow entrances, outbuildings, summer kitchens, and ground burrows. Eggs are deposited in host habitat rather than directly on hosts.

Widespread in North America. Documented from western Canada (Manitoba, Saskatchewan, Alberta, Northwest Territories, British Columbia) and eastern North America (Vermont, New Brunswick). Individual species show more restricted ranges: C. grisea occurs throughout western Canadian provinces; C. fasciata recorded from British Columbia and New Brunswick; C. emasculator, C. americana var. polita, C. similis, and C. tenebrosa documented from British Columbia; C. tenebrosa also recorded from Montana.

Adults active on the wing from June to September. Larvae spend approximately one month in host before exiting to pupate; pupae overwinter in soil.

Adults do not feed; lack functional mouthparts. Larvae feed on host fluids rather than tissue, drawing nourishment from subcutaneous locations.

• Rodentia (rodents) - primary hostMultiple species; host specificity varies by Cuterebra species
• Lagomorpha (rabbits, hares) - primary hostSeven North American species specialize on lagomorphs
• Tamias striatus lysteri (eastern chipmunk) - confirmed hostC. emasculator reared from this host
• Peromyscus leucopus (white-footed mouse) - confirmed hostC. fontinella documented on this host

Eggs laid near host burrow entrances hatch in response to host body heat. First instar larvae enter host through natural orifices or wounds, migrate subcutaneously, and establish in warble with respiratory pore. Larvae molt to second and third instars over approximately one month, feeding on host fluids. Mature third instar exits host, drops to ground, and burrows into soil to pupate. Overwinters as pupa. Adults emerge from puparium, live briefly without feeding, and reproduce.

Adults exhibit shy, elusive habits and are rarely observed despite intensive fieldwork. Females oviposit in host habitat rather than on hosts directly. Larvae exhibit precise host-finding behavior: eggs hatch only upon detecting host body heat, and larvae actively locate and enter hosts.

Obligate parasite of small mammals. Generally low prevalence in host populations; Parker and Wells (1919) found only 2 of 1,000+ rodents parasitized in Montana. Some studies suggest infected hosts may experience neutral or slightly positive survival effects, attributed to long coevolutionary history and reduced tissue damage from fluid-feeding larvae.

Does not parasitize humans. Occasionally infects domestic animals including cats; larvae can establish in subcutaneous tissue or nasal cavities. Veterinary concern in regions where outdoor cats hunt rodents or rabbits.

• Dermatobia hominisHuman bot fly of Central and South America; broader host range, employs phoretic egg dispersal on mosquitoes, and causes more severe host reactions due to less specialized host relationship
• Other OestridaeBot flies in related genera (Hypoderma, Gasterophilus, etc.) attack ungulates or other host groups; distinguished by host association and adult morphology

• bot fly
• myiasis
• parasite
• rodent parasite
• lagomorph parasite
• New World
• Cuterebrinae
• warble
• subcutaneous parasite
• rarely observed adult
• mimicry
• bumble bee mimic

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Oestridae | Beetles In The Bush
• Newly emerged rabbit bot fly | Beetles In The Bush
• The Occurrence of Cuterebra (Diptera, Oestridae) in Western Canada