Cuterebra abdominalis

Distinguished from other Cuterebra species by host association (lagomorphs) and subtle morphological features. The red banding in the eyes is characteristic of rabbit-infesting species in the genus, though precise identification to species level often requires expert examination and reference to specialized literature such as Sabrosky (1986). Distinguished from the similar C. buccata (also a rabbit bot fly) by specific characters detailed in taxonomic revisions. The mimicry of bumble bees can cause initial confusion with Hymenoptera, but the single pair of wings (Diptera), large size, and flight behavior distinguish it.

Adults are large, robust flies with a bumble bee-like appearance. They possess large, rounded heads with prominent compound eyes that often show red banding—characteristic of rabbit-infesting species in the genus. The body is densely hairy, with black and yellow or orange coloration creating a tiger-striped or banded pattern on the abdomen. Wings are typically dark or smoky. Adults lack functional mouthparts. Larvae (bots) are large, thick-bodied maggots with rows of backward-pointing spines on the body segments and a pair of posterior spiracles.

Adults are found in open habitats including glades, prairies, and areas near rabbit burrows. The species is associated with environments where lagomorph hosts are abundant, including grasslands, open woodlands, and edge habitats. Larval habitat is subcutaneous within host rabbits; pupation occurs in soil.

Recorded from the United States, with specific records from Vermont and Missouri. The genus Cuterebra is distributed across North America, with individual species showing varying ranges. Based on host distribution, likely occurs throughout the range of suitable lagomorph hosts in eastern and central North America.

Adults are active in spring and early summer, with observations in Missouri recorded in April and May. This timing coincides with the breeding season of host lagomorphs. The species overwinters as pupae in soil.

Adults do not feed and lack functional mouthparts. First instar larvae enter the host and migrate to subcutaneous locations. Second and third instar larvae feed on host fluids (tissue fluids and exudates) rather than solid tissue, creating a warble—a cyst-like structure with a breathing pore opening to the skin surface.

• Sylvilagus floridanus - larval hostEastern cottontail rabbit
• Lepus - larval hostHares

Adults are extremely short-lived and focus entirely on reproduction. Females lay eggs near rabbit burrow entrances or in host habitat; eggs are stimulated to hatch by host body heat. First instar larvae enter the host through natural orifices or skin breaks, then migrate to a subcutaneous site (often along the back or sides). The larva creates a warble—a swollen, cyst-like structure with a breathing pore—and molts to second instar. After approximately one month of feeding on host fluids, the third instar larva exits through the breathing pore, drops to the ground, and burrows into soil to pupate. The species overwinters as a pupa, with adults emerging the following spring.

Adults are rarely encountered due to their short lifespan and non-feeding habit. They are most active during daylight hours in spring. Females exhibit site fidelity to areas with active rabbit burrows for oviposition. The species exhibits Batesian mimicry of bumble bees, presumably reducing predation risk despite the adults being harmless. Larvae remain within host warbles for approximately one month before exiting.

As a specialist parasite of lagomorphs, C. abdominalis functions as a population regulator of rabbit and hare populations, though infections are generally considered to have minimal negative impact on host survival. The relatively benign host-parasite relationship reflects a long evolutionary association. Adults serve as prey for visual predators that overcome or see through the mimetic protection. Pupae in soil may be subject to predation or parasitism by soil-dwelling organisms.

Not a human parasite. Adults may cause momentary alarm due to bumble bee mimicry and large size, but are harmless. The species is of interest to entomologists studying host-parasite coevolution, mimicry, and the natural history of oestrid flies. Occasionally encountered by mammalogists studying small mammals. May be observed by naturalists in spring in suitable rabbit habitat.

• Cuterebra buccataAlso a rabbit bot fly with similar host range and appearance; distinguished by subtle morphological differences in coloration and eye banding pattern
• Cuterebra fontinellaA rodent bot fly parasitizing mice and other small mammals; distinguished by host association and lack of red eye banding characteristic of rabbit-infesting species
• Cuterebra emasculatorA tree squirrel and chipmunk parasite; distinguished by host association and different adult coloration
• Dermatobia hominisHuman bot fly of Central and South America; distinguished by geographic range, broader host range including humans, and different oviposition strategy (eggs deposited on blood-feeding insects for transport to hosts)
• BombusBumble bees—the model for C. abdominalis mimicry; distinguished by two pairs of wings (four total), different antennal structure, and different flight behavior

Despite the alarming appearance of the large, bee-mimicking adults, they are harmless to humans and lack functional mouthparts. The species name 'abdominalis' refers to the abdominal location of some infections, but this should not be confused with the warble location always being abdominal—larvae can establish warbles in various subcutaneous locations. The related species C. emasculator was historically thought to impact squirrel reproduction due to warble location near genitalia, but research has shown this is not the case; similar misconceptions about reproductive impact do not apply to C. abdominalis.

• parasite
• mimicry
• bot fly
• lagomorph
• rabbit
• Oestridae
• Cuterebrinae
• myiasis
• warble
• Batesian mimicry
• short-lived adult
• non-feeding adult
• soil pupation
• spring emergence

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Diptera | Beetles In The Bush | Page 6
• flies | Beetles In The Bush | Page 8