Obligate-parasite
Guides
Bombus suckleyi
Suckley's Cuckoo Bumble Bee, Suckley's Bumble Bee
Bombus suckleyi is a cuckoo bumble bee (subgenus Psithyrus) and obligate social parasite of other Bombus species. It lacks corbiculae (pollen baskets) on its hind legs, having lost the ability to collect pollen and nectar for its own brood. The species invades host colonies, kills or subdues the resident queen, and manipulates host workers to provision its offspring. Native to northwestern North America, it has experienced severe population declines of approximately 77% and is classified as critically endangered by the IUCN and NatureServe.
Cochliomyia hominivorax
New World screwworm fly, New World screwworm, screwworm, screw-worm
Cochliomyia hominivorax, the New World screwworm fly, is an obligate parasitic blowfly whose larvae feed exclusively on living tissue of warm-blooded vertebrates. It is the only parasitic species in its genus; other Cochliomyia species are facultative parasites or carrion feeders. The species was eradicated from the United States, Central America, and much of the Caribbean through the sterile insect technique beginning in the 1950s, though it persists in tropical and subtropical South America and portions of the Caribbean. A 2016 outbreak in the Florida Keys was successfully eliminated, but detections in southern Mexico in 2024–2025 triggered renewed eradication efforts and trade restrictions.
Cuterebra approximata
bot fly, rodent bot fly
Cuterebra approximata is a New World skin bot fly (family Oestridae) whose natural host is the deer mouse (Peromyscus maniculatus). First instar larvae enter the host through the external auditory meatus and migrate to the dorsal body region, where they form subcutaneous warbles. Larvae develop through three instars from July through September before exiting to pupate in soil. Adults are extremely short-lived, lacking functional mouthparts, and are active for approximately two weeks in late June to early July.
Cuterebra cochisei
Cuterebra cochisei is a species of New World skin bot fly described by Sabrosky in 1986. As a member of the genus Cuterebra, it is an obligate parasite of mammals with larvae that develop subcutaneously in host tissue. The species is one of 34 recognized North American Cuterebra species. Very little specific information has been published about this particular species.
Cuterebra polita
Cuterebra polita is a New World skin bot fly whose larvae are obligate parasites of rodents. Adults are non-feeding and short-lived, lacking functional mouthparts. Larvae develop in subcutaneous warbles on host rodents, feeding on host tissues and fluids. The species has been documented in four rodent hosts in Florida: white-footed mouse, cotton mouse, eastern woodrat, and cotton rat.
Ericrocidini
cuckoo bees
Ericrocidini is a tribe of cleptoparasitic (cuckoo) bees within the family Apidae, containing 11 genera and approximately 42 species distributed throughout the Neotropics. These bees are obligate parasites of oil-collecting bees, primarily attacking nests of Centris (Centridini) and, in one derived case, Epicharis. Females do not construct nests or collect pollen; instead, they invade host nests, kill host eggs or larvae, and deposit their eggs in provisioned brood cells. The tribe diverged from related lineages approximately 74 million years ago in the Cretaceous, with host specialization evolving synchronously with their Centris and Epicharis hosts during the Eocene.
Formica subintegra
Formica subintegra is an obligate slave-making ant that practices dulosis, a form of social parasitism where the species depends entirely on captured workers of closely related host species for domestic tasks. Colonies consist of 70-90% enslaved workers, primarily from the Formica fusca group. The species exhibits relatively frequent nest relocations, moving toward areas of higher host density to improve raiding success. Unlike more specialized obligate parasites, F. subintegra retains the ability to recover degenerated behaviors when isolated from hosts, including foraging, nest excavation, and trophallaxis.
Gasterophilinae
stomach bot flies
Gasterophilinae is a subfamily of Oestridae containing large, parasitic flies whose larvae develop in the digestive tracts of herbivorous mammals. The group includes three genera with distinct host specializations: Gasterophilus (equids including horses, zebras, and donkeys), Gyrostigma (rhinoceroses), and Cobboldia (elephants). Adults are short-lived, non-feeding, and exhibit specialized oviposition behaviors. Larvae are obligate parasites that complete development in the host alimentary tract, causing veterinary significance. The subfamily has achieved near-cosmopolitan distribution through association with domestic horses.
Hippoboscoidea
Louse Flies, Tsetse Flies, and Allies, Pupipara
Hippoboscoidea is a superfamily of calyptrate flies comprising four families: Glossinidae (tsetse flies), Hippoboscidae (louse flies or ked flies), Nycteribiidae (bat flies), and Streblidae (bat flies). All members are obligate blood-feeding ectoparasites of mammals or birds. The superfamily is distinguished by adenotrophic viviparity, in which larvae develop internally and are deposited as fully-formed prepupae. Some members serve as vectors for significant pathogens, including trypanosomes that cause African sleeping sickness and nagana.
Melophagus
sheep ked, sheep louse fly, sheep tick
Melophagus is a genus of wingless, blood-feeding flies in the family Hippoboscidae. All species are obligate ectoparasites of cloven-hoofed mammals in the family Bovidae, particularly sheep, cattle, goats, and related wild species. The genus is native to Europe, Asia, and North Africa, but M. ovinus has been introduced worldwide with domestic sheep. These insects spend their entire life cycle on the host, with females giving birth to pupae that attach to wool fibers.
Pediculus humanus capitis
Human Head Louse, Head Louse
The human head louse is an obligate ectoparasite specialized for life on human scalp hair. Unlike its close relative the body louse, it has remained associated with hair rather than clothing throughout human evolution. Populations in many regions have developed widespread resistance to pyrethrin and permethrin insecticides, complicating control efforts. Transmission occurs primarily through direct head-to-head contact, with infestations clustering in settings where children interact closely.
Polyergus longicornis
Long-horned Amazon Ant
Polyergus longicornis is a dulotic (slave-making) ant species in the genus Polyergus, commonly known as Amazon ants. Elevated to full species status by Trager (2013), it was originally described by M. R. Smith in 1947. The species belongs to the Nearctic lucidus group, which includes P. lucidus, P. montivagus, P. oligergus, P. ruber, and P. sanwaldi. Like all Polyergus species, it is an obligate social parasite dependent on host colonies of Formica ants for survival and reproduction.
Polyergus mexicanus
Western Amazon Ant
Polyergus mexicanus is an obligate social parasite known as the Western Amazon Ant, widely distributed across western North America. This species is incapable of performing basic colony tasks including foraging, nest excavation, and brood care, and depends entirely on enslaved workers of Formica host species. The species performs dramatic, coordinated raids on Formica colonies to capture larvae and pupae, which are then integrated into the parasite colony. Recent genetic studies have revealed substantial population structure associated with different host species, suggesting incipient speciation into host-specific lineages.
Polyergus montivagus
Foothills Amazon Ant
Polyergus montivagus is a dulotic (slave-making) ant in the lucidus group of the genus Polyergus, originally described from the foothills near Colorado Springs, Colorado. The species is an obligate social parasite that raids nests of Formica ants to capture pupae, which mature into enslaved workers that maintain the colony. Workers possess distinctive long, blackish legs and a non-pubescent, shiny gaster. Colony size averages 300-500 workers.
Polyplacidae
spiny rat lice
Polyplacidae is a family of sucking lice (Anoplura) comprising approximately 193 species as of 2010. Members are obligate permanent ectoparasites of small mammals, with documented hosts including rodents (spiny rats, squirrels, pouched rats), lagomorphs (rabbits, hares), and primates (bushbabies, lemurs). The family exhibits cosmopolitan distribution. Molecular evidence suggests the family is paraphyletic and requires taxonomic revision.
Pseudolynchia canariensis
pigeon louse fly, pigeon fly
Pseudolynchia canariensis is an obligate ectoparasitic louse fly in the family Hippoboscidae that specializes on pigeons and doves (Columbidae). It is a significant vector of Haemoproteus columbae, the causative agent of pigeon malaria, serving as the definitive host where sexual reproduction of the parasite occurs. The species exhibits adenotrophic viviparity, producing one prepupa at a time that is deposited in the host's nest or roosting site. Both sexes feed exclusively on blood. The fly has been documented in numerous regions worldwide, particularly where domestic pigeons are kept, and shows limited ability to survive on human blood.