Every Type of Parasitism Explained

Parasites span all domains of life—viruses, bacteria, fungi, plants, and animals—employing parasitism as a survival strategy rather than representing a distinct taxonomic category.

Microparasites include viruses, bacteria, and other microscopic pathogens that infect host organisms internally, causing diseases that recently included a pandemic shutting down global civilization.

Ectoparasites including ticks, lice, fleas, and bedbugs colonize host external surfaces, feeding on blood by penetrating skin while remaining outside the host body.

Micropredators—mosquitoes, vampire bats, leeches—occupy an evolutionary middle ground between parasites and predators by feeding on multiple hosts without killing them or establishing long-term residence.

Endoparasites including tapeworms, rabies viruses, and tongue-eating lice invade host internal spaces—intestines, brains, or body cavities—to extract resources while evading external threats.

Brood parasites, prominently cuckoos and cowbirds, exploit other species’ parental care systems by depositing eggs in host nests, forcing unwitting surrogate parents to raise parasitic offspring.

Kleptoparasites—frigatebirds, skuas, hyenas, and various spider species—steal food or resources from other organisms rather than obtaining them through direct foraging or hunting.

Social parasites—rove beetles, large blue butterflies, and slave-making ants—exploit eusocial insect colonies by infiltrating communication systems and labor structures rather than parasitizing individual organisms.

Parasitic castrators like Sacculina barnacles and castrating isopods destroy or obstruct host reproductive systems, redirecting host resources from reproduction toward parasite growth.

Male anglerfish practice sexual parasitism by permanently fusing to females, degenerating into sperm-producing organs while receiving nutrition from female bloodstreams.

Parasitoids, predominantly wasps, occupy an evolutionary position between parasites and predators by ultimately killing hosts as obligate parts of their reproductive cycles rather than maintaining prolonged host survival.

Behavior-altering parasites including Ophiocordyceps fungi, rabies virus, and Toxoplasma gondii manipulate host nervous systems to promote parasite transmission through induced behavioral changes.