hosts

Definition

Organisms that harbor and provide resources to parasites, parasitoids, or symbionts, serving as sites for feeding, development, or reproduction. In entomology and disease ecology, hosts range from incidental carriers to obligate life-cycle stages, with distinctions made between definitive hosts (where sexual reproduction occurs), intermediate hosts (supporting larval or asexual stages), and reservoir hosts (maintaining populations that infect other species).

Etymology

From Latin hospes (guest, stranger, host), via Old French hoste; biological usage established in parasitology by the 19th century.

Example

Mosquitoes (Anopheles spp.) serve as definitive hosts for Plasmodium parasites, which undergo sexual reproduction in the insect gut before transmission to vertebrate hosts during blood-feeding.

Related Terms

• Host
• Parasite
• Parasitoid
• definitive host
• intermediate host
• reservoir host
• Vector
• Symbiosis
• host switching
• host specificity

Usage Notes

Distinguish from 'vectors' (organisms that transmit pathogens without necessarily serving as developmental hosts). Host status is often context-dependent: a rodent may be reservoir host for Lyme disease spirochetes but dead-end host for certain arboviruses. In biological control, 'host' also denotes the prey or victim of parasitoids—usage that can confuse parasitology-trained readers.