autoecious

Autoecious is a biological term used to describe an organism that can complete its entire life cycle on a single host or within a single organism, without requiring an additional host species. In mycology and plant pathology this term is often applied to rust fungi and other parasites to indicate that all essential reproductive stages can occur on one host rather than on multiple hosts.

In rusts, autoecious contrasts with heteroecious, where the life cycle requires two distinct host species to complete different spore stages. Autoecious rusts may still exhibit multiple developmental phases but do not need an alternate host. The term can also be used more broadly to describe parasites that complete their life cycles on one host species, rather than moving between hosts. The classification can vary among populations or environmental conditions; some species have both autoecious and heteroecious populations.

Autoecious does not specify mating strategies; it describes host usage rather than how organisms mate. However, in some cases, sexual reproduction on the single host can be self-sufficient, while in others it may require individuals on the same host population or environmental conditions to enable outcrossing.

Etymology: autoecious comes from Greek autos, meaning self, and oikos, meaning house or home.

Notes and related terms: The concept is often discussed in the context of rust fungi and powdery mildews, where researchers distinguish life cycles that stay on one host from those requiring an alternate host. It is distinct from homothalpy, which refers to self-fertility in mating, though some autoecious forms may also be capable of self-fertilization.