A heteroecious parasite is one that requires at least two hosts.
Both hosts are required for the parasite to complete its life cycle.
This can be contrasted with an autoecious parasite which can complete its life cycle on a single host species.
Many rust fungi have heteroecious life cycles:[1] In parasitology, heteroxeny, or heteroxenous development, is a synonymous term that characterizes a parasite whose development involves several hosts.
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