noun

• (ecology) The fact of a parasite or dependent organism completing an entire life cycle on a single host species.
  "1972, B. K. Bakshi, Relative Blister Rust Resistance of Native and Introduced White Pines in Asia, North Atlantic Treaty Organization, International Union of Forestry Research Organizations, US Forest Service, University of Idaho, Biology of Rust Resistance in Forest Trees: Proceedings of a NATO-IUFRO Advanced Study Institute, page 254, This may possibly be explained by autoecism (pine-to-pine spread) in the aecial stage of the rust, but autoecism has not been conclusively proved (Spaulding, 1922)."
• (botany, of a plant) The fact of having male and female reproductive organs on the same individual plant.
  "Along with this view of pleomorphism, goes the generally conceived idea that autoecism is the primitive condition, heteroecism being considered a later adaptation (Klebahn, 1904)."