Ecological opportunity and evolutionary relatedness predict parasite sharing differently across mammalian taxonomic scales

Geographic proximity explains parasite sharing from 86.6% within mammalian genera down to 44.7% across all mammals, with evolutionary relatedness becoming predominant at broader taxonomic scales.

• Why it matters: It remains unclear how ecological opportunity versus evolutionary relatedness jointly shape parasite sharing as species meet under global change, limiting disease-emergence forecasting.
• What they did: Using 30,310 recorded host–parasite associations spanning 680 mammalian hosts and 11,107 parasite species, they modeled how geography and host relatedness predict sharing across taxonomic scales.
• The result: Parasite sharing rose nonlinearly with both geographic proximity and host relatedness, varied by parasite type, and counterfactually reducing distance by 99% increased predicted sharing to 13.71% within genera and 1.50% at the class level.

AI summary of the abstract · may contain errors · not medical advice · read the paper.