Individual heterogeneity drives a plant macroparasites life history

Abstract

The population dynamics and life histories of macroparasites are fundamental to examine their impacts on hosts and ecosystems. Still, macroparasite population models often ignore parasite individual heterogeneity and are rarely applied to parasitic plants, where demographic strategies are less well understood. Using a 10-year dataset on European mistletoe (Viscum album), we examine how this macroparasites traits influence its performance. V. album survival and reproduction depend on its size and, to a lesser extent, height on the host tree, with a strong growth-reproduction trade-off. We parameterise these relationships in an integral projection model to compare the life history strategy of V. album with two other macroparasites and 490 free-living plants. Contrary to our hypothesis, V. album and other macroparasites do not follow an extreme strategy, suggesting that parasitic plants may not escape the life history constraints experienced by non-parasitic plants. Our results highlight how incorporating parasite heterogeneity can improve macroparasite models.