Root parasitism by Scybalium fungiforme Schott & Endl. is not random among host species in seasonal tropical forest

Abstract

Though they comprise 1 % of plant species on the planet, plant parasites are poorly known. They have been considered a threat to cultivated plants and to the conservation of host species in natural areas. Due to the complex interactions they have with their hosts, understanding their biology is fundamental to the development of conservation strategies for both parasite species and their hosts. We sampled two populations of the root parasite Scybalium fungiforme (Balanophoraceae) in seasonal tropical forest fragments to identify its host species and their functional attributes. Among the hosts, Croton floribundus seems to be preferred (68 % of parasitized plants), while four liana species were complementary hosts (32 %). Host species preference differed sharply among fragments and seems to be related to the successional stage of these forests. The hosts C. floribundus and the four liana species are perennial, fast growing and have large vessels, all of which are attributes that enable high water and nutrient acquisition efficiency. Despite a lack of clear host specificity at the species level, functional convergence among parasitized species suggests that host specificity is mediated by functional traits.