A new line of carnivorous plants (Triantha) with a unique sticky inflorescence trap

Abstract

Carnivorous plants consume animals for mineral nutrients that improve growth and reproduction in nutrient-poor environments. Here we report that western triantha (Tofieldiaceae) represents a previously neglected carnivorous line that captures insects on sticky inflorescences. Field experiments, isotopic data and mixing models demonstrate significant transfer of N from prey to Triantha, with about 64% foliar nitrogen obtained from the capture of prey in previous years, comparable to the levels inferred for the round-leaved sundew, a recognized carnivore. Nitrogen obtained by carnivorous is exported from the inflorescence and developing fruits and can finally be transferred to the leaves the following year. The glandular hairs of the flowering stems secrete phosphatase, as seen in all carnivorous plants which directly digest their prey. Triantha is unique among carnivorous plants to capture prey only with sticky traps adjacent to its flowers, contrary to theory. However, its glandular hairs only capture small insects, unlike large bees and butterflies which act as pollinators, which can minimize the conflict between carnivore and pollination.