The acidic fluid present in the traps of Nepenthes pitcher plants has a primary function of digesting prey, but also plays a role in the capture of insects. Bazile et al. collect fluid in the field from pitchers of four Nepenthes species and determine retention capacity and time-to-kill for different species of ants and flies under controlled conditions. They find that both the pH and viscoelasticity properties of the fluid influence a plant’s diet and its carnivorous status. Thus the plants may select the prey that they retain by manipulating the secretion of H+ ions and polysaccharides in their pitcher fluid, which has implications for potential adaptive radiation of this genus with regard to the nutrient sequestration strategies of different species in various habitats.
Fluid from pitchers of four Nepenthes species is studied to determine retention capacity and time-to-kill for different species of ants and flies.