I'm a little behind on noticing this (still catching up after my England trip), but Paul Garner recently blogged on a new study in The New Phytologist that
demonstrated that at least three pitcher plant species in the highlands of Borneo do not feed primarily on insects. Instead, they obtain their nutrients from faeces deposited in their pitchers by tree shrews feeding on nectar exuded by glands on the inner surfaces of the pitcher lids (Chin et al 2010).I won't steal Paul's thunder on this one. You should read his report for yourself. I would just like to add that Nepenthes pitchers totally look like toilets. Case closed.