Taming the carnivore

Animals are well known for recognising a good thing when they see it. So, too it seems are carnivorous plants – those erstwhile gentle botanics that are not averse to digesting the odd fly or two to supplement their nitrogen intake. Well, that certainly seems to be the case for Swedish Drosera rotundifolia (common or round-leaved sundew) at least. Using nitrogen isotope measurements, Jon Millett et al. demonstrated this carnivore’s remarkable opportunistic nutritional plasticity – plants in areas that received the greatest levels of N deposition (from the atmosphere) obtained a smaller proportion of N from prey (via their modified leaves) than did those with lower or intermediate depositional N levels (and who were less reliant upon root-sourced N). This may also be an example of ‘every cloud has a silver lining’ since the N that is aerially sourced onto the studied ombrotrophic mires is derived from what is otherwise known as acid rain, which elsewhere has caused serious environmental damage to many Scandinavian lakes. Canny critters, carnivores! However, the study also found that plants that gained more N from prey had an enhanced nutritional status (higher tissue %N). Which maybe also supports the notion that if you have to ‘forage’ for your food, you are fitter than those ‘couch potatoes’ who just sit around to be waited upon…?