Insects feast under high CO₂

Leaf-eating insects in northern temperate forests consume more of the forest canopy when carbon dioxide levels are increased, which could limit forests' capacity to act as carbon sinks in a warming world.

John Couture and his colleagues at the University of Wisconsin-Madison, found that in parts of a research forest exposed to raised CO₂ levels, herbivorous insects increased their consumption of foliage by 88%. This led to an average of 70 grams of carbon-sequestering biomass lost per square metre of forest per year.

Increased CO₂ could be causing this effect by changing the nutrient content of leaves and also by boosting the number of leaf-eating insects, the authors say. They also suggest that insect behaviour should be incorporated into models that estimate the effects of high CO₂ on forest productivity.

Nature Plants http://dx.doi.org/10.1038/nplants.2015.16 (2015)