Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

If you plan to live in the South make sure you are well defended! No, I’m not talking about the Republican Presidential Nomination, but the latest findings by PhD student Daniel Anstett (Johnson Lab) and ROP299 student Nabanita Nawar. Daniel and co. just published “Can genetically based clines in plant defence explain greater herbivory at higher latitudes?” in Ecology Letters. In a field experiment at KSR, Daniel planted out genotypes from 137 populations collected from the entire native range of common evening primrose. Over the course of two years he studied the insects that attacked these plants and measured a variety of chemical defences and additional plant traits involved in defence. He found that plant genotypes from more southern latitudes were attacked less by herbivores and invested in greater chemical defences against insects. These results help us understand how environmental gradients and climate change can impact coevolution between plants and insects.