Tree-munching insects likely to survive cold

Beetles on bark
Eastern larch beetles crawl on a small piece of tamarack bark University of Minnesota researcher Fraser McKee has peeled off. The darker horizontal lines are cavities the beetles have dug to lay their eggs. The tree sends resin to the area to try to repel the beetles. But the beetles emit an aggregation pheromone to attract more beetles to the tree, which can overwhelm its defenses.