New research from the University of Guelph said on Friday that temperatures are becoming too hot for bumblebees, threatening their role as plant pollinators and the food supply for humans and other animals. Researchers said increasing heat is soaring past the optimal temperature for bumblebees, from 86 to 89.6 degrees. Guelph environmental professor Peter Kevan said while bees have the ability to thermoregulate the temperatures inside their hives, that can ...