Effect of extreme heat on bees

Alf Brugman Beekeeping Blog

This summer has seen many days in a row of almost mid 40 degree temperatures in the north of the state where we have some of our hives. After the Red Gum had flowered and bees had collected good stores of high quality pollen, it was surprising to see that as January ended, there wasn’t any pollen left and not much brood. This is unusual after a Red Gum flow but can be explained by the unprecedented heat.
When the outside temperature rises towards high 30’s and higher, the field bees cease nectar and pollen gathering and 100% of the bees switch to water collecting. This water is used to cool the hive by the bees acting as air conditioners and fanning cool air through the hive. This takes a huge toll on their bodies and protein levels in the bees themselves decreases markedly, so not only do bees use pollen to raise brood, they also replenish their body levels of protein as well. This means that when the summer flowering Red Ironbark started flowering, the bees needed to be given a pollen supplement to start brood rearing again.
Unfortunately, with climate change making summers hotter and hotter, it will be much harder to harvest honey and keep bees healthy.