Category: Knowledge
Date published: July 02, 2019

WARNING: Bumblebees – Keep them Cool this Summer!

‘The need to keep your busy pollinators cool increases. Keeping an eye on the temperature in the greenhouse is more important than ever for your bumblebees to be able to function optimally and give the best pollination results for your crop.’ says Koppert’s Pollination Product Manager, Remco Huvermann.

Avoid Radiant Heat and Ensure Correct Placement

Koppert’s guidelines advise growers to protect their hives against radiant heat/direct sunlight and to place them in a cool spot. Radiant heat can increase temperatures in the hive by 5 to 15°C/41 to 59°F. See for the best practice advice this short Koppert video clip .

‘A stable hive temperature ensures that bumblebees are out for the maximum number of pollination hours, and it positively influences the lifespan of a colony. It can make the difference between just enough pollination or a fruitset problem,’ Huvermann explains. ‘All that growers worldwide need to do is to take account of their local conditions and make sure the temperature is such that the bumblebees can concentrate on their pollination work and not purely on incubating and ventilating their hives.’


Keeping Them Cool Outdoors

Bumblebees that work in a greenhouse have an advantage in that it is easier to manage the temperatures indoors unlike outdoors. On a watermelon farm in Texas temperatures can easily reach 100°F and maintain that temperature for hours. Unfortunately, for the bumblebees this can mean death from the heat. Therefore, it is important to ensure proper steps are taken by the grower to help the bumblebees to stay cool.

When bumblebee hives are kept at the proper internal temperature of 39.2-59°F they have no issues focusing their energy on pollination. Once the temperature increases pass the 59°F mark bumblebees start focusing on keeping the hive cool. To do that they stay in the hive and use different methods of keeping cool. For the bumblebees staying cool becomes a necessity to surviving.

One method that we advise our growers to follow, to help the hive stay cool is providing a shade structure. These structures can be purchased from Koppert. This can be seen in the picture to the right. Following the same principle of a shade structure a grower can make one of his own. Our recommendation is to take two pallets and form an 'A' frame type of structure above the hive, as can be seen in the picture below. Then there are some growers that get creative and create many different structures and find different methods of keeping the hives shaded.

A second method that is also known to help in keeping the hive cool is by digging a large enough hole for it to fit. Usually, these holes are about 2 feet deep and wide enough for the Quad to fit into. On top of that is placed a shade structure, whether one from Koppert or one designed by the grower.

Pollination Checklist Outdoor

Koppert's bumblebees ensure natural pollination in both indoor and outdoor crops. Good pollination in outdoor crops can be achieved by following the recommendations in our 'Pollination Checklist Outdoor'.