Study: Extreme heat damages bumblebees and shortens their lifespan

According to a study, extreme heat can damage bumblebees' development and shorten their lifespan.

If the number of bumblebees declines, this could have far-reaching consequences for the ecosystem, said researchers at the University of Regensburg. Bumblebees are therefore important pollinators for many wild and crop plants and thus contribute to biological diversity and food production.

For the study published in the journal "Communications Biology", researchers led by Christoph Kurze examined in the laboratory what effects heat stress has on the development of the dark bumblebee (Bombus terrestris). According to the German Nature Conservation Association, this species is one of the most common bumblebees in this country and is also used as a pollinator in fruit and vegetable cultivation.

To do this, the research team raised larvae and pupae in the laboratory in order to be able to precisely control the intensity and duration of heat stress - comparable to temperatures on extremely hot summer days. The temperature rose every twelve hours to highs of up to 38 degrees during the day. The result: pupal mortality of up to 30 percent and developmental damage that doubles the risk of death in adult bumblebees and significantly shortens their lifespan, according to research leader Kurze.

The bumblebees also showed increased deformations such as crippled wings and antennae. Kurze concluded that the heat appears to have a massive impact on the doll's tissue remodeling. “In addition to a shortened life expectancy, affected bumblebees are, in extreme cases, unable to fly or their sense of smell may be impaired, which reduces collection success or the ability to recognize nest mates.”

The researchers assume that extreme heat stress is rather unrealistic for species that nest in the ground, such as bumblebees. However, species that nest above ground could be affected, such as the field bumblebee and bumblebee colonies that are used for pollination in greenhouses.