Bumblebees undergo many changes throughout their lifecycle. Their development from egg, to larva, to adult is well-known; however, there is a transition in the lifetime of a bumblebee that is often less familiar: old age.
The first step in identifying bumblebees is often through examining the colouration of their hair and their banding – which permits us to differentiate one species from another fairly reliably. Similar to humans and many other animals, as bumblebees age, their hair colour fades. This change is caused by exposure to the elements, through a process called sun-bleaching. Bumblebees that have spent more time outdoors – such as long-lived workers or males, which live the majority of their adult lives outside of the nest – tend to be more exposed to the sun and elements, their hair discolouring and fading to paler forms of their original colour.
Sun-bleaching is not the only way in which wear, tear, and old age affects bumblebees. As they go about their days, they often rub against plants, wood, stone, and more. This wears at and thins their hair and in some cases can even shear it off, revealing their shiny black exoskeleton.
This is not the only weathering you may expect to see: bumblebee wings can show serious wear and tear, with the edges becoming tattered over time. This doesn’t seem to deter the bumblebees or hinder their foraging.
‘Fresh’ bumblebees, who have just reached their adult stage and left the nest for the first time, are the easiest to identify – and the majority of photographs of bumblebees you will have seen will be of such bees in their prime. This fresh male Red-tailed bumblebee (Bombus lapidarius) has bright yellow and red hair which contrasts with its black hair.
Clare Flynn
In practice, there is a significant amount of variation in bumblebees’ appearances, even within species, due to environmental factors like sun-bleaching and wear and tear. Because of this, some bumblebee species can be difficult to identify, particularly towards the end of bumblebee season. This is a great example of a faded male Red-tailed bumblebee where the bright yellow has faded to a cream, the bright red has faded to orange and even some of the black hairs have lightened.
Bumblebee Conservation Trust
If you would like further information on how to ID bumblebees, or even learn about their lifecycle, take a look at the following:
