Finding dead bumblebees in the garden…

Bumblebee nests grow throughout the season, and produce new males and queens in autumn. Throughout the life of the nest a large number of smaller worker bees help the nest to grow by collecting nectar and pollen – these are the bees that you see out and about in summer. These workers only live for a few weeks, and then sadly die. It’s therefore quite normal to see a small number of dead bees in the garden. So long as you are still seeing live bees in the area, then it’s unlikely to be something new that we should be worrying about.

The reason why dead bees are often found in gardens and near nest sites is simply because that’s where they’ve been living. When bees are close to death, they often cling to flowers and look quite lethargic. When they do die, they then drop off the flowers, and you may find a number of these in your gardens, especially near the most bee-friendly plants. Also, you may find dead bees and larvae near nest entrances, because dead and dying bees are removed from the nest so that disease does not spread.

Bumblebee predators…

Click here to read more about what eats bumblebees.

 

Parasites…

Bumblebees, like many insects in fact (and humans!) can suffer from different parasites which live inside them. These parasites can make the bees appear slow and sluggish, perhaps even drunk! Again, sad as this may seem, it is a natural process that has been going on for many, many years and is not at the root of the problem.

Equally, bumblebees may sometimes seem very lethargic just because the weather is cold – but they will recover when it warms up. This is nothing to be alarmed about, and is perfectly natural.

Lime trees…

Sometimes, large numbers of dead bumblebees can be found under Lime/Linden trees. There has been a lot of research into the reason why and the current evidence points to a combination of low sugar content in the nectar, with the possibility of an addictive metabolite which affects the bees’ decision making and may encourage them to continue feeding, despite not getting the energy they need from the nectar. Not all bumblebees are affected by this phenomenon as healthy bees can often be seen foraging from the same tree. The effects seem to be compounded when ambient air temperatures are low as bumblebees require additional energy to warm themselves up to power their flight. Sadly, these bees soon become grounded and eventually starve as they do not have the energy to fly.

Road collisions…

Some people report large numbers of dead bees and other flying insects along busy roads or on bridges over busy roads. In these cases insects are often killed or injured as a direct result of traffic collision. Potentially billions of insects meet this fate across the globe annually. Planting up road verges is often seen as a good way to help bumblebees and other pollinators, however there are many questions which need to be resolved before this advice is implemented wholesale, particularly around busy roads with high levels of traffic and pollution. For this reason the Bumblebee Conservation Trust are partnering with Highways England and the University of East Anglia on a doctoral research project to find out the benefits and drawbacks of planting up road verges for bumblebees.

Poisoning…

Poisoning events are very rare, however, if you find dead bumblebees and suspect that they might have been poisoned by the professional use of pesticides meeting the criteria set out on the Health and Safety Executive website then please report this to the Wildlife Incident Investigation Scheme (WIIS) on 0800 321600.

Comments are closed.

Registered Charity No. 1115634 / Scottish Charity No. SC042830

Copyright © 2019 Bumblebee Conservation Trust. All Rights Reserved.