Ivy bees Colletes hederae are a species of ground-nesting solitary bee that can be found in all regions of France. They are expanding their range and numbers in the north and, since 2001, can be found in the south of the UK, where they are continuing to expand northwards.
An attractive bee, slightly smaller than a honey bee, they have yellow and black bands and a ginger or chestnut brown hairy thorax.
They are often referred to as plasterer bees or polyester bees, due to the method of smoothing the walls of their nest cells with secretions applied with their mouthparts; these secretions dry into a cellophane-like lining.
They start to emerge from late August and, depending on conditions, can be seen until November. This coincides with Ivy flowering, which is their principal source of nectar, and in the case of females, pollen to provision their eggs for when they hatch, hence the common name in both English and French. Nests themselves are created by the females that make a tunnel with several side chambers for the eggs. Although solitary and individual, there can be a large number of nests in an agglomeration.
Anyone who has a poly tunnel or greenhouse with an open door will always find various flying insects that have entered; most, but not all, find their way out again. But these structures seem to be particularly attractive for Ivy bees, where some people find large numbers of them, and they become effectively trapped as they fail to find their way out and subsequently perish.
Why so many are attracted to these places is unclear; I can't find anything definitive, and one can only speculate. It seems to occur regardless of the temperature and with no plants or flowers in them.
So, some very helpful advice on how to encourage them to leave safely from a lady in Brittany, and I quote her as follows.
“Cover the roof with light-proof tarps so the open door becomes the brightest spot. This is the only thing that fully worked for me. Tie them down hard, because wind will pull them loose.
For stragglers, soak strips of kitchen roll in sugar water and leave them in the tunnel. The bees cluster on them, and you can carry the strips outside and drape them over flowering ivy.
Check daily for slipped tarps and for any new arrivals.
Close the doors at dusk once nothing is still trying to leave, and open them first thing in the morning.”
“WHAT NOT TO DO
No sprays, no WD-40, no pest control, and no killing them. Oily or toxic products harm bees and other insects, and more will likely hatch from the ground the next day anyway.
HOW LONG?
A few weeks. They disappear once the ivy finishes flowering.
THE FOLLOWING YEAR
If bees nest nearby, put the tarps on in late August, before the first ones arrive. It's far easier than dealing with a tunnel already full.”
The
bees themselves are harmless, although females can sting; it's
extremely unlikely that one would, and although their numbers are
bucking the trend and actually increasing, we don't want to be
causing harm if we can avoid it.
Chris
