Most of our bees are in trouble and struggling to survive. But, as Suffolk conservationist Audrey Boyle reports, one species is providing a welcome sting in the otherwise gloomy tale
If you have a stand of ivy near you it might be worth giving it a second glance. With the arrival of autumn most bee activity has steadily decreased, but there’s one specialised bee that is only just emerging and will remain active until early November. Recently arrived from continental Europe, the ivy bee has clearly made itself at home.
The ivy bee Colletes hederae is a relative newcomer to the UK, first being recorded in Dorset in 2001. It times its activity to coincide with the flowering of ivy - another great reason to let ivy flourish in your garden! Attractive little creatures with a ginger, “fox-fur” thorax and stripy black and orange abdomen, ivy bees can sometimes be mistaken for wasps or honey bees but on closer inspection they are more delicate with a flatter abdomen.
Dr Richard Comont, data monitoring officer for the Bumblebee Conservation Trust, says the ivy bee was first described as a species in 1993.
“It wasn’t so much discovered, as the Germans and Croatians realising that what they thought were two species - Colletes succinctus and Colletes halophilus - were in fact three. However, it’s also thought to be a fairly recently evolved species - it doesn’t have much co-evolution with parasites and only currently occupies a small proportion of the apparently-suitable areas, Europe-wide, and is spreading out fast. There’s no evidence of it having any negative impacts on any of our native wildlife - it’s filling a niche that was previously empty.
“The lack of competition for the niche is probably the main reason they’ve spread so fast in Britain - they don’t have much competition for food or nesting sites, and no parasites either, so are free to spread across the country where there’s ivy, and nice sandy soil to tunnel in. Climate change probably isn’t a major cause of its spread.”
At this time of year some south-facing sandy slopes can be seen swirling with swarms of thousands of male ivy bees flying close to the ground. Heaps of excavated soil among the short grass mark individual nest-site holes where female bees are preparing to emerge for the annual mating ritual. When she appears she’s immediately mobbed and a copulation cluster forms which can tumble “off piste” down the hill - or off the cliff - so intent are the males on their task.
After mating, female bees equipped with strong fore legs and mandibles, start their nocturnal task of constructing long underground tunnels - old nest sites are also requisitioned.
Although ivy bees are solitary bees the females congregate together to dig individual burrows which can go up to two metres down. Side branches off the main tunnel contain brood chambers which are stocked up with a gooey nectar-pollen mix from the ivy. The female then lines the walls with a cellophane-like fluid from a gland on her head to waterproof the nest chamber - the American names for Colletes species are plasterer or cellophane bees.
The female will then spend a couple of days foraging to collect the three million ivy pollen grains needed to get one larva through to adulthood, stashing them in a brood chamber - mixed with a bit of nectar - before laying a single egg in the chamber and beginning again with the next one, said Dr Comont.
“She’ll do this for about 12 to 18 brood cells before succumbing to exhaustion. The eggs hatch, the larvae munch their way through the pollen grains, and then pupate, before emerging the following year to repeat the cycle,” he said.
Ivy bees are entirely harmless - males do not have stings at all while females have tiny ones, similar to a weak nettle sting, and are very reluctant to use them.
“People are often worried about the swarms, but there’s no need to worry at all, even with children around,” said Dr Comont.
“Essentially, we’re very happy to see them - they do no harm to anything and provide one of the very few bee-related good news stories that we currently have. In terms of encouraging them, the best thing that people can do is leave some ivy to flower - they don’t need much else!”
Adrian Knowles, the Hymenoptera (bees, wasps and ants) county recorder for the Suffolk Naturalists’ Society, said: “In coastal Suffolk we have records from the seafront cliffs at Felixstowe and a couple of sites in Ipswich. I suspect it’s a lot more widespread than that though.”
The Suffolk Biological Records Centre and the Bees, Wasps and Ants Recording Society are monitoring the spread of ivy bees and need people’s records - with photographs if possible - to update distribution maps of the species. They can be contacted at www.bwars.com and www.suffolkbrc.org.uk
The Suffolk Biological Records Centre can also be contacted on 01473 433547.
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