Autumn bees

Autumn is such an exciting month for bee spotting because it’s when Ivy bees – our last solitary bee of the season – emerges. First the males, which have already been sighted in Devon, appear and collect nectar from a variety of flowers. Then later this month, and next, females will forage for nectar and pollen on tiny, white ivy flowers.

The best way to see Ivy bees, is to keep an eye on any ivy bushes and when they flower observe the bees and other insects that come to feed – it’s like a watering hole for insects, especially hoverflies. Can you tell the difference? Top tips here

Many other solitary bees are still around. Small, black bees, including Common furrow bees, the more diminutive Green furrow bee, and Large-headed resin bees.  Tips below for how to tell them apart.

Also, if you’re anywhere near sandy banks, look out for Pantaloon bees which are still nesting. Ivy bees also nest in sandy soil, like bunkers on golf courses, emerging in large numbers at this time of year. Remember these solitary bees are all harmless.

As for bumblebees, the small brown fluffy Common carder bees are foraging on late-flowering lavender, salvia and toadflax. And Red-tailed bumblebees and Tree bumblebees are flying – many of these bees will be large, because they are new queens, or smaller males (which in some species have a yellower-coloured fluffy face than workers and queens). The males are seeking new queens to mate with, and the new queens, once mated, are stocking up on nectar to build up their fat reserves for when they hunker down over winter. A colony that’s produced lots of queens and males is a success story.

THIS SUMMER’S HEATWAVE AND DROUGHT WILL HAVE DEPLETED POLLEN AND NECTAR RESOURCES, MEANING FEWER QUEENS AND MALE BUMBLEBEES WILL HAVE BEEN PRODUCED BY THE COLONY. THIS MEANS NEXT YEAR, THERE IS LIKELY TO BE FEWER NEW BUMBLEBEE COLONIES.

Tips for IDing September bumblebees:

• Red-tailed bumblebees (Bombus lapidarius) – The males, (12-14mm) which are flying now are one of our prettiest bees with their yellow facial hair and red bottoms. The queens are much more dramatic, dressed in black with a fiery red butt. In the south of the UK, queens can produce a second colony of up to 300 bees, so it’s this second generation there are now flying. BUT GIVEN THE DROUGHT/HEAVWAVE THIS MAY NOT HAVE HAPPENED THISYEAR. The queen is one of our biggest bumblebees: measuring 20-22mm. Workers are a smaller version of the queen (14-16mm).
• Tree bumblebees (Bombus hypnorum) – seem to be doing well further north. If you’ve been bee spotting all summer, you may be quite adept at identifying tree bumblebees by now with their ginger thorax, black abdomen and white tails. Perhaps you’ve even had them nesting in a bird box in your garden. GIVEN THE HEATWAVE/DROUGHT WE MAY SEE FEWER AROUND THIS MONTH THAN NORMAL, as a second 150-strong colony may not have been produced. The only difference in appearance between the queen, males and workers (known as the three castes) is their size. Queens are a larger 14-20mm, males 11-13mm and workers 13-15mm.
• Common carder bees (Bombus pascuorum) I am happy to report seem to be everywhere in London at the moment, living up to their name by being frequent garden visitors. New queens are a noticeably bigger than the 11- 13mm workers. Both will be foraging, alongside males too. The castes all have the same ginger pile on their thorax, but it will be much paler on the worker bees whose colouring fades with age to a light brown. They are the smallest bumblebees flying in September.
• Other bumblebees you’re likely to see this month are Buff-tailed bumblebees (Bombus terrestris).  This month huge mated queens (18mm) are flying, as well as workers and males. In the south these queens are stocking up on nectar and looking for a suitable nesting site to raise a new colony during the mild winter. Further north, the queens are stocking up on nectar and looking for a suitable place to overwinter. Outside of London, you may also see White-tailed bumblebees (Bombus lucorum), whose bands are a lighter yellow than the dirty gold-coloured bands of the Buff-tailed bumblebee.

How to ID September solitary bees:

• Pantaloon bee (Dasypoda hirtipes) – I always associate this sand-loving mining bee (13mm in length) with beaches but she is just as happy on sandy brownfield sites mainly in southern England and Wales. Her nest can be distinguished from other burrowing bees by the large fan of sandy spoil she leaves to one of side of the hole. You can see how she makes her nest in this great video. The males don’t sport the over-sized pollen brushes ‘pantaloons’ on their hind legs, but still have long fair hairs.
• Ivy bee (Colletes hederae) – one of the highlights of my autumn is being able to spot an Ivy mining bee. To the untrained eye, they can look deceptively like a honeybee, especially as they are both found en masse buzzing around nectar-rich ivy flowers. However, look closely and you’ll see the Ivy bee has more hair on its thorax and its abdomen has much more defined and shiny segmented bands in buff and brown alternate colours. The males, which are out a couple of weeks before the females, sport a brown quiff, are a little smaller (8-9mm) than honeybees (10mm), and have long antennae.  Despite their name, Ivy bees can gather nectar  from a variety of late flowers before the ivy flowers, but the easiest way to spot them is to inspect the tiny white ivy flowers. Ivy bees belongs to the Colletes family, which mine into the ground to make their nests – often next door to each other in very large numbers – and they line their nest with a cellophane-like waterproof and fungus-resistant substance, which is why Colletes are also called plasterer bees. If you have a south-facing slope with light soil you may see hundreds, even thousands, of these bees emerging from their individual nests. It is easy to forget that they are solitary bees, as you can see on this video from the Hampshire & Isle of Wight Wildlife Trust. 

Fascinating fact – the Ivy bee was only described as a separate species in 1993 and wasn’t discovered in the UK until 2001 in Dorset. Now it has spread as far as Scotland.

• Common furrow bee (Lasioglossum calceatum) – these small solitary bees (8-10mm) with an elongated black, shiny, banded abdomen have been flying since early spring. The easiest way to ID them is to observe them on daisies, like Erigeron karvinskianus,  and in Geranium flowers. The ones you will be seeing now are males and females that were born in July and can fly until October. They makes nests in the ground.

• Green furrow bee (Lasioglossum morio) – an even smaller (4-5mm), black solitary bee, this one has a green metallic hue that you can see in the sun.  They are widespread but tricky to see as they are tiny. However, we’ve found them a number of times eight floors up on London rooftops foraging on hebes and a wildflower called Hoary willowherb (Epilobium parviflorum), or sunning themselves on paving stones.

Fascinating fact: Both of these burrowing, furrow bees can display primitively eusocial behaviour, which means the early flying females in warm climates are actually queen bees that in early summer produce workers. These worker bees will collect nectar and pollen for the new females and males that are born later in the summer.

• Large-headed resin bees (Heriades truncorum) – another small (8mm), black, robust bee often seen at this time of year in the south of England on yellow composite flowers like sunflowers. The easiest way to distinguish it from other small, black bees is that it carries pollen on the underside of its abdomen (like a leafcutter). And the female makes her nest in a pre-existing cavity in wood. After she has laid her eggs in the cavity, she plugs it with tiny bits of grit and stone that she collects and then glues it all together with resin collected from nearby trees. You can help this bee by drilling holes into wooden logs and attaching them to a wall. See how to make a nest for this bee. 

Fascinating fact: She is found in Europe and the east coast of the United States and is thought to have possibly been introduced in the UK by Victorians in imported wood.

Another solitary bee you may still see this month is the tiny Common yellow-faced bee (Hylaeus communis) – these small (5-7mm) predominately black bees with tiny yellow eye spots (female) or a triangle (male) on their face has been a familiar sight in gardens since midsummer. I’ve seen them on tall Fennel plants. They plaster their nests, but unlike other bees they collect pollen in a special stomach, called a crop, and regurgitate it to make a semi-liquid mixed with pollen to feed the larvae.

Fascinating fact: They have been observed blowing bubbles of nectar to evaporate the water. This is known as water homeostasis and it concentrates and thickens the nectar/pollen mixture making it tacky like honey. The bee’s eggs and larvae ‘stick’ to its surface, unlike many other solitary bee larvae which ‘sit’ on top of the more solid pollen mixture.  (Thanks to Nurturing Nature for the info and footage).

How to help bees in September

1. Plant flowers that bloom this month to provide important late sources of nectar and pollen. Especially important this autumn, given that the drought and heatwave led to many summer plants flowering early and setting sead, or dying, leaving a nectar and pollen gap. Sedum, Michaelmas daisy, dahlia, fuchsia, Devil’s bit scabious, Coreopsis (Tickseed) Perovskia Blue Spire, commonly known as Russian sage, and wild marjoram (Origanum) are all good, and don’t forget Common sneezeweed (Helenium autumnale), the solitary bees favourite, according to Rosybee nursery’s fantastically helpful research . A particular fav in our garden is Helianthus ‘Lemon Queen’ a slug-proof sunflower, and of course, the Geranium Rozanne is still going strong! For the long-tongued bumblebees, black horehound, salvias, and buddleia are still flowering. And the Common carder bees are all over Japanese anemones, Caryopteris and Plumbago.
2. The best late forage for short-tongued Ivy bees (and honeybees) without a doubt is ivy. But ivy only flowers when it is mature and that can take 11 years! So if you have any sprawling ivy that needs a trim, please don’t cut it back until after it’s flowered this month.
3. If you only have a window box, Mexican fleabane (Erigeron karvinskianus), trailing nasturtium and Bird’s-foot trefoil are still flowering. Add sedum and annuals such as cosmos and snap dragons. If you grow herbs in pots and window boxes, let the mint and oregano keep flowering.
4. Gather seeds Store them in labelled paper bags in a cool, dry place for sowing or scattering next spring. BUT GIVEN THIS SPRING WAS SO DRY, I AM GOING TO BE SCATTERING MY AROUND MY GARDEN AND ROOFTOP THIS AUTUM WHEN WE GET MORE RAIN, WHILE THE SOIL IS STILL WARM. Lightly rake the soil, scatter the seeds, cover them with fine soil and firm down.
5. Leave parts of the garden undisturbed, as ground nesting bumblebee queens may be looking for a snug place to overwinter – and don’t chop down dead stems that solitary bees may have laid eggs in.
6. Boost your wildflower meadow . If you haven’t already done your summer cut, do it now, scarify the cut meadow to expose bare soil where seeds can grown, then add yellow rattle seeds to suppress grasses taking over next year. Finally, add perennial plug plants of wild flowers that will grow well in the soil to feed bees in the future.
7. Ditch the weed killers and pesticides. 
8. Take semi-ripe cuttings if you are patient and want to propagate heathers, ivy, Mahonia, Escallonia, flowering-currents, verbena, penstemon and salvias. The cuttings should be ready to pot on next spring.
9. Create a bank of sand mixed with some clay soil against a south facing wall, or a free-standing mound, for mining bees which like to burrow into sand. It needs to be about 400mm deep. Create steps in the sand as some bees like to nest vertically and others horizontally. The clay will help the bank to keeps its shape after the bees have tunnelled into it. If you’re lucky you may get Ivy mining bees nesting in it this autumn next door to each other in large neighbourhoods.
10. Drill holes in blocks of wood – 10mm, 8mm, 6mm and 4mm diameters and up to 30 cm deep (although some bees only need a depth of a few centimetres to nest in) – and screw them to a sturdy support. Drill holes in existing structures such as fence posts, or dead trees. Large-headed resin bees, Scissor bees and Yellow-faced bees may take up residence, but probably not until next year.
11. Keep a look out for yellow-legged Asian hornets on ivy bushes. They could have a severe impact on our wild bee populations. 157 credible sightings have been reported in the UK in 2026. And 49 nest have been found. This is less than last year. Most sightings were in Kent, and the south, but one was much further north in Chesterfield. Report any sightings using the Asian Hornet Watch App.