Boisterous Wool Carder Bees

This summer, I discovered a colony of wool carder bees in the Sensory Garden beside the River Witham and these characterful little creatures became the focus of my lunchtime walks for much of the rest of the season. The photographs and slow-motion videos below were all taken in this garden over the course of the summer.

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Wool carder bee feeding on lamb’s ear

The wool carder is a striking bee – chunky and robust with sporty yellow markings down the sides of the abdomen which is tipped with five spikes in the males. They are in the megachile family – alongside the leafcutters – but are the only representative of the Anthidium genus to be found in the UK. More broadly, they are one of the 250 or so solitary bee species in the UK. They are common in England and Wales but are just starting to make their appearance into Scotland.

The name ‘wool carder’ is an intriguing one which relates to an even more intriguing behaviour. ‘Carding’ is a mechanical process which involves disentangling, cleaning and preparing fibres for processing, and the word originally comes from the latin ‘carduus’ relating to teasels or thistles which were historically purposed for the task. In this context, ‘wool carder’ relates to the behaviour of the female bees who shave plant hairs and fibres from leaves and stems. They gather these fibres into a bundle and take them to their nest site – often aerial holes and crevices as well as hollow plant stems and bee hotels – and use them to line the nesting tubes.

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Male wool carder bee resting on the ‘wool’ of a lamb’s ear leaf

The wool carder bees forage on a range of species, specialising in those in the deadnettle and pea families such as betony, woundwort, mint, balm, loosestrife, toadflax and restharrow. This study from Kernowecology found that in native vegetation, marsh woundwort and purple toadflax were the most commonly used flowers for nectaring whilst greater bird’s foot trefoil was most commonly used as a pollen source. They advise that planting those two species together is successful in attracting these bees.

However many people will encounter the bees, as I did, on a garden plant and Stachys byzantina seems to be one of the most popular for this species. This plant is one of the woundworts which is a member of the deadnettle family which the bees favour for nectaring, whilst also having perfect ‘wool’ for the females to gather for their nest tubes – the plant is not known as ‘lambs ear’ for nothing! This combination of the bees’ two key requirements makes them irresistible to the female bees and this is something which the male bees take advantage of.

The male bees are larger than the females, and are highly territorial. I spent many lunchtimes watching them patrol a patch of lamb’s ear, waiting for the females to arrive. Once a female landed to nectar, the male would pounce upon her for a swift and unambiguous mating – see video below – before leaving the slightly startled looking female to continue visiting the flowers.

The males would regularly rest in a spot of sunshine before upping and patrolling the flowers in search of females or rivals.Interestingly, one might expect the male bees to limit their attentions to other male wool carders who represent a direct rival, but instead they will attack and chase away any other bees including honey bees and much larger bumblebees – see videos below. This is thought to be a mechanism of maximising the value of their territory, and thus making the plant more enticing to female bees. They will grapple with these other bees and pull them off the flowers and sometimes pursue them to the ground. The spikes in the base of the thorax are then seen to be not simply for show – the male wool carders use these aggressively, capturing their enemy between their curled thorax and the spines in order to inflict damage.

This behaviour is fascinating to watch, and seemed of little concern in the garden as the wool carder males limited their attention to their patch of lamb’s ear, leaving other bees safe to forage on the multitude of other flowers nearby. However this aggressive behaviour gives significant cause for concern when the bee is invasive in other countries such as the US and New Zealand. Their distribution close to ports in NZ indicates that they may have come across in ships, whilst they have been detected in various parts of the USA since 1963 and are making an appearance across the country, establishing now in western USA. Kelsey Graham is studying the effects of the wool carder as an exotic species on the native US bee populations. As in the UK, there is considerable concern in the USA about the decline of native bees including bumblebees and other solitary bees species such as the Osmia. The impacts of the exotic wool carder bees in the US relate in part to competition for nectar as they are sharing a finite resource with the native species, but particularly relate to the aggressive behaviour of the males in attacking the native species. Kelsey identifies that the chemical changes induced in the plants by the ‘carding’ of the females releases chemical signals which attract further wool carder bees. Native US bumblebees seem most likely to be attacked, and Kelsey’s research has found that this leads to these bees avoiding areas where the wool carder bees patrol, thus reducing the availability of foraging resource to the native bees. You can read more about Kelsey’s research here.

The wool carders are a summer bee, flying from June – August, and visiting the Sensory Garden in September seems somewhat lacking without the antics of this boisterous and charismatic bee. Kate Bradbury wrote a wonderful piece in the Guardian about watching these bees in her newly created wildlife garden where they arrived in less than a year, so I am hoping that the already-established lamb’s ear in the garden of the house we have just moved to will provide this spectacle on our doorstep next summer!

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Wool carder bee in flight
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Walking in the footsteps of Laurie Lee

Cider with Rosie has to be one of my favourite books, with its evocation of life in a wooded Gloucestershire valley at a crucial time when the world around the village was changing but where a more ‘traditional’ country life still persisted. I have wanted to visit the landscape ever since reading it, but it is always that little bit too far or not quite convenient – however a recent site visit took me back past Stroud and so opportunity knocked to call in at Slad – the village where the book is set.

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Look carefully for tiny eyebrights in the grass – their white petals paint-splashed with yellow and purple

I parked up at Swift’s Hill – a SSSI which overlooks the valley and took a look around the grassland before setting off on a walk. The sward is clearly past its summer finery but many flowers still studded the hillside – small scabious, devil’s bit scabious, knapweeds ad eyebrights – frequented by these beautiful little Lasioglossum solitary bees with endearingly long antennae.

I then picked up the Laurie Lee Wildlife Way which takes you down the steep hillside and across open pasture field to an apple orchard where the mustard-green mistletoe nests amongst the branches.

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The view across the valley to the village of Slad with mistletoe hanging from the apple trees in silouette

Next, the path takes you down across the river and into the village itself, before heading up the other side of the valley and into the darker woodlands of Frith Wood where the trees crowd over the pathway to form a shady passageway between the trunks. After crossing the road, and walking beneath some truly majestic beeches, the track winds up a steep wooded hillside and releases you into the meadow of Snows Farm – managed for wildlife and thronged with flowers such as yellow agrimony, blue harebell and scented wild basil and marjoram.

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An old trackway with majestic beech trees lining the way

The way continues then through woodland and wildflower grassland, ending in Laurie Lee wood – a recent Gloucestershire Wildlife Trust aquisition – before ending back at the high open hillside of Swift Hill.

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The view out across the valley with Russian Vine covering the foreground

One of my favourite aspects of the walk was the totems displaying Lee’s poem’s written black on perspex so that the view was visible behind the words. This means of display was an excellent way of placing the poems within the landscape which was so important in inspiring his work.

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After reading Cider with Rosie, I read ‘As I Walked Out One Midsummer Morning’ where Laurie Lee talks about leaving this very village on foot and working in London before making his way to the continent and walking down to the south coast of Spain. The steep valleys and hillsides would be fine training for a long distance walk and I could certainly feel my flatland legs when I got to the end, but this was a magnificent way to spend an afternoon through some of the most quintissential Cotswolds scenery you could hope for. Woodruff and wood sorrel leaves covered the woodland floors, whilst the dead flowering stems promise bluebells in the springtime so I will certainly be back to explore this beautiful place again.

You can read more about the Laurie Lee WIldlife Way here. I didn’t have a copy of the route guide but found the walk quite straightforward to follow for the most part – however there are places where crossroads are not signed so it’s a good idea to pick up the leaflet or to take a map with you as backup!

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The view across pasture fields to the orchards, with the wooded hillside rising to the right hand side

Heather Colletes bees

August is a fairly spectacular sight in the Peak District – up away from the arable fields, the heather turns the landscape pink and purple amongst the gritstone. Such a vast resource does not go un-tapped by the natural world and one solitary bee in particular has evolved to exploit the nectar wich underpins this aesthetic abundance.

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The heather colletes bee – Colletes succinctus

This beautiful little solitary bee is known as the heather colletes – Colletes succinctus. These are slightly smaller than a honeybee but have a similar banded pattern to their abdomen. They are a member of the colletes family – known as the plasterer bees.

These sandy paths, studded with gritstone and lined with heather, offer ideal nesting sites for the heather colletes bees with open substrate for burrows and a plentiful food source just next door.

One of the first misconceptions about solitary bees is that you will find them in isolation. Where the conditions are right however, many species of these bees form dense nesting aggregations. The ‘solitary’ epithet refers to the fact that they do not partition roles in the same way as the social honey bees, such as workers and queens. As we walked the sandy soils of the National Trust‘s Longshaw Estate, we saw these little bees feeding on the heather – their bodies curled almost foetally around the flowers – and soon started spotting their nesting holes too!

Heather colletes bee feeding on heather

At first we saw a few holes here and there, but soon we were coming across dense aggregations of the pencil-sized nesting burrows. Much to the bemusement of a group of American tourists hiking up to the tor, I spent the next 20 minutes on my knees watching their coming and going – the video below shows some their entering and leaving their nesting holes.

The males emerge a little before the females, who themselves appear in August to co-incide with the flowering of the ling. I watched the females leaving their holes and flying up to the heather in whose roots they were nesting. Here they gather nectar and also pollen to stock the larders of their nesting burrows. The females layer their burrows with pollen and then lay their eggs which overwinter as pre-adults (eggs to larvae) to emerge the following summer.

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Heather colletes bee emerging from a nest burrow amongst the heather roots

The males hang around the nesting burrows and mate with the females as they fly to and fro – sometimes a mating ball will form where several males will attempt to mate with a single female, grappling together until one wins out. I did not manage any good images of this behaviour, although I would recommend a read of Phil Gate‘s Guardian Country Diary piece which has a cracking photograph of the mating bees.

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As the weather warmed up, the previously empty holes increasingly revealed their inhabitants which responded to the changing conditions and began to pop out

One thing which was noticable was the difficulty the bees had in keeping their footing on the loose, sandy soil. Often they would slip and fall, or otherwise engage their wings just to stay positioned on the ground. Coupled with their propensity for nesting on bare ground, an opportunity often afforded by well-walked paths, it much be a feat of engineering to maintain the integrity of these burrows in such substrate. The video below shows a couple of such incidents in slow motion:

I took a few more slow-motion videos of their flight as they enter and leave their nesting burrows. They would often land close to their burrow and the look around a while before successfuly locating their hole. I wonder how they know which is their entrance, amongst so many others. From watching other mining bees prviously, they seem to use landmarks in such a way that adding or removing something from the immediate vicinity of the entrance, such as a twig or leaf, can leave them apparently unsure about their home.

Just a few clips of them leaving in slow motion to finish off! As always if you want to find out more about a bee species in the UK, including these heather colletes, I would suggest checking out the BWARS species accounts and Steve Falk‘s Flickr page including images and the text which accompanies the images in his excellent book.