This is a quick roundup of some of my favourite insect encounters of 2018 – there are some beautiful and highly varied species in the UK which reward the close observer!
2018 in Insects
bee
Harebell Carpenter Bees
Our native bees come in all shapes and sizes – from the uvuncular bumble bees to the sporty leafcutters and the tricksy nomads. One of my favourites is also one of the most inconspicuous – you may well have seen them around a garden campanula, mistaken them for small flies and thought no further. Whilst I’m not advocating flies as worthy of oversight, the harebell carpenter bee (Chelostoma campanularum) is certainly rewarding if you take the time to look a little closer.
These tiny black bees are just 6-7mm long and black all over. The females have a white scopa – as illustrated in this BWARS profile of the bees – and the males are very similar in size and appearance.
We have a number of campanula species which are native to the UK, including the harebell along with a range of bellflower species which are larger and more akin to the ornamental garden varieties, such as nettle-leaved bellflower. Fortunately, these little harebell carpenters don’t seem too fussy and I’ve watched them on two different ornamental cultivars in our garden over the past few years.
To watch these bees around the flowers, you might be forgiven for wondering what precisely they’re doing – they often look for all the world as though they love the flowers… but don’t know what to do about it. In fact, they are intimately intertwined with the genus – the females will only collect pollen from bellflowers and this blog from Urban Pollinators has some great images of their specialised means of collecting this. They also mate in the flowers and females will wait for males in the flowers, whilst the males will swarm and circle around on the hunt for females! Males will often shelter in the flowers in dull weather too.
These bees are aerial nesters – this means that they will seek out opportunities such as dry stems and holes in wood to nest in. This makes providing for this species in your garden very straightforward – simply plant some campanulas (the native harebell is a delightful addition to any garden) and provide some bundles of reed or straw at height for them to nest in.
The bee is on the wing from June through to August and has a mostly southerly distribution in the UK but certainly occurs around Grantham in the midlands!
Below is a slow-motion video of the harebell carpenter bees in our garden flying around an ornamental bellflower – but if you want to see some excellent images of the bees at rest, check out Ed Phillips’ blog post here. And if you want the detailed image of males and females, as well as habitat shots, head over to Steven Falk’s flickr albums!
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.
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.
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!
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.
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.
Lassioglossum solitary bee feeding on small scabious
Lassioglossum solitary bee feeding on small scabious
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.
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.
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.
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.
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.
Small teasel
Agrimony
Wild basil
Wild marjoram
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!
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.
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.
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!
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.
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.
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.
Red mason bees
Red mason bees are solitary bees which are commonly found in gardens and urban areas. Many people will have seen the bee hotels which you can buy now from many garden centres and similar locations which are perfectly designed to create a nest site for this species.
There are several species of mason bee in the UK but the red mason – Osmia rufa – is the most common. They are prolific pollinators – estimated to be 120-200x more efficient than the honey bee which makes them a real benefit to any garden, especially those with fruit trees whose flowering period coincides well with the time that these bees are on the wing.
Red mason bees naturally nest in hollow plant stems or holes in cliffs. They also make use of the crumbling mortar of old buildings but their needs can be easily accommodated in the hollow tubes which are the common constituents of bee hotels. After mating, the female bees lay their eggs in the nesting tubes. Each egg is laid and provisioned with pollen and nectar for the young to eat when it hatches. After each egg is laid, a mud-wall is created between it and the next cell which she lays to that the tube, when complete, is a series of individual nest cells. Think a packet of rolo’s where the wrapper is the tube, the chocolate is the mud partition and the caramel inside is the egg, nectar and pollen!
In order to build these cells, the mason bees need to gather mud from a source close to the nest. I found such a ‘mud mine’ down by the banks of the River Witham in Grantham. Close to the waters edge, where the mud is damp, there were small holes which were visited by several bees at the same time, all intent on extracting mud. They scrape this from the surface, roll it into a ball and carry it back to their nest in their mandibles. They seem very faithful to a good location – some of the bees were scraping the mud from the banks on their own, but many used the same spot which had clearly been excavated by several bees over many trips.
Red mason bees are on the wing from around March until June so keep an eye out for them in your back garden and, if you can, provide them with their own nesting site in the form of a bee hotel. If there is no mud source nearby, you can help them out with a tray of damp soil which they will use to line their cells. Your payment will be the services of a highly efficient garden pollinator!
Grantham Ecology 