All smiles on the sunshine isle

Our latest guest blog comes from Tiree, ‘the sunshine island’. Low-lying and fertile, it boasts excellent areas of machair. Although often windy – there was once a wind of 116mph recorded here – it is a fabulous place to enjoy nature, and as Janet Bowler’s blog reveals there has been an exciting finale to the great yellow bumblebee community project on the Isle of Tiree!

By Janet Bowler

It has been a while since my last guest blog about Tiree’s Great Yellow Bumblebee Project, the final one of which should really have been produced in late 2020. But as with so many other efforts, the covid-19 pandemic disrupted some elements of the project, notably by restricting the number of bee surveyors who could visit the island and by delaying the publication of the children’s storybook. Looking on the bright side, however, these delays have enabled inclusion of an extra year’s worth of exciting observations.

Great Yellow Bumblebee (C) and courtesy Andy Robinson

Population Surveys

Although we didn’t have the assistance of additional surveyors in 2021 (or 2020), a handful of locals conducted a few surveys at key sites in August, the busiest month for GYBB colonies when workers, queens, daughter queens and males are all active. We were astounded with our findings: we each counted many more individuals per hour than in any previous year. Excited by this result, we plotted the August data from a few key sites (Figure 1). The data probably wouldn’t stand up to rigorous statistical scrutiny, but they do give an overall impression of GYBB activity over the duration of the project, and an indication of the most productive sites. 

Figure 1. Mean counts of great yellow bumblebees per 1hr survey of flowering machair at Aird, An Fhaodhail dunes (An F), South Hough (S Ho), Barrapol-Sandaig (Barr), and Abhainn Bhi (A Bhi), in the Augusts of 2017-2021. NB. No great yellow bumblebees were seen during the August 2018 survey at An F; surveys at A Bhi did not begin until 2019.

It could be argued that the increase in counts is due to increasing spotting skills amongst the surveyors, but as trends varied between some sites, and as all observers recorded significantly more GYBBs in August 2021, it seems more likely to be a true reflection of numbers. In any case, we can attribute the changes between years to weather conditions.

Growth of the bees’ forage plants was hindered by a prolonged summer drought across all sites in 2018. 2019 was mostly cold and wet but warmed up in late summer. The weather in 2020 created a roller-coaster ride for flowers and bees, but finally settled to warm, wet and sunny conditions resulting in simultaneous blooming of all the GYBBs favoured forage flowers, finally enabling successful breeding and a larger number of daughter queens to stock up for, and survive, winter hibernation.

Between April and June in 2021 was cold and no queens emerged from hibernation until warmer weather in late June, when larger numbers of queens than normal were recorded. Summer 2021 continued warm and windless, with occasional rain relieving the drought. This enabled copious machair flowers to support higher breeding rates for the GYBB colonies and, therefore, higher counts. Hopefully, this means that even more daughter queens will emerge from hibernation in Spring 2022.

Great Yellow Bumblebee (C) and courtesy of John Bowler

The above summary demonstrates the impact that the vagaries of the Spring-Summer weather can have on the GYBB’s success, and why, therefore, the species requires such large areas of diverse key forage flowers to ensure that, regardless of the weather, there are always resources available to keep the species going.

A Nest at Caoles

Against all the odds, two eagle-eyed visitors discovered a GYBB nest as they were cycling along the road to Caoles, at the east end of the island. Knowing that this was an important species (through this project), they stayed a while to watch and saw several bees disappear into the same patch of vegetation in the roadside bank. This was an important find. Not only was it just the third GYBB nest found during the entire five years of the project, but it was also close to an area of machair that GYBBs seemed to have disappeared from, raising our hopes that the population in that area could thrive again.

Great yellow bumblebee at nest site (C) and courtesy Jo Kennedy

Sensory garden success

Most of the ‘mini-machairs’ we sowed throughout the island in 2018 bloomed each year providing nectar and pollen for nesting bumblebees. One in particular was sensational – in the back garden at Tigh a’ Rudha Care Home.

It was a late addition, only being planted in 2019 as part of their Sensory Garden project, but it may be one of the most successful. In 2021, it bloomed spectacularly, delighting the residents with a yellow carpet of kidney vetch, bird’s-foot trefoil and autumn hawkbit, along with scatterings of red and white clovers, and tufted vetch, all favoured by great yellow bumblebees.

Children’s storybook

With much celebrating, the story about Betty – a great yellow bumblebee, created by Tiree Primary School children, was finally published in November 2021. Beataidh Banrigh – Super Bee is a warm and funny tale of friendship and wildlife conservation. It includes a fun plot, great characters and some zingy dialogue, and is told in both Gaelic and English. The children’s drawings, transformed into stunning illustrations by local artist Rou Worsley, are sumptuous in print. There is a page of useful and fascinating Bee Facts (some of which are needed to explain some of the strange behaviours of the characters!), and Forewords by Gill Perkins – CEO of the Bumblebee Conservation Trust, and Roddy MacLean – Gaelic broadcaster, writer and naturalist. What a high note to end Tiree’s Great Yellow Bumblebee Project on!

Further information:

Please email if you would like to purchase a copy of their book.

A cosy brewery

By Athayde Tonhasca

The stinking hellebore (Helleborus foetidus) is a favourite of many gardeners for its evergreen foliage and the abundance of bell-shaped flowers produced in late winter. The adjective ‘stinking’ is a bit libellous, and so is the plant’s alternative name, ‘dungwort’. Although not fragrant, the stinking hellebore produces a strong odour – often described as ‘meaty’ – only when its leaves are bruised.

Stinking hellebore © Uwe und Lukas, Wikipedia Creative Commons

The great British naturalist Gilbert White (1720-1793) commented on the attributed medicinal properties of the stinking hellebore: ‘The good women give the leaves powdered to children troubled with worms.’ But he added: ‘Where it killed not the patient, it would certainly kill the worms; but the worst of it is, it will sometimes kill both’. Like related buttercup or crowfoot plants (Family Ranunculaceae), the stinking hellebore is loaded with toxic glycosides.

Although a bad choice as a worm medicine, the stinking hellebore is an excellent option for a garden. It is one of earliest plants to bloom, which can happen even before the snow has melted away. This is a hard time for bees and other insects because there aren’t many other sources of pollen or nectar, so stinking hellebore flowers can be life savers for emerging bumble bee queens. 

Bees may have another good reason to visit these flowers: the warmth generated by yeast fermentation. Yeasts are single-cell fungi found in a variety of terrestrial and aquatic habitats. They are fundamental for some ecological processes such as litter decomposition, nutrient cycling and the growth of plant roots. One species, the baker’s yeast (Saccharomyces cerevisiae), is the main agent of baking, brewing and wine-making, and thus entwined with human civilisation.

Stinking hellebore nectaries are colonised by some types of yeast that ferment the nectar and warm the flower to more than 2° C above the ambient temperature. Floral warming can enhance plant reproduction by increasing pollen germination, pollen tube growth, and fertilization rates. Some of these effects have been demonstrated for plants that heat up because of their metabolism, or by absorbing solar energy by means of heliotropism, as it is the case for the mountain avens (Dryas octopetala). Higher flower temperatures may also increase the evaporation of volatile organic compounds, which help in attracting pollinators.  

Cell formations of Metschnikowia reukaufii, a yeast frequently found in flowers. Bar = 50 μm © Magyar et al. 2005. Fungal Diversity 20: 103-120

Despite the warming benefits to stinking hellebore flowers, yeasts have a negative side too. Fermentation reduces the sugar content of nectar, which makes the flower less attractive and rewarding to pollinators. We don’t know yet how these conflicting outcomes pan out for plant and pollinators. Flower yeasts however, seem to be clear winners in these interactions. They get energy from an abundant supply of nectar, and are dispersed from flower to flower by insects, just like Saccharomyces yeasts are transported by social wasps.

If you notice stinking hellebore plants flowering in your garden or local park, think about the unseen yeast cells mediating the relationship between plant and pollinator. This three-way invisible interaction is an apt representation of nature’s intricacies. 

A bumble bee, possibly an early bumble bee (Bombus pratorum), having a sip of nectar from a stinking hellebore flower © Daniel Ballmer, Wikipedia Creative Commons


Non-vegan bees

By Athayde Tonhasca

When an animal dies in the wild, it becomes a source of energy and nutrients for other creatures that consume its fresh remains (necrophagous species) and the decaying leftovers (saprophagous species). By breaking down organic matter and recycling nutrients, these decomposers sustain ecosystems; plant succession, habitat regeneration, and every other natural process depends on the cycle of life and death.

A necrophagous burying beetle (Nicrophorus vespillo) in the lookout for a dead mammal or bird © James K. Lindsey, Wikipedia Creative Commons

Certain bird, fly and beetle species are the main necrophages on standby to make a meal out of a recently deceased animal. But in the tropical forests of South and Central America, this club of specialised gourmets has some unusual members: the vulture bees Trigona hypogeaT. crassipes, and T. necrophages. These stingless bees do not collect pollen from flowers like most of their relatives. Instead, they ingest the flesh of dead birds, monkeys, lizards, snakes, and fish. Vulture bees have large, pointed teeth, which they use to break into a carcass through its eyes, just like maggots do. They slice off pieces of meat from the carcass and store them in their crops. Back at their nests, bees regurgitate the meat and mix it with honey. In about two weeks, the mixture turns into a paste rich with free amino acids, proteins and sugars. This nutritious pap is then fed to bee larvae.

Vulture bees attracted to a chicken bait in Costa Rica © Figueroa et al. 2021. Microbial Ecology 12:6

Vulture bees are quite efficient: when a wandering bee finds a corpse, she lays a pheromone trail to attract her nest mates. Once assembled, the gang can consume the whole carcass in a day or two. And they are good at defending their prize: potential competitors such as blow flies are kept at bay, unable to match the bees’ strong teeth.

Trigona hypogea nest and worker © Rasmussen & Delgado. 2019. Abejas sin aguijón (Apidae: Meliponini) en Loreto, Peru

Necrophagous bees may sound outlandish, but this feeding habit has an evolutionary explanation. Bees evolved from a group of carnivorous hunting wasps in the mid-Cretaceous period, so bees can be seen as wasps that turned vegetarian. Meat-eating is nothing more than switching back to an ancestral lifestyle. But why would they do that? Meat is a richer source of protein than pollen, as long as its consumer is capable to digest it. And vulture bees have what it takes: their gut microbes are similar to those found in the guts of carrion-eating birds.

And if you thought that carnivorous bees are just another bizarre tale from exotic, faraway places, think again. Vulture bees are obligate necrophages, that is, they have no option other than to scavenge carrion. But many bees and other insects are facultative necrophages: they occasionally get nutrients from a corpse to supplement their diet. These sporadic carnivores include the Mesoamerican bumble bee (Bombus ephippiatus) from Central America and our very own buff-tailed bumble bee (Bombus terrestris), which have been recorded eating carrion. The common eastern bumblebee (Bombus impatiens) from the United States and Canada and the honey bee (Apis mellifera) have been caught feeding on the fluids exuding from pig carcasses. Other exquisite non-plant food items taken by some of these bees include mammalian faeces, human urine and bird droppings.

Mesoamerican bumble bee (L) and buff-tailed bumble bee, two occasional meat-nibblers © Patylandavr (L) and Vera Buhl, Wikipedia Creative Commons

We don’t know why bees occasionally feed on these non-plant substances; they could be temporarily deprived of proteins or other nutrients normally taken from pollen. Or they could be making use of alternative, readily available sources. Some butterflies do it all the time, and there is a name for it: mud-puddling. That’s when they aggregate on puddles of mud, dung or carrion to suck up minerals and nutrients. Lapses into carnivory by vegetarians are not restricted to insects: deer may turn to fish, dead rabbits, and even live birds especially in the winter months, when dietary minerals become scarce.

Butterflies mud-puddling © Vinayaraj, Wikipedia Creative Commons

The thought of our beloved bees gobbling down bits of corpses, faeces and other unsavoury substances may be repulsive to us, but that’s an anthropocentric view of nature. If a species has the means to ingest and digest them, there is no reason to shun excellent sources of energy and nutrients. Some stuff that makes us squirm could make all the difference for the survival and success of some of our pollinators.

Glasgow Garden Festival

Gardens are seldom out of the news these days.  Regardless of whether the focus in on our own space, or a community space, we know that what we plant has the potential to be great for pollinators. However, this isn’t the first time the ‘garden’ word has commanded headlines. Cast your mind back to April 1988 and you may recall a certain garden buzz in Glasgow.

Few who visited it have really forgotten the Glasgow Garden Festival. It made quite an impact.  On April 24 the people of Glasgow turned up in droves (over 50,000) to enjoy a sneak preview of a Festival that ran from April to late September. A vital staging post on the drive to reinvent post-industrial Glasgow, the Festival was a huge hit.

True, for some the plunging Coca Cola ride was the big draw, but for very many it was the mix of themed gardens that was the inspiration. Science and Technology, Plants and Food, Health and Wellbeing, Landscape and Scenery, Water and Maritime, along with Recreation and Sport were the major subjects covered. These stunning exhibitions, allied to an array of live concerts, made the Festival a ‘must visit’ venue throughout the summer of 1988.

There was a strong Glasgow flavour to what was an international event. Refurbished Glasgow trams ran up and down the site, 100,000 season tickets were sold locally, and every house in neighbouring Govan was gifted free tickets.  

The numbers visiting the site on the banks of the River Clyde probably shocked the organisers, indeed they were almost overrun on the opening day, and the attendance figures quickly dwarfed those from previous festivals held in Stoke-on-Trent and Liverpool. After 152 days the Festival closed having drawn over 4.3 million visitors, making it easily the most successful of the eventual 5 Garden Festivals.  

The opening of the Bell’s Bridge was perhaps an early example of the need for active travel routes, and gave easy north-south pedestrian access across the Clyde to the Festival site. Once through the turnstiles visitors enjoyed not only a range of gardens but a giant yellow teapot and even bigger giant Irises. The visual arts were an integral part of the festival site and sculptures in particular had a major presence. The breaking news that Glasgow was going to be European City of Culture in 1990 was further proof, if any were needed, that Glasgow was going places. 

Here at NatureScot we had a role to play. Although let me qualify that, because back in 1988 Scottish Natural Heritage, let alone NatureScot, was some distance in the future. 

It was one of our predecessor bodies, the Countryside Commission for Scotland (CCS), that had the role of representing the natural landscape of Scotland. There was a youthful feel to their approach as they organised a primary school exhibition as their main feature. In the run up to the Festival, photographer Lorne Gill, and Ranger Lynette Borrodale, visited schools in Comrie, Glen Lyon, Forfar and Dundee; took the children out on location to teach them about the countryside on their doorstep, and ultimately coaxed artwork from the children to feature in our pavilion.  Time has dimmed the memories a little, but Lorne reckons the artwork consisted of large pieces made up of individual drawings by each pupil. The schools chosen were intended to make it possible to reflect our landscapes from the mountains to the sea.

Our garden, designed by Ian White Associates, was themed around ‘Discover Scotland’s Countryside’ and CCS also commissioned a sculpture by Stan Bonnar, who many will have enjoyed seeing in a recent ‘New Towns and Public Art’ BBC documentary alongside his son, Mark Bonnar, of Shetland and Guilt fame. Stan’s CCS sculpture was a bit ‘out there’ for its time, as it was a full-scale naked man with a fish on his head. 

Recalling which specific plants we had in the garden, and what the pollinators made of them, is a big ask over a quarter of a century later, but you can be confident they were a good cross-section of what occurred in Scotland. The CCS garden housed an attractive wooden and glass pavilion which at the close of the festival was sold to Aberdeen District Council for use in their Duthie Park Winter Gardens. 

The weighty event brochure was a worthy souvenir of the Festival and in the entry describing the CCS presence there was mention that “As you move on from the Countryside Commission you’ll pass two graceful meadows with pleasant array of wild flowers and, in contrast, boggy marshy conditions near to the water’s edge – home of the Marsh Marigold and the Kingcup.”

Printed souvenirs were aplenty … a special edition of the CCS ‘Scotland’s Countryside’ quarterly newspaper was issued, as was an accompanying specially designed children’s comic which, with a print run of 120,000, proved hugely popular.

Imagination and hard work were the hallmark of the Glasgow Garden Festival. As an example of how important our environment is it was a runaway success, and arguably provided a seamless link between urban opportunities and nature.

Further reading and viewing:

See briefly the CCS plot on this YouTube video at 6:20

Organic Growers of Fairlie

By Nancy McQueen

Organic Growers of Fairlie is a sustainable community garden with space to grow vegetable and fruit both outside and in polytunnels. We hold workshops and events that everyone can take part in and have established woodland and forest walks. This is now a super rich area for wildlife and a sheltered quiet spot for those wishing the tranquility and peace that a woodland can offer.  This is how Keep Scotland Beautiful sees our garden.

We are rewarded with a multitude of pollinators such as bees, butterflies, moths and hoverfles. There are also many sightings of voles, frogs, bats and hedgehogs which all benefit from the natural environment created by sustainably planting for people with the environment in mind. These are a multitude of natural pest controllers.

This environment has been created over many years by enthusiastic gardeners and volunteers.

The previously derelict site was historically a train yard, and also used for boat repairs.  Contaminants were found in the soil when we first started gardening here fourteen years ago.  The three acre site was also one third covered with Japanese knotweed.  

We were instructed not to walk on the soil and were not able to grow anything  edible  in it either. It was necessary to grow in raised beds and make our own compost or buy it in.  The whole site was covered in wood chip, donated by tree surgeons, and it quickly composted into good soil of a great depth. The site was cleared of Japanese knotweed mainly by persistent and careful hand removal. A grant from Scottish Natural Heritage of £10,000 was helpful in starting the allotment, however our main funders were Hunterston PowerStation, and we were one of the first to receive a grant from The Climate Challenge Fund.

Local children planted many native trees we received from the Woodland Trust along the garden edges, and wood chip was put down to create a woodland nature trail along the perimeters.  A shelter belt of native trees was planted at the front of the garden.  We now have a small woodland at the back we are developing which contains a tree nursery. It was here we released adopted hedgehogs from a wildlife rescue centre. Now after fourteen years the trees are maturing well. There is also a local area we are developing as a community woodland.  

Our gardeners conserve rainwater with water drainage from our roof into bowsers and make organic compost using our own vegetable remains.  Fifteen to twenty tons is produced a year. Two hot bins produce compost as well as a liquid feed.  We have members who are making compost and worm-tea using composting worms and wormeries.  Young gardeners are being mentored in composting and maintaining wormeries as well as other gardening and environmental skills. They work on a ‘Grow and Learn’ Award from The Caley.  Knowledge gained is shared with anyone interested or other groups. We have had groups of youngsters achieve the John Muir Award.

Comfrey is grown for plant feed. Leaf mould and seaweed are used as mulch. It is a coastal garden. Recycled coffee grounds and rock dust help revitalise the soil.  These are all activities  which benefit the environment and encourage the pollinators needed for growing our crops.

We have bat and bird boxes in the garden and bug hotels and bats are seen in the early evening. A bat viewing night was held.  Our pollinating plants are many and have been chosen to attract pollinators throughout the seasons. Crocus bulbs in the spring, pot marigolds in the summer and ivy in the autumn/winter are a few of these.  Clover which attracts many bees is left while mowing the grass. Long grass is kept in some areas for natural habit.  Many nettles for butterflies to lay their eggs are retained. Night scented stock and evening primrose are grown to attract insects for bats to feed on as well.

We are involved in other projects where we have planted for pollinators throughout our village including Fairlie Station garden, two small picnic areas, a green space play area where soft fruits, apple trees and mints are grown for community use. A volunteer from our group improves an area in a neighbouring village as well. One volunteers has established community seating area with attractive planting. Young people have been involved in growing plants for many of these areas such as borage and planting them with wildflower seed which they maintain as well. 

These areas have beautiful wildflower displays which everyone enjoys. We have handed out 40 packets of wildflower seed this past year to encourage a pollinator trail in the village and also about 50 wildflower seed bombs to youngster. The local primary school and the garden co-operate with projects such as making seed bombs and nature surveys. Citizen science surveys have taken place on our site, and we also created a small pond in the garden. 

Our polytunnels are filled with marigolds and nasturtiums to attract pollinators but they also attract birds that feed on them.  A wren was found nesting under a lettuce leaf with a cluster of eggs so we need to be careful.  Most members are so pleased they forgo their gardening until the chicks have fledged. Nesting in the polytunnels is a regular occurrence in the spring.

Two members began to create a wildflower meadow at the front of our garden about four years ago in a grassy area of poor soil. Some plants such a rattle where grown from seed and planted as plugs to get established.

The area has matured over the years and has long attractive grasses interspersed with splashes of colourful plants such as thistles, vetches, vipers bugloss, oxeye daisy, lady’s bedstraw, trefoil and queen of the meadow and more.  Multitudes of bees are found feeding during the summer and butterflies such as the common blue.  

Goldfinches feed on the thistle seeds and other birds which eat small insects are regular visitors.  Ground beetles hide in the grass during the day and feed on slugs and flatworm which is an invasive species in the garden.  Pipistrelle bats eat moths and midges at night.  Frogs use the meadow as a shelter and eat slugs.  Hedgehogs use the meadow to pass through.  

Wildflower seeds are collected in the autumn for next years planting and the meadow grass is cut back in the autumn. There are recycled boxes where we plant wildflower seeds. The biggest challenge in 2021 for gardeners was three months of hot weather without rain. The tiny wildflower seedlings in boxes needed constant watering to thrive which volunteers did regularly.  

In the future we would like to work with the council to have dedicated wood ‘bee boxes’ filled with compost for growing wildflowers in areas in the village where ground planting isn’t possible. We would also like to help the Primary School with a dedicated area for wildflowers. We’ve come a long way in 14 years, and we have ambitions to do much more yet.

The ‘Whomping willow’ and golden pollen

Perhaps the most famous willow in literature is the one which appears in JKR Rowling’s Harry Potter stories. However, the ‘Whomping Willow’ isn’t the only magical willow, away from the pages of novels the real-life goat willow could be described as pretty impressive too, especially when it comes to pollinators.

Male catkins covered in pollen rich anthers

There are few sights in nature as captivating as the golden male catkins of the goat willow. And the early flowering catkins are more than simply attractive to look at; they are a huge bonus for bees in very early spring when sources of pollen and nectar are scarce. The golden colour of the male catkins is down to pure pollen. Before the gold colour appears the catkins will look grey or even slightly pinky-orange.  The catkins have lots of individual flowers, each one with a tiny blackish leaf-like scale.  These minute catkin scales develop lots of grey hairs at their tips making the whole catkin appear furry, protection from the biting cold wind.  If you want to see early pollinators then park yourself near a flowering willow, for hungry pollinators rarely resist them. 

Willows are interesting trees. The goat willow (also known along with other willows as pussy willow) is large for a Scottish willow.  It is said in some quarters that there are 400 or so species of willow, and they come in all shapes and sizes such is the ability of the willow to generate cross breeds. In Scotland alone a list of trees and shrubs native to these shores would include grey willow, dark-leaved willow, tea-leaved willow, and bay willow. Scotland’s smallest tree is the dwarf willow, about 5cm or less in height and found hugging the ground on some of our most exposed mountains.

Around the Ben Lawers area, local bee expert Anthony McCluskey (who many of you will know in his Butterfly Conservation role) studied a restored woodland area, with plenty of willow, to see what insects were foraging on the catkins. He found several mining bees including the stunning Clarke’s mining bee and his Glen Lyon records broke new ground for the species. 

Just as species range can change so the uses we make of natural resources alters too. Times change and the wood of the willow isn’t particularly valued these days, but in earlier times it was used to make a diverse range of goods including handles for hatchets, baskets, peat and lobster creels, and the humble clothes peg. For many willow is synonymous with cricket bats. Indeed the phrase ‘leather on willow’ came to encapsulate the height of English summer, with the sound of a cricket ball being whacked with a willow bat ringing out on village greens up and down the nation. 

Tree bumblebee feeding on catkins

There was also a time when the willow had greater aesthetic appeal. Many Scottish families will recall a time when their family used to cut pussy willows to put in a vase of water with daffodils.  The name too conjures up the famous Wind in the Willows, beloved of children and adults now for several generations.

Salix caprea, to give the goat willow its ‘Sunday’ name, with careful coppicing can remain a ‘shrub’. But turn your back for any length of time and you may indeed have a ‘Whomping willow’ on your hands. With many stems this is a plant that can gallop to heights of around 15 metres if left unchecked.

The catkins are fascinating because a willow can produced either all male or all female catkins, but never both together on the same tree. We now know that willows are dioecious, that is the plants are either male or female, and we appreciate too that they are pollinated by the wind. Indeed despite considerable interest in the gathering hordes of pollinators in spring the key pollination time for the goat willow is actually late winter or perhaps very early spring, and usually in advance of the distinctive oval leaves showing on the tree. 

There is yet more to the willow (which can live for up to 300 years) than feeding early emerging pollinators.

The glossy green leaves act as a source of food for the larvae of several species of butterfly and moth, including in the south of England the impressive Purple Emperor. Closer to home it is worth looking out for the sallow kitten or puss moth. These are both extremely furry moths, with impressive caterpillars. The former is interesting because it is one of the species that has two generations a year in the south of its range, and only one in the north, including northern Scotland. They both feed on poplars as well as willows – the two genera are closely related and quite a number of species use both. Our native poplar, aspen, flowers quite rarely in Scotland, so it’s less useful for pollinators, although it still supports a lot of insects that use other parts of the tree.

Few would deny that it is the bright yellow blooming catkins which are the star of the show attracting honey bees, bumblebees and solitary bees in good numbers. Come early March it is worth keeping an eye out for willow and their eye-catching catkins. If there are any pollinators around you won’t be the only one impressed. This is one tree that can cast a magical spell in early spring.

Northern star

They are busy folk at the Bumblebee Conservation Trust. Their mission may sound deceptively simple –  to increase the number and distribution of bumblebees – but they are astute enough to know that  you need many tools and heaps of energy to deliver such a critical ambition.

Their partnership with Scottish and Southern Energy Networks in the northern reaches of Scotland is a point in case. When the energy company looked, in 2017, to improve the area around their Thurso South substation for wildlife they sensibly sought out the Bumblebee Conservation Trust. The result was a highly productive partnership which resulted in a sizeable and well-thought out meadow.

That meadow was one step along the route to helping bumblebees in the north of Scotland. It was a well-designed project. A tailored pollinator seed mix, in harmony with the local conditions, was put to good use and surveys in 2018 and 2019 confirmed that insects were quickly using the site. In 2020 came the great news that the Great Yellow bumblebee had been spotted using the site.

The first Great Yellow bumblebee recorded at Thurso south substation meadow, August 2020.
Image (C) Katy Malone, BBCT.

The Great Yellow bumblebee was once widespread throughout the United Kingdom, but is now only found in a handful of areas, all of them here in Scotland –  Caithness, north-west Sutherland, the Hebrides and Orkney.  It is one of our rarest bumblebees, needing extensive meadows and particular types of habitats, such as machair, to survive from year-to-year. 

Twelve months on from that individual 2020 sighting the regular visits of a local volunteer established conclusively good numbers of Great Yellows using the site. And there was yet more good news when the Bumblebee Conservation Trust staff visiting in August 2021, during a research trip, were rewarded with a view of more than one queen bumblebees making the most of the Thurso resource. It’s not a quantum leap from there to surmise that the species is probably nesting on the site.

The success in Thurso helps illustrate progress and makes it easier to engage with the general public and landowners in a bid to inform future conservation of this species.

The Bumblebee Conservation Trust provides tailored advice to farms and landholdings to support beneficial management of sites for Great Yellow bumblebee through the Saving the Great Yellow Bumblebee project which as been running since 2019. New projects are always in the pipeline to carry forward this work and expand it even further. They provide follow-up support to farmers, landowners and agents across high priority Great Yellow areas and, where appropriate, advice on management options funded by SRDP-AECS (Scottish Rural Development Programme, Agri-Environment Climate Scheme). This advice is highly tailored to each site, ranging from suggesting suitable voluntary measures to adopt, through to helping with written letters of endorsement.

One element has been to employ survey consultants to gather data on forage and conduct bee surveys along the north coast of Sutherland, and the Outer Hebrides, in June through to early September. The intention is that these reports will highlight suitable areas to target more intensive surveys for Great Yellow bumblebees in the areas, record the quality of forage across the landscape, and suggests where a change in management might help encourage better habitats for this rare bumblebee. Another strand is looking at the genetic variability in Great Yellow populations to find whether genetic relatedness is increasing – this would affect the long term viability of these remote populations and help the Bumblebee Conservation Trust work out new approaches to conservation.

Conservation Officer (Scotland) Katy Malone is delighted to see these different threads coming together in a coherent drive to address the challenges facing the Great Yellow bumblebee. “We’ve made great steps forward in helping this iconic species thrive in new areas, but there is still so much work to do. Only with the help of our supporters, members and volunteers, and in partnership with business and conservation organisations, can we sustain this effort and see bumblebees thriving again across our landscapes. We need to deliver across entire landscapes from the Outer Hebrides right up to Orkney. I’m really excited to be a part of the development of new projects which will help us establish even more sustainable solutions.”

Trust staff finding Great yellow bumblebees at SSE Thurso south substation in 2021 during a research trip. Image (C) Katy Malone, BBCT.

Founded in 2006 and with almost 8,000 members, the Bumblebee Conservation Trust has a level of specialist knowledge, active nationwide groups and targeted projects that makes them a key partner in successfully delivering the Pollinator Strategy for Scotland. 

They work on a range of projects simultaneously, ranging from research and monitoring, through public engagement and information services, to leading effective campaigns. If you want to find out more then settle down in front of their website. It’s a fantastic resource to not only gain in insight into their projects, but find all sorts of practical and easy to follow advice on how to help bumblebees. Their ‘Bee Kind’ section is just one example featuring planting recommendations to enable us all to do our bit to help bumblebees and other pollinators.  

There is no doubting the Bumblebee Conservation Trust are busy, but equally there is no doubting their relentless focus in the battle to tackle the many challenges facing our native bumblebees. What’s going on in the north of Scotland is just one fine example.

Find out more:

The Bumblebee Conservation Trust website

Bumblebee Conservation Trust 2021 cash appeal

Bumblebee Conservation Trust gift membership

The writing on the pollen

By Athayde Tonhasca

Palynology, from the Greek palynō (‘sprinkle’), is the study of microscopic organic particles such as spores, planktonic organisms and pollen. The branch of palynology focussed on pollen contained in honey is called melissopalynology – the ‘melisso’ part refers to bees, from the Greek mélissa for ‘bee’. This tongue-twister sounds as arid and academic as a study subject could be, but this is not the case. By examining the pollen in a sample of honey, it is possible to determine its purity, geographical location and floral sources. Melissopalynology is a tool to combat fraud and inaccurate labelling of honey, which is handy if you want to buy pure Elvish honey from Turkey, Manuka honey from New Zealand, or other expensive honey bee products. 

Morphology of different pollen from honey samples © Obigba, S.O. 2021. IntechOpen 10.5772/intechopen.97755

Melissopalynology has other applications. It can be used to assess climatic conditions such as rainfall and temperature at the honey’s place of origin, or tell us about environmental changes. This is particularly useful in light of the rapid losses of natural habitats around the world, mostly because of agricultural expansion and intensification.

Half of the world’s habitable land is used for agriculture ©

By comparing pollen in honey samples from 1952 and 2017, researchers recorded a profound shift in the most important flower sources for honey bees in the UK. White clover (Trifolium repens) was present in 74% of the 1954 honey samples, but it decreased to about 30% in 2017. Brambles (Rubus fruticosus agg.) and related species were found in 5% of the 1954 samples, but in 2017 they became the most foraged plants.

Predominant and secondary honey bee pollen sources in 1952 (left) and 2017 © Jones, L. et al. 2021. Communications Biology 4, 37

These changes in honey bee preferences have reasons: with the intensification of managed grasslands, crop rotation decreased, and the use of fertilizers and herbicides increased. So clovers became less abundant; countryside surveys revealed a 13% decrease of white clover distribution from 1978 to 2007. Changes in the rural landscape favoured opportunists like brambles and invasive species such as Himalayan balsam (Impatiens glandulifera) (a great source of nectar), which increased their distributions from 1978 to 2007 by 21 and 100%, respectively.

A change of main course for honey bees; from white clover (L) to brambles © Harry Rose (L) and H. Zell, Wikipedia Creative Commons

A shift in sources of food may not sound too bad; honey bees still have their flowers. But not all flowers are equal: brambles have lower levels of proteins and essential amino acids than white clover. Honey bees may compensate for this nutritional deficit, but that requires more time and energy spent on foraging.

Pollen is the main source of proteins, fat, minerals and vitamins for honey bees and many other pollinators. But it is also a rich source of information: pollen attached to museum specimens has helped us understand changes in the distribution and abundance of bumble bees and other pollinators. Taxonomists, earth scientists, climatologists, archaeologists, palaeontologists, and criminal investigators – those examining suspect honey, or those tracing a body, dead or alive, to specific surroundings – have also tapped into the data extracted from pollen. So, a shout out to palynologists, who understand so well the value of those grains of plant dust.

Palynologist Dr Kat Holt doing climate research ©

Yorkhill’s Green Spaces: Perfect for Pollinators

We continue our series of articles looking at the fantastic projects which entered the Keep Scotland Beautiful pollinator-friendly category. Today we feature Yorkhill Green Spaces who won first prize with a wonderfully wide-ranging project that delivers for pollinators and people.

By Scott Shanks

Yorkhill Green Spaces (YGS) are a group of community volunteers in Yorkhill in the west end of Glasgow. They meet regularly for litter-picks, planting and other greenspace management tasks. Their aim is to improve local parks for biodiversity and the community in an area of the City where few people have gardens. The group’s three main sites are Yorkhill Park, Cherry Park and Overnewton Park. These green spaces, close to the COP26 campus provided peaceful retreats for attendees of the recent COP26 conference.

Meadow management day at Yorkhill Park

Yorkhill Park is the largest, and the ‘wildest’ of Yorkhill’s green spaces. It sits on a south-facing slope behind the former Yorkhill Maternity Hospital, close to where the River Kelvin meets the Clyde.

The proximity to these blue-green corridors has helped channel a diversity of species to this wee oasis for wildlife.  In 2021 YGS gained permission to manage about 1hectare of neutral grassland in the park as a cut and lift wildflower meadow. After years as intensively managed amenity grass, and then at least 5 years with no cutting, the slopes were dominated by rank grass with few flowers. To improve the floral diversity about 60% of the slopes were cut in late September 2021 and the clippings raked-up and removed by volunteers to reduce nutrients. Hemi-parasitic Yellow rattle seed was then sown and trampled into the short grass, which will help further reduce the dominance of grass when it germinates next spring. Wildflower plug plants of 15 species have been planted on the slopes, along with crocuses and native bluebells close to foot paths to help bring more spring colour, nectar and pollen for pollinators.

The remaining 40% of the grass was left uncut to provide shelter for invertebrates including Meadow Brown and Ringlet butterfly caterpillars, and habitat for Bank voles which attract the Foxes and Kestrels that are often encountered in the park. The uncut areas will be rotated each year. An additional 400mof verge was sown with a mix of 40+ native wildflowers and grasses after footpath upgrades created lots of bare ground this year.

Cherry Park and Overnewton Park are more traditional parks, with play areas, seating and short, amenity grassland. Areas were identified in both parks in 2021 that will only get perimeter cuts along the paths in 2022 and will then managed as cut & lift meadows next autumn. We’ve planted a range of spring bulbs in both parks. Flower beds and borders have been planted with pollinator-friendly herbaceous perennials such as Heathers, Lavenders, Perennial wallflower, Hardy germaniums, Lungwort, Fennel and scatterings of Borage and Garlic mustard.  

We created two wildflower pollinator strips at Overnewton Park in 2019 by striping-off short turf and sowing with a variety of native wildflower mixes including cornfield annuals and perennials to give bursts of colour, nectar and pollen for pollinators. Every year they get better and better, although high nutrients led to an issue with invading couch grass in one strip this year. These pollinator strips are cut and lifted in the autumn to keep nutrients low. Crocus, Grape hyacinths and Snowdrops help give the borders and wildflower strips some early spring zing!

We are keen to promote sustainability and only use peat-free media in planters and don’t use pesticides or herbicides. In early 2021 we planted a range of pollinator-friendly herbaceous perennials and grasses in 6 new sensory garden planters (funded by Morrison’s), filled with 4 different brands of peat-free compost. All have been very successful. We also collect wildflower seed in autumn to sow in new areas.

Flowering native hedging planted at Cherry Park in early 2020 and 2021 will help support wildlife including pollinators, acts as a lovely perimeter feature which captures carbon and filters out particles from car exhausts. More native hedging will be planted along the perimeter of Yorkhill Park this winter.

Recording biodiversity during volunteer events has become very popular, and in September 2021 the group recorded their 1000th species: a wee flower bug (Anthocoris confusus). The YGS species list currently (November 2021) has 1,036 species including 29 species of bees, 21 wasps, 97 flies, 12 butterflies and 202 different moths. One of the exciting 2021 finds was a female Northern sallow mining bee (Andrena ruficrus) which is a Scottish Biodiversity List priority species. This wee mining bee only collects pollen from willows and sallow catkins to stock her nest burrow. 

A dead standing tree in Yorkhill Park has proven to be a fantastic feature for biodiversity. It supports at least 2 species of solitary bees: Red-mason bee (Osmia bicornis) and Patchwork leafcutter (Megachile centuncularis), and at least 8 species of breeding solitary wasps, including beautiful Ruby-tailed wasps (Chrysis ignita). 

All three parks sit within one of Buglife’s mapped B-Lines and help enhance this network of stepping-stone sites for pollinators to move across the city.

The group encourages members and the local community to take part in national biodiversity recording events such as the Big Garden Birdwatch, Big Butterfly Count, National Bee Week, City Nature Challenge, and carry out ‘FIT count’ surveys for the UK National Pollinator Monitoring Scheme.

Looking to the future YGS are keen to improve the habitat connectivity between their parks and other green spaces in Glasgow. Projects for 2022 will include installing further sustainability improvements such as water butts and more compost bins. They hope to convert flowerbeds in Cherry Park into raingardens to help the area cope with more frequent storm events predicted in the future. 

Find out more

Yorkhill Green Spaces Facebook group:

YGS Twitter:

A sweet and addictive drug

By Athayde Tonhasca

When the Greek gods invited Zeus’ son Tantalus for a feast at Olympus, they couldn’t have imagined their guest had sticky fingers. Tantalus stole their food (ambrosia) and drink (nectar) intending to give the loot to his people to make them immortal and privy to divine secrets. The gods didn’t take the betrayal lightly: they shipped Tantalus to the Underworld and made him stand in a pool of water under the branches of a fruit tree. Every time Tantalus tried to pick up a fruit, the branches would grow out of his reach, and when he wanted to drink, the water would recede away. Next time you find yourself ‘tantalisingly close’ to something but not getting it, spare a thought for poor Tantalus, going hungry and thirsty for eternity.

Tantalus’ punishment for stealing ambrosia and nectar © Jacques Favereau, 1655

The magical diet of the Olympians made such an impression on Western culture that many food and drink products have ‘ambrosia’ or ‘nectar’ attached to their names. Most of them are wishful thinking or just gimmicks, but the term ‘nectar’ was adopted quite appropriately in one case: to label the mixture of sugars and water that can be secreted by any vegetative part of a flowering plant, but mostly by flowers. 

Floral nectar contains 15% to 75% (by weight) of sugars, mostly glucose, fructose and sucrose. Free amino acids, proteins, minerals and lipids add to the nutritional content of the mixture, although we have only a vague understanding of their workings. As a ready-to-use source of energy and nitrogen to a wide range of animals, nectar is fundamental for the support of food webs.

Nectar is a reward to attract pollinators, but it is also a metabolically expensive product: plants can’t afford to give it away willy-nilly. So they may resort to some manipulation, which often involves intoxicating flower visitors with secondary metabolites. These are compounds such as tannins, phenols, alkaloids and terpenes, which have no apparent role in metabolism but may defend the plant against plant feeders and pathogens.

Plants such as citrus, coffee and camellias secrete nectar laced with caffeine. This bitter-tasting alkaloid reduces the palatability of plant tissues, thus protecting the plant against herbivores. But diluted in nectar, caffeine is a behaviour-altering drug: honey bees feed more and do their waggle dance more frequently if they have a sip of caffeine-spiked nectar. Plants can take advantage of this caffeine high; they can reduce the nectar quality, while bees carry on on feeding. That’s not so good for the honey bees, who produce less honey. 

Japanese camellia (Camellia japonica) in a London garden, a caffeine bar for honey bees © Emőke Dénes, Wikipedia Creative Commons

Nicotine, another insect-repelling alkaloid, has a similar addictive effect on bumble bees. Nectar containing nicotine helps bees learn more quickly how to find their food source and once learned, they tend to stick with the same source, coming back again and again. Naturally, this is a good result for the drug-peddling plant. 

Nicotine encourages bumble bees to stick around, but it may send other visitors packing. Just like caffeine, nicotine decreases the palatability of nectar. As a consequence, some pollinators consume less of it but visit more flowers, which leads to a higher rate of cross pollination. The alkaloid gelsemine, found in the nectar of the yellow jessamine (Gelsemium sempervirens), has a similar effect on flower visitors: it decreases frequency and length of visitations but increases the number of flowers visited.

Coyote tobacco (Nicotiana attenuata) (L) and yellow jessamine encourage pollinators to take a sip of their nectar and move on © USDA Natural Resources Conservation Service (L) and Jim Evans, Wikipedia Creative Commons

More than half of all flowering plants secrete secondary metabolites with their nectar, but except for a few cases involving honey bees, bumble bees and some moths, we know little about the effects of these chemicals on pollinators. The scant information we have suggests that nectar is more than a sweet lure: plants use it to manipulate flower visitors for their own benefit, and this often involves the use of addictive stimulants. In nature, anything goes to increase your chances of success.