We’ve been expecting you

Just as we long for the sight of the first summer swallow swooping overhead, or the distinctive call of the first cuckoo, so we await the appearance of the first snowdrop with a mixture of excitement and anticipation. Once seen we can be confident that our dark winter is nearing an end, and that Spring is around the corner.

Of course, it doesn’t always work out that way, but what the heck, it’s the hope and expectation that keep us going.

Snowdrops can be an early bonus for pollinating insects. A popular image beloved of wildlife photographers is capturing a honey bee or queen bumblebee visiting a snowdrop for an early foraging boost. The bumblebee in question is likely to be the buff-tailed bumblebee (Bombus terrestris) which, with a seemingly increasing ability to be active in winter, might hope to find Mahonia, winter-flowering honeysuckle or snowdrops in your garden.

One of the nice things about the ‘proper’ names for flowers is that they reveal so much. In the case of the snowdrop — Galanthus nivalis — we are talking ‘milk flower of the snow’.  Now, how good is that at describing a seeming fragile white flower, set amid a wintry snowscape? Mind you other names are equally descriptive such as the English candlemass bells, the French perce-neige (snow piercer), and Spanish campanilla de la nieves (snow bell) as well as rompiendo la nieve (breaking the snow). Candlemass falls 40 days after Christmas and is a major date in the Christian calendar, although a less popular association with churches was that as snowdrops were often planted around graveyards for many folk they became associated with death.

In modern times the word ‘snowdrop’ acquired a more menacing meaning, albeit in a work of fiction. A thriller by A. D. Miller titled ‘Snowdrops’ was so called as his book suggested some Russians gave the name snowdrops to bodies that came to the surface when the snows thawed. His novel suggested a time when murder victims were likely to emerge from beneath receding snow drifts, like budding snowdrops.

We’ve had plenty of time to come up with descriptions of snowdrops. Although not native to the British Isles, the snowdrop was recorded in the wild as long ago as the 1770s and today there are reckoned to be hundreds of varieties, bred from several different species. 

In general terms snowdrops are pretty unmistakable, no mean feat in the complex and uncertain world of plant identification. Generally they are anywhere between 7–15 cm tall, but always boast white bell-shaped flowers which droop downwards from a flower stem that rarely has more than a couple of exceedingly narrow leaves attached. The flowers tend to have six bright white segments and a green ‘v-shape’ pattern on the flower head is not uncommon. Probably the most likely confusion flower is its larger cousin the (less popular) snowflake.

And snowdrops are super popular.  Amongst their aficionados, “galanthophiles”, snowdrop bulbs can change hands for significant sums.  In one instance £1,390 was spent on a single ‘golden fleece’ bulb. Stan de Prato, in one of his consistently excellent plant updates for Keep Scotland Beautiful, once noted that “The highest price paid for a Scottish snowdrop was £725 for a yellow form of G. woronowii at an auction in 2012”.

There is some debate around how snowdrops reproduce. Some observers suggest that they can produce seeds if there are pollinators around, others advise that new bulbs grow attached to the mother bulb (so-called offsets). It may very well be that both methods apply, dependent on opportunity or conditions. 

Where there are plants there are usually ancient medicinal uses. In the case of the snowdrop these are fairly mundane but included is a cure for headaches. Had you been a galanthophile and realised that in a fit of enthusiasm you had spent over £1,000 on a bulb you might have be tempted by that old resort. Don’t be, snowdrop bulbs are poisonous. That might explain why in some superstitious quarters snowdrops were seen as symbolising death and it was reckoned bad luck to take one into your home.

Back in February 2005 snowdrops were bad news for a group of plant thieves in Fife. Police intercepted a van containing stolen bulbs reckoned to be worth in the region of an eye-watering £60,000. Alan Stewart was the Tayside Police Officer dealing with wildlife crime at the time and was of the opinion that snowdrop thefts were a significant element of wildlife crime.  

Around these parts snowdrops are best seen along riverbanks and in some of our woodlands. It’s a short window of sight-seeing for they tend to be gone by the end of February. Make the most of the opportunity, the snowdrop has a captivating quality and you might just catch a glimpse of a hungry pollinator into the bargain.

Mind the gap

By Athayde Tonhasca

At this time of the year, gardeners are making their plans for the coming season. Undoubtedly flowers are on their list of priorities, which hopefully will comprise an array of plant species. Floral diversity is important to cater for the nutritional needs of different pollinators, with the bonus of increasing the garden’s aesthetic appeal thanks to an assortment of colours and shapes. 

The value of species diversity in a garden is usually understood; perhaps less appreciated is the importance of an uninterrupted provision of nectar and pollen throughout pollinators’ flight period, roughly from March to September. Many of gardeners’ pickings from plant nurseries are good for providing for pollinators from mid-May to July. But no matter how much nectar and pollen is produced by these plants, pollinators will not make it through the year if they go hungry in the earlier or later months. 

Spring flowers (March to May) are particularly important for those pollinating species coming out of hibernation, who need to build up energy reserves to kick start their nests. The problem is the relative scarcity of flowering plants at this time of the year, a period known as spring ‘hunger gap’. 

The mean sugar production (black line) of plants at three English sites (squares, circles and triangles) over an entire flowering season © Timberlake et al. 2019. Journal of Applied Ecology 56: 1585–1596

So a judicious gardener can manage this hunger gap by tolerating a certain level of ‘undesirables’ such as dandelion (Taraxacum officinale), daisy (Bellis perennis) and creeping thistle (Cirsium arvense), which are excellent sources of early season nectar. It wouldn’t be wise to introduce weeds because they can get out of hand, but existing ones could be left alone in a sunny corner of a garden or allotment. 

L: Ground elder (Aegopodium podagraria), found in a variety of disturbed habitats. Its umbels (umbrella-like flower clusters) are good sources of nectar, especially for hoverflies. R: A daisy field © Wikipedia Creative Commons

Bluebells (Hyacinthoides spp.), wild garlic (Allium ursinum) and comfrey (Symphytum spp.) are other good early providers, together with many commercial garden plants. Trees and hedges are also important components of a garden well stocked with spring food: species like hazel (Corylus avellana) and willows (Salix spp.)

Goat willow (L) and hazel, sources of spring food © David Hawgood (L) and KatherineGrundy, Wikipedia Creative Commons

Filling the hunger gap by planting flowering plants or sparing weeds has another benefit: the number of pollen sources is bound to increase, which is important for bumble bees, solitary bees and possibly for other pollinators. In the case of many bumble bee species, their larvae depend on the abundance and diversity of pollen for healthy growth. If their options are narrow, these larvae develop more slowly or are smaller than those fed a diversified pollen diet. As a consequence, workers will be smaller and less efficient in collecting pollen and nectar for their colony. Just like us, pollinators need a variety of food for good health. With some planning and little effort, we can give them a hand during the tough spring time. 

A nest of red-tailed bumble bee (Bombus lapidarius) with full honey pots. A healthy brood depends on abundant pollen from several sources © Phelyan Sanjoin, Wikipedia Creative Commons

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 gybb@friendsoftiree.org.uk 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 hypogea, T. 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.

A 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