Nature repeating itself

It was Georgia O’Keefe who said, ‘When you take a flower in your hand and really look at it, it’s your world for the moment’. It’s worth doing this, nature is captivating close up; perfectly packaged and clinically efficient, each flower has an adapted shape and look gleaned over hundreds of thousands of years for maximum productivity. This economy of engineering uses patterns and shapes that are repeated again and again throughout the natural world and dotted all around the Botanic Garden. (more…)

Walking among bees with Steven Falk

By Nicola Temple

Steven speaking to us in front of the limestone
meadow. Photo: Nicola Temple
I thoroughly love watching insects visit my garden (aphids and a few other pests excepted). However, I have to admit that beyond broad groupings, bumblebee, honey bee, hover fly, fly etc, I’m not very good at identifying them down to species. This clearly isn’t necessary to enjoy them, but I do find that when I know a species, when I know its routines and habits (as much as anyone does), then I have a deeper appreciation for them. So, when the University of Bristol Botanic Garden offered a bee identification workshop with Steven Falk, I signed myself up.
Steven Falkhas had an interest in insects since his childhood in London in the 1960s and 70s. Insects inspired his artwork and his skill as an artist earned him the honour of illustrating the book British Hoverflies, which he began working on when he was only 15. He has gone on to illustrate and write many publications since, including my newly acquired Field Guide to the Bees of Great Britain and Ireland (Bloomsbury, 2015).
Steven began the talk with some fast facts about insects in England. There are about 24,000 species of insect in England, 6,000 of which are regular visitors to flowers. “The biggest slice of this insect pie is wasps,” he explained. Even parasitic wasps visit flowers, and all together there are around 2,800 species.  Bees make up a mere 280 species and hover flies another 280. However, though they are less diverse in terms of species, bees and hoverflies are both abundant and extremely effective pollinators – so they punch above their diversity, so to speak.
Steven holding a yellow-legged mining-bee.
Photo: Nicola Temple
We start our walk in the Botanic Garden in the limestone meadow, just beside the West Terrace and the pond. If you unfocus your eyes a little and stare across the flowers, it is alive with activity. Steven shows us Myathropa florea, a reasonably sized hoverfly that has distinct grey markings on its thorax. It has an aqueous larvae, which lives in little rot holes at the base of trees. Then Steven points out a bumblebee mimic, Cheilosia illustrata, which tends to spend time near Hogweed because its larvae tunnel through the stems and roots. Apparently you can tell the age of a forest by the species of hoverfly present because they are so closely associated with certain plants.
Within minutes we’ve also spotted a common carder-bee (Bombus pascuorum) with its chestnut thorax – though Steven explains that this can be quite variable. It has a longer tongue and so this species is able to get down into the clover flowers. But there are also some buff-tailed bumblebees (Bombus terrestris) flying about also, which have shorter tongues and so they bite a hole at the base of the flower to rob the nectar. We spot lots of honey bees (Apis mellifera), which Steven also explains can be extremely variable in appearance, ranging from the typical striped appearance to almost entirely black – the tell tale sign being that its hind legs hang down as it flies. We haven’t even moved on the tour and we’ve already spotted at least six pollinator species – probably far more, I just can’t write fast enough to keep up with Steven listing them off!
The ‘fuzz’ of lamb’s ear is used by the female
wool-carder bee to line her nest.
Photo: Nicola Temple
Using what he calls his ‘praying mantis’ technique, Steven grabs a yellow-legged mining-bee (Andrena flavipes), and holds it so that we can all have a look at it. The long antennae tell you that this is not a fly, however, Steven goes on to list the colour variations that you can encounter. With all of these colour variations, I’m pretty sure I don’t stand a chance of accurately identifying anything on my own!
As we wander past some Lamb’s ear (Stachys byzantina), Steven mentions that the female wool-carder bee (Anthidium manicatum), a solitary bee, uses the fuzz from the plant’s leaves to line its nest. Steven then spots a patchwork leaf-cutter bee (Megachile centuncularis) and explains that it doesn’t collect pollen on its hind legs, but rather on its underbelly. Using his insect net, he catches it and place it temporarily in a little tube so that we all get a chance to look at it.
We walk past the wall germander (Teucrium chamaedrys) and there doesn’t appear to be a single flower that isn’t being visited by a bumblebee. It becomes obvious that while many of the tour participants are interested in the bees, they are equally interested in noting down which of the plants in the Botanic Garden are popular with pollinators so that they can create more bee-friendly gardens at home.

A great pied hoverfly (Volucella
pellucens
).
Photo: Nicola Temple
As one would expect, near the end of the tour Steven begins to discuss some of the challenges that our pollinators face these days. He discusses the use of pesticides and the loss of habitat. He mentions that more erratic weather patterns and mild winters can lead to mortality – the latter causing over-wintering bees to go mouldy. But, he also finds the silver lining, stating that some bee species are expanding their distribution due to climate change.
It was only the commitment to another tour that forced Steven to end our walk. His love and enthusiasm for insects was apparent and he could have no doubt gone on to discuss far more than he did.
I definitely had different expectations for the workshop. I’m not sure whether it was the term ‘workshop’ or my own background in biological sciences that set my expectations that we would be looking at example specimens and comparing their features so that we might be able to better identify them. This was more of a garden tour and pollinator walk, which was lovely, but I’m not entirely sure I feel better equipped to identify bees in my garden as a result of being on the tour. If anything, it has shown me how much variation there can be within species let along adding in mimics and related species into the mix!  In the end I bought the Field Guide because really, in the end, that’s what it takes…good ol’ practice! And if I’m unsure Steven said to send him a picture on Twitter and he’ll help me identify it, which is brilliant! Not to mention, he has a fantastic free site on Flickr with pictures and information about all the British species, which is an incredible resource.
Germander (Teucrium chamaedrys) attracts
a tremendous number of pollinators.
Photo: Nicola Temple
This is the Year of the Pollinator at the Botanic Garden, so there are any number of pollination themed activities happening this year, including a beekeeping taster day, short courses for encouraging pollinators to your garden, and of course the annual bee and pollination festival in September.  And if you happen to snap a great photo of a pollinator this summer, you can enter the Botanic Garden’s photography competition, which will earn you a signed copy of Steven’s Field Guide to the Bees of Great Britain and Ireland as well as tickets to the Bee and Pollination Festival, visit the website for more details on how to enter.

Bumblebees who brave the winter

By Nicola Temple

This past weekend, my family and I met with friends in the village of Shipham, in Somerset, for a walk. It was torrential rain, yet we were determined. We dressed ourselves and three children under the age of 10 in waterproofs and set out. We arrived at a local country pub, not more than 3 km away, resembling drowned rats. And as a Canadian living here in the UK, I still marvel at the fact that nobody took one bit of notice at the state of us. It’s what you do. You get wet. You find a pub. You hunker down for a hot Sunday lunch. And you hope it tapers off before you have to head out again. (It didn’t.)

Pollinators, at least of the flying insect variety, aren’t terribly keen on this kind of weather either. Most hunker down for the winter months as there is generally not a lot of nectar to forage this time of year anyway. How they do this depends on the species. Honeybees reduce the colony to a minimal size and rely on their honey stores to see them through, while they dance in order to regulate the temperature of the hive. Most bumblebee colonies die out completely and the queens that mated at the end of the season find a place to hibernate. Solitary bees may hibernate as adults or as larvae, emerging only when the weather conditions are suitable. To each their own.

Martin Cooper spotted this buff-tailed bumblebee queen
foraging on his Mahonia flowers in Ipswich on a sunny
January day in 2015.
Photo credit: Martin Cooper [via Flickr CC]

However, there is one flying pollinator that can be spotted this time of year here in Bristol, and indeed, other warmer regions of the UK. It is the common buff-tailed bumblebee (Bombus terrestris). This species was first spotted during the winter of 1990, in Exeter. Sightings have been increasing ever since and include nest-founding queens, workers and males, suggesting this is a winter generation of the species.

The mated queen will emerge from her subterranean dormant state (diapause) during warm winter weather and set about establishing a new colony. The potential cost of waking up early is that the warm weather could be short-lived and temperatures could plummet. The benefit, of course, is that there’s nobody to compete with for food. If successful, the queen can establish a colony before the other pollinators even wake up from their winter nap.

Introduced plants provide winter forage

Of course, there is potentially another cost to emerging early – there could be nothing to eat. Bees are able to forage at temperatures around 0oC, but if there aren’t enough plants in flower, they won’t find the pollen and nectar needed to sustain the colony. Few native UK species flower in winter, but species introduced by avid gardeners to bring some winter colour to the garden, also bring some much-needed food to the buff-tailed bumblebee.

Researchers at Queen Mary University of London and The London Natural History Society, conducted a study of buff-tailed bumblebees foraging in London parks and gardens during winter about ten years ago. They wanted to see just how much food the bees were finding as food is directly related to the success of the colony.

The researchers found that there was plenty of forage to sustain the colonies and, in fact, the foraging rates they recorded near the end of winter were equivalent to peak foraging rates found in the height of summer. This doesn’t mean that the winter-flowering plants, such as the evergreen shrubs of the Mahonia spp., are providing more pollen and nectar than all the plants in the height of summer. But it does mean that each flower might have more pollen and nectar available because there aren’t other pollinators out and about also using the resource. The bumblebees, therefore, don’t need to go as far to find an equivalent amount of food and so they can collect it at a faster rate.  

Strategies for tolerating cold

Buff-tailed bumblebees aren’t as tolerant to cold as some other bee species; workers will freeze solid at about -7.1oC while queens freeze at -7.4oC. The bumblebees can obviously find warmth in the colony, but they need to forage and therefore be able to tolerate short spells of cold during the winter months. They may even need to tolerate cold temperatures for up to 24 hours as bumblebees often overnight away from the colony when they are unable to return from foraging.

Researchers from the University of Birmingham looked at the different cold tolerances of this bumblebee species a few years ago. They found that 50% of workers died after being exposed to 0oC for 7.2 days while queens could last over 25 days at this temperature – likely due to their fat reserves. However, as the forage study showed, the bees seem capable of finding food sources closer to the colony during winter months, which may reduce the likelihood of them having to endure cold temperatures for a lethal period of time.

These bumblebees may also have adopted some strategies to help reduce their possibilities of freezing. Pollen is an ice-nucleating agent in that it promotes the development of ice at higher temperatures. Other insects have been observed to expel any ice-nucleating agents from their gut when they experience low temperatures to avoid freezing. While this wasn’t observed in the bumblebees, it is a strategy that individuals might employ when caught out in the cold.

The more frequent observation of buff-tailed bumblebees in winter is thought to be a result of warmer autumn temperatures brought about by climate change. In a study from 1969, researchers reported a 6-9 month dormancy of all bumblebees in southern UK, so in a relatively short period of time there has been a considerable change in their seasonal pattern. There seems to be some flexibility in these patterns among bumblebees and for now, establishing winter colonies seems to be working for the buff-tails. However, with so many of our pollinators under threat, there is obviously also concern among the scientific community that more frequent extreme weather events could also spell disaster for these colonies that have selected to brave the winter months. As gardeners, we can perhaps do our bit by planting some winter forage species.

This year, the University of Bristol Botanic Garden will embrace a pollinator theme, with the aim of highlighting some of the lesser-known pollinators that are so important here in the UK. We love our pollinators, but research is still revealing so much about their unique and complex relationships with plants. So watch this space as we share some of these wonderful stories through our blog. We will also be posting pictures of pollinators we see in the Botanic Garden on our Twitter feed and Facebook page. But to see these polli
nators in action, take some time to visit the Botanic Garden. Make space in your busy schedule to watch nature at its best – it’s worth it.

Sources:

Alford DV (1969) A study of the hibernation of bumblebees (Hymenoptera: Bombidae) in Southern England. Journal of 
     Animal Ecology 38: 149-170.
Owen EL, Bale JS, Hayward SAL (2013) Can winter-active bumblebees survive the cold? Assessing the cold tolerance of 
     Bombus terrestris audax and the effects of pollen feeding. PLoS ONE 8(11): e80061.          
     doi:10.1371/journal.pone.0080061
Stelzer RJ, Chitka L, Carlton M, Ings TC (2010) Winter active bumblebees (Bombus terrestris) achieve high foraging 
     rates in urban Britain. PLoS ONE 5(3): e9559. doi: 10.1371/journal.pone.0009559 

Bristol is buzzing, how the city is helping pollinators

By Helen Roberts

There has been a substantial amount of press coverage recently on the plight of our pollinators. They are now less abundant and widespread than they were in the 1950s. A number of threats are responsible, including habitat loss, disease, extreme weather, climate change and pesticide use.
A swathe of flowers for pollinators bring a
lot of cheeriness on a grey autumn day on
Horfield Common, Bristol.
Photo credit: Nicola Temple
There is not one smoking gun among these threats, but rather the combination that has endangered some species in the UK. Loss of wild flower rich habitat (due to intensive agriculture, industrialisation and urbanisation) escalates the effect of disease, extreme weather, climate change and pesticide use. Without food or shelter, pollinators are more vulnerable.

 Whilst visiting the University of Bristol Botanic Garden this autumn, I noticed the abundance of pollinators busily visiting many different flowers from the orchid look-a-like flower of Impatiens tinctoria to the swathes of Rudbeckia sp. and Verbena bonariensis. This year saw the 6th year of the University of Bristol Botanic Garden hosting the Bee and Pollination Festival in September. The Community Ecology Group from Bristol’s School of Biological Sciences was exhibiting and promoting their research as well as the exciting Get Bristol Buzzing initiative.
To find out more about pollinator research at the University, I met up with Dr Katherine Baldock, a Natural Environment Research Council Knowledge Exchange Fellow from the School of Biological Sciences and the Cabot Institute, to discuss the group’s work.
“Most people know that pollinators are important, but quite often don’t know what to do to help them, “ explained Katherine. “And this is where our research at the University comes into play”.
The aim of Katherine’s fellowship is to improve the value of the UK’s urban areas for pollinators by working with various stakeholders, such as city councils, conservation practitioners and the landscape industry. 

Translating science into solutions

NERC KE Fellow Dr Katherine Baldock.
Photo credit: Nicola Temple.

Up until 2014, Katherine worked on the Urban PollinatorsProject, which is researching insect pollinators and the plants they forage on in urban habitats.
Building upon research from this project and her current Fellowship, Katherine and her Bristol colleagues have contributed to the development of  a Greater Bristol Pollinator Strategy(2015-2020). The University research group has teamed up with Bristol CityCouncil, the Avon Wildlife Trust, Friends of the Earth Bristol, Buglife, SouthGloucestershire Council and the University of the West of England to implement this with the aim of protecting existing habitat and increasing pollinator habitat in the Greater Bristol area.
The group is also raising awareness of the importance of pollinators to a wide-ranging audience within the city and further afield. This is the first local pollinator strategy within the UK and follows closely in the wake of the Department for Environment, Food and Rural Affairs’ National Pollinator Strategy launched in 2014. It will help to promote aspects of the national strategy relevant to urban areas and hopefully set a precedent for the development of other local pollinator strategies throughout the UK.
The local pollinator strategy outlines actions that will help fulfill the strategy aims, including:
·         formation of a Local Pollinator Forum intended to share knowledge and best practice,
·         establishment of a joined-up approach to pollinator conservation by linking projects through the Get Bristol Buzzing initiative,

·         working with the public in local areas to explain actions they can take as individuals.

“Urban green spaces are important corridors for wildlife and help to provide linkages across the country”, explained Katherine. I envisaged a series of insect aerial motorways linking the whole of the UK, invisible threads connecting countryside, urban fringe and city centres.

The bee link-up

The Get Bristol Buzzing initiative is doing just that, as one of its strategic aims with the local pollinator strategy for 2016-2020, is to “Map pollinator habitat and identify target sites that allow habitat networks and stepping stones to be created to enable pollinators to move through urban areas”.
Katherine talked about how engaging the public at ground level was really important to Get Bristol Buzzing. The initiative is the pollinator component of My Wild City, a project whose vision is for people in Bristol to help transform spaces into a city-wide nature reserve. A number of interactive maps have been created that allow people to add what they have been doing in their area to help wildlife. The Get Buzzing initiative will feed into these maps.
Kath said, “The fact that you can add yourselves onto a map makes the Get Buzzing Initiative really visually appealing to people and much more personal.”

So, what can you do at home to help urban pollinators?

·         Plant for pollinators. Think about what plants you have in your garden. Could you change the planting or improve on it to make it more attractive to pollinators? Think about growing species that have nectar and pollen rich flowers and let your lawn grow longer to allow plants to flower.
·         Avoid pesticides. Most gardeners like their plants to remain pest free but avoid the temptation to use pesticides and accept the fact that you will lose some plants to pests. Instead try to encourage wildlife that will devour those pests or cultivate plants that will deter pests. 
·         Provide habitat. As pollinators need a home, you can always make your own nest boxes if you want to give your pollinating visitors a helping hand by drilling holes in a log or by bundling up lengths of hollow sticks such as bamboo. Visit the Botanic Garden’s bee hotel for inspiration!
“Setting aside a wild bit of garden can help pollinators by providing food, but provides nesting sites too”, remarked Katherine.

Additional information:

·         The Urban Pollinators Project was recently listed as one of the top 10 ground-breaking research projects in the Daily Telegraph. Read more.

·         Results from this research have recently been published in the Proceedings of the Royal Society B with more publications in press. A list of publications can be found here.

·         You can read more about Dr Katherine Baldock and the Urban Pollinators Project on page 7 of the 2015 edition of the Cabot Institute’s magazine.