Tag Archives: Christmas

The mystery of what pollinates poinsettias – China Diary 3

Is it too early to talk about Christmas? Not if you’re interested in pollinators and pollination! The mid-winter festival has featured quite a number of times on my blog over the years, especially in relation to the iconic plants that represent this time of year in Northern Europe, and what one might describe as the ‘cultural biodiversity‘ of Christmas. The final plant that I included in that last post was the poinsettia (Euphorbia pulcherrima) – this is how I described it:

In many ways this is an unusual plant to have such a strong cultural association with Christmas: it’s a mildly toxic species of spurge from tropical Mexico that was introduced to North America in the 19th century, then subsequently to Europe. However its festive connotations date back to the earliest period of Spanish colonisation in the 16th century, so it’s older than some…other Christmasy traditions…

I also discuss poinsettia, and specifically its pollination, in my recent book Birds & Flowers: An Intimate 50 Million Year Relationship – this is what I say in the chapter called ‘Urban flowers for urban birds’:

Just occasionally one sees a bird-pollinated tree planted in a city. The most common in my experience are various banksias in Australia, and the Royal Poinciana (from Madagascar) and the African Tulip Tree in the urban tropics and subtropics elsewhere in the world. I’ve also occasionally encountered large specimens of Poinsettia: when they are given free rein they are a much more impressive plant than their Christmas cousins. The vivid red bracts that surround the clusters of flowers suggest that they may be hummingbird-pollinated in their native Central America, but as far as I know their pollination ecology has not been studied.

Here at the Kunming Botanic Garden there’s several quite large specimens of poinsettia that, as I write, are in full flower, their red bracts a signal to pollinators that can be seen for quite a distance. However we’ve not seen any of the local sunbirds or white-eyes visit the flowers, and, as I said in the book, as far as I know the pollination ecology of poinsettia has never been studied in the wild. Close inspection of the flowers in the garden revealed that almost all of the nectaries had at least one nectar-collecting ant sticking out from it, their prominent backsides a deterrent to the Asian Honey Bees (Apis cerana) that also wanted a piece of the action.

Based on the position of the nectaries in relation to the stamens, if the plant is hummingbird-pollinated then the pollen is likely to end up under the chin of the bird. That’s certainly been described in other plant-bird pollination systems. But it does not have to be birds that move the pollen around – red flowers are also associated with other kinds of pollinators, for example butterflies and beetles. But until someone in Mexico does the necessary field work, we’ll just have to speculate.

“Arches of evergreen that scarce let through, A single feather of the driving storm” – how evergreen trees alter local microclimate

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Yesterday, Karin and I took a winter walk through one of the local woodlands, our feet crunching on the iced-over crust which is all that remains of last week’s snowfall. No doubt more snow is on its way as we approach the deepest part of winter here in Denmark. But seeing this holly tree reminded us that some parts of the woodland might remain snow-free no matter what the conditions.

Although I’m no meteorologist (and any who are reading this can correct me if I’m wrong), I suspect that two things are going on here. Firstly, the tree is sheltering the ground and reducing the amount of snow that falls below it. That umbrella effect is fairly obvious. But secondly, and more subtly, the small amount of warmth that there is in the soil is being prevented from radiating off into space by the presence of the holly leaves. So the warmer soil and surface layer of vegetation melts any snow that manages to make it through or under the holly’s canopy.

In both of these ways, the evergreen holly is affecting the microclimate of this part of the woodland. That in turn adds to the ecological heterogeneity of the habitat, proving greater access to food for animals, affecting the phenology of the ground flora, reducing local soil moisture, and so forth. All of these, in turn, will potentially lead to greater diversity of species with the local area.

On this blog and in my book Pollinators & Pollination: Nature and Society I’ve often written about evergreen trees, shrubs and climbers such as ivy, holly and mistletoe, including both their cultural associations (especially with Christmas) and their ecological importance. As so often is the case, the English poet John Clare thought about all of this two centuries ago. The quote I used in the title of this post is from his poem Winter Walk:

The holly bush, a sober lump of green,
Shines through the leafless shrubs all brown and grey,
And smiles at winter be it e’er so keen
With all the leafy luxury of May.
And O it is delicious, when the day
In winter’s loaded garment keenly blows
And turns her back on sudden falling snows,
To go where gravel pathways creep between
Arches of evergreen that scarce let through
A single feather of the driving storm;
And in the bitterest day that ever blew
The walk will find some places still and warm
Where dead leaves rustle sweet and give alarm
To little birds that flirt and start away
John Clare (1793-1864)

This might be my last post of the year, and so it only remains for me to wish a Glædelig Jul and Merry Christmas to all of my readers!

Books as gifts this Christmas – here’s some ideas for adults and children

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Although we are still in the early part of November, it’s never too soon to be thinking about buying Christmas gifts for friends and family. And what better gift than a book? Here’s a few suggestions for some that I’ve read this year that I think will make fine presents.

Who doesn’t love a good story, and Stephen King is a master storyteller. I’ve really enjoyed his more recent novels and Billy Summers stands out for me. It’s part thriller, part romance, and as always there’s a little touch of the uncanny. Very different, but just as much a page turner, is The Ministry for the Future by Kim Stanley Robinson. Although Robinson is known as a science fiction writer, this novel is set in the near future when climate change breakdown is forcing governments and businesses into making radical changes. As much as anything this is a road map for how we can get ourselves out of the current climate crisis.

Talking of which, Michael Mann’s The New Climate War should be read by everyone interested in understanding how big corporations have colluded with the media and governments to trivialise and misrepresent the problems that we currently face. I reviewed this and a book about the insect biodiversity crisis, Silent Earth by Dave Goulson, in this blog post.

If you are looking for a book to help young children understand the importance of bees and other pollinators then I can highly recommend Can We Really Help the Bees? by Katie Daynes and Róisín Hahessy, for which I acted as science advisor.

For the ornithologically minded you might want to consider the lavishly illustrated Hummingbirds: A Celebration of Nature’s Jewels by Glenn Bartley and Andy Swash. Those who love writing and art with an environmental focus would appreciate an annual subscription to Dark Mountain, which gives you two beautifully produced volumes every year. A couple of my essays appeared in earlier volumes and the quality of the contributions never fails to impress me.

There’s lots of great natural history authors and books to choose from on Pelagic Publishing’s list, including of course my own Pollinators & Pollination: Nature and Society! I especially enjoyed Ian Carter’s recent memoir Human, Nature: A Naturalist’s Thoughts on Wildlife and Wild Places.

For the budding or experienced cook, Niki Webster’s Rebel Recipes serves up some amazing vegan dishes that Karin and I have really enjoyed trying. And speaking of my wife, of course I have to include her Essential Companion to Talking Therapy as the perfect gift for anyone considering or currently undergoing counselling or therapy, or who is thinking about becoming a practitioner.

Finally, if you’re looking for particular book ideas or just like browsing through lists of what others recommend, there’s lots of inspiration over at the independent Shepherd site.

I hope that you’ve found this useful. Feel free to comment with suggestions for other books that you’ve enjoyed.

A healthy Christmas and a biodiverse New Year to all of my blog readers!

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On Sunday, following almost a week of form-filling, covid-testing and passport-stamping, Karin and I flew back to the UK to see friends and spend time with our kids. We’ve rented a large cottage in Glastonbury for the duration and the above image is taken from the back garden.

I hope that all of my blog readers have a healthy and happy Christmas, and that the New Year is both more prosperous and more biodiverse for you.

After being in rural Denmark for five months, Britain feels very congested and busy. All going to plan, we’ll be back walking the beaches of Odsherred and enjoying the scenery. See you in 2022!

The holly, the mistletoe, and the pollinators: an update on an old story

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Holly and mistletoe are two of Europe and Scandinavia’s most iconic plants, steeped in folklore and cultural significance, and redolent of the dark days of mid-winter and its festivities. Last year, together with my colleagues Jim Rouquette and Tom Breeze, I published a study of the value that pollinators add to the wholesale auction prices of these two plants using data from the UK’s largest holly and mistletoe auction that has been held in the town of Tenbury Wells for 160 years.

Holly and mistletoe are excellent subjects for a study of the added value that pollinators bring to a crop as they are 100% reliant on pollination by a range of wild bees, flies and other insects. This is because both species are dioecious with separate sex plants, therefore any berries produced on a female plant must be due to the activities of pollinators.

Here’s a link to last year’s blog post about that paper and here’s the reference for the paper itself, with a link to the journal where you can download it for free:

Ollerton, J., Rouquette, J.R. & Breeze, T.D. (2016) Insect pollinators boost the market price of culturally important crops: holly, mistletoe and the spirit of Christmas. Journal of Pollination Ecology 19: 93-97

The data set in that paper only developed the story up to 2015 as the 2016 auctions took place too late to include within our analyses. However I’ve collected the auction reports for 2016 and 2017 and added them to the data set. The results are graphed below*.

The auction price for holly with berries is rather volatile, but on average over this time period, berried holly has twice the commercial value of holly without berries. Indeed in the last auction of 2017, holly without berries failed to sell, hence the value of £0.00. The very wintry weather on the auction day reduced the number of buyers, but nonetheless, to have no one bidding for the unberried holly was unprecedented.

Holly auction prices plot

The pattern for mistletoe is rather similar, but in this case the value of berried material is less volatile than that of holly, and the average value is around three times greater than for auction lots of unberried plants.

Mistletoe auction plot

This data set offers a unique insight into the value of pollinators for two culturally important crops (all other such studies have focused on food or, rarely, fibre crops). I’ll continue to archive the auction reports and to update these analyses every few years in the run up to Christmas. If anyone is interested in accessing the data, please drop me a line.

If you want to learn more about the botany of different types of mistletoe follow this link to Mike Fay’s blog post on the Kew website.

Also worth checking out is Manu Saunders’ recent piece highlighting some old Christmas-themed blog posts.

Yesterday was my last day in the office, I’m now officially on leave and looking forward to a restful Christmas and New Year break. Season’s greetings to all of my readers and thank you for your continued support and interest in biodiversity!

*There are three auctions each year and therefore three data points per annum, except for 2016 when only two auction reports were produced.

Spiral Sunday #16 – Christmas is over

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Yesterday we took down the Christmas decorations that have festooned the house this year. Whilst I was taking apart the wreath we’d hung on the door I noticed for the first time that the bow had a lovely spiral design. I thought it would make a nice Spiral Sunday for this year, and we’ll re-use it next year.

More on that wreath later in the week….

Spiral Sunday #14 – Merry Christmas!

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Christman bauble 20161225_180146.png

A double helping of Spiral Sunday for Christmas Day 2016 – two glass baubles on our Christmas tree with very different spiral forms. In the first, the spiral is integral to the design, it is spiral in form. In the second, molten coloured glass has been trailed in a spiral pattern on the surface to create the pattern. Both very different, but both beautiful in their own way.

Merry Christmas everyone!

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Insect pollinators boost the market price of holly and mistletoe: a new study just published

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Holly and mistletoe 20161211_103252.png

Each year I’ve always added at least one Christmas-themed biodiversity post to the blog, for example: Thank the insects for Christmas, A Christmas vignette, and Six Kingdoms for Christmas. That’s partly because I really like Christmas as a winter festival, with its folklore and customs. But it’s also because these are a great vehicle to demonstrate how pervasive and important is natural capital and the ecosystem services it provides to society.

This year I’ve gone one stage further and actually published some Christmassy research to back up the blog post. Now, in a new study published in the Journal of Pollination Ecology, we have shown how important insect pollinators are in determining the market value of two of the most emblematic of Christmas plants: holly (Ilex aquifolium) and mistletoe (Viscum album). Here’s the full reference with a link to the paper itself, which is open access:

Holly and mistletoe are two seasonal crops that play a culturally important role as symbols of Christmas across the world, though both also have pre-Christian pagan roots. Now for the first time the role of insect pollinators in determining the commercial value of these plants has been investigated, using sales records going back over the last eleven years from Britain’s largest annual auction of holly and mistletoe, held every year in Worcestershire.

Analysis of the sales records of Nick Champion Auctions in Tenbury Wells shows that insect pollination raises the sale price of these crops by on average two to three times. This is because holly and mistletoe with berries is more sought after than material without berries, with wholesale buyers paying higher prices at auction. These berries in turn are the result of pollination by insects such as flies and bees: both holly and mistletoe are 100% dependent on insect pollination due to their having separate male and female plants.

There is some annual variation to the prices, and in years where berries are scarce (possibly due to low insect numbers) the price difference can be four-fold.

Due to concerns about pollinator declines and food security there is huge interest in the role of bees and other insects in supporting agriculture, and how we can value that role. However we believe that this is the first study showing that insect pollinators play a large part in determining the value of culturally symbolic, non-food crops. Almost all of the economic valuations of insect pollination to agriculture have focused on food crops such as beans, apples, cocoa, coffee, and so forth. Very little is known about how the value of non-food crops (fibres, construction materials, pharmaceuticals, ornamentals, etc.) is enhanced by insect pollination. This is an area where much more research is required.

But in the mean time, where better to end than with a bit of seasonal John Clare?

The shepherd, now no more afraid,
Since custom doth the chance bestow,
Starts up to kiss the giggling maid
Beneath the branch of mistletoe
That ‘neath each cottage beam is seen,
With pearl-like berries shining gay;
The shadow still of what hath been,
Which fashion yearly fades away.

The Shepherd’s Calendar (1827)

Six Kingdoms for Christmas: the cultural biodiversity of a winter festival

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Since beginning this blog in 2012 I’ve traditionally posted one or two Christmas-themed items around this time of year, including a piece on “Thanking the pollinators for Christmas” and a true story from 2013, “A Christmas vignette“. The role of pollinators in producing much of the traditional Christmas fare has subsequently been picked up by others (last year the University of Bristol, this year a blog from Trinity College Dublin) so I’ve decided to break with tradition and consider the ways in which biodiversity (both wild and farmed, though the latter of course originated as the former) adds to the cultural experience of Christmas through its traditions and rituals.

In this regard I’m coming at the topic as a north-European agnostic who values Christmas as an opportunity to relax and unwind at the darkest, coldest* part of the year, rather than as a Christian. And because I’m a British scientist much of what I say relates to British customs, though I’ve tried to include non-British examples where I’m aware of them – feel free to let me know about examples I’ve missed by commenting below.

I’ve decided to structure this post taxonomically and focus on a Six Kingdom Classification** of life on Earth as that’s been the theme of my first year undergraduate teaching since October. Four of the six Kingdoms can be dealt with fairly quickly as their significance to Christmas is marginal or non-existent. The two “bacterial” Kingdoms (Archaea and Eubacteria) contribute little to Christmas other than providing much of the gut flora that’s going to help us digest our Christmas dinner. Important but not specifically festive. Likewise the protists and algae (Kingdom Protoctista) add nothing specific to Christmas unless there are traditions associated with seaweed of which I am unaware.

The other three Kingdoms are the ones where cultural biodiversity associations are more apparent. The Kingdom Fungi (yeasts, mushrooms and moulds) provides us with several Christmas traditions including (in Germany) hanging mushrooms on the Christmas tree for good luck, and in parts of Scandinavia hanging strings of dried mushrooms around the house as decorations and as a source of winter food. There is also the association between the red-and-white colour scheme of fly agaric magic mushrooms (Amanita muscaria) and the robes of Santa Claus, though I’ve seen that idea debunked in a few places and it appears that the “traditional” interpretation of Santa’s suit originated in the USA in the 19th century.

The Kingdom Animalia (both invertebrates and vertebrates) affords us a host of cultural connections to Christmas. Birds include the turkey (Meleagris gallopavo) which in times past were famously walked to London from Norfolk; the domestic goose (Anser anser domesticus); and much of the song Twelve Days of Christmas refers to birds, including the turtle dove (Streptopelia turtur) one of the UK’s most declining and threatened bird species. Mammals we associate with Christmas include of course reindeer (Rangifer tarandus) pulling Santa’s sleigh, led by the nasally-advantaged Rudolph, but also domesticated farm animals. For example in Denmark in osme households it’s more traditional to eat pork (Sus scrofa domesticus) for Christmas dinner than goose.

Staying with the vertebrates, in our house it’s traditional to have smoked salmon (Salmo salar) with scrambled eggs for breakfast on Christmas Day, and (again in Denmark) sild (Clupea harengus) is also traditionally served as a starter, but I don’t know of other fish traditions. Likewise I’m unaware of any invertebrates that are specifically associated with Christmas, though there have been recent reports of sustainably-sourced lobsters (Homarus americanus and H. gammarus) becoming “traditional” in Europe. There are also some local traditions such as honey bees singing in their hives on Christmas Eve.

The last of the Six Kingdoms is the Plantae, which, whilst the least taxonomically diverse, provides us with a wealth of cultural associations to Christmas. These traditionally include evergreen plants that have been used to decorate homes, probably since the earliest pagan Yuletide festivals, such as: Christmas trees (various conifers in the genera Picea, Abies and Pinus); European ivy (Hedera helix); holly (Ilex aquifolium); and mistletoe (Viscum album). However such traditions evolve and adapt to local needs and availability of plants. For example in North and South America other genera of conifers not found in europe, such as Pseudotsuga and Araucaria, may be used as Christmas trees***. Likewise the absence of European mistletoe in North America means that people have adopted native mistletoes in the related genus Phoradendron for decorating and snogging traditions. Over at her blog, ecologist Manu Saunders has recently discussed how native Australian species can substitute European plants for Christmas decorations.

The final example from the Plantae is the poinsettia (Euphorbia pulcherrima) which I’ve pictured above. In many ways this is an unusual plant to have such a strong cultural association with Christmas: it’s a mildly toxic species of spurge from tropical Mexico that was introduced to North America in the 19th century, then subsequently to Europe. However its festive connotations date back to the earliest period of Spanish colonisation in the 16th century, so it’s older than some of the other Christmasy traditions I’ve discussed.

Of course biodiversity is about more than just species and taxonomic diversity, it also encompasses the diversity of habitats in which that life is found. Here too we see strong influences of the natural world on the culture of Christmas, including festive scenes of snow-bound boreal conifer forest. As our planet warms, however, that might be a view that is found only on Christmas cards and old movies, rather than directly experienced*.

And on that sobering note, I wish all of my readers and restful and biodiverse holiday: have a great Christmas everyone!

*Ha! It’s looking to be the warmest December on record, and at times has felt more like early summer than mid-winter.

**I’m aware that there are other Kingdom-level classifications out there which could be used, but the Six Kingdom approach is a good starting point.

***Closer to home, colleagues in the office adjacent to mine have adorned their large weeping fig (Ficus benjamina) with home-made Christmas decorations. Looks good.

Did you remember to thank the insects for Christmas?

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This year I decided not to re-post my traditional “Thank the insects for Christmas” piece, in part because I don’t want to bore the good readers of this blog with too much repetition, but also because the idea has been taken up by the Urban Pollinators Project at the University of Bristol, and developed into an infographic (on which I advised) that you can view here. The BBC News Website used the information for a nice article called “The insects that made Christmas“. So look back on your Christmas dinner, if you had one, and give thanks to the many invertebrates that made it happen!

The other reason for not doing a full re-post of that piece is that I was feeling worn out by a long university term that ended not with a whimper, but a stressful double-bang of publication of our pollinator extinctions paper (and the associated media interest, which I may talk about early in 2015) and the release of the results of the Research Excellence Framework, which I coordinated for my department. We were pleased with the outcome, with over 40% of our research papers rated as “world leading” or “internationally excellent”, and most of the rest being “recognised internationally”. For a young, mainly teaching-focused, non research-intensive institution such as the University of Northampton (which doesn’t enjoy the facilities and funding of older, larger universities), that’s an impressive result.

A final bit of news is that this blog made it onto the MySciBlog survey 2014, by Paige Brown Jarreau (Louisiana State University) who asked more than 600 science bloggers “to list up to the top three science blogs, other than their own, that they read on a regular basis”. The initial results can be found at Figshare, and I’ve inserted network graphic below (click on it for a larger view). The size of a node is proportional to the number of respondents who read that blog regularly and my blog is part of the green section near the top, tucked just under the dominant Dynamic Ecology. It’s gratifying to know that other bloggers are reading this in significant numbers!

Thanks to everyone who has read my blog over the past year, particularly those who have commented on the ideas and information I’ve presented: best wishes to you all for 2015!