Category Archives: Food and biodiversity

A “weed” that you should be eating and an introduction to our new garden

It’s been a rather nomadic couple of years. After Karin and I sold our house in Northampton, we travelled around in the UK and then in Denmark, renting places as we needed them, plus we spent a month in Kenya. We’ve now become more settled in Sjælland and, after some deliberation about whether to buy a house or continue renting, we’ve reached a compromise and bought into an andelsbolig, one of the many Danish cooperative housing schemes – see this article in The Guardian for more details.

The development of twenty-eight small properties has been newly built to the highest standards of insulation and is plugged into the district heating system which uses a combination of solar warming and gas (in part using methane generated from food waste).

It’s nice to have a garden again. I hadn’t realised how much I’d missed having a space in which to plant and potter. All gardens present challenges, of course, and this one is no exception. Until about 600 years ago the area was under the shallow Kattegat sea. It’s now above sea level due to post-glacial rebound and in fact this whole region of Odsherred is a UNESCO Global Geopark because of the postglacial landscape.

What this means for us is that we are gardening on “soil” which has a very high sand content and is filled with stones, large and small.

Added to that, we’re in one of the driest parts of Denmark (certainly this year) and a persistent coastal wind rapidly strips the moisture from the soil. So as we dig up or find large stones we are using them around plants to retain water and mulching with the smaller stones that we find in abundance. As yet we don’t have any rain water butts so we’re using the kitchen water from washing up to supplement the hosepipe.

It’s not easy gardening here, but we like a challenge and we’re calling in favours from friends and family to provide us with cuttings and divisions of plants from their own gardens, which should mean that they are better adapted to the local conditions than most of the shop-bought plants. We’ve also started a small vegetable and fruit patch and planted apples and pears around a paved patio that over time we will train as self-supporting espaliers.

Gradually we’ll fill up the space and move things around as needed. But for now I’m also interested in seeing what plants come up spontaneously, especially the annual species that are benefitting from the disturbance. I don’t use the term “weed” to refer to these: weeds are just plants in the wrong place at the wrong time. Many such plants are ecologically important, especially as nectar and pollen sources for bees and other insects. This includes Common Bugloss (Anchusa officinalis) with its richly purple, velvet-textured flowers.

Another plant that we are tolerating is a fast-growing relative of spinach that’s variously called Goosefoot or Fat Hen (Chenopodium album). I’d long known that it was edible (it’s grown as a crop in parts of Asia) but until last night I’d not cooked with it.

In fact it’s delicious! I threw some roughly chopped leaves and stems into a mushroom omelette and I have to say that it was better than any commercial spinach I’ve bought or grown. In particular, the texture is much nicer as the leaves are very water-repellant which mean that they don’t absorb as much moisture during cooking. Highly recommended as an alternative to spinach but make sure you correctly identify the plant before you try it – there’s some good advice on this website: https://www.wildfooduk.com/edible-wild-plants/fat-hen/.

As well as Fat Hen we also have the close relative Tree Spinach (Chenopodium giganteum), with it’s beautiful magenta-tinged leaves, coming up in the garden. I’m looking forward to trying that too:

I’ll try to post more as the garden progresses, if I have time. But as I mentioned yesterday, even though the manuscript is complete and submitted to the publisher, there’s still lots to do on my next book! Have a good weekend.

Pollinators and the UN Sustainable Development Goals – free webinar on Monday!

2 Replies

There’s been a lot of discussion recently about how pollinators can contribute to the United Nations’ 17 Sustainable Development Goals. It’s a topic that I reflected on in Pollinators & Pollination: Nature and Society, and I’ve seen a few papers and articles that raise the subject – see here for instance. This free webinar on Monday 27th March is therefore very timely! To register, follow this link: forms.office.com\r\T5HrW0VZvS

Although I’m one of the speakers, I can’t make it in person as I’ve got teaching commitments at Roskilde University, so I’ve recorded my ten minute piece and I’m happy to answer questions via the Contact page on my website.

Soybean is more dependent on bee pollination in the tropics – a new study just published

1 Reply

It’s been an interesting start to the year in the world of pollinators and pollination. The European Union has revised its 2018 initiative for pollinator conservation with an update called “A New Deal for Pollinators“. At the same time the UK Government has released its plans for Post-Brexit farm subsidies, many of which focus on environmental action that can support pollinators, such as planting hedgerows. I think that it’s fair to say that there’s been a mixed response to these planned subsidies. There’s also mixed news in Butterfly Conservation’s State of the UK’s Butterflies 2022 report. The headline figure is that 80% of butterflies in the UK have decreased since the 1970s. However there are enough positive conservation stories in that report to demonstrate that this decline does not have to be irreversible, we can turn things around.

Against this wider backdrop of pollinator actions, I was pleased to have a new research paper published this week, which is an output from the SURPASS2 project with which I’ve been involved. Led by Brazilian researcher Nicolay Leme da Cunha, this paper assess the variability of soybean dependence on pollinators. Although soybean is one of the most widely grown crops globally, there’s still much that we don’t understand about which of the many different varieties have improved yields when visited by bees, and which are purely self-pollinating. One of our main findings was that for some varieties, especially in the tropics, an absence of pollinators results in a decline in yield of about 50%.

The paper is open access and you can download a copy by following the link in the reference:

da Cunha, N.L, Chacoff, N.P., Sáez, A., Schmucki, R., Galetto, L., Devoto, M., Carrasco, J., Mazzei, M.P., Castillo, S.E., Palacios, T.P., Vesprini, J.L., Agostini, K., Saraiva, A.M., Woodcock, B.A., Ollerton, J. & Aizen, M.A. (2023) Soybean dependence on biotic pollination decreases with latitude. Agriculture, Ecosystems & Environment 347, 108376

Here’s the abstract:

Identifying large-scale patterns of variation in pollinator dependence (PD) in crops is important from both basic and applied perspectives. Evidence from wild plants indicates that this variation can be structured latitudinally. Individuals from populations at high latitudes may be more selfed and less dependent on pollinators due to higher environmental instability and overall lower temperatures, environmental conditions that may affect pollinator availability. However, whether this pattern is similarly present in crops remains unknown. Soybean (Glycine max), one of the most important crops globally, is partially self-pollinated and autogamous, exhibiting large variation in the extent of PD (from a 0 to ∼50% decrease in yield in the absence of animal pollination). We examined latitudinal variation in soybean’s PD using data from 28 independent studies distributed along a wide latitudinal gradient (4–43 degrees). We estimated PD by comparing yields between open-pollinated and pollinator-excluded plants. In the absence of pollinators, soybean yield was found to decrease by an average of ∼30%. However, PD decreases abruptly at high latitudes, suggesting a relative increase in autogamous seed production. Pollinator supplementation does not seem to increase seed production at any latitude. We propose that latitudinal variation in PD in soybean may be driven by temperature and photoperiod affecting the expression of cleistogamy and androsterility. Therefore, an adaptive mating response to an unpredictable pollinator environment apparently common in wild plants can also be imprinted in highly domesticated and genetically-modified crops

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

2 Replies

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.

Food system resilience: concepts, issues and challenges – a new, open access review just published

Pollinator-flower interactions in gardens during the COVID-19 pandemic lockdown of 2020: the data paper has just been published!

8 Replies

During the lockdown period of the COVID-19 pandemic in 2020, many pollination ecologists were stuck at home: universities and research institutes were closed and restrictions on travel meant that it was not possible to get out and do field work. In order to keep active and motivated, and to turn adversity into an opportunity, an ad hoc network of more than 70 researchers from 15 different countries (see the map above) decided to collect standardised data on the plant-pollinator networks in their own gardens and nearby public spaces.

When combined with information about location, size of garden, floral diversity, how the garden is managed, and so forth, this would provide some useful data about how gardens support pollinators. For those with kids at home it could also be a good way of getting them out into fresh air and giving them something to do!

Following discussions, several different protocols were instigated which depended upon the time available to the researchers, including one that mirrored the UK Pollinator Monitoring Scheme’s FIT (Flower-Insect Timed) counts.

The resulting data set of almost 47,000 visits by insects and birds to flowers, as well as information about flowers that were never visited, is freely available and will be an invaluable resource for pollination ecologists. For example, analysing the links between ornamental flowers that share pollinators with fruits and vegetables such as apples and beans, will allow us to make recommendations for the best plants to grow in home gardens that can increase yields of crops.

There’s an old saying about turning adversity into a positive outcome: “When life gives you lemons, make lemonade”, and the researchers were pleased to find that there’s one record of Citrus limon in the data set!

The paper describing the data set has just been published in the Journal of Pollination Ecology and you can download a PDF of the paper and the associated data for free by following this link.

Sincere thanks to all of my co-authors for their commitment to the project!

Pollinators (not) on the menu at Kew

Do bumblebees make honey? Yes and no…and…maybe [UPDATED]

9 Replies

As kids, my friends and I did a lot of digging. We always seemed to be burrowing into slopes or excavating trenches, pretending to be archaeologists or treasure hunters. Indeed, there was a lot of ground treasure to be found in the part of Sunderland where I grew up. The area has a long history of pottery and glass making, and ship building, and the remnants of these industries could be uncovered every time we stuck a spade in the earth. Over time I developed my own small museum of interesting, unearthed fragments, including bits of hand-painted ceramics, glass bottles, and unidentifiable metal shards, alongside various animal bones I’d excavated. My parents quietly indulged this interest, and my muck-streaked face and clothes, even if they didn’t quite understand what I was doing.

Aged about 10, my first encounter with a bumblebee nest was during one such dig. On the waste ground behind a large advertising hoarding, we began digging into a low, grass-covered mound and accidentally excavated what was probably a small nest of Buff-tailed Bumblebees (Bombus terrestris). I can recall being fascinated by the waxy, odd shaped cells and by the sticky fluid that some of them were leaking. Being an adventurous sort of child I tasted the liquid: it was sweet and sticky, and that was my first encounter with bumblebee “honey”.

I’m going to leave those quotation marks in place because if you do an online search for “do bumblebees make honey?” you generally find that the answer is “no, only honey bees make honey”.

Now, defining honey as something made by honey bee strikes me as a circular argument at best. And it also neglects the “honey” made by meliponine bees that is central to the culture of stingless bee keeping by indigenous groups in Central and South America, and the long tradition pre-colonial tradition of honey hunting by Aboriginal Australians. So if we widen our definition of “honey” as being the nectar*-derived fluid stored in the nests of social bees, then Apis honey bees, stingless bees and bumblebees must all, by logic, make honey. And likewise there’s wasps in the genus Brachygastra from Central and South America that are referred to as “honey wasps” because, well, I’m sure you can work it out!

But this is where things become a little trickier, because turning nectar* into honey involves some complex evaporation and enzymatic activity, so that the resulting fluid is more concentrated and dominated by the sugars glucose and fructose. Although analysis of honey bee honey is commonplace, and there’s been some research conducted on the honey of stingless bees, I don’t know of any studies that have compared Bombus honey with that of other bees, or with what is stored in the nests of honey wasps**. If I’ve missed anything, please do comment and let me know, but this strikes me as an area of research demanding some attention.

So do bumblebees make honey? That very much depends on our definitions, but I’m happy to accept that they do because “honey” is not a single thing: it’s an insect-derived substance that can take a range of forms but serves the same broad purpose of feeding the colony. And although insects have probably been producing it for millions of years, I think I’ve known the answer to the question for almost 50 of them…

UPDATE: A couple of people have commented on social media that there are legal definitions of “honey” as a foodstuff. Here’s the definition according to UK law***:

“the natural sweet substance produced by Apis mellifera bees from the nectar of plants or from secretions of living parts of plants or excretions of plant-sucking insects on the living parts of plants which the bees collect, transform by combining with specific substances of their own, deposit, dehydrate, store and leave in honeycombs to ripen and mature”

So, legally, we can’t call anything that isn’t made by Apis mellifera “honey”, at least from a foodstuffs regulation perspective. But that’s clearly different to what we have been discussing above, which is about a biological definition of honey.

It’s also interesting to look at the compositional requirements of honey as a foodstuff (presented in Schedule one of that document, if you follow the link above). The lower limit for moisture content is 20%. Now if you consider that most nectar in flowers has a sugar content of between about 20% and 50%, clearly there’s been a lot of evaporative work done by the bees to reduce the amount of water in the honey. I would love to know how bumblebee (and other insect) “honey” compares to this: do they put the same kind of effort into evaporating the water from the stored nectar? Given that the purpose of reducing the water content is to prevent fermentation by yeasts when it’s stored for a long time, and that there are bumblebee species which have colonies that are active for more than one year, I imagine that at least some species in some parts of their range may employ similar tactics.

Thanks to everyone who has been commenting and discussing the topic. It never ceases to amaze me how much we still do not understand about some fundamental aspects of the natural history of familiar species!

*And honeydew to a greater or lesser extent.

**I’m going to ignore honey pot ants for now as this is complex enough as it is and they don’t store the “honey” in nest cells.

***From what I can gather definitions in other countries are similar.

Practical methods for assessing insect pollination services provided by sites – download our new study for free

2 Replies

In September 2016, along with 11 other pollinator & pollination scientists, I took part in a two-day two-day workshop held at the UNEP-World Conservation Monitoring Centre in Cambridge. The aim was to develop a range of simple, practical methods to enable the valuation of insect pollination services to agricultural crops that are provided by a nature reserves or other natural or semi-natural habitats, for TESSA – the Toolkit for Ecosystem Service Site-Based Assessments.

After a long gestation, caused not least by the COVID-19 pandemic, the paper outlining the methods that we developed has been published. It’s open-access and downloadable for free. Here’s the full reference with a link to the paper:

Ratto, F., Breeze, T. D., Cole, L. J., Garratt, M. P. D., Kleijn, D., Kunin, B., Michez, D., O’Connor, R., Ollerton, J., Paxton, R. J., Poppy, G. M., Potts, S. G., Senapathi, D., Shaw, R., Dicks, L. V., & Peh, K. S.-H. (2022) Rapid assessment of insect pollination services to inform decision-making. Conservation Biology 1–13

And here’s the Abstract:

Pollinator declines have prompted efforts to assess how land-use change affects insect pollinators and pollination services in agricultural landscapes. Yet many tools to measure insect pollination services require substantial landscape-scale data and technical expertise. In expert workshops, 3 straightforward methods (desk-based method, field survey, and empirical manipulation with exclusion experiments) for rapid insect pollination assessment at site scale were developed to provide an adaptable framework that is accessible to non-specialist with limited resources. These methods were designed for TESSA (Toolkit for Ecosystem Service Site-Based Assessment) and allow comparative assessment of pollination services at a site of conservation interest and in its most plausible alternative state (e.g., converted to agricultural land). We applied the methods at a nature reserve in the United Kingdom to estimate the value of insect pollination services provided by the reserve. The economic value of pollination services provided by the reserve ranged from US$6163 to US$11,546/year. The conversion of the reserve to arable land would provide no insect pollination services and a net annual benefit from insect-pollinated crop production of approximately $1542/year (US$24∙ha^–1∙year^–1). The methods had wide applicability and were readily adapted to different insect-pollinated crops: rape (Brassica napus) and beans (Vicia faba) crops. All methods were rapidly employed under a low budget. The relatively less robust methods that required fewer resources yielded higher estimates of annual insect pollination benefit.

Diversity and surplus: foraging for wild myrobalan plums

3 Replies

Cycling back from town this afternoon, Karin and I passed a hedgerow that was bursting with wild myrobalan or (cherry) plums (Prunus cerasifera). We had to stop and collect some, and soon filled a bag. What’s always intrigued me about these small, tart little plums is just how diverse they are: the image above shows the plums from six different trees. All of these are, in theory, the same species; but clearly there’s a lot of genetic diversity. In colour, the ripe fruits range from golden yellow through to dark purple, and vary in the amount of dark-contrasting streaking, lighter speckling, and waxy bloom. They are also variable in size, shape and taste.

All of this variation probably reflects the long history of cultivation of this European archaeophyte. The species is originally native to southeast Europe and western Asia, and was likely spread throughout Europe by the Romans. The local deer population is very fond of the fruit and we’re seeing a lot of deer droppings that are packed with seeds. We don’t usually think of these large mammals as seed dispersers, but I suspect that they are very successful in that ecological role.

As well as being a great source of wild fruit, for humans and wildlife alike, at the other end of the year these trees are important for pollinating insects. As I pointed out in my book Pollinators & Pollination: Nature and Society, Prunus cerasifera is one of the earliest flowering woody plants in northern Europe, and its flowers are an important nectar and pollen source for early emerging bumblebee queens, hoverflies, and honey bees.

Delicious, abundant fruit combined with a valuable role for pollinators: what’s not to like?