Tag Archives: Nature

Which honeybees are declining and which are not?

Over the weekend there was a discussion on Twitter about “beewashing” that was spun out of this tweet by London beekeeper Richard Glassborow. Richard and his colleagues are some of the most responsible beekeepers that I know and they are getting increasingly frustrated by claims from irresponsible companies that keeping a hive of bees in your garden will help to “save the bees”, backed up by spurious claims that “honeybee colonies are dying out”.

The Twitter exchange prompted me to produce the Condescending Wonka meme that you see above because, as I discussed in my recent book Pollinators & Pollination: Nature and Society, pollinator conservation is a really complex area. But there’s no doubt that beekeeping as it’s being widely promoted is not the answer to bee conservation. Let me explain why.

The word “honeybee” does not refer to just one species. It’s most often* applied to bees in the genus Apis, especially the Western Honeybee Apis mellifera, but there are another seven or so Apis species to which the word can be applied. Of those other Apis species, most have never been domesticated and they live as free-living colonies is the various parts of Asia where they evolved. Only Apis cerana is kept in hives, as far as I am aware. The conservation status of most of these other Apis species is unclear but given that they are predominantly forest species, and deforestation is a chronic problem in Asia, we can surmise that some species may be declining. If you want to know more about them the Wikipedia page is a good starting point.

In this short post I just want to consider the Western Honeybee (Apis mellifera). This is a really knotty species to get to grips with because there are multiple subspecies and within subspecies there are various genetic lineages. In addition, the Western Honeybee has been subject to artificial selection for desirable qualities, such as docility, amount of honey produced per hive, and disease resistance, as well as cross-breeding between different subspecies**. The best recent summary of our current understanding of Western Honeybee genetics and conservation is this 2019 review by Fabrice Requier and colleagues, from which I’ve drawn quite a bit of information.

For the purposes of this explaining what’s going on, it’s easiest to think about the species as comprising three “megapopulations”:

Western Honeybees that are managed in hives: For the most part these are not endangered. Britain has as many hives now as it did in the mid-1950s and indeed globally we have more hives than ever (about 90 million hives at the last count). They are found far beyond their natural range and have been introduced into places where they are not native such as the Americas, parts of Asia, and Australia. STATUS: doing just fine.

Western Honeybees that have founded “feral” colonies: These have escaped from hives in countries where they have been introduced and become naturalised. They are doing well, too well in fact: they are a significant conservation issue in places like Australia. STATUS: doing just fine.

Western Honeybees that are living wild in their native range: This is where things become a little muddier. The African populations of the various subspecies seem to be doing well, but more studies are needed to confirm this. In Europe, actually defining what constitutes “wild” honeybees across a region where a lot of selection and hybridization has gone on, probably for thousands of years, is tricky. However there’s no doubt that wild colonies of Apis mellifera are not uncommon in suitable woodland: see this paper about free-living colonies in Ireland by Keith Browne and colleagues, for instance. Note their statement that genetic evidence shows that “the free-living population sampled is largely comprised of pure A. m. mellifera“, i.e. the European Black Honeybee. STATUS: probably doing quite well though more data is needed.

Conclusion: as I said, it’s really complicated and I don’t pretend to have all of the answers, no one does. But what IS clear is that managed Western Honeybees are not declining and keeping yet more hives of them is not going to help us to “Save the Bees”. I’ll leave the last word to Requier et al., whose review I really do recommend: “We argue for the redirection of attention from managed honey bees to the neglected conservation of wild honey bees.” Amen to that.

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*The term “honeybee” is sometimes also used for other social bees that produce honey, for example stingless honeybees in the genus Trigona, but there’s no real consensus on what “honey” actually is, and as I’ve argued in another post, bumblebees (Bombus spp.) also produce honey.

**You may be horrified (but perhaps not surprised) to learn that in the 1930s the Nazis enacted policies to ensure that German beekeepers kept only European Black Honeybees (Apis mellifera mellifera), in line with their views on racial “purity”. Then in the early 1940s, German beekeepers suffered a huge number of colony losses due to disease. The restrictions were lifted to allow beekeepers to cross their bees with disease-resistant A. mellifera carnica. Go figure.

Have honey bees declined in Britain? An update of the numbers

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If you’ve read my book Pollinators & Pollination: Nature and Society you’ll know that I have a section in the chapter “The shifting fates of pollinators” that deals with the honey bee situation. In that section I bring together the most comprehensive data set so far available on changes in number of hives in Britain. It’s based on a couple of earlier blog posts and if you’ve not read my book take a look at this one first and then this one to give you some context and more information about the sources of the data.

So far this year I have had several requests from people for the original data (which I’m happy to supply) and queries about what it means. So I thought that the time was right to update the graph with the latest official government figures from BeeBase.

The graph above brings the story up to 2021 where the official estimated number of hives is 272,631. That’s an increase of more than 40% since the first BeeBase estimate in 2015.

The take home from this figure is that the current number of honey bee hives in Britain is similar to what it was in the mid-1950s.

So the answer to the question “have honey bees declined in Britain?” is a resounding NO! They are at least as abundant as they were almost 70 years ago. This reflects the global situation where there’s been a substantial increase in hive numbers since the 1960s, as you can see in the figure below.

So if you want to “Save the Bees” or otherwise support pollinators, please focus on the wild, unmanaged species rather than the managed Western Honeybee (Apis mellifera). As always, comments and questions are welcome below or send me a message via my Contact page.

Tracking trends in Neotropical pollinators: how good is our understanding and is more data always better?

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In my recent book Pollinators & Pollination: Nature and Society I discussed the current state of our knowledge of how populations of pollinators have changed over time. Although we have some quite detailed data for particular, often charismatic, species or for certain geographic localities or regions, for most species we know almost nothing. As I wrote in the chapter “The shifting fates of pollinators”:

“For most pollinators we are ‘data deficient’, in other words, we don’t know how their populations are performing. They could be doing well, but they may not be”

This is particularly true for those regions for the world that hold the greatest terrestrial biodiversity: the tropics. For the vast majority of species in the tropics we know precious little about trends in their populations and how their distributions have changed over time in the face of wide-scale land transformation and recent climatic shifts. Filling in some of the gaps in our knowledge of Neotropical pollinator distributions is one of its aims of SURPASS2, a collaboration between South American and UK ecologists, and one of several research and outreach projects with which I’m involved.

In a new study that’s come out of that work, led by Rob Boyd from the UK Centre for Ecology and Hydrology, we’ve used the GBIF database to look at the changing distributions of four important groups of pollinators: bees, hoverflies, leaf-nosed bats and hummingbirds. In particular we were interested in understanding the kinds of biases that come with such publicly available data, and whether recent efforts to add data to GBIF has improved our understanding of trends.

Our overall conclusion is that there are significant limitations and biases inherent in all of these data sets even for groups like hummingbirds which one would imagine are well documented by scientists and bird-watching naturalists. In addition, having more data does not necessarily help matters: it can introduce its own biases.

The paper is open access and feely available; here’s the reference with a link:

Boyd, R. J., Aizen, M.A., Barahona-Segovia, R.M., Flores-Prado, L., Fontúrbel, F.E., Francoy, T.M., Lopez-Aliste, M., Martinez, L., Morales, C.L., Ollerton, J., Pescott, O.L., Powney, G.D., Saraiva, A.M., Schmucki, R., Zattara, E.E., & Carvell, C. (2022) Inferring trends in pollinator distributions across the Neotropics from publicly available data remains challenging despite mobilization efforts. Diversity and Distributions (in press)

Here’s the abstract:

Aim
Aggregated species occurrence data are increasingly accessible through public databases for the analysis of temporal trends in the geographic distributions of species. However, biases in these data present challenges for statistical inference. We assessed potential biases in data available through GBIF on the occurrences of four flower-visiting taxa: bees (Anthophila), hoverflies (Syrphidae), leaf-nosed bats (Phyllostomidae) and hummingbirds (Trochilidae). We also assessed whether and to what extent data mobilization efforts improved our ability to estimate trends in species’ distributions.

Location
The Neotropics.

Methods
We used five data-driven heuristics to screen the data for potential geographic, temporal and taxonomic biases. We began with a continental-scale assessment of the data for all four taxa. We then identified two recent data mobilization efforts (2021) that drastically increased the quantity of records of bees collected in Chile available through GBIF. We compared the dataset before and after the addition of these new records in terms of their biases and estimated trends in species’ distributions.

Results
We found evidence of potential sampling biases for all taxa. The addition of newly-mobilized records of bees in Chile decreased some biases but introduced others. Despite increasing the quantity of data for bees in Chile sixfold, estimates of trends in species’ distributions derived using the postmobilization dataset were broadly similar to what would have been estimated before their introduction, albeit more precise.

Main conclusions
Our results highlight the challenges associated with drawing robust inferences about trends in species’ distributions using publicly available data. Mobilizing historic records will not always enable trend estimation because more data do not necessarily equal less bias. Analysts should carefully assess their data before conducting analyses: this might enable the estimation of more robust trends and help to identify strategies for effective data mobilization. Our study also reinforces the need for targeted monitoring of pollinators worldwide.

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SURPASS2 has been a hugely productive project as you’ll see if you look at the Publications page of the website. There’s much more to come and I’ll report on those research papers as they appear.

Watch my recent interview on Earth To Be

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

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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.

What are the best books about bees and other pollinators?

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Clearly that’s a very subjective question and everyone has their own view on which books about a particular subject they would recommend! So coming up with a list of just five for the Shepherd book recommendation site was not easy. My list features authors such as Brenda Z. Guiberson, Megan Lloyd, Steven Falk, Dave Goulson, Mike Shanahan and Stephen L. Buchmann, which will hopefully inspire you to read some of these books.

Here’s the link: https://shepherd.com/best-books/bees-and-other-pollinators

If you think that I’ve missed your favourite from the list, please do comment below. And if you’re an author, consider signing up for Shepherd and curating your own list, they’ve been really helpful and it’s a useful service for readers and authors.

A new study shows that even short-tubed flowers can specialise on hawkmoths as pollinators

The value of butterfly specimens for understanding species extinctions – a new study just published.

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The Chequered Skipper Reintroduction Project has featured in several posts over the last few years – see here and here – and University of Northampton PhD researcher Jamie Wildman has been working hard to complete his thesis under the less-than-ideal conditions imposed by the COVID-19 pandemic. The first paper from the project has just been published and it deals with Jamie’s monumental efforts to bring together all of the scattered data relating to preserved Chequered Skipper specimens held in museums and private collections. An existing database contained just 266 records; Jamie’s efforts increased that by an order of magnitude, adding a further 3,533 new records that document where and when specimens were collected, and by whom.

This 1,328 % increase in data means that we now know much more about the historical distribution of this butterfly and how that changed over time.

The Chequered Skipper went extinct in England in 1976 and this enhanced database will allow us to understand why that extinction occurred. This initial paper documents the strategy used to find the additional records as a road map for how others might proceed in the future. The full reference with a link to the paper is here:

Wildman, J.P., Ollerton, J., Bourn, N.A.D., Brereton, T.M., Moore, J.L. & McCollin, D. (2022) The value of museum and other uncollated data in reconstructing the decline of the chequered skipper butterfly Carterocephalus palaemon (Pallas, 1771). Journal of Natural Science Collections 10: 31-44

This is the abstract:

The chequered skipper butterfly Carterocephalus palaemon (Pallas, 1771) was declared extinct in England in 1976 after suffering a precipitous decline in range and abundance during the 20th Century. By searching and collating museum and other records, we show how a deeper understanding of this decline can be achieved, thus furthering conservation objectives. A preexisting Butterflies for the New Millennium (BNM) database of United Kingdom butterfly species records, created by Butterfly Conservation in conjunction with the Biological Records Centre (BRC), contained 266 historic C. palaemon records from England. United Kingdom (UK) museums and natural history societies were contacted for specimen data, and these sources added 2175 new records to the BNM. Owners of private specimen collections were also contacted, and these collections accounted for a further 465 records. Specimens originating from UK museums, other institutions, and private collections represent 2640 (71%) of total new records. Other sources, such as personal accounts held in museums, published and unpublished texts produced an additional 894 records. A further 437 records from museums, private collections, and other sources were considered partial and omitted from the data due to limited or misleading date and/or locality information. In summary, data from UK museums and other sources has infilled English C. palaemon distribution prior to 1976, offering further insight into potential environmental and anthropogenic drivers of decline at key sites. The quality and quantity of data obtained using the method outlined in this study suggests similar work could be carried out for other extinct or declining butterfly species to improve our knowledge of habitat requirements and historical distribution via modelling, identify causes of decline, and provide valuable information for potential reintroductions.

Join me on Thursday for a free talk!

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Join me this Thursday at a free online talk organised by Buglife where I’ll be giving an introduction to how flowers function and the ways in which their behaviour manipulates pollinators to ensure reproduction. I’ll be covering:

What are flowers and where did they come from?
How flowers function and reward pollinators.
Some case studies from my own research on flower and pollinator behaviour.
Why is it important that we understand floral biology?

Here’s the link to register for the event: https://www.buglife.org.uk/events/to-be-a-flower-with-professor-jeff-ollerton/

I look forward to seeing you there!

The value of nature, the value of guitars

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How we, as a society, value nature, and the tension between valuing (or appreciating) nature versus appreciating (or pouring money into) human cultural activities, have been consistent themes of this blog since I started it almost a decade ago; see for example my posts “How do we value nature? Costanza, Monbiot and the clash of concepts” and “Is the angry response of (some) environmentalists in the aftermath of the Notre Dame fire reasonable?“

Putting a monetary price on nature runs counter to the personal philosophies of many conservationists, which I completely understand: I have mixed feelings too. However there’s a whole field of research devoted to it called Ecological Economics and the valuation of natural capital and ecosystem services now plays a central role in the policies and strategies of both businesses and governments: see for instance the UK Government’s recent report on “The Economics of Biodiversity: The Dasgupta Review“. And whether we like it or not, the Earth’s ecosystems and the biodiversity that they contain support our global economy in very tangible ways, a point that I emphasise in my book Pollinators & Pollination: Nature and Society. If you’re reading this with a cup of coffee in your hand, you have to consider the ecological and financial impact of the billions of wild and managed bees that support the global coffee industry.

“What’s all of this got to do with guitars?” I hear you asking. Well, music, and especially guitars, are another constant theme of the blog, including my love of the songs of Crosby, Stills, Nash and Young, and my restoration of an old acoustic guitar back in 2020.

These themes converged together in a rather unexpected way just over a week ago. It was my birthday and as a present Karin had offered to buy me a new guitar. So off we went to Copenhagen for the day. One of the city’s best guitar shops is Akustikken and there I tried out several makes and models of acoustic guitar, of varying price and quality, before finally settling on an Epiphone Texan in an aged sunburst finish (see the image below). It plays very nicely, felt right in my hands, and was moderately priced despite its solid wood construction (cheap guitars often use laminated wood).

The guitar that really caught my eye, however, was the one in the photograph above: a Martin 045-S Stephen Stills Signature Model. Now, this is a serious, serious guitar. Based on a 1930s model owned by Stills himself, it was hand made in the USA in a limited edition of 91, of which this was number 48. The woods from which it’s made are rare and exceptional, including Adirondack spruce, Madagascar rosewood, and ebony, all species about which there are significant conservation concerns (see Richard Hobbs’s great blog The Nature of Music for more on this – highly recommended for anyone interested in the interface between human culture and ecological conservation).

The price tag for this guitar? A mere160,000 Danish kroner, about £18,000 or $20,000…..

That was WAY outside of our budget! But when the staff learned that it was my birthday they kindly took the Martin out of its humidity-controlled glass case and let me play it. I was a bit overwhelmed and very nervous if I’m honest, it was easily the most expensive guitar I have ever had in my hands! Karin took a short video of me strumming a few chords which I uploaded to Twitter:

The day I played a $20,000 guitar…

On Friday, during a visit to a Copenhagen guitar store with @KarinBlak, I had the unexpected pleasure of playing a #StephenStills signature model Martin 045-S #guitar. It was…1/n#CSNY #guitarplayer pic.twitter.com/VeHAAOCuJO
— Prof. Jeff Ollerton (@JeffOllerton) February 13, 2022

Now, I’d played guitars up to around $2,000 in price that day, so a reasonable question is: did the $20,000 guitar sound ten times as good? Well, not in my hands it didn’t…. But in one sense it doesn’t matter, you’re not just paying for what it sounds like, you’re paying for the story, for the association with Stills, and the highly skilled crafting of the guitar – it is an exceptionally beautiful and fine-sounding instrument.

This brings us back to nature. We know from a lot of ecological experiments that have been conducted over the years that there’s a positive relationship between biodiversity (measured by the number of species in an ecosystem) and the way in which that ecosystem functions. So if you have more different kinds of plants in a grassland, for example, there tends to be greater carbon capture, more efficient use of water and uptake of nitrates from the soil, more resilience to events like drought and fire, and so forth. This is a strong and pervasive argument for conserving species within ecosystems: the more we have, the better the “health” of that ecosystem.

But, as with the sound of guitars, there’s probably an upper limit to this and ecosystems with ten times as many species probably do not function ten times as well. But they do function better. Having said that, this is a complex area of research with some competing ideas (and scientists) – this Wiki provides quite a good summary.

Regardless of the technical details, there’s no doubt that having more pollinators in an ecosystem, for example, increases the reproduction of a wider range of the plants that are present. Or that the presence of a greater diversity of dung beetles improves the rate of dung removal in grasslands.

But of course nature is more complicated than this. Just as a well made and high-value guitar is never going to sound good in the hands of a poor guitarist, likewise, species diversity in itself is insufficient. It is the interactions between those species that determines much of the way in which the ecosystem functions, and an ecosystem is never going to function well over the long term if it is inappropriately managed or if the processes that shape ecosystems, such as grazing by wild herbivores or natural fire regimes, are absent or have been altered.

Ecology is a hugely complex science but perhaps by exploring metaphors like this, some of that complexity can be made accessible to a wider range of people. Tell me what you think, does the metaphor work for you?