Category Archives: Honey bees

Surveying for Pollinators: join me for an online live webinar on 2nd October!

On Thursday, October 2 at 6:30pm, I’m running an online webinar on the theme of Surveying for Pollinators. Follow that link for more details and to book a ticket.

Here’s an overview of what I’ll be covering:

Pollinators like bees, butterflies, hoverflies and even beetles play a vital role in keeping our ecosystems thriving. They help plants reproduce, support biodiversity, boost food production, and contribute billions to the global economy. Beyond their ecological importance, they’re also excellent indicators of environmental health — when pollinators are doing well, nature usually is too.

But how do we actually find out what’s happening with pollinators?

In this webinar, we’ll explore the fascinating world of pollinator surveys — from simple, hands-on methods anyone can try, to more advanced techniques used by experienced entomologists and ecologists. You’ll get an overview of popular approaches, including:

Flower-Insect Timed Counts – A quick and accessible method inspired by the UK Pollinator Monitoring Scheme (PoMS).
Transect Walks – Great for spotting pollinators along a fixed route and comparing habitats.
Plant-focused sampling – for when you really want to delve deep into the pollinators of a species.
Trapping methods – including pan traps, vane traps, Malaise traps, and moth traps.
Camera Traps – A non-intrusive way to capture who’s visiting flowers when you’re not looking.

We’ll break down the pros and cons of each technique, which approaches are best suited to the question being asked, what to consider before starting your own survey, and how your efforts can feed into national monitoring schemes like PoMS, the UK Butterfly Monitoring Scheme, and BeeWalk.

Whether you’re a curious beginner, a budding citizen scientist, a research student, or a conservation professional, this session will give you the knowledge and tools to design a pollinator survey that fits your goals — and helps protect the buzz behind biodiversity.

The 90-minute event will consist of a 1-hour presentation followed by a Q&A with the tutor using questions provided by the live audience.

The presentations will be recorded and shared with those who booked, alongside Q&A transcripts and relevant links following the event via a password-protected website.

Have we passed “peak honey bee” in Britain? An update of hive numbers for World Bee Day 2025

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Since publishing what I believe are the most comprehensive data on the number of honey bee hives in Britain in my book Pollinators & Pollination: Nature and Society, I’ve posted occasional updates on my blog as more recent data become available. I believe that the last of these was in 2022 – see Have honey bees declined in Britain? An update of the numbers – so it feels like it’s time for another. And what’s more appropriate than to post this on World Bee Day 2025?!

Rather than the complex, multi-coloured graph that I’ve produced in the past, I’ve decided to streamline the presentation and simply fit a smoothed LOESS line with a 95% confidence ribbon to the (sometimes contradictory) data points, in order to show the overall trend (see the graph above). If you compare it with the 2022 update you’ll see that the general message from the data is the same: a peak in numbers of hives in the late 1940s (which may or may not be an artefact*), then a steep decline into the 1970s and 1980s, followed by recovery from the 1990s onwards. Note that I’ve removed the two very early data points because I don’t think that they are at all accurate.

The most recent data (2015 to 2024) come from the National Bee Unit which relies on beekeepers to submit their own records, but are probably no less accurate than some of the other data that’s available! If we take a close look at that time period we see something interesting – honey bee hive numbers are decreasing:

What are we to make of this? In an analogy with peak oil, why do we seem to have passed ‘peak honey bee’? If this is a real pattern (and only time will tell) I suspect that it’s because of at least two factors. The first is that interest in beekeeping reached a peak in the early 2020s, after which some initial enthusiasts discovered that beekeeping is actually quite a technical and demanding hobby, and gave it up. The second factor is that word has spread that , globally, managed Western honey bees are not declining, and too many bee hives in an area can have negative impacts on other, wild pollinators. This may have impacted those people who were persuaded by “Save the Bee” campaigns to take up the hobby, to give up beekeeping.

There could well be other reasons that I’ve not considered and, as always, I’d be interested in your thoughts – please leave a comment below. I’ll finish by saying that I make no judgement on this. There’s no doubt that there are too many hives in some parts of Britain, especially in London, and if the trend I describe reduces the pressures on wild pollinators, that’s a good thing. At the same time, honey bees are important agricultural pollinators in some circumstances, especially where there’s mass-flowering crops that require huge numbers of pollinating bees to be available over a short time period. And I like honey as much as the next person.

Happy World Bee Day to my readers!

*There’s a long-standing suggestion that beekeepers in the post-war years inflated the number of hives that they kept in order to obtain a larger sugar ration.

Biodiversity Net Gain and pollinators: catch up with my talk on YouTube

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Yesterday I delivered a webinar for the Biological Recording Company on the topic of what Biodiversity Net Gain (BNG) could mean for pollinator conservation. It’s a topic that clearly has a lot of resonance for the ecology community: almost one thousand people (994 to be precise) booked to attend, of which 380 actually watched. That’s a fairly typical ratio for free webinars, in my experience – many people book a place in the expectation that they will receive a link to watch the recording later.

The talk was indeed recorded and can be viewed by following this link to YouTube. There was a Q&A session afterwards which is not part of the recording but the questions and my answers have been transcribed and can be viewed on the Biological Recording Company’s blog, together with links to all of the references and data sources that I cited. Here’s the link to the blog.

I had a lot of really positive feedback during and after my talk, plus some extremely useful comments about where my interpretation of BNG was incorrect (or at least didn’t tell the whole story). As I stressed during my talk, BNG is a journey not an end point and we are all at the start of that journey! It’s going to be fascinating and important to see whether BNG can positively impact declining pollinator populations.

Biodiversity Net Gain and pollinators – join me for a FREE webinar next Monday!

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Biodiversity Net Gain is generating a lot of attention in the UK at the moment, some of it positive*:

“when designed and delivered well, BNG can secure benefits for nature, people and places, and for the economy”

“[BNG is] a game-changer for health and wellbeing”

And some of it extremely negative*:

“Biodiversity Net Gain is a lie but most people without enough ecological knowledge cannot see this & are fooled by the lie”

“[BNG is] a horrible legalistic contrivance, and it means nothing”

Regardless of how you feel about BNG, it’s here to stay, at least for the foreseeable future, and so we need to explore it and understand how (or whether) it can positively improve the state of nature in Britain.

Although I don’t pretend to be an expert on BNG**, I have thought a lot about how it might impact the group that I do have some expertise in, pollinators, and the implications for the pollination services that they provide to wild and crop plants.

Last October I produced a short report that considered the implications of BNG for insect pollinators – you can download a copy from the original blog post, though do be aware that some of the dates I mentioned were later revised by the then government and I have yet to revise the document.

As a follow up to this I have been invited by the Biological Recording Company to lead a one-hour webinar discussing this topic on Monday 28th October at 1pm. It’s free to attend and you can book a ticket by following this link. There’ll be a short presentation (30 minutes or so) followed by a live Q&A.

I hope that some of you can join me!

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*Real quotes, culled from reports and social media.

**Indeed, it’s such a new approach to development and nature conservation, can anybody consider themselves an expert?

What are the limits to pollinator diversity? A new article poses the question

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The most globally significant groups of pollinators are well known and have been studied for a long time: bees and wasps, flies, butterflies and moths, birds, bats and beetles are all familiar to those of us with an interest in pollination ecology. However, every few years a new type of pollinator or a novel pollination system is described from nature or from the fossil record, or we add further examples of previously neglected pollinator groups such as cockroaches.

This begs the question: how much is there still to discover? How close are we to describing the full diversity of animals that act as pollen vectors? Can looking at the past help us to predict what we might find in the future? That’s the topic of a Perspective article that I was invited to write for the special issue of the Journal of Applied Entomology on the theme of The Neglected Pollinators that I mentioned last month. It’s a subject that I’ve thought about a lot over the last few decades and it was great to get an opportunity to air some ideas and speculation.

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

Ollerton, J. (2024) What are the phylogenetic limits to pollinator diversity? Journal of Applied Entomology (in press)

Here’s the abstract:

Although huge progress has been made over the past 200 years in identifying the diversity of pollinators of angiosperms and other plants, new discoveries continue to be made each year, especially in tropical areas and in the fossil record. In this perspective article I address the following questions: Just how diverse are the pollinators and what are the phylogenetic limits to that diversity? Which other groups of animals, not currently known to regularly engage with flowers, might be found to be pollinators in the future? Can we predict, from the fossil record and from discoveries in under-researched parts of the world, which animal groups might turn out in the future to contain pollinators? I also discuss why adding to our knowledge of plant–pollinator interactions is important, but also stress that an incomplete knowledge may not be a bad thing if it means that remote, inaccessible and relatively pristine parts of the world remain that way.

A use for invasive Yellow-legged Hornets? – China Diary 4

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The UK media has fueled something of a moral panic over the last couple of years, in relation to the Yellow-legged Hornet (Vespa velutina) which has become established as an invasive species in Europe. It also looks likely to become established in Britain and Ireland, where beekeepers have claimed that it poses “a severe threat to pollinators“. The only study that I know of that’s tested this idea in Britain – by Thomas O’Shea-Wheller, Juliet Osborne, et al. – suggests that the impact on bumblebees, at least, is not as great as feared.

In Asia, where the species originates, they’ve lived with this hornet for centuries and learned to exploit it. On a visit to a recent farmer’s market near Kunming we encountered a local man selling bottles of adult hornets steeped in alcohol, to be used as a liniment. It’s rubbed on arthritic joints and (apparently) soothes the pain.

The guy who was selling the bottles of embrocation had several hornet’s nests on display:

Later, on a trip to Lijiang I also spotted a hornet’s nest on a building, not the usual place you expect to see one:

The other use for hornets is as food – the larvae are apparently quite delicious and very nutritious. This is from a different market and is a different species:

Later on the Lijiang trip we visited a farm that was part of a Yi community, one of the local ethnic minorities. They keep the indigenous honey bees (Apis cerana) in these small hives:

The honey bees pollinate an early-flowering local cherry variety that farmers grow in small orchards. The fruit is extremely small but also extraordinarily sweet:

These ones are past their best though still edible:

Much fresher cherries were being sold in farmer’s markets and at the roadside:

We’re still trying to work out what variety of cherry this is – possibly a landrace of the highly variable Chinese Cherry (Prunus pseudocerasus).

Of course, hornets can be pollinators too, though a study last year of the Yellow-legged Hornet in Spain showed that they negatively impact pollination of ivy in that region. These insects are definitely a cause for concern, though whether their impacts will be as great as some fear remains to be seen.

The mystery of what pollinates poinsettias – China Diary 3

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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.

Aggressive dominance of acacia floral resources by wild East African lowland honey bees – a new study just published

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Back in August 2022, Karin and I traveled to Kenya where I was teaching on a Tropical Biology Association field course at the Mpala Research Centre – see my posts from the time here and here.

Students on the course have to complete an extended group project, with supervision by teaching staff. Two of the groups looked at the visitors to flower heads of one of the dominant savannah acacias and the interactions between wild honey bees of the native subspecies and the other insects. There have been rather few studies of this honey bee in the wild and so we wrote up the work as a short research note that has now been published in the African Journal of Ecology.

The photo above shows the authors – ‘Team Etbaica’ – from left to right: Luis Pfeifer, Swithin Kashulwe, me, Caka Karlsson, and Janeth Mngulwi.

Here’s the reference with a link to the publisher’s site – the paper is open access:

Kashulwe, S., Mngulwi, J. B., Karlsson, C., Pfeifer, L., & Ollerton, J. (2024) Aggressive dominance of acacia floral resources by wild east African lowland honey
bees. African Journal of Ecology 62, e13271. https://doi.
org/10.1111/aje.13271.

Here’s the abstract:

The East African lowland honey bee (Apis mellifera scutellata) is reported as an aggressive subspecies of the Western honey bee, but few studies have investigated the impact of its aggressiveness on other insect pollinators. Observations of flower visitors to Vachellia (Acacia) etbaica and interactions between honey bees and other insects were conducted in 2022 in Mpala, Kenya. A total of 873 individual flower visitors were recorded, the most frequent being Hymenoptera, followed by Diptera and Lepidoptera. Honey bees dominated floral resources in the morning and late afternoon. When honey bees encountered other types of insects, they displaced the latter from flowers 100% of the time. This has never been observed in other Western honey bee subspecies, and we recommend further research on these taxa.

New study just published: The effect of elevation, latitude, and plant richness on robustness of pollination networks at a global scale

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During the 2020 lockdown caused by the COVID-19 pandemic, I coordinated an international network of pollination ecologists who used standardised methods to collect data in their gardens. I blogged about it at the time – see here and here for instance – and also put up a post when the data paper from that work was published.

Several research groups are now working with that huge data set and interrogating it for answers to a wide range of questions. The first group to actually publish a paper from the data is a largely Chinese set of researchers from the Key Laboratory of Plant Resources, Conservation and Sustainable Utilization, at the South China Botanical Garden in Guangzhou, assisted by Kit Prendergast and myself.

In this paper we’ve considered how robust these plant-pollinator networks are to simulated extinctions of species, and how this is affected by the elevation, latitude, and plant species diversity of the network.

Here’s the full reference with a link to the study:

Wang, X.-P., Ollerton, J., Prendergast, K.S., Cai, J.-C., Tong, M.-Y., Shi, M.-M., Zhao, Z.-T., Li, S.-J. & Tu, T.-Y. (2024) The effect of elevation, latitude, and plant richness on robustness of pollination networks at a global scale. Arthropod-Plant Interactions (in press) https://doi.org/10.1007/s11829-024-10056-7

If you can’t access it and need a PDF, please send me a request via my Contact page.

Here’s the abstract:

Plant-pollinator interactions play a vital role in the maintenance of biodiversity and ecosystem function. Geographical variation in environmental factors can influence the diversity of pollinators and thus, affect the structure of pollination networks. Given the current global climate change, understanding the variation of pollination network structure along environmental gradients is vital to predict how global change will affect the ecological interaction processes. Here, we used a global plant-pollinator interaction data collection by the same sampling method at the same period to explore the effects of elevation, latitude, and plant richness on the structure and robustness of pollination networks. We analyzed a total of 87 networks of plant-pollinator interactions on 47 sites from 14 countries. We conducted a piecewise structural equation model to examine the direct and indirect effects of elevation, latitude, and plant richness on the network robustness and analyzed the function of network structure in elucidating the relationship between robustness and these gradients. We found that plant richness had both positive effects on robustness under random and specialist-first scenarios. Elevation, latitude, and plant richness affected network connectance and modularity, and ultimately affected network robustness which were mediated by nestedness under specialist-first and random scenarios, and by connectance under the generalist-first scenario. This study reveals the indirect effects of elevation, latitude, and plant richness on pollination network robustness were mediated by nestedness or connectance depended on the order of species extinctions, implying that communities with different pollination network structures can resist different extinction scenarios.

Reusing Plant-Pollinator Datasets – a free WorldFAIR webinar on 18th April

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A message from Dr Debora Drucker, WorldFAIR Agricultural Biodiversity Case Study Lead:

Registration is open to our contribution to the WorldFAIR webinar series – “Reusing Plant-Pollinator Datasets: a Global Perspective with Guidelines and Recommendations inspired by Pilot Studies from Africa, the Americas and Europe”.

It will be held on April 18 at 2:00 pm – 3:00 pm (Times in UTC) – https://worldfair-project.eu/event/the-worldfair-webinar-series-reusing-plant-pollinator-datasets-a-global-perspective-with-guidelines-and-recommendations-inspired-by-pilot-studies-from-africa-the-americas-and-europe/

We will present results from Deliverables 10.2 & 10.3, with focus on our pilot studies:

Drucker, D., Salim, J. A., Poelen, J., Soares, F. M., Gonzalez-Vaquero, R. A., Ollerton, J., Devoto, M., Rünzel, M., Robinson, D., Kasina, M., Taliga, C., Parr, C., Cox-Foster, D., Hill, E., Maues, M. M., Saraiva, A. M., Agostini, K., Carvalheiro, L. G., Bergamo, P., Varassin, I.; Alves, D. A., Marques, B., Tinoco, F. C., Rech, A. R., Cardona-Duque, J., Idárraga, M., Agudelo-Zapata, M. C., Marentes Herrera, E. Trekels, M. (2024). WorldFAIR (D10.2) Agricultural Biodiversity Standards, Best Practices and Guidelines Recommendations (Version 1). Zenodo. https://doi.org/10.5281/zenodo.10666593

Drucker, D. P., Salim, J. A., Poelen, J., Soares, F. M., Gonzalez-Vaquero, R. A., Devoto, M., Ollerton, J., Kasina, M., Carvalheiro, L. G., Bergamo, P. J., Alves, D. A., Varassin, I., Tinoco, F. C., Rünzel, M., Robinson, D., Cardona-Duque, J., Idárraga, M., Agudelo-Zapata, M. C., Marentes Herrera, E., Taliga, C., Parr, C.S., Cox-Foster, D., Hill, E., Maués, M.M. Agostini, K. Rech, A.R., Saraiva, A. (2024). WorldFAIR (D10.3) Agricultural biodiversity FAIR data assessment rubrics (Version 1). Zenodo. https://doi.org/10.5281/zenodo.10719265

We reserved a good amount of time for Q&A – I hope to see you there and have a nice discussion!