Category Archives: Bees

Project ‘Butterfly’ takes flight in Paris!

At the end of last week I joined researchers from across Europe and beyond who gathered at Norway House on the campus of the Cité Internationale Universitaire de Paris, for the official launch of the EU-funded project ‘Butterfly’. This bold, four-year interdisciplinary initiative is focused on the future of pollinators and the ecosystems that depend on them, and is one of a series of projects that have spun out from the EU’s Pollinators Initiative.

Over two days of lively discussion, the project’s key themes came into focus: the urgent need to restore pollinator populations, the value of integrating ecological and economic data, and the importance of including people—farmers, citizens, policymakers—in shaping practical, long-term solutions to pollinator decline.

Connecting Science and Policy

I arrived in Paris early Wednesday evening to be fresh for the meeting’s opening session the following morning. This set the stage by grounding the project in real-world policy contexts, including the EU Pollinators Initiative and the Nature Restoration Law. These frameworks are increasingly recognising the vital role pollinators play not just in nature, but in the economy and public well-being.

Nine Work Packages, One Mission

Participants got a crash course in the project’s structure through short presentations from each of the nine work packages. These range from ecological modelling and ecosystem valuation to resilience thinking, communication tools, and understanding human relationships with pollinators. A strong emphasis was placed on collaboration—how each work package connects with the others and contributes to the project’s broader vision. For example, one of my roles will be to work closely with Maria Clara Castellanos and her team at the University of Sussex on the integration of the UK-focused Database of Pollinator Interactions (DoPI) and the Global Biotic Interactions (GloBI) platform, to create an online European Atlas of Plant-Pollinator Associations (EuroAPPA). This in turn will feed plant-pollinator data into the modelling and economic valuation tasks in some of the other work packages.

Living Labs and Global Perspectives

One of the most exciting aspects of the Butterfly project is the network of “Living Labs” being established across Europe and the test sites in overseas territories. From Murcia to Martinique, each site represents a unique ecological and cultural landscape with its own pollination challenges. These test sites, some of which are shared with a parallel project called RestPoll, will serve as experimental spaces to co-develop and test strategies for enhancing pollinator resilience in real-world contexts. Another of my roles in the project is to help with the field work on the Caribbean island of Curaçao, where we will be assessing birds and bats as pollinators, as well as insects.

Thematic Sessions and Cross-Pollination

The meeting featured targeted discussion sessions on everything from economic modelling chains and ecosystem indicators to human dimensions like eco-literacy, historical agency, and “slow hope.” Again, one of my contributions will be to the work package dedicated to understanding and reacting to the human dimensions of pollinator decline, where I hope to provide a case study that builds on the work I published almost a decade ago on how the auction prices of holly and mistletoe are a reflection of the work of wild pollinators. In the evening we had a “cross-pollination” networking buffet dinner, themed around pollinator-dependent food crops, that provided an opportunity for participants to mix across disciplines, brainstorm, and spark new collaborations in an informal setting.

Laying the Groundwork for Action

Day two shifted toward practicalities—data sharing, financial management, ethics, and stakeholder engagement—as well as discussions about how Butterfly will connect with other major EU-funded projects, including VALOR, which is Butterfly’s partner and with which we will closely collaborate. Thematic sessions continued to dive deep into topics like mainstreaming pollinator stewardship and developing indicators to track the societal impacts of pollinator loss.

Looking Ahead

The meeting wrapped up with a plenary session with the project’s Advisory Board, reinforcing the importance of external perspectives in guiding the project’s evolution. Dinner that evening was an informal affair (not funded by the project!) at a really wonderful, traditionally French restaurant – Le Temps des Cerises – where service was slow, the food and wine were delicious, and the conversations continued to flow.

For those of us who stayed an extra day, a field visit on Saturday offered a first-hand look at urban pollinator research at the Jardin Écologique within the Jardin des Plantes—a fitting reminder of why this work matters! Here’s some photographs from that trip:

My sincere thanks to all of the colleagues who made the Butterfly kick-off meeting such a success: I look forward to working with you all over the next four years! Particular thanks to Paolo Biella who allowed me to use the photo at the top of the post, of a female mason bee outside our venue. We kept an eye on her during the meeting and I’m pleased to report that she successfully sealed up her nest. May her offspring thrive!

If you’d like to delve deeper into Butterfly’s objectives, here’s the project summary from our funding application:

Butterfly aims to significantly enhance society’s capacity to appraise, foresee, and respond to the threats posed by cascading impacts of pollinator decline. To reach that goal it will establish a test system of geographically well spread multi-actor communities across sectors for co-creating proactive pollinator restoration solutions and: (1) collect, integrate, manage and share ecological and spatial information on a wide range of known and lesser known pollinators and pollination services provided for wild and cultivated plants, across Europe and selected overseas territories; (2) advance the monetary and non-monetary valuation of marketed and not marketed direct and indirect ecosystem functions and services provided by pollinators, and advance ecosystem accounting; (3) comprehensively model and quantify the macro-economic implications of pollinator decline and country-specific economic butterfly effects of dependencies on pollinators, and assess policy options and scenarios; (4) assess how five key biomass supply chains (food/micronutrients, pharmaceuticals, cosmetics, biomaterials, biomass energy) depend on pollination and co-create pollinator restoration options that increase resilience of these supply chains; (5) devise, co-create, test and implement transferable tools, interactive atlases and guidelines that enable systematic mainstreaming of proactive pollinator stewardship in vulnerable sectors; (6) conceive indicators for human dimensions and assess and exploit the socio-cultural capacity of the concepts: ‘pollinator stewardship’, ‘ecoliteracy’, ‘historical agency’ and ‘slow hope’ in reversing pollinator decline. It will inform EU policy processes and build strategic alliances for high-level impact. The Butterfly network of Living Labs will accelerate knowledge transfer and uptake of new business models and serve as breeding place for multi-actor co-creation of knowledge and sustainable solutions, paving the way to pollinator stewardship in all sectors.

Evolutionary implications of a deep-time perspective on insect pollination – a new review just published

What is happening to wild bees in Britain?

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Recently the Bumblebee Conservation Trust (BCT) reported that, in 2024, British bumblebees experienced their worst year since the BCT started its monitoring campaign. Overall, the numbers of bees were down by more than one fifth, with one of our commonest species, the Red-tailed Bumblebee (Bombus lapidarius) declining a staggering 74%! The cause seems to be the cold, wet spring of 2024 and we have to hope that this is a blip that will not be repeated in 2025. So far the year has been cold and I didn’t see my first queen bumblebee flying until early March. But the very warm weather over the last few days has encouraged bumblebees out of hibernation and plants to start flowering.

Long-term monitoring of the type that the BCT undertakes with its volunteers, is vital if we are to understand how British pollinators are faring. When I compiled the evidence for the chapter entitled ‘The shifting fates of pollinators’ in my book Pollinators & Pollination: Nature and Society, I tried to give a global overview, but also focused on British records, which are probably the best long-term data that is available on trends in pollinators. This information is compiled by the Joint Nature Conservation Committee (JNCC) as part of its annual UK Biodiversity Indicators reports. Each year it produces an indicator showing trends in bees, hoverflies, and the two combined as an overall pollinator trend*. To quote the JNCC website:

The indicator is based on 394 species (158 species of bee and 236 species of hoverfly), and measures change in the number of 1 kilometre grid squares across the UK in which they were recorded in any given year: this is referred to as the ‘occupancy index’.

The bee data comes from the Bees, Wasps and Ants Recording Society (BWARS) and the graph of bee trends that I used in that chapter of my book assessed records up until 2017. It looked like this:

As you can see, the index fluctuated a bit but was on average fairly stable up until 2005, after which there was a sharp decline, then an uptick from about 2014, though still low compared to the 1980 baseline. The overall impression is that bees had a tough time from the early 2000s onward, but things seem to be improving.

Since my book came out in 2021 I’ve given a lot of talks to natural history societies, ran training with consultancies and local councils, and so forth. Each year I update the JNCC graphs in my talks to give the audience the latest information. This is the one I used last year, which took the data up to 2019**:

This looks a bit different – the fluctuations are more pronounced – but overall the trend is similar, though the drop after 2015 is worrying. The impression is that there’s been big (cyclical?) fluctuations in the bee index over time, but its generally always below the 1980 baseline.

Updating the story to 2022 (the most recent available) shows a very different picture:

The impression it gives is that there’s been some modest fluctuations in the bee index, but then from about 2013 onward, the index has massively improved and now wild bees are doing better than ever!

What’s happening here? Why are these three graphs – published over a period of about five years – giving such different impressions of what’s happening to wild bees in Britain? As far as I can tell there’s two main reasons for the changes. The first is that the number of bee species included in the index increased from 137 to 148 to 158. Adding species for which there was previously no or little data is clearly going to have an effect.

The second reason, perhaps more fundamental, is that the method used for calculating the index has been refined, as explained in the technical annex to the study. That’s important because the data underlying the bee index was never collected in a standardised way for the purposes of assessing species’ trends. For this reason the UK Pollinator Monitoring Scheme (PoMS) was developed and it’s interesting to see that the data in the latest PoMS report shows some stability in wild bee abundance from 2017 to 2022:

So the latest data suggests that, for once, there’s some good news in the world of British wildlife. Does this mean that we should be complacent about the state of our wild bees? Absolutely not! As always, the devil’s in the details. The BCT report that I cited at the start of this post provides one level of (worrying) detail. But another is provided by the JNCC’s own statistics. As well as showing the overall trend in the bee index, the analysis digs into what is happening for individual species and provides a helpful summary figure like this:

Clearly many species are doing well, or at least have not changed since the 1980s. But more than one quarter of British wild bees are showing a weak or strong decline over the long term. That’s a clear signal that we need to keep on with our efforts to support wildlife and enhance our strategies to improve the state of nature in Britain.

As always, feel free to comment on the post or get in touch via my Contact page.

My sincere thanks to all of the volunteer naturalists who collect the data used by JNCC and PoMS – the task of assessing trends in wildlife would be impossible without your commitment!

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*Why JNCC does not include butterflies – which are assessed separately – in this overall trend is unclear to me, as we know that they can be important pollinators for some plants – see my blog post: ‘Butterflies, bumblebees and hoverflies can be equally effective pollinators of some plants says a new study‘.

**The data in the JNCC report is always a couple of years behind the publication date.

How urban spaces support pollinators – a new study just published

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Bees play a vital role in pollination, supporting both natural ecosystems and our food supply. However, their numbers are declining globally due to multiple threats—including urbanisation. As cities expand, understanding how different habitats within urban areas affect pollinator populations is crucial for conservation efforts and for supporting urban and peri-urban agriculture. It’s a topic to which I devoted whole chapters in my books Pollinators & Pollination: Nature and Society and Birds & Flowers: An Intimate 50 Million Year Relationship.

The latest paper from Muzafar Sirohi‘s PhD thesis has just been published in the journal Urban Ecosystems. It follows on from his two other recent papers on plant–bee interactions and resource utilisation and how the timing of emergence of solitary bees varies between urban and non-urban settings.

This element of Muzafar’s work explored how solitary and primitively eusocial bees (those that live alone or in simple social groups) respond to different aspects of city landscapes. He examined local habitat factors such as floral diversity, bare soil availability, and sunlight exposure, alongside broader urban features like green spaces, roads, and paved areas.

The findings highlight that small-scale habitat conditions—especially the variety of flowering plants and access to sunlight—had a greater influence on bee diversity and abundance than overall habitat size. While larger landscape features, such as urban green spaces, played a role at a broader scale, even small patches of wild vegetation and roadsides were found to be important for bees.

These results challenge the idea that bees need large, uninterrupted green spaces to thrive. Instead, even fragmented urban habitats, when managed thoughtfully, can support pollinators. By planting diverse flowers, preserving patches of wild vegetation, and maintaining sunlit areas, cities can become havens for these essential insects.

Simple changes—like creating wildflower-rich roadside verges or maintaining natural pockets of greenery—can make a significant difference. As urbanisation continues, ensuring that bees have the resources they need to survive will be key to supporting biodiversity and maintaining the critical pollination services they provide.

Here’s the reference with a link to the published study; if you are not able to access it, send me a request for a PDF via my Contact page:

Sirohi, M.H., Jackson, J. & Ollerton, J. (2025) Influence of urban land cover and habitat quality on wild bees. Urban Ecosystems 28:78 – https://doi.org/10.1007/s11252-025-01687-6

Here’s the abstract:

Solitary and primitively eusocial bees are important pollinators of plants, which are experiencing a global decline. Urbanisation is one of the contributing factors to this decline. It is crucial to understand the complex community dynamics of solitary and primitively eusocial bees in urban areas as urbanization grows globally. For bee communities, the local habitat as well as the surrounding urban landscape play an important role. The study considered four local habitat variables: habitat size, floral species richness, bare soil and shade. Moreover, five common land cover types (green space, buildings, roads, car parks, and paved surfaces) were assessed at multiple spatial scales from 40 m to 200 m from the centre of the sites with 20 m steps, analysing their potential impacts on the bee community. The study found a greater effect of local habitat compared to landscape variables at a smaller spatial scale. However, landscapes affected the bee community at larger spatial scales. The size of the habitat did not affect the bee community in urban areas. However, habitats with a higher number of plant species and exposed to sunlight attracted relatively more bees. This study suggests that urban areas are capable of conserving solitary and primitively eusocial bees. Although green space is important for the dispersal of species at larger landscape scales, small patches of wild, leftover vegetation and roadsides are equally important for bees. The management of bee friendly open vegetation with wildflowers would be beneficial for the successful conservation of solitary and primitively eusocial bees in urban areas.

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!

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

The diverse nature of ‘nature writing’: in conversation with Jack Cornish and Ben Masters – 5th October

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Why do authors write about ‘nature’? What are their motivations and how did they start their writing journey? Do they even recognise this label of ‘nature writer’?

These are just some of the questions I’ll be exploring with two other authors at the Market Harborough Book Festival on Saturday 5th October.

Jack Cornish is author of The Lost Paths, an exploration of the ancient pathways that have criss-crossed England and Wales since prehistoric times, the peoples who made them, and the landscapes through which they currently run. It’s a reminder of ‘just how precious these paths are, and have been, to the human story of this island’. I’ve only just started The Lost Paths, but what I’ve read so far is wonderful. Check out this recent review on The Great Outdoors site.

Ben Masters’ most recent book is The Flitting, an account of the final months of his relationship with his late father, a keen natural historian with a devotion to butterflies, and how they come to share ‘passions, lessons and regrets as they run out of time’. There’s a nice review of The Flitting by Mark Avery on his blog, and I have to agree with him, it’s a lovely book.

Coincidentally, earlier this year Mark wrote a review of the book that I will be discussing, my recent Birds & Flowers: An Intimate 50 Million Year Relationship, though I may also dip into Pollinators & Pollination: Nature and Society, because there’s at least one thing that unites the three of us as writers: a love of the poet John Clare! Ben discusses him at length in The Flitting, and indeed Clare provided the title of the book. Likewise, Jack name checks Clare in The Lost Paths, and I used the poet as the jumping off point for a couple of explorations of the importance and conservation of bees and other pollinators.

As well as discussing our roles as ‘nature writers’ we’ll be reading extracts from our books and answering audience questions. There will also be an opportunity to buy personally signed copies of our books. We look forward to seeing you there!

Butterflies, bumblebees and hoverflies can be equally effective pollinators of some plants says a new study

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Just after I arrived in Northampton in 1995, I set about looking for suitable local sites for conducting pollination ecology field work for myself and students. The campus on which we were situated at the time was adjacent to an urban park – Bradlaugh* Fields – parts of which were designated as local nature reserves. In the intervening years, data from that area have made their way into a wide range of published studies, including:

I still have data collected during that time that have never been published, but good data are hard won and they may see the light of day at some point. Case in point is that we’ve just published a paper based on data from Bradlaugh Fields, the first of which were collected in 2001!

In this paper we’ve tested how effective hoverflies, butterflies and bumblebees are at pollinating the flowers of a common generalist grassland plant, colloquially called Field Scabious (Knautia arvensis). The expectation was that bumblebees, being generally larger, hairier and more flower-focused than the other groups, would be the most effective at transferring pollen to stigmas. To our surprise, they were not: hoverflies and butterflies performed just as well! In fact we argue that butterflies may be MORE important as pollinators of this plant because they fly further distances between individual plants, rather than hopping between the inflorescences of the same plants, as bumblebees tend to do.

Crucially, the importance of these different groups of pollinators varies enormously as the relative abundance of the insects visiting the flowers differs between seasons. In some years butterflies dominate as pollinators, in other years bumblebees or hoverflies. This is driven, we think, both by fluctuations in the populations of these insects and by the availability of other, more preferred flowers that may bloom at the same time.

The paper is part of a special issue of the Journal of Applied Entomology devoted to The Neglected Pollinators. It’s open access and you can download a copy by following the link in this reference:

Ollerton, J., Coulthard, E., Tarrant, S., Woolford, J., Ré Jorge, L. & Rech, A.R. (2024) Butterflies, bumblebees and hoverflies are equally effective pollinators of Knautia arvensis (Caprifoliaceae), a generalist plant species with compound inflorescences. Journal of Applied Entomology (in press)

Here’s the abstract:

Plant-pollinator interactions exist along a continuum from complete specialisation to highly generalised, that may vary in time and space. A long-held assumption is that large bees are usually the most effective pollinators of generalist plants. We tested this by studying the relative importance of different groups of pollinators of Knautia arvensis (L.) Coult. (Caprifoliaceae: Dipsacoideae). This plant is suitable for such a study because it attracts a diversity of flower visitors, belonging to different functional groups. We asked whether all functional groups of pollinators are equally effective, or if one group is most effective, which has been documented in other species with apparently generalised pollination systems. We studied two subpopulations of K. arvensis, one at low and one at high density in Northampton, UK. To assess pollinator importance we exposed unvisited inflorescences to single visits by different groups of pollinators (butterflies, bumblebees, hoverflies and others) and assessed the proportion of pollinated stigmas. We then multiplied the effectiveness of each pollinator group with their proportional visitation frequency in five different years. For each group we also compared time spent on flowers and flight distance between visits. The relative importance of each pollinator group varied between years, as did their flight distances between flower visits. Butterflies were the best pollinators on a per visit basis (in terms of the proportion of stigmas pollinated) and flew further after visiting an inflorescence. Different measures and proxies of pollinator effectiveness varied between taxa, subpopulations, and years, and no one group of pollinators was consistently more effective than the others. Our results demonstrate the adaptive value of generalised pollination strategies when variation in relative abundance of different types of pollinators is considered. Such strategies may have buffered the ability of plants to reproduce during past periods of environmental change and may do so in the future.

*Named after the estimable local MP and radical Charles Bradlaugh – see my blog post When Charles collide: Darwin, Bradlaugh, and birth control for Darwin Day 2016

Urban bees are often early bees says a new study

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The latest paper from Muzafar Sirohi‘s PhD work on urban solitary bees has just been published in the journal Zoodiversity, a publication of the National Academy of Sciences of Ukraine. In this paper we looked at how the flight periods of urban populations of bees differ from those in surrounding nature reserves and other “natural” settings. One of the most interesting findings is that urban bees tend to emerge earlier, and be active longer, than their rural counterparts. The quote the study:

“We observed a substantial effect of urban microclimate on bee flight periods. A total of 153 individuals of nine bee species were recorded one to nine weeks before or after their expected flight periods. In contrast, only 14 individuals of four species were seen at unusual flight periods in nature sites.”

In my book Pollinators & Pollination: Nature and Society I discussed the importance of towns and cities for supporting pollinator populations, and conversely how important those populations are for urban food production. Likewise, in Birds and Flowers: An Intimate 50 Million Year Relationship I have a chapter entitled “Urban flowers for urban birds”. The relationship between our built environment and pollinators is a fascinating topic, but there’s still much we don’t understand about how these insects and vertebrates respond behaviorally to urbanisation. Are they adapting in an evolutionary sense, or simply responding flexibly to the different conditions that cities impose on their biologies? Will future climate change make towns and cities uninhabitable for these animals? Hopefully our paper will stimulate further work on these and other topics.

Here’s the full reference with a link to the paper (which is open access):

Sirohi, M. H., Jackson, J., & Ollerton, J. (2024). Comparison of Flight Periods of Solitary and Primitively Eusocial Bees in Urban Environments and Nature Conservation Areas: a Preliminary Report. Zoodiversity 58: 317-334

Here’s the abstract:

Solitary and primitively eusocial bees, an important group of pollinators, have declined in the past few decades. In view of the recent focus on safeguarding pollinating insects, it is vital to understand the basic ecology of species for their conservation, for example their phenologies. We observed the flight periods of solitary and primitively eusocial bees in both the urban core of a large British town and nearby nature conservation areas. The bee surveys were conducted with standardised methods, on warm sunny days from the first appearance of bees in March 2012 and continued until October 2012. This study confirmed that a high number of species are active in the spring season. The emergence dates of species in urban areas and nature sites varied; about 26 of the 35 species were recorded at least one week earlier in urban areas; in contrast, only four species were seen earlier in nature conservation sites. When comparing this with the expected flight periods recorded (largely in nature sites) in the literature, many species were recorded at their expected time. However, a few individuals were recorded after their usual flight activity time, suggesting that the populations were possibly affected by the microclimate in urban areas. More urban phenological data are needed to understand the phenological trends in bees in urban habitats.