Tag Archives: Pollinators

What China’s mountain meadows and forests can teach us about pollinators

For several years now I have been fortunate to collaborate with colleagues in China on the ecology of plant–pollinator interactions. One of the things that makes that work so exciting is the sheer variety of landscapes in which these interactions play out. In a newly published paper led by Dr Xin Xu, we have studied pollination networks on Yulong Snow Mountain in Yunnan, in south-west China, a place where forests and flower-rich meadows sit side by side in a spectacular high-elevation environment.

The question we asked was simple enough: how do these adjacent habitats – woodland and grassland – differ in the way that plants and pollinators interact? But answering it required a huge amount of field effort. Over two flowering seasons, the team recorded more than 11,000 interactions between 229 pollinating insect species and 89 flowering plant species. That is an extraordinary reminder of how much ecological complexity can be packed into a relatively small area of mountain landscape.

What emerged was a very clear pattern. The open meadows supported far more activity than the neighbouring forests: more visits, more pollinator species, more plant species, and more interaction links. In fact, nearly 9,700 of the recorded interactions took place in meadow habitat, compared with about 1,365 in forest. Meadows were especially important for bumblebees, which are among the key pollinators in these cool, high-elevation systems.

But the forests were not simply poor relations. They supported their own distinctive subset of the wider pollinator community, and the network of interactions there was structured differently. Some pollinator species altered their daily foraging schedules depending on whether they were in meadow or forest, suggesting that they are responding flexibly to changes in light, temperature, floral resources, and perhaps competition. That is one of the aspects of pollination ecology that fascinates me most: these are not static systems, but living networks that shift across space and time.

More broadly, the study reinforces something that has become increasingly clear from ecological research: habitat heterogeneity matters. A landscape made up of different, connected habitat types can support a richer and more resilient community than one that is uniform. On Yulong Snow Mountain, the meadows seem to act as hotspots of pollinator diversity, while the forests add further complexity and help shape how those pollinators behave. Conserving that mosaic is therefore likely to be crucial if we want to maintain pollination services and biodiversity in mountain regions facing rapid environmental change.

For me personally, this paper is also a reminder of why international collaboration is so valuable. Working with Chinese colleagues has opened a window onto ecological systems that are both scientifically important and visually stunning. Yunnan is one of the world’s great biodiversity regions, and studying pollination there helps us understand not only how these mountain ecosystems function, but also how species interactions may respond to climate change and habitat alteration in the future.

Pollination ecology is about more than just bees, birds, or other animals visiting flowers. As a focus of study, it is much richer. It is about networks of interactions, about the timing of activity through the day, about the way species respond to different habitats, and about how whole ecosystems are stitched together. High on a Chinese mountain, among meadows and forests, we can see that complexity in action.

Here’s the full reference:

Xu, X., Maruyama, P.K., Ollerton, J., Wang, H. & Ren, Z.-X. (2026) Spatio-temporal variation in plant–pollinator networks between adjacent meadow and forest habitats in a high-elevation environment. Oecologia (in press)

Here’s the abstract:

Understanding how habitat heterogeneity influences the structure and stability of ecological networks is critical for predicting ecosystem responses to environmental change. In alpine ecosystems, open meadows and forests represent contrasting habitats with distinct vegetation structures, resource availability, and microclimatic conditions. In this study, we integrated spatial and temporal data on pollinator-plant interactions to investigate network structure, species roles, and diurnal foraging dynamics across meadow and surrounding forest habitats during two flowering seasons on Yulong Snow Mountain, Yunnan, China. A total of 11,094 plant–pollinator interactions were recorded, involving 229 pollinator and 89 flowering plant species. Meadows supported significantly higher interaction frequencies, species richness, and α-diversity for both plants and pollinators, although they showed a striking numerical dominance of a single key pollinator, Bombus friseanus. Network dissimilarity analyses revealed substantial differences between habitats, with both species turnover and rewiring contributing to interaction dissimilarity. Diurnal foraging dynamic analysis revealed that some key species, such as Bombus lepidus, displayed distinct foraging patterns across habitats indicating behavioral adaptation and temporal niche partitioning to microclimate. Our findings highlight the strong influence of habitat type on pollination network architecture and reveal many shared pollinator species, indicating some degree of cross-habitat linkage. These results underscore the importance of habitat heterogeneity and spatial coupling in shaping pollination services and sustaining biodiversity in mountain ecosystems under environmental change.

Join me for two webinars exploring the links between biodiversity, pollinators and the UN Sustainable Development Goals

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The diversity of life on Earth, and the interactions between the species that make up that diversity, are fundamentally important to the functioning of ecosystems and to human well-being. Yet these connections are often poorly appreciated, despite the fact that biodiversity supports everything from food production and clean water to climate resilience and human health.

At the end of March and the end of May I will be presenting two lunchtime webinars which explore this as part of the Biological Recording Company’s Skills for Ecology series. These talks will look at how biodiversity in general, and plant–pollinator interactions in particular, connect to the United Nations Sustainable Development Goals (UN SDGs), showing why the conservation of nature is central to a just, healthy, and sustainable future.

Here are the dates and the links for booking:

I look forward to seeing some of you there!

Join me on 26th February in Leicester for a talk: “Adventures in Pollination!”

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On Thursday 26th February I’m giving a talk to the Friends of the University of Leicester Botanic Garden with the title that you see above.

The talk starts at 7.30pm and non-members are welcome to attend, for a donation of £2 (which sounds like a bargain to me!) I’ll also have copies of my books Pollinators & Pollination: Nature and Society and Birds & Flowers: An Intimate 50 Million Year Relationship for sale.

More details can be found here:

https://le.ac.uk/botanic-garden/friends-of-the-garden

I hope to see some of you there!

As you might have guessed, the image above was generated by my personal tool with collaborator-like affordances – blame it for any biogeographical errors!

Pollinators and politics in China

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Last week I returned from a 14 day visit to China to colleagues at the Kunming Institute of Botany in Yunnan, part of a three-year commitment to working there that I documented on the blog last year, starting here. Some of my recent trip involved a long weekend in the city of Nantong, just north of Shanghai, where I was an invited speaker at the International Pollinator Insect Biology and Pollination Symposium. During a full day of talks from researchers and practitioners, via the excellent simultaneous interpretation service provided by the organisers, we learned about recent developments in the world of Chinese honey bees and wild pollinators. There were also international guest speakers from Australia, Argentina, and the UK, in person and online.

Too much was presented to give you a full account of the meeting – if you’re interested in details I’ve uploaded a copy of the English version of the symposium brochure here – but several themes emerged that I think are worth noting.

First of all, a number of speakers commented on the growing realisation in China that the value of crop pollination services by honey bees (both the native Asian Apis cerana and the European A. mellifera) far outweighs the value of the hive products such as honey, wax and royal jelly – see this from the 2021 study by Shibonage K Mashilingi and colleagues:

The total economic value of pollination amounted to US$ 106.08 billion in 2010, representing 19.12% of the total production value of Chinese agriculture

In comparison, the global honey market was valued at just US$ 9.01 billion in 2022. That such an understanding of the much greater economic value of pollinators to agriculture was relatively slow in coming is perhaps not surprising – it’s easier to weigh a physical product than it is to assess the contribution of bees and other insects to an apple harvest, for instance. But this awareness is a crucial step towards understanding the many reasons why pollinators need protection.

Which leads me to my next point: there was considerable political interest in the conference and in the topic more broadly. The meeting opened with almost an hour of introductory remarks by high-ranking Chinese officials, including the Vice Mayor of the regional government, the Vice President of the Chinese Academy of Agricultural Sciences, and the Secretary General of the Ministry of Agriculture and Rural Affairs of China. All of them commented on the importance of pollination to both crops and wild plants, and the need to reduce the amount pesticides being used in Chinese agriculture. I can’t recall ever being in a pollination symposium in any other country where there was such a political presence. I think that it says a lot about the Chinese willingness to translate science and technology into government policy and actions.

At the end of the opening session I had the chance to talk briefly with Liu Jian, former Vice Minister of Agriculture and Rural Affairs of China. Via an interpreter we agreed on the importance of pesticide reduction for protecting pollinators, a theme he had emphasised strongly in his talk, and I presented him with a copy of my book Pollinators & Pollination: Nature and Society:

Following the opening addresses there was a talk by the President of the Apicultural Science Association of China, Prof. Peng Wenjun, who gave us “An overview of the development of China’s bee pollination industry”. He described pollinators as the “invisible pillar” of agriculture, which is a wonderful phrase, and set out a strategy for greater integration of government policies, science, and technological innovation in order to support both managed and wild pollinators.

The first set of talks ended about 6pm, then it was back to the hotel for a quick dinner, before returning to the venue for a set of 15 shorter, but no less excellent, talks by postgraduate and postdoctoral researchers. This over-ran slightly and finally drew to a close at about 10pm, signalling the end of a very long, but very stimulating, day.

The following morning we were up early for a tour of some local agricultural facilities, including a high-tech glasshouse demonstration project and a loquat orchard that included trees which are thought to be around 300 years old. The thing that links these two contrasting agricultural systems is the requirement for managed pollinators to produce a crop: bumblebees (Bombus spp.) in the case of glasshouse tomatoes and the Asian honey bee (Apis cerana) for the winter-flowering loquat. Here are some photographs from that trip:

My sincere thanks to the organisers of the symposium for the invitation to speak and to my colleagues Zong-Xin Ren, Scarlett Howard, Yuansheng Fu, and Carlos Matallana-Puerto for their companionship on the trip. I’m grateful also to our personal translator-guides Yang and Gao who surprised us at the airport and made us feel so welcome:

Pollinators need more space and 10% habitat is not enough says a new study just published in Science

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Pollinators such as wild bees, butterflies, and hoverflies are in trouble worldwide. A major new study, published in Science and led by Gabriella Bishop and other scientists at Wageningen University & Research, shows that the oft-quoted figure of 10% semi-natural habitat in farmland landscapes is far too little to safeguard pollinators. Instead, the evidence points to a need for somewhere between 16% and 37% habitat cover, depending on the type of pollinator, if we are serious about halting declines. Suitable habitats include hedgerows, patches of woodland, species-rich grasslands, and flowering margins, and as a general rule, hoverflies need less of it whilst bumblebees and butterflies require more.

I was fortunate to play a part in this global assessment, contributing an unpublished dataset collected with my former PhD student, Sam Tarrant, who studied plant-pollinator interactions on restored landfill and established grassland sites. Seeing those data joined with dozens of other studies from around the world underlines something we have known for years: no single dataset, however carefully gathered, can give us the whole picture. To really understand what is happening to biodiversity—and to design conservation solutions that work—we need these kinds of global, mega-author syntheses that draw together evidence from many landscapes, taxa, and approaches.

The message from this analysis is stark but hopeful. More habitat means more pollinators, across all groups. Richer habitats with abundant flowers give an additional boost, but the overriding priority must be to increase the sheer area of natural habitat in farmed landscapes. Small-scale fixes like wildflower strips offer short-term benefits, but without enough space they can’t deliver recovery at scale. Long-term, secure habitat creation—on the order of decades, not seasons—is what pollinators, farmers, and ecosystems need.

Although the policy debate in Europe provided the backdrop for this study, the lessons (and the data) are global. Wherever agriculture dominates, the health of pollinator populations—and by extension our food security and biodiversity—depends on our willingness to give these insects the space and quality of habitat they require.

Looking ahead, we need to think bigger and work together. That means more international collaborations, more sharing of data, and more commitment to long-term solutions that transcend borders. The image at the start of this post is from my trip back to China in July this year. I deliberately chose it because, as you’ll see from the map below which is taken from the paper, there was no suitable data available for the study from that country. Or from Africa. Or Australasia. Or from most of tropical South America. That shows that as pollination ecologists we need to coordinate more in advance on these types of syntheses, and maximise the value of the kinds of data that we collect. The main take away from this study, however, is that if we want to reverse the declines in biodiversity, scientists, policymakers, businesses, farmers, and citizens all have a role to play. Pollinators remind us that nature is interconnected and global—our conservation efforts must be, too.

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

Bishop, G.A., Kleijn, D., Albrecht, M., Bartomeus, I., Isaacs, R., Kremen, C., Magrach, A., Ponisio, L.C., Potts, S.G., Scheper, J., Smith, H.G., Tscharntke, T., Albrecht, J., Badenhausser, I., Åström, J., Báldi, A., Basu, P., Berggren, N., Beyer, N., Blüthgen, R., Bommarco, B.J., Brosi, H., Cohen, L.J., Cole, K.R., Denning, M., Devoto, J., Ekroos, F., Fornoff, B.L., Foster, M.A.K., Gillespie, J.L., Gonzalez-Andujar, J.P., González-Varo, J.P., Goulson, D., Grass, I., Hass, A.L., Herrera, J.M., Holzschuh, A., Hopfenmüller, S., Izquierdo, J., Jauker, B., Kallioniemi, E.P., Kirsch, F., Klein, A.-M., Kovács-Hostyánszki, A., Krauss, J., Krimmer, E., Kunin, B., Laha, S.A.M., Lindström, Y., Mandelik, G., Marcacci, D.I., McCracken, M., Monasterolo, L.A., Morandin, J., Morrison, S., Mudri Stojnic, J., Ollerton, J., Persson, A.S., Phillips, B.B., Piko, J.I., Power, E.F., Quinlan, G.M., Rundlöf, M., Raderschall, C.A., Riggi, L.G.A., Roberts, S.P.M., Roth, T., Senapathi, D., Stanley, D.A., Steffan-Dewenter, I., Stout, J.C., Sutter, L., Tanis, M.F., Tarrant, S., van Kolfschoten, L., Vanbergen, A.J., Vilà, M., von Königslöw, V., Vujic, A., WallisDeVries, M.F., Wen, A., Westphal, C., Wickens, J.B., Wickens, V.J., Wilkinson, N.I., Wood, T.J., Fijen, T.P.M. (2025) Critical habitat thresholds for effective pollinator conservation in agricultural landscapes. Science 389: 1314-1319

Here’s the abstract:

Biodiversity in human-dominated landscapes is declining, but evidence-based conservation targets to guide international policies for such landscapes are lacking. We present a framework for informing habitat conservation policies based on the enhancement of habitat quantity and quality and define thresholds of habitat quantity at which it becomes effective to also prioritize habitat quality. We applied this framework to insect pollinators, an important part 5 of agroecosystem biodiversity, by synthesizing 59 studies from 19 countries. Given low habitat quality, hoverflies had the lowest threshold at 6% semi-natural habitat cover, followed by solitary bees (16%), bumble bees (18%), and butterflies (37%). These figures represent minimum habitat thresholds in agricultural landscapes, but when habitat quantity is restricted, marked increases in quality are required to reach similar outcomes.

A new review gives us a deeper understanding of the evolution of plant-pollinator interactions

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If you’ve read my book Birds & Flowers: An Intimate 50 Million Year Relationship, you’ll know that I spend a few pages discussing the long-standing paradigm of how interactions between plants and their pollinators evolve and result in the formation of new plant species. This is referred to as the Stebbins (or Grant-Stebbins) Most Effective Pollinator Principle (MEPP). The MEPP is fairly straightforward and intuitive: flowers evolve their colour, shape, scent, rewards, and so forth as adaptations to the type of flower visitor that successfully moves the most pollen between flowers.

However, the MEPP is not the only Principle in town – there’s also Aigner’s Least Effective Pollinator Principle (LEPP) which is not so intuitive. In the LEPP, flowers can adapt to pollinators that are less successful at pollination, as long as those adaptations do no interfere with the pollination services provided by other flower visitors.

As I note in Birds & Flowers, we don’t know which of these Principles is more frequent in nature, because the LEPP has been much less intensively studied than the MEPP. That’s in part because it’s less well known, but also because the field work and experimental procedures required to test the LEPP are much more challenging.

Hopefully this is about to change with the publication of a brilliant critical review of the MEPP by pollination ecologists Kathleen Kay and Bruce Anderson published in the journal Annals of Botany, entitled: Beyond the Grant–Stebbins model: floral adaptive landscapes and plant speciation. The paper is open access – follow that link and you can download a copy.

Kathleen and Bruce discuss not just the MEPP v the LEPP, but also other ways in which flowers can evolve, framed around the idea of floral evolution as movement across an “adaptive landscape,” where plants are not shaped only by one pollinator but by the need to maximise overall reproductive success. This perspective allows us to explore how flowers evolve when influenced by multiple pollinators, how transitions between floral forms take place, and how speciation occurs through a combination of factors beyond pollination alone. It emphasises that pollinators are important drivers of floral change, but speciation is more likely when divergence happens across several aspects of a plant’s ecology, not just through its flowers.

It’s a great review and well worth your time reading in detail. Perhaps my favourite line in the paper comes from the abstract: “The Grant–Stebbins model, while inspiring decades of empirical studies, is a caricature of pollinator-driven speciation and explains only a limited range of adaptive outcomes.” This is something that many of us have been arguing for years: the natural world is extremely complex, so we should not expect these ecologically critical interactions between flowers and their pollinators to have simple origins or ecologies.

Join me for a “Birds & Flowers” talk in Cambridge on the 12th September!

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If you are in or around Cambridge next week, I’m giving a talk on Friday 12th September at the Cambridgeshire Bird Club about my recent book Birds & Flowers: An Intimate 50 Million Year Relationship.

The event takes place in the Wilkinson Room, St. John’s Church, Hills Road. Doors open at 7pm and the talk begins at 7.30pm. There’s a £2.00 charge for non-members – more details can be found by following this link.

I’ll bring copies of both Birds & Flowers and Pollinators & Pollination: Nature and Society, if anyone wants to buy a signed book.

I hope to see you there!

(Bee) Sex in the city: a new study shows how urban life skews pollinator populations

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Bees are among the most important pollinators in the natural world, quietly sustaining ecosystems and food production. While honeybees often steal the spotlight, a vast number of solitary and primitively eusocial bees play equally vital roles. But across both urban and natural landscapes, many of these species are facing worrying declines.

As cities expand, they’re increasingly being seen not just as threats to biodiversity, but as potential refuges for pollinators. Yet urban environments are very different from natural ones. The heat generated by buildings and concrete – known as the urban heat island effect – and the way green spaces are managed (often with little consideration for flowering plants) could be affecting bees in ways we’re only beginning to understand.

As part of a recent study led by my former PhD student Muzafar Sirohi, we explored how urban conditions might be influencing the timing of bee emergence and the sex ratios of different species. This work formed part of Muzafar’s PhD research, and I was pleased to be part of the team that supported and collaborated on the project.

We found that several solitary bee species were producing females before males – a reversal of the more typical pattern known as ‘protandry’, where males emerge first. Most bees in the families Apidae and Megachilidae did follow the usual male-first pattern, but there were some interesting exceptions, including Nomada marshamella and Nomada fabriciana. Soil-nesting species also showed a lot of variation in emergence timing, likely influenced by microclimatic differences in urban soils.

When we looked at overall sex ratios, patterns varied across bee families. In Halictidae, females were more common, whereas Apidae and Megachilidae were skewed towards males. Interestingly, the Colletidae family showed no strong bias either way. However, in five species from the Andrenidae and Halictidae families, we saw a clear difference between urban and natural environments: urban populations had a higher proportion of males.

This could suggest that urban habitats – especially those with limited floral resources due to mowing, paving, or the removal of wild plants – may not be supporting as many female bees. Since females are the ones responsible for nest-building and potentially pollination, as they visit more flowers, this imbalance could have long-term effects on bee populations and the pollination services they provide.

Our study adds to the growing body of evidence that urban environments can support pollinators – but only if managed thoughtfully. Cities need more than just green space: they need flowering plants, nesting habitats, and careful planning that recognises the delicate balance of bee ecology. With the right actions, we can make urban areas part of the solution to pollinator decline.

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

Sirohi, M.H., Jackson, J. & Ollerton, J. (2025) Sex ratios and sex-biased emergence of solitary and primitively eusocial bees in urban settings and nature conservation areas. Ethology Ecology & Evolution (in press)

Here’s the abstract:

Solitary and primitively eusocial bees are essential pollinators of plants. However, recent observations indicate a decline in their populations in both urban and natural environments. Urban areas are increasingly recognized as potential habitats for bee conservation. Nonetheless, these urban habitats can influence the taxonomic and functional diversity of bee populations. Therefore, we hypothesize that the distinctive warmer climate of urban areas – resulting from the urban heat island effect – along with the potential scarcity of floral resources, contributes to shifts in emergence patterns and the sex ratio of solitary and primitively eusocial bees. We found that many solitary bee species produced females before males. Additionally, most species within the Apidae family were recorded as protandrous, with the exceptions of Nomada marshamella and Nomada fabriciana. All species of Megachilidae were found to be protandrous. We also observed significant variation in the emergence patterns of soil-nesting species. Notably, we did not find any relationship between sociality and nesting preferences in relation to sex-biased emergence. The overall sex ratio varied among different bee species and families. In Halictidae family, sex ratios were biased towards females, while the Apidae and Megachilidae families exhibited a skewed ratio towards males. The sex ratio in the Colletidae family did not show any significant difference. However, among the Andrenidae and Halictidae families, we identified five species with significantly different sex ratios between urban and nature areas, with a higher proportion of males observed in urban sites. This suggests that these species may have been affected by limited food resources, potentially due to urban management practices such as the removal of floral resources. This could lead to increased competition for resources among the species.

Join me for this event in Market Harborough on Wednesday night!

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All the details that you need are on the poster.

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

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When we think of pollination, we often picture bees buzzing around flowers or butterflies flitting from bloom to bloom. This relationship between plants and pollinators is one of the most well-known interactions in nature. But insect pollination didn’t begin with the colorful flowers we see today. In fact, pollinators were at work millions of years before flowering plants (angiosperms) even existed. In a new review led by Spanish researchers David Peris and Ricardo Pérez-de la Fuente, to which I added a modern ecological perspective, we explored this topic and why it’s relevant to our current understanding of plant-pollinator relationships.

Despite centuries of research on pollination, the fossil record of pollinating insects has only gained serious attention in the past few decades. What palaeontologists have uncovered is reshaping our understanding of pollination’s origins. It turns out that insects were pollinating plants long before flowers evolved—playing a crucial role in the reproduction of ancient gymnosperms, the group of seed-producing plants that includes conifers, cycads, and ginkgos.

Most people assume that insect pollination began with flowering plants, but the evidence tells a different story. Fossilised insects with specialised body structures for carrying pollen—such as hairy bodies or mouthparts adapted for nectar-feeding—have been found in deposits dating back hundreds of millions of years. These early pollinators likely visited gymnosperms, helping them reproduce in a world that looked vastly different from today’s landscapes.

Ancient pollination was driven by a diverse range of insects, many of which are now extinct. The fossil record reveals that various insect groups—including beetles, flies, wasps, and even some long-lost relatives of modern lacewings—were already acting as pollinators long before the first flower bloomed. This means that pollination as an ecological process has far deeper evolutionary roots than many realise.

As plants evolved, so did their pollinators. The rise of flowering plants during the Cretaceous period (around 100 million years ago) transformed pollination systems, leading to the incredible diversity of plant-pollinator relationships we see today. Many of the insect groups that once dominated pollination in prehistoric times have since declined or disappeared, replaced by the bees, butterflies, and other familiar pollinators that thrive in modern ecosystems.

Understanding this long history is essential—not just for scientists, but for anyone interested in biodiversity and conservation. When we focus only on present-day pollinators and plants, we miss a crucial part of the story. The fossil record helps us see how pollination has changed over time, which in turn can offer insights into how today’s ecosystems might respond to environmental pressures such as climate change and habitat loss.

Recognising the ancient history of insect pollination isn’t just an academic exercise—it has real-world implications. If we understand how pollination evolved and adapted to past environmental changes, we can better predict how it might shift in the future. Conservation efforts that aim to protect pollinators today can benefit from a long-term perspective, ensuring that we’re not just responding to recent trends but also considering deep-time ecological processes.

So the next time you see a bee visiting a flower, remember—you’re witnessing the latest chapter in a story that began hundreds of millions of years ago. The relationship between plants and pollinators is far older, more complex, and more fascinating than we ever imagined.

Here’s the reference with a link to the paper. It should be open access, but if you have problems obtaining it, send me a message via my Contact page:

Peris, D., Ollerton, J., Sauquet, H., Hidalgo, O., Peñalver, E., Magrach, A., Álvarez-Parra, S., Peña-Kairath, C., Condamine, F.L., Delclòs, X. & Pérez-de la Fuente, R. (2025) Evolutionary implications of a deep-time perspective on insect pollination. Biological Reviews (in press)