Category Archives: Bees

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

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.

Seeds have power far beyond their size – China Diary 2

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In the image above, the three glass tubes on the right contain different cultivated varieties of soybean (Glycine max), one of the world’s most important (and controversial) legume crops. The tube on the left contains the seeds of what is considered the wild ancestor of soybean (Glycine soja). Archaeological evidence suggests that by about 5,000 years ago farmers in several areas of Asia had artificially selected varieties that had much bigger seeds than the wild type. I like this image because it’s a great demonstration of the power of humans to positively influence the food that we eat – and the power of those seeds to affect us via our diets and farming methods.

Of course it’s not just soybean that’s been subject to this sort of artificial selection – we’re encountering many other species and varieties of beans at the various farmer’s markets we’re visiting here in Yunnan:

Many of these beans require pollinators such as bees to initiate or at least enhance the crop, as we found in our recent study of soybean as part of the SURPASS2 project.

I took the main image last week when I had a tour of the Germplasm Bank at the Kunming Institute of Botany, a really impressive facility that stores both seeds in deep freeze and living plants in tissue culture. It’s one of the ways in which we can help to conserve the genetic diversity of wild and cultivated plants. Here are a few more photographs from that visit:

Dr Jie Cai, the manager of the seed bank, kindly hosted the tour and introduced the facility:

Seeds are stored at about -20C in huge, security-controlled freezers:

Collected seeds are first cleaned, sorted, and then counted – a laborious task that requires patience:

Samples of seeds are also germinated at various points to assess how well they are responding to storage:

Plants with seeds that do not respond well to being stored, such as many orchids and bamboos, are grown in tissue culture:

The building also hosts the genetic sequencing facility, another extremely impressive set of laboratories in which progress of sequencing the Chinese flora can be seen in real time:

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.

Bumblebee Pollen Citizen Science Project – get involved!

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Researchers at the University of East Anglia (UEA) are calling for volunteers to contribute to their investigation of the springtime pollen diets of bumblebees in the UK countryside.

Spring is a critical season for colony-establishing bumblebees, but little is known about what types of pollen they collect at this time. In particular, trees, shrubs, and woodland flowers may make significant contributions to bumblebee pollen diets.

Volunteers are needed from across the UK to collect pollen samples from live bumblebees in April and May this year. These will then be analysed by the researchers to determine their taxonomic composition.

Volunteers can collect as many or as few samples as they like – every contribution will help! For an information pack detailing what is involved, and to receive a registration form, please email Guthrie Allen (BIO – Postgraduate Researcher): G.Allen [at] uea.ac.uk.

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!

The flower that’s pollinated by birds, bees….and the wind!

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In my new book Birds & Flowers: An Intimate 50 Million Year Relationship I spend a bit of time discussing the idea of the bird pollination syndrome that we refer to as ‘ornithophily’, its limitations, and the fact that it has two distinct meanings that are often conflated. One of the problems with ornithophily, and indeed all of the syndromes, is that historically it’s sometimes blinkered scientists to the extent that they only look at the flower visitors that are “right” for the syndrome, ignoring the rest or dismissing them as “secondary pollinators”, a term I dislike.

Why do I dislike that term? Because it fails to capture the complexity of flower-pollinator interactions and relegates an important component of plant reproduction to a subsidiary role. I could go on about this at some length, but if you’re interested in discovering more, look at pages 62-65 of Birds & Flowers. There I contrast the classical Most Effective Pollinator Principle with the equally valid (but much less well studied) Least Effective Pollinator Principle, with a segue into one of my favourite tracks from Led Zeppelin’s second album: What is and What Should Never Be.

But back to the real subject of this post – a flower that corresponds to the classical bird pollination syndrome BUT is also pollinated by bees and (very surprisingly) wind! It’s such an interesting paper by Brazilian ecologists Amanda Pacheco, Pedro Bergamo & Leandro Freitas – here’s the reference and a link to the study:

Pacheco, A., Bergamo, P.J. & Freitas, L. (2024) An unexpected case of wind pollination: ambophily in an ornithophilous tropical mountaintop Orobanchaceae. Plant Systematics and Evolution 310, 9. https://doi.org/10.1007/s00606-024-01890-6

For over 100 years the classical pollination syndromes have acted as a framework for understanding the ecology and evolution of plant-pollinator interactions. But we’ve long known that while they can be a useful shorthand, they do not fully reflect the complexity of how pollination systems evolve. That shouldn’t surprise us because, as I point out in my two recent books, we have data (of any quality) on no more than 10% of the 350,000 or so species of flowering plants!

In addition, those plants for which we do have good data are NOT a random subset of the flowering plants: they have been specifically chosen by researchers because they look to be good systems with which to address particular ecological or evolutionary questions.

Which is fine, but we MUST recognise that this imposes significant restrictions on our understanding of the biodiversity of plant-pollinator interactions. The authors of this paper expressed it very well when they wrote that assumptions about:

“predictability may cause researchers to take for granted that only birds pollinate ornithophilous flowers, hindering research on the contribution of other vectors.”

To which I’d add: it also hinders our understanding of how these interactions evolve over long time scales and across multiple populations.

An obvious question is: how frequent are these sorts of complex pollination systems, involving different pollen vectors of an apparently specialised flower? The answer is that we simply don’t know, because most researchers would have not gone into this level of detail. So a huge congratulations to the authors for a great study – I hope it stimulates others to look beyond the ‘expected’ pollinators of flowers.

Photos: Nathália Susin Streher from the original paper.

More from the WorldFAIR Project: Agricultural biodiversity FAIR data assessment rubrics for plant-pollinator interactions

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The final deliverable from the WorldFAIR Project with which I’m involved has recently been published and can be freely downloaded from Zenodo by following the link below. The report is called “Agricultural biodiversity FAIR data assessment rubrics” and in it we present the results from a series of six pilot studies that adopted the FAIR* standards and our recommendations from the previous report.

This document complements the previous one by giving examples and setting out guidelines that allow researchers and practitioners to ensure FAIRness in their plant-pollinator interaction data.

Here’s the full reference:

Although this is the last formal deliverable from our WorldFAIR work package, it’s not the final output that we have planned. I’ll report back on the journal paper(s) that we are writing as and when they are published.

*Findable, Accessible, Interoperable & Reusable (or sometimes Reproducible)

Can coffee plantation design boost both productivity and sustainability? A new study says YES!

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One of the most productive research collaborations in which I’ve had the pleasure to be involved has been with André Rodrigo Rech in Brazil. It started when he was a postgrad working on his PhD, and has now continued as André has developed into fully-fledged academic with his own research group. That productivity has been fueled by a lot of coffee, of course, as you’ll know if you’ve read my book Pollinators & Pollination: Nature and Society!

Our most recent paper concerns coffee production in Brazil and how the design and management of plantations can both support wild bee populations AND increase the quality and quantity of the crop. One of the lead authors Gudryan Baronio has written a post about the work over on The Applied Ecologist blog – here’s the link: https://appliedecologistsblog.com/2024/02/26/can-coffee-plantation-design-boost-both-productivity-and-sustainability/

Here’s the reference – if you want a PDF of the paper, please send me a message via my Contact page:

Pereira Machado, A.C., Baronio, G., Soares Novaes, C., Ollerton, J., Wolowski, M., Natalina Silva Lopes, D. & Rech, A. (2024) Optimizing coffee production: Increased floral visitation and bean quality at plantation edges with wild pollinators and natural vegetation. Journal of Applied Ecology (in press)

Here’s the abstract:

Animal pollination is important for more than 75% of agricultural crops, including coffee, whose productivity can increase with adequate pollination. Bees, including many solitary species, are diverse pollinators, with around 85% of them considered more effective than honeybees in pollen transfer. We assessed the coffee plantation and its surrounding vegetation for solitary bee nesting throughout the coffee flowering season and measured their impact on coffee productivity.
We installed collection stations with trap nests inside a coffee plantation, on the border and inside the native vegetation in a farm in Diamantina, MG, Brazil. We used 10 weekly monitored replicates at least 1 km apart. We evaluated fruiting by autogamy in relation to natural pollination and used the increase in fruit set from pollinators to calculate the farmer’s monetary gain. We recorded bee visits to the exposed flowers during coffee flowering considering both on the edge and inside the coffee plantation. Ripe fruits were dried, counted and weighed.
We discovered 132 solitary bee nests outside the plantation, with 54% containing coffee pollen grains, indicating coffee as an essential resource for bees even outside the crop area. More bee visits occurred at the coffee plantation’s edge, resulting in increased fruit production, denser fruits, and rounder fruits in that area. Bagged flowers produced consistent seeds in all locations. The farmer could earn an extra US$1736.37 per hectare if the entire area received the same level of pollination contribution from bees as observed at the coffee border.
Synthesis and applications. Our study emphasises the key role of pollinators in coffee production and their impact on fruit and seed characteristics. Bee visits were more frequent on border areas, emphasising their reliance on natural nesting sites. Bee-mediated pollination positively affected fruit traits and self-pollinated fruits in plantation borders had reduced mass. Solitary bee nesting was primarily observed in native vegetation, underlining its importance for bee populations. Pollen composition in nests varied with proximity to coffee plantations, indicating landscape vegetation influences pollinator foraging. These findings support optimising coffee plantation design by preserving native vegetation to increase coffee yields and conserve biodiversity.

Read my author interview and get a 25% discount off ‘Birds & Flowers’, ‘Pollinators & Pollination’ and other books from Pelagic Publishing!

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I recently did a short interview with Pelagic Publishing’s marketing person, Sarah Stott, which you can read here: https://pelagicpublishing.com/blogs/news/birds-and-flowers-author-interview.

On that page you can sign up to Pelagic’s newsletter (which I STRONGLY recommend, because they produce some great natural history and science books, and not just mine!) and by doing so you can receive a 25% discount on all orders.

What are you waiting for?