Tag Archives: Pollinators

Join me on Thursday for a free talk!

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

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

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

I look forward to seeing you there!

Ivy binds the landscape and bridges the seasons: a new article just published

If you check out the latest issue of Bees and Other Pollinators Quarterly you’ll see that, as well as having a piece on the forthcoming COP26 climate change meeting and what it means for pollinators, the magazine has also published a short opinion piece by me called “In Praise of….Ivy”. The magazine is currently in the shops or you can subscribe by following this link: https://bq-mag.store/.

Although it can be invasive and an environmental nuisance in parts of the world where it’s introduced, common or European ivy (Hedera helix) is clearly one of the most vital plants across its native range of Europe, southern Scandinavia and the Mediterranean. Its clinging stems bind the landscape and provide habitat for a diversity of creatures. By offering nectar at a time when there’s few other plants in flower, and berries at a crucial point in the winter, ivy bridges a food gap for both nectar feeding insect and fruit eating birds and mammals.

Ivy is a very popular subject for student research because it’s in flower at the start of the university academic year. In the past I’ve had several students carry out their final year projects using ivy to test ideas about pollinator effectiveness and plant reproductive success. Because the open, densely-clustered flowers can dust pollen onto any insect that visits, the most effective pollinators will vary depending on which are abundant at any time and place, and include various types of flies and bees, plus those much-misunderstood wasps!

Perhaps we should leave the final word on ivy to the Northamptonshire ‘Peasant Poet’ John Clare who wrote ‘To the Ivy’ in the early 19th century:

Dark creeping Ivy, with thy berries brown,

That fondly twists’ on ruins all thine own,

Old spire-points studding with a leafy crown

Which every minute threatens to dethrone;

With fearful eye I view thy height sublime,

And oft with quicker step retreat from thence

Where thou, in weak defiance, striv’st with Time,

And holdst his weapons in a dread suspense.

But, bloom of ruins, thou art dear to me,

When, far from danger’s way, thy gloomy pride

Wreathes picturesque around some ancient tree

That bows his branches by some fountain-side:

Then sweet it is from summer suns to be,

With thy green darkness overshadowing me.

Further reading

Bradbury, K. (2015) English ivy: berry good for birds. https://www.theguardian.com/lifeandstyle/gardening-blog/2015/feb/19/english-ivy-berry-good-for-birds

Bumblebee Conservation Trust (2021) Ivy mining bee: https://www.bumblebeeconservation.org/ivyminingbee/

Jacobs, J.H., Clark, S.J., Denholm, I., Goulson D., Stoate, C. & Osborne J.L. (2010) Pollinator effectiveness and fruit set in common ivy, Hedera helix (Araliaceae). Arthropod-Plant Interactions 4: 19–28

Ollerton, J. (2021) Pollinators & Pollination: Nature and Society. Pelagic Publishing, Exeter, UK

Ollerton, J., Killick, A., Lamborn, E., Watts, S. & Whiston, M. (2007) Multiple meanings and modes: on the many ways to be a generalist flower. Taxon 56: 717-728

Woodland Trust (2021) Ivy. https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/plants/wild-flowers/ivy/

A milkweed on the shore: tracking down an elusive Danish plant

Since arriving in Odsherred towards the end of August I’ve been looking out for one plant in particular on our bicycle rides and hikes around the region. Vincetoxicum hirundinaria is a widespread asclepiad or milkweed: a member of the family Apocynaceae, subfamily Asclepiadoideae. This is a group of plants on which I’ve published quite a few research papers and which feature heavily in my book Pollinators & Pollination: Nature and Society.

So far the species has proven elusive and a few Danish ecologists that I’d spoken with told me they had never seen it in the wild. The GBIF account of the species shows a few populations in this part of Denmark but I wasn’t sure if they were old records of populations that no longer exist. But as of yesterday I can confirm that at least one of those populations is extant!

We had cycled out to the small town of Klint about 13km west of us, to see the glacial moraine landscape for which the area is famous and which gives Odsherred UNESCO Geopark status. As we approached the small fishing harbour at Klint I let out an excited shout to Karin who was just ahead of me: in amongst the roadside vegetation I’d spotted the distinctive and immediately recognisable yellow of Vincetoxicum hirundinaria in its autumnal hues! In the photos that follow you can see how well that yellow stands out against the colours of the other plants in the community.

At this time of the year the plant has ceased flowering, but the occasional swollen green seed pod was evidence of successful pollination of their morphologically complex flowers.

I was surprised at just how close to the sea the plants were growing; they must get inundated by sea water during stormy tidal surges.

So what is pollinating these flowers on this exposed shoreline? That’s a question that I want to pursue in the coming years. The Pollinators of Apocynaceae Database has remarkably few records of pollinators in this species, given how widespread it is. Flies certainly pollinate it, but there’s also records of wasps and bees as visitors, including bumblebees on flowers of a plant that I had in cultivation in Northampton. There’s a couple of other research groups in Scandinavia and Europe who are looking at the pollination ecology of the species and I’m hoping that we can collaborate on a study of spatial variation in its reproduction. Vincetoxicum is quite a large genus (around 150 species) and only around 10% of the species have been studied in any detail. But these studies are revealing a complex diversity of pollinators, including most recently, cockroaches in the Chinese species Vincetoxicum hainanense. I’m sure this intriguing group of plants has more fascinating stories to tell us about the ecology and evolution of its pollination systems.

FIGURE 4 from Xiong et al. (2020) Specialized cockroach pollination in the rare and
endangered plant Vincetoxicum hainanense in China. American Journal of Botany 107:

Claims that only 10% – and not 75% – of crops are pollinator dependent are misleading and dishonest

Earlier this week the Genetic Literacy Project site posted an essay entitled ‘10% — not 75% — of crops pollinator-dependent: Our World in Data debunks claims that global food supply is imminently endangered by ‘disappearing’ insects‘. That click-bait title is hugely misleading, some of the purported ‘facts’ are incorrect, and indeed the whole thing reeks of dishonesty and bad faith.

First the misleading title. This ‘debunks’ claim actually compares two different things: 75% of CROPS being dependent on pollinators versus 10% of crop YIELD. However, even if we focus on the 10% claim, a small increase in yield can be the difference between profit and bankruptcy for small-scale farmers. And most of the world’s farmers are small-scale and living on the borderline between loss and break-even. In addition, there’s no acknowledgement of the food production from home gardens, allotments, and community gardens, which is significant but largely unquantified.

Next, by focusing on yield and comparing, say, wind-pollinated wheat with insect-pollinated apples, the article takes no account of the fact that many of these crops that depend to some extent on pollinators mainly provide essential vitamins and minerals – not calories – to diets. When I tweeted about this earlier in the week, one person commented that they describe the insect-pollinated foods as ‘an important source of flavour and colour in our diets, rice and wheat are all well and good, but you do kinda need something more than grey slop to live’. Another said: ‘I’m so glad you mentioned this. I’m sick of reading articles that praise innovations to increase calories, when what we need is better nutrition from vitamins, minerals & fibres’.

Both great points, and well made.

That essay was also factually incorrect when it described roots crops such as carrots or some of the leafy cabbages and lettuces as not requiring pollinators. Many varieties of these crops ARE pollinator dependent: how do they think we get the seed for the next year’s crop?! And there are many crops and varieties that have not been evaluated for their dependency on pollinators: the 75% figure actually refers to the 115 most productive crop plants (Klein et al. 2007).

When I tweeted about the essay I commented that I was very disappointed by ‘Our World in Data’ – they are usually better than this when it comes to the facts. What I hadn’t appreciated at the time was that in fact the Genetic Literacy Project had highjacked the original piece by Hannah Ritchie and reworked it to give it a very different slant*.

This is where it starts to get dishonest and in fact the Genetic Literacy Project (GLP) has form in this area. The Sourcewatch site describes the GLP as ‘a corporate front group that was formerly funded by Monsanto’ with a remit to ‘shame scientists and highlight information helpful to Monsanto and other chemical producers’. In other words it’s heavily tied to Big Agriculture which, of course, would like us to believe that there’s not an issue with declining pollinators, that pesticides and agricultural intensification are our friends, and that Everything Is OK. Read the full account here.

Frankly, the GLP is so tainted that I’d not believe anything that they publish.

Pollinator decline and the role of pollinators in agriculture are complex issues. If you’d like to know more about the importance of pollinators to agriculture, complete with some accurate and objective facts, then there’s a whole chapter devoted to the topic in my book Pollinators & Pollination: Nature and Society.

*Note that I’ve been communicating with Hannah about the root and leaf crop issue and she accepts that this needs to change in the original. She’s also asked the Genetic Literacy Project to take down their version as it contravenes copyright.


Klein, A.-M., Vaissière, B.E., Cane, J.H. et al. (2007) Importance of pollinators in
changing landscapes for world crops. Proceedings of the Royal Society of London B
274: 303–313.

What to do if you have beewolves nesting in your garden? Leave them alone!

Earlier today we had a message from the owner of the AirBnB that we are staying in to let us know that he’s expecting a guy to come and spray pesticide around the house to kill the ‘invasive’ beewolves. The European beewolf (Philanthus triangulum) is a type of wasp in the family Crabronidae that is only distantly related to the typical wasps that you find trying to share your barbecue and beer. As its name suggests, it preys upon bees, but it’s actually a pollinator itself and visits a range of flowers.

I immediately got back to our host and pointed out that beewolves are gentle insects, completely harmless, and less dangerous than the pesticide the company would use to kill them, and that he was wasting his money. He informed us that the pest control company had told him that he needed to control them other wise he’d be ‘over-run’ with them next year!

When I explained to him that this was nonsense, and that the beewolves cause no damage to people or property, he promised to get back to the company to cancel the order, and thanked me for the information. I’m hoping that I’ve made a convert to the cause of insect conservation!

It maddens me that pest control companies are preying on people’s fear of insects to make money in this way. Insects are subjected to enough assaults by human activities without making up spurious reasons for poisoning them.

So if you are lucky enough to have beewolves in your garden, please treat them with respect and watch their fascinating behaviour:

The largest West African flower: Pararistolochia goldieana!

Some years ago, browsing in a second hand bookshop, I happened across a copy of an old magazine from 1950 called Nigeria. Published by the then colonial government, it was a miscellaneous collection of articles about the culture, geography and natural history of that fascinating West African country. Although aspects of the contents are problematical by modern standards, I bought it because of a short article about a wild plant with enormous flowers and a remarkable pollination strategy. In particular, the spectacular photograph of a man holding a flower that’s the length of his forearm grabbed my attention: who couldn’t love a flower like that?!

The plant is Pararistolochia goldieana, a vine found in the forests of this region, as described in the introductory text:

These types of flowers are pollinated by flies, a common strategy in the Birthwort family (Aristolochiaceae) to which the plant belongs. This strategy of fly pollination in which flies are deceived into visiting the flowers by their stink and colour, and temporarily trapped in the enclosed chamber, is something that I explore in detail in my book Pollinators & Pollination: Nature and Society, particularly in the genus Ceropegia. Those plants show convergent evolution with the pollination systems of Aristolochiaceae, though they are unrelated.

Pararistolochia goldieana has a wide distribution across West Africa, including Cameroon, Equatorial Guinea, Nigeria, and Sierra Leone. The IUCN Red List categorises it as ‘Vulnerable’ due to habitat loss. The population where these photographs were taken is described on the final page of the article:

The city of Ibadan is one of the largest in Nigeria and has grown enormously, ‘from 40 km2 in the 1950s to 250 km2 in the 1990s‘. I wonder if this forest, and its botanical treasures, still exists?

During field work in Gabon in the 1990s I was fortunate enough to encounter a species of Pararistolochia in the rainforest of Lopé National Park. It was a different species to P. goldieana, with rather smaller but no less spectacular flowers, and it stank to high heaven! We knew it was there long before we saw it. I collected some flies from the flowers and had them identified, though I’ve never published the data: it’s available if anyone is working on a review of pollination in the family.

This 1950 article is anonymous, so I don’t know who to acknowledge for the amazing images. However the botanist R.W.J. Keay was working on a revision of the family for the Flora of West Tropical Africa project at the time, so it may have been written by him.

A spectacular new plant has been named to honour a colleague: meet Ceropegia heidukiae!

Finding organisms that have not previously been described by scientists is not unusual; every year, hundreds of ‘new’ species enter the taxonomic literature, a testament to how little we still understand about the Earth’s biodiversity. The majority of these species are insects, because that’s the most diverse group of organisms on the planet. But new species of plants and fungi also turn up regularly: for example in 2020, botanists and mycologists at Kew named 156, including some from Britain.

So although discovering undescribed species is not uncommon, any field biologist will tell you that it’s an exciting moment to spot something that you’re never seen before and which could turn out to be new. That was certainly the case when my colleague Dr Annemarie Heiduk’s attention was drawn to a South African plant that was clearly something special. As Anne said to me this week:

‘I will never ever forget the very moment when I spotted it and immediately knew it was something no-one has ever seen before. And I was so lucky to find it in flower. I cannot describe how beautiful it looked sticking out of the surrounding grass vegetation. It is certainly one of a kind and I really know how lucky I was to have found it. Not once did it ever cross my mind that I will discover a novel Ceropegia species, let alone one that is so distinct!’

So it was that last year Anne discovered the plant that was to be named in her honour: Ceropegia heidukiae. The species has been described by David Styles and Ulrich Meve in the journal Phytotaxa (from where the image above was taken). There’s also an account of the species on the Pollination Research Lab blog, with further photographs and information about the plant.

Anne has been honoured in this way not just because she discovered the plant, but also because, to quote the paper, she:

‘is a pollination ecologist who with her research on the floral chemistry and deceptive pollination strategies of Ceropegia trap flowers has acquired recognition as an expert in this field’

Anne tells me that she has already collected pollinator and floral scent data for this new species, so we can look forward to seeing that published in the near future. I described the fascinating pollination ecology of Ceropegia, including some of Anne’s earlier work, in my recent book. This is a genus of plants that has intrigued me since I first saw photographs of them and started growing them as a teenager, 40 years ago. Since then I’ve published several papers about their pollination strategies, and how they compare with the family Apocynaceae as a whole: see the following links for some examples:



So, a big congratulations to Anne, and to David and Ulrich – it’s an amazing plant! I wonder what else is still waiting to be discovered in the stunning grasslands of South Africa?

Protecting British Pollinators event TOMORROW – 25th March

I meant to post about this earlier but it’s been a really busy few weeks, so apologies if this is late in the day for any of you. Tomorrow morning there’s a webinar being run by the Public Policy Exchange entitled: “Protecting British Pollinators”. There’s an interesting set of speakers and I’ve been asked to provide the opening introduction and to chair the event.

Here’s the link for more details and booking information:


It should be a good meeting, hope to see some of you there.

Pollinators are allies in the fight against climate change: a new commentary just published in New Scientist

Over the past few months I’ve been thinking a lot about the relationship between the “Climate Emergency” (CE) and the “Ecological Emergency” (EE), and how they overlap considerably in terms of causes and solutions, but that the priorities of the CE often trump those of the EE. One of the outcomes of this has been a commentary that’s been published in New Scientist this week. It’s free to access – here’s the link:


It’s extracted from a much longer article that discusses the role of pollinators in relation to climate change. Hopefully that will be published in the not too distant future.

The other thing that’s happened this week is that, in my role as Visiting Professor of Biodiversity at the University of Northampton, I was asked to take part in a webinar that’s one of a series being produced in support of the Levelling Up Goals. The LUGs, modelled on the UN’s Sustainable Development Goals (SDGs) have cross-party support in Parliament and aim to bring economic prosperity to those parts of the country that have lagged behind in recent decades. The “Green Economy” is seen as central to this.

The webinar was recorded and you can view it here: https://www.fit-for-purpose.org/engage/how-to-level-up-harness-the-energy-transition

It was interesting and I learned quite a bit, for example about how the government is investing the state pension pot in sustainable energy projects. The format of the webinar, however, with the chair asking individuals a question and each of us responding, was a little frustrating as there was no real opportunity to counter statements being made, particularly by the MP for Hexham.

Yesterday Karin and I had out first COVID-19 vaccination; today we both feel a little under the weather, but it will pass. It’s certainly better than the alternative!

Finally, a physical copy of my book!

Yesterday I was delighted to finally receive an advance copy of my book Pollinators & Pollination: Nature and Society! It’s been over three years in the writing and production, much longer than I had anticipated. But, as I describe in its pages, the book is the culmination of >50 years of experience, study and research. So perhaps three years isn’t so bad…

If you’re interested in buying a copy you can order it direct from Pelagic Publishing and from most of the large online booksellers. Let me know what you think.