Tag Archives: Pollinators

Recent research and seminars on pollinators and pollination that have caught my eye

There’s so much good science and so many great talks coming out of the (broad) field of pollinator and pollination research at the moment! Here’s a few things that have come up on my radar. Feel free to comment and add your own examples of things I may have missed.

The effects of the decline of a keystone plant species on a dune community plant-pollinator network by Dan Sandacz and colleagues is a nice example of what can happen when plants that provide important nectar and/or pollen resources are lost from a community.
Phylogenetic reconstruction and mapping of pollination systems indicates the dominance of “Insect pollination for most of angiosperm evolutionary history” say Ruby Stephens and co authors, which I don’t think is a huge surprise but it’s nonetheless great to see this laid out so clearly and (given my forthcoming book) the relatively high frequency of transitions to vertebrate pollination. See also their commentary in The Conversation.
Full disclosure, I was one of the reviewers of Pollinators and plants as ecosystem engineers: post-dispersal fruits provide new habitats for other organisms by João Cardoso et al., and I know that there was quite a bit of back and forth between authors, editor and reviewers about what the findings really meant and how best to frame them. My view was that this study should be published because it’s another demonstration of the importance of pollinators and their interactions with plants that goes beyond the obvious outcomes of plant reproduction and support of pollinator populations.
Non-Forest Woody Vegetation: A Critical Resource for Pollinators in Agricultural Landscapes—A Review by Małgorzata Bożek and colleagues provides a summary of a rather important but neglected topic.
Again, full disclosure, I reviewed Adriano Valentin-Silva’s Reproductive biology of Piper species (Piperaceae): a review to link the past to the future, because it’s an important and diverse genus that I’ve had a long-standing interest in, and deserves an up to date summary of its reproduction.
Global distribution and evolutionary transitions of floral symmetry in angiosperms by Yunyun Wang et al. challenges some earlier conclusions about the relationship between zygomorphy and plant diversification.
Pollination crisis Down-Under: Has Australasia dodged the bullet? by Graham Pyke, Kit Prendergast & Zong-Xin Ren gives a southern hemisphere perspective on current concerns about loss of pollinators.
Dark-centred umbels in Apiaceae: diversity, development and evolution gives a broader perspective to Darwin’s original speculations about wild carrots, which is something else that has intrigued me for many years.
Peter Bernhardt’s recent lecture “So You Want to Study Orchid Pollination” is now on YouTube: https://www.youtube.com/watch?v=M0wFvm6PFYk
This seminar on pollinators and plant conservation in the Cape Floristic Region of South Africa by Anton Pauw was extremely interesting: https://sabotanyblog.wordpress.com/saab-webinar-recordings-2023/

We’ve just named a new species of fly from Yemen! And it came out of a flower from Kew

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Back in the late 1990s and early 2000s, whenever I had a (rare) day free from teaching, marking, supervision, meetings, writing, and other university commitments, I would hop on the train from Northampton to London. My destination was the Spirit Collection of the Herbarium at the Royal Botanic Gardens, Kew, where bottled flowers are preserved in their three-dimensional complexity, rather than squashed flat onto herbarium sheets. To this day, the smell of formaldehyde in the “Kew Mix” takes me back to the chilly basement space of that collection.

The Kew Herbarium is a massive, internationally important resource for taxonomy, evolutionary biology and ecology, and one which ought to stay where it is, in my opinion.

The purpose of my visits was to exploit the large number of Ceropegia specimens that had been collected by botanists working in Africa, the Middle East, and Asia. These amazing flowers are so complex that they are best preserved in spirit, and that complexity in turn is a function of their sophisticated pollination systems. The flowers temporarily trap their pollinators, releasing them unharmed after a period, during which they will have picked up pollen and/or the flower will have been pollinated. If you have ever grown String-of-Hearts as a house plant, that’s the group we are talking about.

The botanists who collected these flowers were, of course, only interested in the plants. But as well as pickling the blooms they sometimes pickled the insect contents of the flowers, giving us a record of what the flowers were luring into their temporary traps. Not only that, but Ceropegia belongs to the milkweed subfamily of Apocynaceae, which means that their pollen is in the form of pollinia. These are coherent packages of pollen that mechanically, and persistently, clip to the insect. This gives us an opportunity to sort out the real pollinators (with pollinia attached) from other insects that may be inside the flowers for other reasons, such as looking for prey or sheltering from the dry heat of the day.

It had occurred to me that if someone was to check these flowers for insects, and extract any that were found, then we could build up an unprecedentedly complete picture of the diversity of pollinators in a large, mainly tropical plant genus of around 200 species. So that’s what I did, whenever time allowed. Having gained permission to do this, I was pleased to discover that the process was considerably speeded up by the fact that preserving the flowers in this way clears the tissues, making them colourless and translucent. By shining a bench light through the bottles I could see which flowers contained insects and carefully dissect them out.

Most flowers were empty, but occasional visits over a period of a few years resulted in a data set of flower visitors and pollinators for about 60 species and subspecies of Ceropegia. The first paper from that work was published in 2008 in Annals of Botany as ‘Fly pollination in Ceropegia (Apocynaceae: Asclepiadoideae): biogeographic and phylogenetic perspectives‘. Later work by colleagues and myself meant that in 2017 we could publish an update in the journal Flora (Diversity of Diptera families that pollinate Ceropegia (Apocynaceae) trap flowers: An update in light of new data and phylogenetic analyses).

The work also fed into our large study of pollination systems in Apocynaceae and I even published a small note about an ant specimen that I had extracted which still had the evidence of its last meal (a fly’s wing) protruding from its mouth.

The work at Kew had given us a short cut to understanding how pollination systems have evolved in this big plant species radiation. The equivalent field work required to collect the same data would have taken many person years and no funding agency would have given it the time of day. Not only that, but a portion of the data is from parts of the word that are war-torn, dangerous, and largely inaccessible to field scientists at the moment. Which brings us to the present paper.

All of the pollinators, and most of the flower visitors, to Ceropegia that have been discovered to date are small flies (Diptera) often only a couple of millimetres in length. There are relatively few taxonomists who can identify such flies and most of the specimens I extracted were identified to genus or family by Andrew Whittington. One such specimen was determined to be a species of Lygistorrhina, known as ‘long-beaked fungus gnats‘. It was found in a flower of Ceropegia aristolochioides ssp. deflersiana, which is something of a generalist in this genus of specialists: it’s pollinated by at least four fly genera and 11 others have been collected from its flowers sans pollinia, including this one.

The flower was collected in 1975 by botanist John Wood, in Yemen – like I said, inaccessible – and the semi-arid climate in which it was found, whilst typical for Ceropegia, is unusual for Lygistorrhina. When National Museums Scotland entomologist Vladimir Blagoderov looked at the specimen he quickly realised that it was a new species and contacted Andrew and myself to discuss describing it. The paper documenting the new species, which we have named Lygistorrhina woodi in John’s honour, was published today. Here’s the reference with a link to the paper, which is open access:

Blagoderov, V., Ollerton, J. & Whittington A. (2023) A new species of Lygistorrhina (Lygistorrhina) Skuse, 1890 (Diptera: Keroplatidae, Lygistorrhininae) with a key to the subgenus. Zootaxa 5361: 151–158

Here’s the abstract:

A new species of Lygistorrhina (Lygistorrhina) Skuse, 1890, Lygistorrhina woodi sp. nov., is described. The specimen was dissected from an alcohol-preserved flower of Ceropegia aristolochioides ssp. deflersiana Bruyns (Apocynaceae, Asclepiadoideae, Ceropegieae) stored in the Kew herbarium. This is the first occurrence of the lygistorrhine gnats in a hot, semi-arid climate. A key to all known species of the subgenus Lygistorrhina (Lygistorrhina) is provided.

Key tropical crops at risk from pollinator loss due to climate change and land use – a new study just published

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PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) is one of the most important sources of data for large-scale modelling of how changes in land use is impacting biodiversity. Marry that with future climate models and you have a powerful tool for understanding how these two major factors in global change will shape both biodiversity and human society over the coming decades.

In recent years it’s been a privilege to be part of a project led by Joe Millard and Tim Newbold that’s using PREDICTS to model how pollinators and pollination services are likely to be impacted by human activities. The first paper from that work (which was Joe’s PhD) was entitled ‘Global effects of land-use intensity on local pollinator biodiversity’ and came out in 2021, as I documented on my blog at the time.

Yesterday a second paper was published, this time focused on how land use and anthropogenic climate change interact to potentially affect insect-pollinated crops across the world.

Our main finding is that it’s tropical crops, especially cocoa, mango, watermelon, and coffee, that in the future will suffer the greatest negative impacts from loss of pollinators. Although we can have perfectly healthy diets without consuming any of those, they currently support tens of millions of farmers across the tropics and are part of global supply chains worth billions of dollars per year.

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

Millard, J., Outhwaite, C.L., Ceaușu, S., Luísa G. Carvalheiro, da Silva e Silva, F.D., Dicks, L.V., Ollerton, J. & Newbold, T. (2023) Key tropical crops at risk from pollinator loss due to climate change and land use. Science Advances 9, eadh0756

Here’s the abstract:

Insect pollinator biodiversity is changing rapidly, with potential consequences for the provision of crop pollination. However, the role of land use–climate interactions in pollinator biodiversity changes, as well as consequent economic effects via changes in crop pollination, remains poorly understood. We present a global assessment of the interactive effects of climate change and land use on pollinator abundance and richness and predictions of the risk to crop pollination from the inferred changes. Using a dataset containing 2673 sites and 3080 insect pollinator species, we show that the interactive combination of agriculture and climate change is associated with large reductions in insect pollinators. As a result, it is expected that the tropics will experience the greatest risk to crop production from pollinator losses. Localized risk is highest and predicted to increase most rapidly, in regions of sub-Saharan Africa, northern South America, and Southeast Asia. Via pollinator loss alone, climate change and agricultural land use could be a risk to human well-being.

“Birds & Flowers” book update: here’s the list of chapters!

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Today I returned the final, edited files of the book manuscript to the publisher. It’s been a long summer of ‘fine distinctions and nice judgements’, to quote my editor, the inimitable Hugh Brazier. Now that’s all finalised, I thought that it was time to share the chapter titles with you – here goes:

Introduction: Encounters with birds and flowers

1 Origins of a partnership

Understanding 50 million years of bird and flower evolution

2 Surprising variety

The astounding diversity of pollinating birds

3 Keeping it in the family

Accounts of the different groups of bird pollinators

4 A flower’s point of view

How many plants are bird-pollinated, and where are they found?

5 In the eye of the beholder

What do bird flowers look like?

6 Goods and services

The enticements given to birds for pollinating flowers

7 Misaligned interests

The ongoing conflicts between flowers and birds

8 Senses and sensitivities

How bird brains shape the flowers that they pollinate

9 Codependent connections

Networks of interacting flowers and birds

10 Hitchhikers, drunks and killers

The other actors in the network and how they affect the main players

11 The limits to specialisation

How ‘specialised’ are the relationships between birds and flowers?

12 Islands in the sea, islands in the sky

Isolation, in oceans or in mountains, results in some remarkable interactions

13 The curious case of Europe

Why did we believe that Europe had no bird-pollinated flowers?

14 ‘After the Manner of Bees’

The origins of our understanding of birds as pollinators, and their cultural associations

15 Feathers and fruits

Birds as pollinators of edible wild plants and domesticated crops

16 Urban flowers for urban birds

Bird pollination in cities and gardens

17 Bad birds and feral flowers

The impact of invasive species

18 What escapes the eye

The decline and extinction of bird–flower relationships

19 The restoration of hope

People as conservationists of birds and their flowers

There you have it! I’m incredibly excited that the book is now just about finished (I still have to proof read the typeset text and produce an index) and I look forward to finally having a copy in my hands. Birds & Flowers: An Intimate 50 Million Year Relationship is available for pre-order from Pelagic Publishing, or via online bookshops.

Weevily good pollinators – a recent review of a neglected interaction

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A pollination ecologist was recently working on the reproduction of a tropical plant species and discovered that the flowers were visited by two species of weevils, one large and one small.

The larger weevil was too big to access the nectar from the front, so it chewed its way into the flowers, destroying the petals, and in the process picking up no pollen.

The other weevil species was, however, able to enter the flowers, where it became smeared with pollen, which it then transferred to the stigmas in flowers of other plants.

The pollination ecologist therefore concluded that the true pollinator of this plant was, indeed, the lesser of the two weevils…

That’s not an original joke by any means – it comes from the movie Master and Commander. But it nicely sets up this short post about a review paper that came to my attention earlier in the summer and which fits neatly with my previous post about a special issue of the Journal of Applied Entomology dedicated to the “neglected pollinators”.

Writing in the open access Peer Community Journal, Julien Haran, Gael Kergoat, and Bruno de Medeiros have produced a really fascinating review of weevil pollination called:

Most diverse, most neglected: weevils (Coleoptera: Curculionoidea) are ubiquitous specialized brood-site pollinators of tropical flora

Weevils are beetles, members of the superfamily Curculionoidea, which contains an estimated 97,000 species. Many are herbivores, including seed predators – I first encountered them as a researcher during my PhD when I assessed the impact of one species as a seed predator of my study plant Bird’s-foot Trefoil. Surprisingly, however, pollinating relationships have evolved multiple times between weevils and plants. Drawing on published studies and their own unpublished observations, the authors conclude that such “associations have been described or indicated in no less than 600 instances.” Most of these are brood-site pollination systems that have probably evolved from seed predation relationships.

No doubt many more examples of weevil pollination remain to be discovered but as it stands, this review paper is a great summary of a fascinating and still rather neglected corner of pollination ecology.

Plant-based diets are a problem for bees! A new study of the significance of the ratio of food K:Na in bee ecology and evolution

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At the moment Karin and I are in the UK for a couple of weeks. I had work to do as an external examiner at the University of Swansea, plus we wanted to catch up with some family and friends. Our main base has been the home of our mates Ian and Simone and we’ve enjoyed some warm, muggy evenings sitting in their garden chewing the fat. Every now and again my eyes have been drawn to the activities of bumblebees as they move in and out of the foliage of a small Silver Fir. The bees are attracted to the large colonies of an aphid that is feeding on the tree’s trunk, from which they are collecting honeydew, as you can see in the photograph above.

When we think of the diets of bees we automatically think “nectar and pollen”. Honeydew, as a sugar-rich fluid, fits broadly into this concept, though as far as I know there’s been little study of its relative importance as a food source for bees. Aside from a few “vulture bees”, all of the 20,000 or so species are vegetarian. And therein lies a problem. Bees evolved from carnivorous wasps and so the evolution of bees, and their complex ecologies, is tied into this profound dietary shift toward a plant-based diet.

A particular issue that has hardly been investigated until recently is that the ratio of elements within meat is very different to that of plants. In particular, animal tissue has a high ratio of sodium (Na) relative to potassium (K), whereas for plants the ratio is reversed – high ratio of K:Na.

In a new conceptual review paper with my colleagues Zuzanna Filipiak and Michał Filipiak, we have explored the implications of this difference in elemental ratios for bee ecology and evolution, and for the conservation of these important insects. The paper is open access and you can download a copy by following a link in this reference:

Filipiak, Z.M., Ollerton, J. & Filipiak, M. (2023) Uncovering the significance of the ratio of food K:Na in bee ecology and evolution. Ecology e4110. https://doi.org/10.1002/ecy.4110

Here’s the abstract:

Bees provide important ecological services, and many species are threatened globally, yet our knowledge of wild bee ecology and evolution is limited. While evolving from carnivorous ancestors, bees had to develop strategies for coping with limitations imposed on them by a plant-based diet, with nectar providing energy and essential amino acids and pollen as an extraordinary, protein- and lipid-rich food nutritionally similar to animal tissues. Both nectar and pollen display one characteristic common to plants, a high ratio of potassium to sodium (K:Na), potentially leading to bee underdevelopment, health problems, and death. We discuss why and how the ratio of K:Na contributes to bee ecology and evolution and how considering this factor in future studies will provide new knowledge, more accurately depicting the relationship of bees with their environments. Such knowledge is essential for understanding how plants and bees function and interact and is needed to effectively protect wild bees.

Week-long Master’s course in Italy – March 2024 – on Pollination as an Ecosystem Service

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I’m excited to announce that in March 2024 I will teach a week-long, Master’s-level residential course entitled “Pollination as an Ecosystem Service” at the University of Pavia in Italy. It will be taught in English. Here’s a summary of the course and a brief description of the the syllabus, which is broadly accurate but subject to change as it develops:

POLLINATION AS AN ECOSYSTEM SERVICE

A 3 credit Master’s course for the University of Pavia

Overview

The pollination of crops by bees, flies, birds, bats and other animals, is an ecosystem service that increases crop yields and quality. This is valued at hundreds of billions of Euros each year to European and global agriculture. In addition, these same animals pollinate around 90% of the world’s wild plants which in turn provide us with ecosystem services such as wild food, flood alleviation, microclimate modification, and carbon capture.

In this course, students will explore pollination as an ecosystem service from its first principles and historical roots through to the latest research findings around the consequences of pollinator decline and climate change. The emphasis of the course is on the students learning by actively participating during classes. Each day has a particular theme and will be a mix of interactive lectures, short video clips to illustrate particular points, discussion seminars (for which they will be expected to do some guided reading) and local excursions.

At the end of the course the students will have a developed a deep understanding of the diversity of pollinators, the ecological nature of their interactions with flowers, and the importance of these relationships to nature and to society.

Assessment

At the end of the course, the students will be asked to give a 10 minute presentation based on one of the topics covered in the course, and posed as a question such as “What is….?”, “Why does….?”, “What would happen if….?”, and so forth. The questions will be agreed with me in advance. Presentations will take place on the final day of the course and at the end of each presentation the students will have 5 minutes to answer questions posed by their peers and myself.

Syllabus

Day 1

Theme: Pollinators and pollination – first principles; including historical perspectives, the diversity of pollinators and flowers, and the biology of pollination. Introducing the course assessment.

Excursion: a walk around the local area to observe flowers and pollinators in action.

Day 2

Theme: Pollination as an ecosystem service; including the types of crops that are animal pollinated, how we calculate the value of pollination, and going beyond agriculture to look at the other ecosystem services provided by pollinators; approaches to studying pollinators and pollination.

Day 3

Theme: Pollinator conservation: including reasons for pollinator decline, impacts of climate change, the “politics of pollination”, the consequences of that decline for crop and wild plant pollination, how we can manage and restore habitats for pollinators.

Day 4

Theme: Urban pollinators: understanding the importance of pollinators in an urban setting and in gardens, and how towns and cities support pollinators. Excursion: How is the city of Pavia supporting pollinator populations and what could be improved?

Day 5

Theme: Summing up what we’ve learned, followed by assessed student presentations.

The course is open to all and there’s details of how to apply (in Italian and English) in the following link: https://portale.unipv.it/it/didattica/corsi-di-laurea/ammissioni/casi-particolari-di-iscrizione/iscriversi-ai-corsi-singoli

The brochure with all available courses can be downloaded here: http://news.unipv.it/?p=84031

I’d be very happy to talk with other universities who might be interested in running such a course.

If you have any questions, please use my Contact page to get in touch.

Insect pollination in deep time – a new review just published

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As a teenager one of my main interests was collecting fossils. In search of specimens I wandered for hours, scouring the Carboniferous coal shale heaps and Permian reef outcrops of my native Sunderland. I spent so much time bothering the geology curator at the local museum with my inquiries that he offered to host me for a year as the placement part of my college course. If I had been able to convince my tutors that paleontology was really just biology in deep time I may have ended up as a professional fossil researcher. But it was not to be and instead I spent a (mostly happy) year working in the microbiology laboratory of a local brewery.

My interest in the ecology of the past has never left me, and over the years I’ve contributed a few articles to journals commenting on the latest fossil findings as they relate to pollination and flowering plant evolution. So I was delighted to be asked by Spanish paleontologist David Peris to help with a new review of insect pollination in deep time, led by PhD candidate Constanza Peña-Kairath. That review has just been published in Trends in Ecology & Evolution, and for the next 50 days it’s available for free download by following the link in the reference:

Peña-Kairath, C., Delclòs, X., Álvarez-Parra, S., Peñalver, E., Engel, M.S., Ollerton, J. & Peris, D. (2023) Insect pollination in deep time. Trends in Ecology & Evolution (in press)

Here’s the abstract:

Inferring insect pollination from compression fossils and amber inclusions is difficult because of a lack of consensus on defining an insect pollinator and the challenge of recognizing this ecological relationship in deep time. We propose a conceptual definition for such insects and an operational classification into pollinator or presumed pollinator. Using this approach, we identified 15 insect families that include fossil pollinators and show that pollination relationships have existed since at least the Upper Jurassic (~163 Ma). Insects prior to this can only be classified as presumed pollinators. This gives a more nuanced insight into the origin and evolution of an ecological relationship that is vital to the establishment, composition and conservation of modern terrestrial ecosystems.

Pesticides and pollinators: please sign this petition!

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As part of our roles as ambassadors of the new conservation organisation Restore (more of which later this year), several of us including Dave Goulson, George McGavin, and myself, are promoting this online petition to get the government to take the issue of neonicotinoid pesticides seriously. Here’s some text from Dave explaining the situation with a link to a petition that you can sign:

“For three years in a row our government has granted farmers special permission to use banned neonicotinoid pesticides on sugar beet. This is contrary to the expert advice of their own Expert Committee on Pesticides, who specifically recommended that permission should not be granted. It also flies in the face of a huge body of scientific evidence showing that these chemicals are phenomenally toxic to all insect life, and that their use on any crop contaminates soils, hedgerow plants, and nearby streams and ponds for years to come. We are in a crisis, with insect populations in freefall. It is about time our government woke up to this, and acted accordingly. This petition https://petition.parliament.uk/petitions/631948 is a necessary means of holding the government to account. Please sign and share, as signing will ensure the issue is debated in Parliament.”

This petition now has more than 15,000 signatures which ensures that it gets a response from the Government. If it reaches 100,000 mark, it will trigger a debate in Parliament. Please sign and promote this important initiative!

Pollinators and the UN Sustainable Development Goals – free webinar on Monday!

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There’s been a lot of discussion recently about how pollinators can contribute to the United Nations’ 17 Sustainable Development Goals. It’s a topic that I reflected on in Pollinators & Pollination: Nature and Society, and I’ve seen a few papers and articles that raise the subject – see here for instance. This free webinar on Monday 27th March is therefore very timely! To register, follow this link: forms.office.com\r\T5HrW0VZvS

Although I’m one of the speakers, I can’t make it in person as I’ve got teaching commitments at Roskilde University, so I’ve recorded my ten minute piece and I’m happy to answer questions via the Contact page on my website.