There’s an estimated 350,000 described species of pollinators, and many, many more undescribed. Only about 20,000 of these (i.e. less than 6%) are bee species, although you wouldn’t know it from the media obsession with bees. It’s important and and timely, therefore, that a team of South American scientists have come together to propose a special issue of the Journal of Applied Entomology that focuses on these “other” insects.
The special issue will be called “The Neglected Pollinators: Understanding the Importance of Lesser-Known Insect Taxa in Pollination”. Consider submitting a manuscript if you work on anything except bees! Here’s the link to the details of how to submit your work:
The summer of 2019, before the COVID-19 pandemic turned the world on its head, feels like a very long time ago. Early in that summer, as I recounted on this blog, Zoe Xirocostas joined my research group for a while in order to collect data for her PhD on the comparative ecologies of plants that are native to Europe but invasive in Australia. That work has proven to be very successful, and the latest paper from Zoe’s PhD has just been published.
The paper focuses on the “enemy release hypothesis” (ERH), a well-studied concept in invasion ecology that nonetheless generates significant debate and disagreement. In essence, the ERH posits that the reason why so many species become invasive is that they leave their consumers, pathogens and parasites behind when they move to a new locality. Those “enemies” would normally reduce the fecundity of the invader, putting a brake on their population growth. But in their absence, the invader can become far more successful. Of course, as well as leaving “enemies” behind the invader also loses its “friends”, such as pollinators, seed dispersers, and defensive or nutritional partners. This “Missed Mutualist Hypothesis” is something that I’ve recently explored with Angela Moles, who was Zoe’s main supervisor, and other collaborators in Australia. Expect to hear more about this from Zoe’s work in the near future.
But back to the enemies. Drawing on the most extensive set of standardised comparisons yet collected of the same plants in native and invasive habitats, Zoe found that plants in the invasive populations suffer on average seven times less damage from insect herbivores, as predicted by the (ERH). Rather remarkably, however, the amount of enemy release enjoyed by a plant species was not explained by how long the species had been present in the new range, the extent of that range, or factors such as the temperature, precipitation, humidity and elevation experienced by the native versus invasive populations.
In other words, it’s extremely hard to predict the extent of enemy release based on historical and ecological considerations that one might expect to impose a strong influence.
The study has just appeared in Proceedings of the Royal Society series B and is open access. Here’s the reference with a link to the paper:
When a plant is introduced to a new ecosystem it may escape from some of its coevolved herbivores. Reduced herbivore damage, and the ability of introduced plants to allocate resources from defence to growth and reproduction can increase the success of introduced species. This mechanism is known as enemy release and is known to occur in some species and situations, but not in others. Understanding the conditions under which enemy release is most likely to occur is important, as this will help us to identify which species and habitats may be most at risk of invasion. We compared in situ measurements of herbivory on 16 plant species at 12 locations within their native European and introduced Australian ranges to quantify their level of enemy release and understand the relationship between enemy release and time, space and climate. Overall, plants experienced approximately seven times more herbivore damage in their native range than in their introduced range. We found no evidence that enemy release was related to time since introduction, introduced range size, temperature, precipitation, humidity or elevation. From here, we can explore whether traits, such as leaf defences or phylogenetic relatedness to neighbouring plants, are stronger indicators of enemy release across species.
Late on Wednesday night, Karin and I returned, tired but happy, from an eight-day trip to southern Spain, where we celebrated the marriage of our son Oli to his partner Kate. Our base for the trip was the small town of Benahavis, a former Moorish enclave in the mountains above the Costa del Sol.
As well as spending time with Oli and Kate and the other guests, Karin and I took the opportunity to explore some of the many trails that meander through this wonderful landscape. One of these crosses, then follows, the spectacular canyon of the Guadalmina river, the trail shaded by over-arching trees that provided relief from the hot sun.
Many of these small trees, I was delighted to see, were oleanders (Nerium oleander) growing in what is (arguably) their natural habitat. It’s been so widely planted for thousands of years that the true origin of this species is unclear, but it’s almost certainly native to the Mediterranean basin.
Twining through one of these oleanders was a plant with heart-shaped leaves and dangling fruit that I instantly recognised – the Andalusian pipe vine (Aristolochiabaetica). As a climber, this plant needs the support of trees and shrubs to enable it to reach the light. The supporting species is not harmed and likely benefits from the nutrients in the dead leaves and flowers that fall beneath it.
The juxtaposition of these two species was so perfectly symbolic of our reason for being in Spain that I had to take the photo that you see above. Why, you may ask? Well the oleander is a member of my all-time favourite plant family, Apocynaceae, that I’ve worked on for more than 30 years. The pipe vine belongs to the Aristolochiaceae, another fascinating family that’s also in my top five favourites.
That’s the thing with families, sometimes they come together and entwine in ways that just feel and look…right. Huge congratulations to Oli and Kate, and our very best wishes for a long and happy future together!
One of the projects in which I’m currently involved is the WorldFAIR project. Funded by the European Commission, WorldFAIR is exploring how to make data FAIR – Findable, Accessible, Interoperable and Reusable – across a range of different disciplines in the sciences and humanities.
My involvement is specifically with Work Package 10, which is focused on data standards for plant-pollinator interactions, particularly as they relate to pollination of agricultural crops. After a year of hard work, I’m delighted to announce that our interim draft report from this Work Package has just been published! You can read the summary and download the report from Zenodo – here’s the link: https://zenodo.org/record/8176978
There’s more to come over the next twelve months and I’ll post updates as and when they appear. In the meantime, do check out the WorldFAIR website for information about the other Work Packages, their webinar series, FAIR data standards, and so forth.
Regular readers of the blog will know that I’m a keen gardener as well as having a deep interest in the natural world, and I know from personal experience how being amongst plants, flowers, birds and insects can lift a person’s mood and improve their health.
It was interesting, therefore, to get a message via my Contact page from a tutor on the Students For Research programme. They had been looking at my blog and the tutor had challenged her students to find a web resource that they thought might interest me. And indeed they succeeded! They found this web page about Clinical Trials on the Positive Effects of Gardening and Experiencing Nature and it makes for very interesting reading. There’s a lot of good research happening in this area.
Earlier this week, the East Midlands Environment Agency proudly tweeted that they had placed honey bee hives on an ecologically important site that they own. As you might imagine, the response from pollinator experts such as myself, conservation NGOs, and some beekeepers, was not positive, as you can see if you look at the comments beneath my tweet:
If this is an important site for nature conservation, as claimed, then the #EnvironmentAgency should NOT put hives of honey #bees on it!
— Prof. Jeff Ollerton – @JeffOllerton@ecoevo.social (@JeffOllerton) July 12, 2023
By coincidence, overnight I received a message from someone in the USA asking for advice. Here’s a redacted version of their message:
My community has a 4 acre serpentine barren site that is part of a larger string of these unique barrens ….. Honey bee hives have recently been located adjacent to the barrens. Can you advise me as to the best way to determine whether there are, and to document any, adverse effects to the serpentine barrens native pollinators?
Going back to the question of how to assess any impacts, the simple answer is that it’s not easy and it relies on having good data. This was my response to my American correspondent:
Ideally you would need to take a before-and-after approach where you have data on things like number of native pollinator species, their abundance (including nest sites), rates of visitation of different pollinators to flowers, and fruit or seed set from particular plants. You’d then compare what was going on before the hives arrived with what’s occurring since their arrival.
If you don’t have the “before” data it’s much more difficult to assess if there has been an impact from the honey bees. However, the advice of most conservation groups is to adopt the “precautionary principle” and not site hives on or adjacent to areas of nature conservation value, especially if they are relatively small areas. See for example the Bumblebee Conservation Trust’s advice: https://www.bumblebeeconservation.org/managed-honeybees/
The precautionary principle is a well established concept across a range of areas, including health and engineering, as well as nature conservation. In the latter it needs to be more widely applied, especially when it comes to questions of where to site honey bee hives, and how many.
Last year I posted about the work that I’ve been doing on railways and biodiversity with UIC – the International Union of Railways – and the UK Centre for Ecology & Hydrology. That work is now complete and the second of our two reports called UIC Guidelines on Managing Railway Assets for Biodiversity is now out.
UKCEH has produced a press release and I’m copying it verbatim below:
New guidelines for the management of Europe’s railway network to protect and enhance biodiversity have been published.
The UK Centre for Ecology & Hydrology (UKCEH) has worked with the International Union of Railways (UIC), the professional association representing rail companies across the world, to provide technical recommendations and key design features for incorporating and enhancing habitats within the existing European network and new line upgrades, providing examples of best practice.
The UIC European region comprises 118-member companies from 39 countries, amounting to 350,000 kilometres of rail network.
Professor Richard Pywell, Head of Biodiversity at UKCEH who is one of the lead authors of the report, said: “We worked closely with railway companies across Europe to distil the best available knowledge on managing railway assets to benefit nature. For each asset, we considered the most effective measures to protect and restore biodiversity, and how to monitor the outcomes of these interventions.”
Another report author, independent consultant Professor Jeff Ollerton, added: “Working with UIC on this project has revealed just how important the land managed by Europe’s railway companies is for nature. The next step is to better understand how nature supports Europe’s economy, and the health and wellbeing of its people.”
The authors used the widely-adopted mitigation hierarchy approach which guides, developers on protecting existing habitats and ecosystems where possible.
The new UIC Guidelines for Managing Railway Assets for Biodiversity have been drawn up as part of the REVERSE project, in which UIC has worked with its members and UKCEH to formulate a collective vision for protecting and enhancing biodiversity across the European rail network. They now form part of the European Railways: Strategy and Action Guide to ensure management for biodiversity is embedded at every level of the railway business, alongside safety, performance and sustainability. The adoption of the guidelines by member companies will be promoted through various UIC meetings and online events.
The REVERSE project comprises more than 20 European rail companies including Network Rail and SNCF as well as WWF (Worldwide Fund for Nature).
In 2021, UKCEH worked with Network Rail to draw up the rail company’s Biodiversity Action Plan to inform lineside habitat management across the UK. This involved using high-resolution imagery from satellites and aircraft to produce a detailed national map of all the habitats alongside the rail network.
There’s a frequently cited statistic that one third of the food produced for human consumption is wasted every year. That waste occurs for a variety of reasons, including spoilage, over-production and inefficient processing methods. This has clear environmental (and therefore human) consequences, for example in terms of increased carbon dioxide and other greenhouse gas production; excessive use of fertilisers and pesticides; unsustainable water extraction; and conversion of natural habitats to farmland.
Much of the wastage occurs before the food ever reaches shops and markets, so individual consumers have little control over the waste, other than to try to pressure business and political leadership into action. However, we can all do our bit when it comes to reducing food waste in our home, which has positive impacts on our health and our bank balance.
When it comes to fruit and vegetables, we in the west often throw away perfectly edible parts, I suspect because it doesn’t fit with our expectations of what the food “should” look like. A good example is radishes (Raphanus raphanistrum subsp. sativus) where it’s not uncommon to discard the perfectly edible leaves. People who grow them often pull out plants that have flowered, despite the fact that the seed pods are delicious and arguably nicer than the roots, as I discussed in this blog post from a few years ago.
There’s lots of other examples like this, one of my favourites being the crunchy central pith that you find in the thick stems of broccoli (Brassica oleracea var. italica). I love it raw and it has a flavour quite distinct from the normal part that we consume.
It was only quite recently that Karin introduced me to the fact that the mature pods of peas (Pisum sativum) are also edible, if you know how to process them correctly. If you eat the pod as it is, the texture is tough and stringy and not very pleasant. But if you carefully peel away and discard the thin inner membrane of the pod, the remaining flesh is sweet and delicious. It’s fiddly and takes a bit of practice. The easiest way is to gently snap one corner of the half-pod and peel from there – see the example third from the top in the accompanying photograph. Below that in the photo is the thin membrane, which can be put into your food waste or composted, and below that the edible portion of the pod.
Karin and I just eat this raw, but no doubt you could add the pod flesh to any number of dishes. If you have children or grandkids, set them the task of removing the membrane in one piece – it’s not easy!
Please leave a comment below and let me know your favourite bits of edible fruit and veg that are normally discarded.
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:
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.
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.
Prof. Jeff Ollerton - ecological scientist and author 