Tag Archives: Nature

Flowers can be assholes – quite literally!

WARNING: There’s a high yuck factor to this post, it’s not for the squeamish or easily offended!

One of my Twitter contacts, Traci Birge in Finland, has been reading Pollinators & Pollination: Nature and Society, and making some very nice comments about it. I had to laugh at this one in which she describes some plants as “assholes” because of the way in which they deceive pollinators into visiting their flowers but offer no reward in return:

Pollinators and Pollination is a great journey.

Still thinking about plants manipulating animals – plants can be assholes (@JeffOllerton's description is more scientific), e.g. using scent to convince flies they are carrion & suitable site for egg-laying.
— 🐟 Traci Birge🐝 (@TraciInFinland) January 17, 2021

If you follow that thread you can see that Traci was closer to the truth than perhaps she realised: there are some plants with flowers that appear to mimic the anuses of dead mammals, particularly in the families Apocynaceae and Araceae. By their smell, texture, colour and hairiness they are fooling flies into visiting the flowers, because assholes, like any mammalian orifice, provide an entry point for maggots of carrion-feeding flies. Sometimes the deception is so great that the flies lay their eggs on these blooms, though of course the maggots starve.

A great example of an anus-mimicking bloom is the Dead Horse Arum (Helicodiceros muscivorus). Check out the image above: if that doesn’t look like a horse’s ass, I don’t know what does!

Other examples might be found within the stapeliads, especially the genus Huernia which often have a thickened annulus to the centre of the flower. However that could also be interpreted as mimicking an open, inflamed wound on the side of an animal:

As I point out in the book, you might imagine that there would be strong natural selection against flies visiting these flowers if they lose fitness by laying eggs on such an unsuitable substrate. But the flowers are tapping into really deep-seated behaviours and clearly the flies can’t distinguish the flowers from the real thing.

This is flower pollination that is far removed from the deliciously perfumed, cute-and-cuddly, heart-warming world of bees and flowers. Isn’t nature wonderful?

All photos from Wikipedia, as follows:

Helicodiceros muscivorus: Göteborgs botaniska trädgård (photographer: Ingemar Johansson) – http://www.mynewsdesk.com/se/pressroom/goteborgs_botaniska_tradgard/image/view/dracunculus-muscivorus-128973, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19265330

Huernia zebrina: Enzo^ – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=10963668

Huernia schneideriana: Juan Carlos Fonseca Mata – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94705877

“Bee Together” with YDMT – pollinator online talks during January and February

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As I write a slow haze of fine snow is falling, covering our garden with a thin white dusting. Spring feels a long way off, despite the emerging spears of daffodil leaves. But you can get a taste of what the new season will bring by signing up for a short series of free evening online talks on the topic of pollinators that has been organised by the Yorkshire Dales Millennium Trust – here’s the link for the Bee Together programme – and here’s more details of the talks:

Thursday January 28 at 7pm: Pollinators and Pollination: Nature and Society
An overview of the diversity of pollinators in Britain, why they are important, and the threats to that diversity with Jeff Ollerton.

Thursday February 18 (7pm): The B-Lines Project
Buglife’s B-Lines network is an imaginative solution to the problem of the loss of flowers and pollinators. B-Lines are a series of ‘insect pathways’ running through our countryside and towns, along which Buglife are restoring and creating a series of wildflower-rich habitat stepping stones. Catherine Jones talks about mapping the recently completed B-Lines map and some of the projects that have already created habitat for pollinators.

Thursday February 25 (7pm): The Hidden Lives of Garden Bees
Brigit Strawbridge Howard will explain some of the basic differences between bumblebees, solitary bees, and honeybees – including lifecycles and nesting behaviour; the problems they all face; and, most important, what we can do to help. Brigit is a wildlife gardener, amateur naturalist and advocate of bees. She writes and campaigns to raise awareness of the importance of native wild bees, and is the author of Dancing with Bees: A Journey Back to Nature.

I hope to see some of you there: Happy New Year everyone!

Finally, a physical copy of my book!

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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.

Magnolia, Mississippi, and American politics: a guest post

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This is a short guest post by Dr Peter Bernhardt who recently retired as a professor at St Louis University and continues to be active in pollination biology.

Each of the 50 American states has its own flag. On Election Day in November 2020 the citizens of the state of Mississippi will vote on whether they want a new flag featuring the flower of their state tree, the southern magnolia or bull bay (Magnolia grandiflora). Of the eight Magnolia species native to the continental United States six have natural distributions including the state of Mississippi.

By voting in the magnolia flag Mississippians drop its 126-year old predecessor, which incorporated an emblem (the stainless banner) adopted by southern states during the American Civil War (1861-1865). This will also mean that Mississippi will be the only state with a flag depicting a flower in which tepals, stamens and carpels are all arranged in a continuous spiral and is pollinated by beetles (see Leonard Thien’s study published in 1974).

The popularity of M. grandifora far exceeds silviculture in the American south as successful exports stretch over two centuries and its cultigens are found as far as China and Australia.

Politics in America have turned floral in the last months of 2020: kamala, as in vice-presidential candidate Kamala Harris, is an Indian word for sacred lotus (Nelumbo nucifera).

To which Jeff adds: the flag above is the one that Mississippi citizens will be voting on – follow the link at the start to get the full story of the competition that was run to select a new flag.

Just published: An empirical attack tolerance test alters the structure and species richness of plant–pollinator networks

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The latest paper from Paolo Biella‘s PhD work, on which I collaborated and that I’ve discussed before on the blog, has just been published in the journal Functional Ecology. It’s entitled “An empirical attack tolerance test alters the structure and species richness of plant–pollinator networks“. The paper presents more of Paolo’s work showing how the experimental removal of the floral resources provided by the more generalised plants in a community can significantly (and negatively) affect the patterns of interaction between flowers and pollinators that we observe. It’s another piece of evidence that demonstrates how important it is to not neglect the common plants that attract a lot of flower visitors when considering how to manage a habitat.

If anyone has trouble accessing the PDF, drop me a line and I will send it to you.

Here’s the reference:

Biella, P., Akter, A., Ollerton, J., Nielsen, A. & Klecka, J. (2020) An empirical attack tolerance test alters the structure and species richness of plant-pollinator networks. Functional Ecology DOI: 10.1111/1365-2435.13642

Here’s the abstract:

Ecological network theory hypothesizes that the structuring of species interactions can convey stability to the system. Investigating how these structures react to species loss is fundamental for understanding network disassembly or their robustness. However, this topic has mainly been studied in‐silico so far.

Here, in an experimental manipulation, we sequentially removed four generalist plants from real plant–pollinator networks. We explored the effects on, and drivers of, species and interaction disappearance, network structure and interaction rewiring. First, we compared both the local extinctions of species and interactions and the observed network indices with those expected from three co‐extinction models. Second, we investigated the trends in network indices and rewiring rate after plant removal and the pollinator tendency at establishing novel links in relation to their proportional visitation to the removed plants. Furthermore, we explored the underlying drivers of network assembly with probability matrices based on ecological traits.

Our results indicate that the cumulative local extinctions of species and interactions increased faster with generalist plant loss than what was expected by co‐extinction models, which predicted the survival or disappearance of many species incorrectly, and the observed network indices were lowly correlated to those predicted by co‐extinction models. Furthermore, the real networks reacted in complex ways to plant removal. First, network nestedness decreased and modularity increased. Second, although species abundance was a main assembly rule, opportunistic random interactions and structural unpredictability emerged as plants were removed. Both these reactions could indicate network instability and fragility. Other results showed network reorganization, as rewiring rate was high and asymmetries between network levels emerged as plants increased their centrality. Moreover, the generalist pollinators that had frequently visited both the plants targeted of removal and the non‐target plants tended to establish novel links more than who either had only visited the removal plants or avoided to do so.

With the experimental manipulation of real networks, our study shows that despite their reorganizational ability, plant–pollinator networks changed towards a more fragile state when generalist plants are lost.

The chapter titles for my book: Pollinators & Pollination: Nature and Society

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A few people have asked me about what’s covered in my book which is being published by Pelagic and is currently in production. Here’s the chapter titles:

Preface

1 The importance of pollinators and pollination

2 More than just bees: the diversity of pollinators

3 To be a flower

4 Fidelity and promiscuity in Darwin’s entangled bank

5 The evolution of pollination strategies

6 A matter of time: from daily cycles to climate change

7 Agricultural perspectives

8 Urban environments

9 The significance of gardens

10 The shifting fates of pollinators

11 New bees on the block

12 Managing, restoring and connecting habitats

13 The politics of pollination

14 Studying pollinators and pollination

As you can see it’s a very wide-ranging overview of the subject, and written to be accessible to both specialists and non-specialists alike. To quote what I wrote in the Preface:

“While the book is aimed at a very broad audience, and is intended to be comprehensible to anyone with an interest in science and the environment, and their intersection with human societies, I hope it will also be of interest to those dealing professionally with plants and pollinators. The subject is vast, and those working on bee or hoverfly biology, for example, or plant reproductive ecology, may learn something new about topics adjacent to their specialisms. I certainly learned a lot from writing the book.”

The book is about 100,000 words in length, lots of illustrations, and there will be an index. My copy editor reckons there’s 450 references cited, though I haven’t counted. I do know that they run to 28 pages in the manuscript, and that’s with 11pt text. All going well it will be published before Christmas.

SCAPE gets a new website and registration for the 2020 conference is now open

Pollinators and pollination in the UK: an introductory workshop – 26th August

Animal deaths in the Australian bushfires even greater than first feared – and what about the plants?

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2019-12-27 15.07.16

Earlier this year I reported on the unprecedented Australian bushfires with some reflections of what I was observing during my time as a Visiting Research Fellow at the University of New South Wales – see: How are the Australian bushfires affecting biodiversity? Australia reflections part 4. Karin also wrote a piece about the fires, focusing on the human impacts – see: Climate Change Stories From a Nation on Fire.

At the time scientists and the media were suggesting that perhaps half a billion reptiles, mammals and birds had been killed, a figure that provoked a strong public reaction when accompanied by images of fire-scorched koalas. This was then revised upwards to 1 billion. But it turns out that even a billion is nowhere close to the real number of animal deaths. A new interim report commissioned by WWF-Australia suggests that just under 3 billion animals were either directly killed or displaced. Those which were displaced were vulnerable to feral predators such as foxes and cats, or more likely to succumb to starvation. An article in The Guardian about the WWF-Australia report is worth reading – here’s the link.

The actual figure is 2.69 billion individual animals. Think about that for a moment. That’s about equivalent the number of people living in India and China combined. This is the breakdown for the different animal groups that were assessed:

● 143 million mammals
● 2.46 billion reptiles
● 180 million birds
● 51 million frogs

One thing should be immediately apparent: this is not a complete list of the “animals” that have been killed. A lack of data means that fish, turtles and (crucially) invertebrates such as spiders, bees, beetles, and earthworms, were excluded. Those invertebrates live at much higher densities than any of the animal groups that were assessed and indeed are the sole or principle food for many of those species. The number of insects required to support just the insectivorous birds is staggering: globally, birds are estimated to eat 400-500 million tonnes of insects and other arthropods every year.

Even if we were to consider just the larger invertebrates, those bigger than say 0.5 cm in length (which are a minority – most are considerably smaller), then then the true scale of the animal deaths is going to be one or two orders of magnitude higher. Or possibly more. Thirty billion, 300 billion, 3 trillion…? Who knows? It’s impossible to estimate, we just don’t have enough information about those organisms.

The other major component of wildlife that is missing from the report is the plants. I know that studies of plant mortality are being undertaken at the moment and it will be important that this is given the same level of publicity as the assessments of animals.

Writing in the foreword of the report, Dermot O’Gorman the CEO of WWF-Australia pointed out that: “It’s hard to think of another event anywhere in the world in living memory that has killed or displaced that many animals. This ranks as one of the worst wildlife disasters in modern history”.

I disagree. I think it’s THE worst wildlife disaster in terms of the scale of animal losses over such a short period of time. No doubt deforestation and destruction of grasslands in South America, Asia and Africa has killed more animals and plants. But that’s over a timescale of decades to hundreds of years. Australian wildlife was devastated in a matter of months. And no one knows exactly what the 2020-21 fire season will bring. But I think that we can safely predict further impacts on wildlife – and people.

A simple online ecosystem model: like Tamagotchi for the green generation