Cockroaches as pollinators: a new example just published

When you think of the word “pollinator” what comes to mind? For most people it will be bees, particularly the western honeybee (Apis mellifera). Some might also think of hoverflies, butterflies, moths, bats, hummingbirds…..but cockroaches?! The first published example that I know of which demonstrated that the flowers of a plant are specialised for cockroach pollination is from the mid-1990s. Since then only a handful of well documented cases have come to light, but there are undoubtedly more out there waiting to be discovered, particularly in the wet tropics. Most of the c. 4,600 species of cockroaches are nocturnal, and cockroach-pollinated flowers tend to open at night, which is one reason why they are under documented.

In a new study, published this week in the American Journal of Botany, a team of Chinese, German and British biologists has shown that a species of Apocynaceae from China is the first known example of cockroach pollination in that large family. Here’s the reference with a link to the study; if anyone wants a copy please email me:

Xiong, W., Ollerton, J., Liede-Schumann, S., Zhao, W., Jiang, Q., Sun, H. Liao, W. & You, W. (2020) Specialized cockroach pollination in the rare and endangered plant Vincetoxicum hainanense (Apocynaceae, Asclepiadoideae) in China. American Journal of Botany (in press)

The abstract for the paper follows:

Premise

Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were designed to provide direct proof of cockroach pollination and compare the effectiveness of other flower visitors.

Methods

We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition, we reviewed reports of cockroaches as pollinators of other plants and analyzed the known pollination systems in Vincetoxicum in a phylogenetic context.

Results

The small, pale green flowers of V. hainanense opened during the night. The flowers were not autogamous, but were self‐compatible. Flower visitors included beetles, flies, ants and bush crickets, but the most effective pollinator was the cockroach Blattella bisignata, the only visitor that carried pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Plants in this genus are predominantly pollinated by flies, moths and wasps.

Conclusions

Globally, only 11 plant species are known to be cockroach‐pollinated. Because their range of floral features encompass similarities and differences, defining a “cockroach pollination syndrome” is difficult. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.

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A change of career and development of this website

Yesterday was my last day of employment at the University of Northampton, I have stepped down from my professorship to work independently. However I will be staying in touch as a Visiting Professor to complete some projects, supervise my remaining postgraduate researchers, and tidy up the last bits of our REF submission.

It’s been quite a journey over the last 25 years from Nene College > University College Northampton > University of Northampton. I’m proud to have played a part in its development and to have taught some great students along the way. I’ve also made some amazing friends and worked with incredible, talented colleagues. I will miss all of that, but it was time to move on.

So, what of the future? From today I am self-employed as a consultant scientist and writer, focusing on the conservation of pollinators and their plants in our rapidly changing world. No amount of pandemics, Brexits, and American elections can hide the fact that we are having a devastating effect on the nature we rely on to put food on our plates and air in our lungs. The rest of my career is going to be focused on working with individuals and organisations to help to reduce our impact and restore nature.

My philosophy for this is to use the science that I have spent more than 30 years researching and developing, and apply it to the conservation of pollinators and their interactions with plants. At the same time I will continue to take a pragmatic and down to earth approach to thinking about the science that I publish from the perspective of the knowledge and understanding that conservation professionals require to do their work. Some of this is detailed in my book Pollinators & Pollination: Nature and Society (which I hope will be in the shops before Christmas!) but by no means all of it.

Over the next couple of weeks the format of this website will change as I develop it to become more of a shop window for the work I do and the services that I offer. Watch this space!

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Guitarchaeology and hidden black histories

Regular readers of my blog will know that I’m an enthusiastic, if not very talented, player of the acoustic guitar. What I love just as much as playing is the history of these instruments and the music that they have made, and in the past I’ve linked this to the main topic of my blog, biodiversity: see this post on restoring an old guitar.

October is Black History Month in the UK so it seems fitting to share this bit of guitarchaeology: Robert Johnson and Johnny Shines in Steele Missouri – A Research Paper by John Seabaugh

In this video essay John pulls together what’s known, and what he has inferred, about a formative period in the lives of two iconic early blues musicians. Give it a read/listen, it’s really interesting.

John kindly sent me a PDF of the paper so I’ve had a chance to study it closely. What especially struck me was the table of Nightclubs in the Bootheel that appears 4 minutes into the video. John lists 28 nightclubs, the names of all but two of which are known from contemporary newspaper reports. The two unnamed clubs both had black owners.

It’s known from occasional written references and oral histories that there were many other music and drinking joints that were owned, and frequented, by the African-American population in this area. But in an era of strict racial segregation the names of these venues were not recorded in any of the white-run media. A big part of black social history is thus undocumented. And given the importance of black music from this time in shaping popular music around the world, the loss of this history is a tragic loss for everyone.  

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Recipe: Jeff’s salt-fermented sloes

It has been an exceptional year for wild fruit of all kinds and British hedgerows are painted crimson by hawthorn berries, with splashes of purple-black where the sloes hang in succulent bunches. Sloes are, of course, the fruit of the blackthorn tree (Prunus spinosa) and are perfectly edible. In fact blackthorn is one of the progenitor species for cultivated plums. In Britain we tend to associate sloes with sloe gin. But, if you follow this link, you’ll see that there are lots of other edible uses for the fruit. However sloes are notoriously astringent so they need to be processed in some way before they are palatable.

The mention of umeboshi plums in that section of the Wikipedia article got me thinking because it chimes with things that I have been reading in the new book Fermentation by Rachel de Thample. As I mentioned in this post on sourdough bread from a couple of years ago, I have a longstanding interest in fermented foods and drink that goes back to my time working in a brewery in my home town of Sunderland.

Fermentation talks a lot about lacto-fermentation in which salt is used to prevent the growth of “bad” fungi and bacteria and promote the growth of Lactobacillus. These “good” bacteria then ferment the sugars in fruit and vegetables, releasing lactic acid and increasing the edibility and digestibility of the foodstuffs. Sauerkraut is a good example of this process in action. As well as salt you have to exclude air to make the process at least partially anaerobic.

After a bit of reading I experimented with a basic recipe to lacto-ferment sloes to turn them into something resembling the flavoursome wonders that are umeboshi plums. And do you know, it worked! Lacto-fermenting the sloes transforms their flavour from mouth-puckeringly astringent to sour-and-salty.

Here’s the procedure:

Pick your sloes before they are frosted, discarding any that are shriveled or have been damaged by insects or fungi. Immediately wash them to get rid of any dust and rescue the spiders and other invertebrates that are bound to be flushed off! Put the sloes to one side.

Wash and rinse a glass jar with a tight fitting lid, which is equal to the capacity of the sloes but no more, i.e. you want the sloes to fill it to the top. Sterilisation shouldn’t be necessary as the conditions inside will not be suitable for growth of anything other than the Lactobacillus. But it’s best to rinse out any detergent.

Weigh the sloes and then weigh enough fine sea or rock salt to equal 8% of the weight of the sloes. In other words, for every 100 grams of sloes, you need 8 grams of salt*. Don’t use standard table salt as it usually contains chemicals of various kinds.

Add about a quarter of the sloes to the jar and then sprinkle in a quarter of the salt, put the lid on and invert it a couple of times to distribute the salt. Add another quarter of sloes and salt and invert again. Repeat until you have filled the jar with sloes and salt.

Put the lid on tightly, write the date on the jar or on a label, and put in a cupboard or shelf away from direct light. It’s best to stand the jar on a plate to catch any of the liquor that may come out of the fruit.

Invert the jar a couple of times once a day to keep the salt distributed over the sloes. After a few days a purple liquid will start to build up. This is the water from the sloes being drawn out by osmosis. After four or five days open the jar and try one or two sloes. If you like the flavour, put the jar in the fridge to stop the fermentation. Otherwise let them ferment until the flavour suits you.

At the moment I am just snacking on these sloes but I am sure they could be used in recipes that require a salty-sour note. The liquor that builds up in the jar could also be used to flavour dishes or as the basis for a salad dressing.

*8% salt was based on something that I read which I can’t now find and might be overkill. I am going to try it with 2% to 4% salt and see if that works.

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Himalayan pollinators talk by Alan Moss now available to view on YouTube

The Missouri Botanical Garden’s annual John Dwyer Public Lecture in Biology for 2020 that I highlighted in a post last month is now available to view on YouTube – follow this link.

The talk by Alan Moss of Saint Louis University is called: “Ecology and Botanical History of the Himalayas: The Amazing Diversity of Bumblebees and Their Wildflowers on Yulong Mountain”.

Highly recommended and very, very interesting!

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Seasonal blog post views are a widespread phenomenon: a response to Leather (2020)

In a recent study [that was never published] in Nature, Leather (2020) argued that “Time of year determines some, but not all, views of my blog posts“. An analysis of an independent data set confirms this observation: the blog post “How to deal with bumblebees in your roof” shows clear seasonal periodicity (see figure above) with peaks during the most active period of Tree Bumblebee nest activity in May and June.

In contrast, posts such as “How does a scientist’s h-index change over time?” show no such periodicity (see online Supplementary Information).

I conclude that Leather (2020) is correct in his assertion that insect-related posts such as these “show a correlation (OK, not tested) with the time of year associated with the appropriate part of the life cycle”. Furthermore, one of the research councils should give us a wodge of cash to explore this phenomenon in more detail*

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*Only slightly tongue-in-cheek – I think that Simon’s results and those above are telling us something quite interesting about the ways in which people engage with insects throughout the year. Check out Simon’s piece for a fuller discussion of the phenomenon.

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Magnolia, Mississippi, and American politics: a guest post

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.

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

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.

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

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.

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Filed under Bees, Biodiversity, Biodiversity and culture, Butterflies, Ecosystem services, Gardens, Honey bees, Hoverflies, IPBES, Journal of Pollination Ecology, Macroecology, Mammals, Moths, Mutualism, Neonicotinoids, Personal biodiversity, Pollination, Tenerife, Urban biodiversity, Wasps

Is it safe to use oleander to treat COVID-19 symptoms?

No, it’s not safe. It’s a really, really dumb idea. Oleander is VERY poisonous and you could die. Do not do it.

OK, that was the short version; here’s the longer version. Oleander (Nerium oleander) is a plant belonging to the plant family that’s been the focus of much of my research for the past 30 years: Apocynaceae. The plant is widely grown in warm temperate and subtropical areas as an ornamental shrub or small tree and there are cultivars with flowers in a diverse palette of colours. In the Mediterranean, where it’s native, it’s a pollination generalist and pollinated by large bees, hawkmoths, and small flies. However, visitation to flowers is infrequent because, as Javier Herrera showed in this study, the flowers produce no nectar. It’s a rare example of a species of Apocynaceae with rewardless flowers in a family with very diverse pollination systems, as we showed in our study last year.

Although it’s very beautiful, oleander is also extremely poisonous. Many members of the family Apocynaceae are toxic: they are crammed full of alkaloids, cardiac glycosides, and other nasty chemicals that defend the plant against all but the most specialised of herbivorous insects, such as monarch butterflies (Danaus plexippus). But even in a family renowned for its toxicity, oleander stands out as being especially lethal.

Recently, a chemical derived from oleander called oleandrin has been touted as a health supplement to treat patients with the COVID-19 coronavirus. However there is no evidence that it is effective as a treatment but a LOT of evidence that it is highly toxic to both animals and humans. The fact that’s being touted as a COVID19 treatment by President Trump and some of his pharmaceutical industry donors should ring alarm bells for anyone with any common sense. And just because it’s a “natural” product does not in any way make it safe. DO NOT EAT OLEANDER!

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