Category Archives: Pollination

What exactly is a “pollination system”?

Pollination systems

This is a post I’ve been meaning to write for some time, but have never got round to.  What’s catalysed me is an email this morning from Casper van der Kooi asking me about how I define the term “pollination system”, as he’d had some discussions about its use with his colleagues in The Netherlands.

“Pollination system” is one of those terms that seems to mean different things to different people. The way I use it, and I think the way we meant it in the 1996 paper Generalization in pollination systems and why it matters, is that the pollination system = floral phenotype + pollinators.  That is to say, the colour, shape, size, odour, rewards, etc. produced by a flower (or an inflorescence functioning as a single reproductive unit) plus the animals that effectively transfer pollen.

To me this is distinct from a “pollination syndrome” which refers only to the floral phenotype, or “pollinator guild/functional group” which refers only to the flower visitors.  However I have seen “pollination syndrome” used to include floral phenotype + pollinators.  But to my mind they are distinct things.

I have also seen other authors use “pollination system” to mean the community of plants and pollinators in an area, or as analogous to the breeding system, but neither of those are the way that I use it.  I decided to look at the history of the term on Web of Science and the earliest use on there is a paper by Levin & Berube (1972): Phlox and Colias – efficiency of a pollination system.  There were a few other papers from the same decade and all were using pollination system in the way I described above, i.e. floral phenotype + pollinators.

To look for earlier usage of pollination system I searched the Google Ngram Viewer; as you can see in the image above, I found examples of the term back as far as the 1940s in which the pollination system of grasses is referred to as being “cross pollination” (i.e. what we would now refer to as the breeding system).  There’s also texts from the 1950s referring to artificial wind pollination of date palms as a “helicopter pollination system”.

Does it matter how “pollination system” is used, or that it varies in meaning according to the author?  Probably not as long as the meaning is defined in the text.  Ecology is replete with terminology that has slightly different usage according to the researcher (“biodiversity” being an obvious example) and I don’t get a sense that this has held back the field.  Or is that too optimistic a conclusion?  Do you use the term in a different way to me?  As always, your comments are welcomed.

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Filed under Biodiversity, History of science, Pollination

Auto-bee-ography – a new genre of writing?

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In the post today I was pleased to find a copy of Brigit Strawbridge Howard’s first book Dancing With Bees that she had kindly signed and sent after I reviewed some of the text.  It was great timing – I’ve just finished Mark Cocker’s Our Place, a really important historical and future road map of how Britain got to its present position of denuded and declining biodiversity, and what we can do to halt and reverse it. Highly recommended for anyone interested in environmental politics and action.  So Brigit’s book will be added to the pile on my bedside table and may be next in line, though I still haven’t finished Dave Goulson’s The Garden Jungle – perhaps I will do that before I start Dancing With Bees?

And thereby lies a problem – there’s just too many interesting books to read at the moment if you are interested in the environment, or indeed even just in pollinators.  Because a new genre of writing seems to be emerging that I call “auto-bee-ography”. A number of writers are using bees to frame their memoirs and anecdotes.  Dave’s trilogy of Buzz in the Meadow, Sting in the Tale, and Bee Quest is probably the best known. Then there’s Buzz by Thor Hanson; Following the Wild Bees by Thomas Seeley; Bees-at-Law byNoël Sweeney; Keeping the Bees by Laurence Packer; Bee Time by Mark Winston; Bees Make the Best Pets by Jack Mingo; Buzz: Urban Beekeeping and the Power of the Bee
by Lisa Jean Moore and Mary Kosut; The Secrets of Bees by Michael Weiler; and The Bumblebee Flies Anyway by Kate Bradbury.

All of these books fall more-or-less into the category of auto-bee-ography, and I’m sure there are others that I’ve missed (feel free to add to the list in the comments below).  They follow a strong tradition in natural history and environmental writing of using encounters with particular groups of organisms, for example birds and plants, as a way of exploring wider themes  Which is great, the more high profile we can make all of these organisms, including pollinators, the better in my opinion*.

However there’s not enough written about the other pollinators, that does seem to be a gap in the literature.  Mike Shanahan’s Ladders to Heaven has a lot about his encounters with figs and their pollinating wasps, but that’s about it, unless I’ve missed some?  Perhaps in the future I’ll write something auto-fly-ographical called No Flies on Me.  But before that, look out for Pollinators and Pollination: nature and society which I’m currently completing for Pelagic Publishing.  It should be out in Spring 2020.


*Though not in everyone’s – I had a very interesting discussion on Twitter with some other ecologists recently about whether pollinators had too high a profile compared to organisms that perform other functional roles in ecosystems such as seed dispersers.  You can follow the thread from here: https://twitter.com/JMBecologist/status/1165565465705496576

 

 

 

 

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Filed under Bees, Biodiversity, Biodiversity and culture, Book review, Pollination

Websites about bees and other pollinators that are not in English – can you add to my list?

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The book I’m currently completing is going to have a list of useful websites with information about bees and other pollinators, and pollination itself, that are not written in English.  Following a shout-out on Twitter I’ve come up with the following list – can anyone add to it?  There’s a lot of countries/languages missing.  Please respond in the comments section or send me an email:

 

Belgian:

https://www.wildbnb.brussels/

 

Brazilian:

https://www.semabelhasemalimento.com.br/home/polinizacao/

https://abelha.org.br/

 

Chilean:

https://www.abejasdechile.com/

 

Dutch:

http://sapoll.eu/nl/  

http://www.bestuivers.nl/ 

https://www.nederlandzoemt.nl/

 

French:

https://www.pollinis.org/ 

http://www.florabeilles.org/

 

French Canadian:

http://m.espacepourlavie.ca/des-pollinisateurs

 

German:

http://wildbienen.info

http://wildbienen.de 

http://wildbiene.com

 

Norwegian:

https://snl.no/honningbie

https://www.lahumlasuse.no/humlens-liv/

 

Portuguese:  

http://www.cienciaviva.pt/aprenderforadasaladeaula/index.asp?accao=showobj&id_obj=1532

 

Spanish:

http://www.abejassilvestres.es/index2.html

http://apolo.entomologica.es/

http://www.rjb.csic.es/jardinbotanico/jardin/index.php?Pag=697&len=

 

With thanks to everyone on Twitter who responded.

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What happens when pollinators lose their flowers? A new study suggests some answers

 

Biella et al image

Pollinators such as bees and butterflies are highly dependent on flowers to provide nectar as food; at the same time, those plants are reliant on the pollinators for reproduction.  Over the past few decades, declines in both flower and pollinator diversity and abundance have prompted ecologists to wonder about the consequences of flower loss for pollinator communities and for plant pollination.

In a ground breaking new study, a team from institutions in the Czech Republic and the University of Northampton in the UK have published the results of experiments that seek to answer these questions.  Led by PhD researcher Dr Paolo Biella, the team performed experiments in both countries that involved temporarily removing thousands of flower heads from grassland plant communities.  They assessed how the pollinator assemblage responded to their removal, and how effectively the remaining flowers were pollinated.  The team focused on generalist plant species that support the majority of pollinators within a community because these have traditionally been less well studied than highly specialised relationships.

The results are published today in the open access journal Scientific Reports and provide the first demonstration of the ways in which pollinators flexibly adjust their behaviour when faced with a sequential loss of resources.  This flexibility is constrained by the type of flowers they visit, however:  pollinators will tend to switch to flowers of a similar shape to the ones that have been lost.  From the plant’s perspective, things are less clear: the patterns of pollination for the remaining species were idiosyncratic and not as predictable.  Some plants received more pollination during the experiment than before, others less.

For the first time we are seeing the consequences of sudden loss of flowers for both the pollinators and the plants in a habitat.  That the pollinators can respond flexibly to this loss is a welcome indication that these insects might be more resilient to sudden changes than we had thought.  However, the erratic pollination of the flowers shows that there is a great deal of random chance within these ecological systems that is not easily predictable.  In the same week that the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report on Biodiversity and Ecosystem Services was published, our study reminds us that there is much that we do not currently understand about the consequences of sudden changes in the natural world.

One of the team’s recommendations is that pollination-generalist plant species should be given much more attention in conservation assessments than has previously been the case.  These plants are at the core of plant-pollinator communities and without them the rarer and more specialised species could not exist.

Details of the study are as follows:

Biella P., Akter A., Ollerton J., Tarrant S., Janeček Š., Jersáková J. & Klecka J. (2019) Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging.  Scientific Reports 9: 1-13

Here’s the abstract:

Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1-4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions.

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Filed under Bees, Biodiversity, Butterflies, Hoverflies, Pollination, University of Northampton, Wasps

Are these first photographs of a living specimen of a rare African butterfly?

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Earlier this year my colleague at the Royal Botanic Gardens Kew, David Goyder, tweeted a link to a new book about the biodiversity of Angola which you can download for free by following this link.  David’s an authority on Apocynaceae, the family of plants on which I’ve also worked for many years (see this recent post), and has been sorking in Angola in recent years on a large biodiversity project.  So I was interested to see what was in the chapter  he had co-authored called “The flora of Angola: Collectors, Richness and Endemism“.  I was immediately struck by one of the images in Figure 5.3 showing an unnamed butterfly feeding on the flower of a species of Apocynaceae (Raphionacme michelii).

I made a note to myself to talk to David about adding the record to our Pollinators of Apocynaceae Database. But before I had a chance to do that, another apocynologist colleague, Ulrich Meve in Bayreuth, forwarded the chapter with a similar idea in mind.

We emailed David about the image and he sent us originals, but confessed he didn’t know what the insect was.  So I uploaded it to an African Lepidoptera forum on Facebook.  At which point a wave of excitement broke, because after some discussion as to whether it might be a new species, it turned out that the most likely candidate was an exceptionally rare butterfly called Acraea mansya in the family Nymphalidae.

According to Dominique Bernaud, an authority on the group, this species is hardly known beyond a few collections and he has never seen a photograph of a living specimen: if you follow this link you will see that the known distribution of the species does not include Angola,  and indeed it is not listed in the chapter on butterflies in the Angola biodiversity book.  So this is a new country record and (we think) the first images of living insects: so a double first for a beautiful species.

Here’s links to collection information for the plant and to David’s checklist of plants from the region, which gives details of the vegetation and the habitat.

An unanswered question, of course, is whether the butterfly is a pollinator of this species of plants.  Raphionacme belongs to a subfamily of Apocynaceae that have hardly been studied from the perspective of pollination ecology, so we simply don’t know.  Hopefully someone in the future will visit this remote region of Africa and find out!

Thanks to David for sending the images (a complete set of which is below), the National Geographic Okavango Wilderness Project, and the Wild Bird Trust, Parktown, South Africa.

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Filed under Apocynaceae, Biodiversity, Biogeography, Butterflies, Pollination

Is pollination really an ecosystem service?

Ashy Mining Bee 2017-06-17 10.55.53

Yesterday on Twitter Prof. James Bullock from the Centre for Ecology and Hydrology posted a slightly provocative tweet asking: “why pollination is so often called an ecosystem service. To my mind it is an ecosystem process which can, in some circumstances (e.g. crop pollination), support services such as food provision”.

I confess to being a bit surprised to see this; I’d always referred to pollination (at least by animals) as an ecosystem service, and it’s classified in that way in large status-and-trend reports such as the Millennium Ecosystem Assessment and (more recently) the IPBES Assessment Report on Pollinators, Pollination and Food Production which describes animal pollination as “a regulating ecosystem service that underpins food production and its contribution to gene flows and restoration of ecosystems”.

The crux of James’s question is illustrated in this diagram from a paper by Prof. Georgina Mace and colleagues in 2012 entitled Biodiversity and ecosystem services: a multilayered relationship.  However note that even here, pollination straddles the line between ecosystem processes and services:

Mace ES image

My initial response to James’s tweet was that animal pollination is really a community process as the interaction, and its outcomes, between animal and crop plant is dependent mainly on species diversity and abundance.  Remember, an ecosystem is the sum of the biotic (i.e. community) plus abiotic (e.g. energy, water, mineral nutrients, etc.).  So as far as crop pollination is concerned, the abiotic components of an ecosystem don’t really come into it except in as much as they influence diversity and abundance of all life on Earth.  This is in contrast to more strictly ecosystem processes that link directly to the abiotic factors, such as primary productivity and soil formation, that then support ecosystem services.

It’s further complicated by the fact that many of the plants that perform ecosystem services, such as carbon capture by trees, are themselves dependent upon animal pollination to maintain their populations.  It’s the plants that are providing the ecosystem services but the animals are playing an important role in supporting that.

If you’d like to follow that discussion, which has some interesting contribution from a range of people, here’s the link:

 

But ultimately I feel that these are fairly arbitrary definitions across a continuum of causes and effects: we know what animal pollination of crops and wild plants is and why it’s important, so what we call it doesn’t really matter, does it?  Other things are much more concerning.  At the moment the UK is experiencing unprecedented weather: for the first time ever, earlier today, a temperature of in excess of 20 Centigrade has been recorded in winter.  It currently feels more like late April or early May than February.  I’m already seeing a lot of pollinator activity in the garden and beyond, and each day more plants come into flower, far earlier than expected.

The current and future effects of such changes in the climate are far more important than discussions of the semantics of processes versus services, however interesting that might be.

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Filed under Bees, Biodiversity, Climate change, Ecosystem services, IPBES, Pollination

A poem for Valentine’s Day

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I have to confess that I forgot completely about Valentine’s Day, it’s not a celebration that I generally pay much attention to, as expressions of love are something that everyone should be doing all the time, surely?

Anyway, this bastardised version of “Roses are red” is for my wife Karin:

Some bees are red
Others are blue
There’s twenty thousand species
Of every hue

Some flies are yellow
Some wasps are cerise
Many of them pollinate
Better than bees

 

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Filed under Bees, Biodiversity, Poetry, Pollination, Wasps

Recent reviews in pollination biology: an annotated list: UPDATED x 3

2019-02-09 13.47.49

As it’s my birthday today, I thought I’d reward myself by completing a blog post that I started just after Christmas and never got round to finishing.  Review articles that summarise recent developments in a field are an important contribution to the scientific literature that allow us to pause and reflect on where a topic has been and where it is headed.  Having recently (co)authored a couple of reviews I can attest that they are useful in this respect for both the writers and for the readers.

In the past couple of years quite a number of critical and timely reviews have been published which are proving very useful to me: I’m currently writing a book and these reviews have been invaluable in summarising aspects of a field that is currently publishing in excess of 1000 research papers per year. So I thought I’d bring them together into a single listing with a short commentary on each.  No doubt I have missed many other reviews so please feel free to point out any gaps and I will update the list as I go along.

Each review is hot linked to the source; a good proportion of the reviews are open access, notably those from the recent special issue of Annals of Botany devoted to the ecology and evolution of plant reproduction.  Some reviews are very focused, but most are quite broad.  Several of these complement one another.  I hope you find them interesting and useful.

Barrett, S. & Harder, L. (2017) The ecology of mating and its evolutionary consequences in seed plants. Annual Review of Ecology, Evolution and Systematics 48: 135-157

Mating systems, i.e. who breeds with whom, are just as complex in plants as they are in animals.  However some features of seed plants, such as the fact that they don’t move, that most species have both male and female functions, and that their growth is modular and often indeterminate, represent significant challenges that have been overcome in a bewildering variety of ways.

 

Braun, J. & Lortie, C.J. (2018)  Finding the bees knees: A conceptual framework and systematic review of the mechanisms of pollinator-mediated facilitation.  Perspectives in Plant Ecology, Evolution and Systematics 36: 33-40

In a community, if one plant species positively affects another, we term this “facilitation”.  It can occur at a variety of life stages, including reproduction whereby the presence of one species increase the likelihood of another species being pollinated.  This review shows that it occurs fairly frequently at a variety of spatial scales, but there are still significant gaps in our understanding of the phenomenon.

 

Fuster, F., Kaiser‐Bunbury, C., Olesen, J.M. & Traveset, A. (2018) Global patterns of the double mutualism phenomenon. Ecography https://doi.org/10.1111/ecog.04008

When species provide benefits to one another in two different ways, for example an animal is both a pollinator and a seed disperser of a plant species, we refer to it as a “double mutualism”.  As this fascinating review shows, double mutualisms are very uncommon, but they are widespread, and probably under-recorded.

 

Minnaar, C., Anderson, B., de Jager, M.L. & Karron, J.D. (2019) Plant–pollinator interactions along the pathway to paternity. Annals of Botany 123: 225-245 

The male aspect of plant reproduction, i.e. pollen donation, is often neglected when we consider how pollination systems evolve.  This review provides as up to date account of where we are in understanding how paternity influences floral characters such as shape and colour.

 

Ollerton, J. (2017) Pollinator diversity: distribution, ecological function, and conservation. Annual Review of Ecology, Evolution and Systematics 48: 353-376

A very broad over view of our current understanding of the biodiversity of pollinators, taking a deep time and a wide spatial perspective to put current concerns about loss of pollinators into a wider perspective.

 

Parachnowitsch, A.L., Manson, J.S. & Sletvold, N. (2019) Evolutionary ecology of nectar. Annals of Botany 123: 247–261 

We often take nectar for granted – it’s just sugar and water, isn’t it?  As this review shows, nectar is dynamic and complex, and affects a range of ecological functions beyond just providing pollinators with a reward.  However there’s still a huge amount we don’t understand about how nectar traits evolve.

 

Toledo-Hernández, M., Wangera, T.C. & Tscharntke, T. (2017) Neglected pollinators: Can enhanced pollination services improve cocoa yields? A review.  Agriculture, Ecosystems and Environment 247: 137-148

Chocolate is most people’s favourite confectionery and is famously pollinated only by small midges.  Or is it? As this review shows, lots of other insects visit cocoa flowers, but their role as pollinators has not been well studied.

 

Vizentin-Bugoni J, PKM Maruyama, CS Souza, J Ollerton, AR Rech, M Sazima. (2018) Plant-pollinator networks in the tropics: a review. pp 73-91 In Dáttilo W & V. Rico-Gray. Ecological networks in the Tropics. Springer.

This book chapter that I co-authored with some very energetic and creative young Brazilian researchers summarises what’s currently known about plant-pollinator interaction networks in tropical communities.  One of the conclusions is that they are really not so different to those in temperate and subtropical biomes.

 

Wright, G.A., Nicolson, S.W. & Shafir, S. (2018) Nutritional Physiology and Ecology of Honey Bees. Annual Review Entomology 63:327-344

A review of how bees use nectar and pollen at the level of both the individual and the colony, focused on the most widespread of pollinator species.

UPDATE 1:

As expected, several people have told me about reviews I’d missed, and in some cases ones that I had read but forgotten about!  I’ll list them below, though without annotations:

Bennett, J. et al. (2018) A review of European studies on pollination networks and pollen limitation, and a case study designed to fill in a gap, AoB Plants 10:  https://doi.org/10.1093/aobpla/ply068

Knight, T. et al. (2018) Reflections on, and visions for, the changing field of pollination ecology. Ecology Letters 21: 1282-1295

Vallejo-Marin, M. (2018) Buzz pollination: studying bee vibrations on flowers. New Phytologist https://doi.org/10.1111/nph.15666

 

UPDATE: 2

I had deliberately restricted the reviews to 2017 onwards, but via email David Inouye kindly sent a few older ones through which are equally useful:

Brosi, B. J. (2016) Pollinator specialization: from the individual to the community. New Phytologist: 210: 1190–1194

Hahn, M. and C. A. Brühl (2016) The secret pollinators: an overview of moth pollination with a focus on Europe and North America. Arthropod-Plant Interactions: 1-8

Inouye, D. W., et al. (2015) Flies and flowers III: Ecology of foraging and pollination. Journal of Pollination Ecology 16

 

UPDATE 3:

A more recent addition to this set of reviews was sent to me by Anne-Laure Jacquemart.  Although it’s focused just on one (rather variable) crop, I think it will be really useful for anyone interested in the pollination biology of crop plants:

Ouvrard, P. & Jacquemart, A.-L. (2019) Review of methods to investigate pollinator dependency in oilseed rape (Brassica napus).  Field Crops Research 231: 18-29

 

 

 

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Filed under Bees, Biodiversity, Brazil, Honey bees, Mutualism, Pollination

Tantalising evidence for a new type of pollination system in Madagascan Apocynaceae

cynanchum obovatum with wasp_madag -angavokely_meve 1

As I recounted in my post last summer, the plant family Apocynaceae contains species with a very wide diversity  of pollination systems – see:  The evolution of pollination systems in one of the largest plant families: a new study just published – download it for free.  Confirmed pollinators include bees, birds, moths, butterflies, flies, beetles, and wasps of a dizzying diversity.  So I was intrigued to receive an email earlier this week from my colleague Prof. Dr Ulrich “Ulli” Meve of the University of Bayreuth with the subject line “Wasp expert needed”.  Ulli is an authority on Apocynaceae taxonomy, also has an interest in their pollination biology, and is a co-author of the study last year.

Attached to the email were a couple of images showing a wasp visiting flowers of Cynanchum obovatum, an endemic species of Apocynaceae from northern and eastern Madagascar.  Ulli had taken the photographs during field work there in preparation for the Flora of Madagascar project.  Here’s the global distribution of the species according to GBIF records:

cynanchum obovatum from gbif

I was excited because Madagascar has a very rich diversity of Apocynaceae (between 500 and 1000 species).  However we have flower visitor observations for only a small fraction of them, fewer than 20 species, and good evidence that the visitors are pollinators for only a couple of those.

I didn’t immediately recognise the family to which the wasp belonged: it didn’t look like either Vespidae or Pompilidae, two groups that are known pollinators of Apocynaceae.  So I uploaded the shots to the Hymenopterists Forum on Facebook and within minutes had received an answer:  it was a species of Scoliidae, commonly referred to as scoliid wasps.  The distinctive wing corrugation found in this family is clearly visible on this image:

cynanchum obovatum with wasp_madag -angavokely_meve 2

Scoliids are parasitoids of beetles and are some of the world’s largest wasps, but it’s not a very diverse family, with only about 560 described species, and only a single species in the UK (on the Channel Islands).  Compare that with the Pompilidae and Vespidae, both of which contain c. 5,000 species worldwide.

Ulli tells me that when he saw the scoliid on C. obovatum “the wasp knew what to do with the flowers”, something I’ve experienced with vespid and pompilid wasp pollinated species in Africa: these wasps are really familiar with the flowers, they know how to work them to get a reward as they are regular and committed visitors.  We believe that this is likely to be the legitimate pollinator of the plant, in which case it’s one of the few records for Scoliidae pollinating Apocynaceae, and the first for Madagascar.  Other examples are mainly in South America, India and South Africa, and usually as one of a broad set of other wasps and/or bees visiting generalist flowers.

It’s interesting that this species of Cynanchum is one of the few in which the corona which covers the gynostegium (the fused sexual parts) is closed over:

cynanchum obovatum_madag - angavokely_meve

That means it requires quite a strong, large insect to get inside and access the nectar.  So the prediction is that the pollen masses (pollinaria) will be found on the mouthparts of these wasps.  Intriguingly, a very closely related species C. repandum has no such closed corona, begging the question of whether it might be pollinated by a different type of insect:

cynanchum repandum sl 2867_low

For now this record will go into the Pollinators of Apocynaceae database as pollinator unproven, but i would be great if someone working in Madagascar could confirm the status of this pollination system.

My grateful thanks to Ulli for sharing his pictures and allowing me to tell the story of what may be a whole new Madagascan pollination system for our favourite family.  Apocynaceae is full of surprises!

cynanchum obovatum with wasp_madag -angavokely_meve 3

 

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Climate change at Christmas: did the hot, dry summer of 2018 cause the record-breaking prices of holly and mistletoe?

Over the past two festive seasons I have posted about the research we published assessing the auction prices of holly and mistletoe, two culturally important seasonal crops that are 100% pollinator dependent for berry production.  The first post was called Insect pollinators boost the market price of holly and mistletoe: a new study just published; the second was The holly, the mistletoe, and the pollinators: an update on an old story.

Follow those two links to get the full background to this research and a link to the original paper published in the Journal of Pollination Ecology.

I’ve collated the auction prices for the 2018 season and added them to the time series data set, and it’s clear that something very interesting has occurred.  Both berried holly and mistletoe have achieved record-breaking average prices, whilst auction prices for material without berries have hardly changed at all.  Here are the updated graphs; each data point is the average price per kilo paid at an auction:

Holly and mistletoe prices 2018

So what’s gone on this year?  What could have affected the auction prices?  One interesting possibility is that the long, dry summer of 2018, a likely consequence of climate change, has negatively affected berry production in these two species.  This could come about if the holly or the mistletoe host trees are water stressed and shed part of their berry crops.  It’s unlikely to be a consequence of too few pollinators as these species flower too early in the year to have been affected by the dry weather.   We have more work planned in the future using these data and this will be an interesting question to address.

Yesterday I popped out to do some Christmas shopping and tried to buy mistletoe at a local garden centre.  That’s the second time I’ve tried this year (the first was at a nearby green grocer’s) and the second time that I’ve been told that they have none because it’s very expensive this year and not worth stocking.  That seems predictable from the wholesale auction results I’ve just described.  Has anyone else in the UK had similar experiences this year?

The British holly and mistletoe market is relatively small and clearly seasonal, and probably not worth more than a few millions of pounds each year.  However it seems to be very sensitive to external factors and may be a microcosm for how some crops, at least, might respond to future extreme weather brought about by climate change.  Brexit might also have an effect in the coming years as we import a large amount of mistletoe from northern France.  But then Brexit is going to have an effect on large areas of British society…..

On that sour note, Happy Christmas to all of my readers, however you voted in the referendum.  I hope you have a restful holiday, spending it as you wish, with the people you want to!  And if you, or someone you know, are spending the festive season on your own this year, take a look at Karin’s latest blog post:  Preparing a Christmas Just For You.

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Filed under Biodiversity, Biodiversity and culture, Climate change, Ecosystem services, Journal of Pollination Ecology, Pollination