Tag Archives: Pollinators

Dispelling the myth that orchid species usually only have a single pollinator

Orchids at Kew 2014-02-24 15.30.32

The idea that members of the plant family Orchidaceae (the orchids) “typically have exclusive relationships with their pollinators“, such that each orchid has only one pollinator, is a persistent one.  Recently I’ve encountered it on horticultural websites (follow that last link), in grant proposals, and on Wikipedia.

The problem is that it’s not true: it’s a myth that is perpetuated by people (often botanists or horticulturalists) who may know a lot about orchids but don’t know as much as they think they know about pollination ecology.

Orchids certainly have some fascinating and often quite intricate floral mechanisms to ensure pollination, but these have not necessarily evolved to attract and exploit just one species of pollinator.  Even in the case of sexually deceptive orchids that fool their (male) pollinating insects into believing that they are mating with a female of the same species, it is sometimes the case that more than one insect species is involved.  For example, in the well studied genus Ophrysflowers are pollinated by a narrow taxonomic range of pollinators, from a single species to up to five closely related species“.  As the authors of that last paper state, this is not the same as the mythological “extreme case of one orchid/one pollinator”.

Likewise different species of orchid bees may pollinate the same orchid flowers as they visit to collect scent compounds; for example in the Brazilian species Dichaea pendula, species from at least two different bee genera act as pollinators (Nunes et al. 2016).

The fact that “one orchid/one pollinator” is a myth is not new knowledge, it’s been widely discussed in the pollination ecology literature for decades.  For example, in our 1996 paper “Generalization in Pollination Systems, and Why it Matters” we showed data from the late 19th/early 20th centuries that clearly indicated a range of specialization in European orchids (follow that link and look at  Figure 3B).  Even earlier than this, in his 1992 paper “Trends in the pollination ecology of the Orchidaceae: evolution and systematics” Raymond Tremblay showed that only about 62% of species for which he could find data had a single pollinator, and that this varied considerably between different subfamilies of Orchidaceae, with some subfamilies being more specialized than others.

More recently, in a chapter in the 2006 book I co-edited with Nick Waser entitled “Geographical Variation in Diversity and Specificity of Pollination Systems” Steve Johnson, Andrew Hingston and myself looked at data from southern African compared to North American and European orchids; here’s the figure from that assessment:

 

Ollerton et al Figure 7 - JPEG

Orchids  are more specialized in southern Africa compared to Europe and North America (as are a number of other plant groups including the asclepiads, which we’re comparing them with here).  But even in southern Africa, only about 65% of the orchids studied have a single pollinator species.  It’s worth pointing out, though, that many of the species included in this analysis, and in Raymond Tremblay’s paper, have been studied only at single sites and often in single years, meaning that we have no idea if there is any spatio-temporal variation in the pollinators a particular orchid species exploits.

Why does this myth persist?  I think it’s for the same reason that myths are retold from generation to generation: they are great stories that fascinate the teller and the audience.  Indeed, orchids are very special plants with some amazing floral and vegetative adaptations, fascinating relationships with fungi, and incredible diversity.  But we don’t have to mythologise their relationships with their pollinators to try to make orchids more special than they already are.

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The decline of the “humble bee” – a short follow-up from yesterday’s post

The piece I posted yesterday about whether the names two of our most well known pollinators should be spelled honey bee/honeybee or bumblebee/bumble bee generated a lot of interesting comments on Facebook, Twitter, and on the blog.  A few people pointed me to the “Snodgrass Rule” that informal names should be combined only if the species concerned are not members of that particular taxon (e.g. “butterfly” rather than “butter fly”, because they are not “flies”), in which case “honey bee” and “bumble bee” are correct.

If I was ever aware of this entomological convention I’d certainly forgotten about it, but it strikes me that there’s a lot of examples outside of entomology that break the rule, e.g. hummingbird, goldfinch, catfish, ground ivy, etc.

A couple of commentators also asked me about the old term “humble bee”, as used in Frederick Sladen’s 1912 book “The Humble-Bee, its Life-History and How to Domesticate It”.  So I added this to the bumblebee/bumble bee search on the Google Ngram Viewer, taking the time frame back to 1500, and the results are very intriguing:

screen-shot-2017-03-01-at-09-59-55 It would appear that “bumble bee” pre-dates “humble bee” by a considerable period, with the former being superseded by the latter from the late 1600s onwards, until “humble bee/humblebee” started to decline in use from the end of the 19th century.

I’ve also searched using the term “dumbledore”, which is an old local name, but it was also applied to other buzzing insects such as chafers, making interpretation of the results difficult.  There’s more on the etymology of bumblebees on Wikipedia if you’d care to follow it up.

Many thanks to everyone who contributed to the discussion!

 

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Honey bee or honeybee; bumblebee or bumble bee?

screen-shot-2017-02-28-at-10-18-20

Language is fascinating, particularly the way in which it changes over time to incorporate new words, or old words used differently.  In science this has important implications for understanding: semantics matter.  With this in mind I’ve been curious about the alternative ways in which authors write the informal names of species.  Scientific names (Genus species)  should be fairly stable in their spelling and presentation (though not always, especially in the older literature); but “common” names of species vary widely geographically and temporally.

Here’s an example using Google’s Ngram Viewer which is a useful tool for tracking changes in word use over time.  Different authors currently use the terms “honey bee” and “honeybee”, sometimes in the same publication.  But as the image above shows. historical analysis suggests that “honey bee” is the more traditional term, and that “honeybee” only came into common usage from the start of the 20th century, and by the late 1920s had taken over “honey bee”.

Likewise “bumblebee” and “bumble bee”; despite “bumble bee” having a much earlier usage, “bumblebee” has dominated since the late 19th century:

screen-shot-2017-02-28-at-10-16-51It’s interesting to speculate about what might have caused these shifts in use, and it’s possible that in these examples it was the publication of especially influential books that used one term over another and influenced subsequent writers.  Could make a good project for a student studying how use of language varies in different time periods.

For my own part I tend to prefer “honey bee” and “bumblebee”, but I can’t precisely articulate why; perhaps it’s because in Europe we talk about “the honey bee” as a single species (Apis mellifera) but not “the bumblebee” because there is usually more than one co-occurring Bombus species in a particular area.  Do others have a particular preference?

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Links to some recent pollinator-related papers, posts, projects…. and pedals

oxalis-fly-p1030303

For weeks now I’ve been meaning to post some links to pollinator-related items that have caught my eye, but have only just found time to pull them together, hence some of these are a little dated but should still be of interest:

  • By pure coincidence Hazel Chapman (the senior author of that paper) came to Northampton a few weeks ago to give a seminar about her Nigerian Montane Forest Project which is well worth checking out and which, in the future, will have a large pollinator focus.
  • The Journal of Pollination Ecology (where I remain an editor) has a new volume out – it’s open access and has some really nice papers – here’s the link.
  • There’s been a few stories doing the rounds about robot pollinators and how they are going to replace insects.  It’s all nonsense, of course, and in a recent blog post Dave Goulson nails the arguments very well – see: Are robotic bees the future? [spoiler alert – the answer’s “No”].  Likewise, over on her blog, Manu Saunders opines that: “Artificial pollinators are cool, but not the solution“.  What the technologists who are promoting these ideas, and related concepts around the “Internet of Things”, don’t seem to get is that all of this tech has environmental costs associated with it: resource/pollution costs for making it; energy costs for using it; and disposal/pollution costs when it reaches the end of its life.  Applying a green wash of “let’s use drones for pollinating flowers” doesn’t make the tech any more environmentally sustainable, quite the opposite.  Sorry, rant over…
  • Ben Geslin and colleagues have written an interesting review in Advances in Ecological Research called “Massively Introduced Managed Species and Their Consequences for Plant–Pollinator Interactions” that focuses on both mass-flowering crop plants (e.g. oil seed rape) and domesticated, highly abundant pollinators such as honey bees, and what their increase might mean for natural communities of plants and pollinators, particularly in sensitive environments such as oceanic islands.
  • There’s a guitar effects pedal called the Pollinator – from the review:  “The Pollinator is a living thing, sensitive to its environment and surroundings, and it becomes an extension of the guitarist playing it.”  Quite.
  • Nine species of bee in the genus Perdita that are new to science have been described from localities in the the southwestern USA.  Here’s a link to a lovely video that shows these bees, their distinguishing features, and how they were named (mainly for characters from Shakespeare’s plays).  Not very impressed with the snarky “if scientists had bothered to look” title of the article though.
  • Finally, a new citizen science project has been launched designed to understand how hoverflies evolve mimicry of bees and wasps – looks interesting, please take part – here’s the link.  Just be aware, it’s a bit addictive!

As always, feel free to suggest links to items you found of interest.

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Insect pollinators boost the market price of holly and mistletoe: a new study just published

Holly and mistletoe 20161211_103252.png

Each year I’ve always added at least one Christmas-themed biodiversity post to the blog, for example: Thank the insects for Christmas, A Christmas vignette, and Six Kingdoms for Christmas.  That’s partly because I really like Christmas as a winter festival, with its folklore and customs.  But it’s also because these are a great vehicle to demonstrate how pervasive and important is natural capital and the ecosystem services it provides to society.

This year I’ve gone one stage further and actually published some Christmassy research to back up the blog post.  Now, in a new study published in the Journal of Pollination Ecology, we have shown how important insect pollinators are in determining the market value of two of the most emblematic of Christmas plants: holly (Ilex aquifolium) and mistletoe (Viscum album).  Here’s the full reference with a link to the paper itself, which is open access:

Ollerton, J., Rouquette, J.R. & Breeze, T.D. (2016) Insect pollinators boost the market price of culturally important crops: holly, mistletoe and the spirit of Christmas. Journal of Pollination Ecology 19: 93-97

Holly and mistletoe are two seasonal crops that play a culturally important role as symbols of Christmas across the world, though both also have pre-Christian pagan roots. Now for the first time the role of insect pollinators in determining the commercial value of these plants has been investigated, using sales records going back over the last eleven years from Britain’s largest annual auction of holly and mistletoe, held every year in Worcestershire.

Analysis of the sales records of Nick Champion Auctions in Tenbury Wells shows that insect pollination raises the sale price of these crops by on average two to three times. This is because holly and mistletoe with berries is more sought after than material without berries, with wholesale buyers paying higher prices at auction. These berries in turn are the result of pollination by insects such as flies and bees: both holly and mistletoe are 100% dependent on insect pollination due to their having separate male and female plants.

There is some annual variation to the prices, and in years where berries are scarce (possibly due to low insect numbers) the price difference can be four-fold.

Due to concerns about pollinator declines and food security there is huge interest in the role of bees and other insects in supporting agriculture, and how we can value that role. However we believe that this is the first study showing that insect pollinators play a large part in determining the value of culturally symbolic, non-food crops. Almost all of the economic valuations of insect pollination to agriculture have focused on food crops such as beans, apples, cocoa, coffee, and so forth. Very little is known about how the value of non-food crops (fibres, construction materials, pharmaceuticals, ornamentals, etc.) is enhanced by insect pollination. This is an area where much more research is required.

But in the mean time, where better to end than with a bit of seasonal John Clare?

The shepherd, now no more afraid,
Since custom doth the chance bestow,
Starts up to kiss the giggling maid
Beneath the branch of mistletoe
That ‘neath each cottage beam is seen,
With pearl-like berries shining gay;
The shadow still of what hath been,
Which fashion yearly fades away.

The Shepherd’s Calendar (1827)

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Filed under Bees, Biodiversity, Biodiversity and culture, Ecosystem services, Hedgerows, Mutualism, Pollination, University of Northampton

The macroecology of animal versus wind pollination – a new study just published

In collaboration with colleagues in Brazil, Denmark, and elsewhere in the UK, we’ve just published a new research paper which looks at the global spatial distribution of wind and animal pollinated plant species, and the underlying historical and contemporary ecological causes of that distribution.  It’s a study that builds on my “How many flowering plants are animal pollinated?” paper in Oikos, and has been a long time in its gestation.  We’re very excited by its findings and plan to develop this project in the future.

As a bonus we made the cover of the journal with the amazing image below!  Big thanks to Pedro Viana and Jesper Sonne for the photos.

Here’s the citation with a link to the publisher’s website; the abstract is below.  If anyone wants a PDF copy, please ask.

Rech AR, Dalsgaard B, Sandel B, Sonne J, Svenning J-C, Holmes N & Ollerton J (2016) The macroecology of animal versus wind pollination: ecological factors are more important than historical climate stability. Plant Ecology & Diversity 9: 253-262

 

Abstract:

Background: The relative frequency of wind- and animal-pollinated plants are non-randomly distributed across the globe and numerous hypotheses have been raised for the greater occurrence of wind pollination in some habitats and towards higher latitudes. To date, however, there has been no comprehensive global investigation of these hypotheses.

Aims: Investigating a range of hypotheses for the role of biotic and abiotic factors as determinants of the global variation in animal vs. wind pollination.

Methods: We analysed 67 plant communities ranging from 70º north to 34º south. For these we determined habitat type, species richness, insularity, topographic heterogeneity, current climate and late-Quaternary climate change. The predictive effects of these factors on the proportion of wind- and animal-pollinated plants were tested using correlations, ordinary least squares (OLS) and logistic regression analyses with information-theoretic model selection.

Results: The proportion of animal-pollinated plant species was positively associated with plant species richness and current temperature. Furthermore, in forest, animal pollination was positively related to precipitation. Historical climate was only weakly and idiosyncratically correlated with animal pollination.

Conclusion: Results were consistent with the hypothesised reduced chance for wind-transported pollen reaching conspecific flowers in species-rich communities, fewer constraints on nectar production in warm and wet habitats, and reduced relative effectiveness of wind dispersal in humid areas. There was little evidence of a legacy of historical climate change affecting these patterns.

andre-capa-1

 

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Third International Conference on Pollinator Biology, Health and Policy – Pennsylvania – 18-20 July, 2016

P1030210

Keeping with the theme of Bees’ Needs Week, and the importance of pollinators to natural and agricultural ecosystems*, the Third International Conference on Pollinator Biology, Health and Policy takes place at Penn State University, USA,  from the 18th to 20th July.

Here’s a link to the PDF of the programme with the abstracts, speakers’ details, etc.  I won’t be attending** but I am involved as a collaborator*** in one of the talks being presented – Luísa Carvalheiro’s project on “Direct and indirect effects of soil eutrophication on pollination services“.

Best of luck to all the speakers and attendees, looks like it’s going to be a great conference.
 

 

*Wednesday’s grumpiness has almost disappeared, though it reached a new peak yesterday when we had a paper rejected by a journal after 10 months.  There was one positive review, one middling review, and then a third in which the reviewer provided no comments – just “reject”!  I was not happy about that and made my feelings known to the editor…..

**I’m actually in the Azores next week attending the Island Biology 2016 conference.  More about that at the weekend.

***With about a gazillion other people!  Luisa has pulled together an amazing data set.

 

 

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“Insect pollinated” crops that don’t actually require insect pollination

Cucumber fruit 20160713_103558

Yesterday evening I learned that a large grant application that I’d submitted earlier this year had failed to secure funding.  Statistically there was a high likelihood of this happening but that doesn’t make it feel any better: weeks and weeks of work have come to nothing.

So in a mood of bloody-minded contrariness and general displeasure at the unfairness of the world I thought I’d provide an alternative to the Bees’ Needs week I mentioned yesterday by focusing on food crops that look as though they should be insect pollinated (and their ancestors certainly were) but which don’t actually require pollinators.

The example pictured above is an F1 hybrid cucumber (Cucumis sativus) variety called “Mini Munch”, kindly grown from seed and given to me by my friend and colleague Dr Janet Jackson.  Many cucumbers don’t need insect pollination, despite their large, colourful flowers, and the fact that related crops (melons, courgettes, squashes, etc.) generally do require pollinators.  Indeed some varieties taste bitter if they are pollinated.  I can recommend this web page on how to grow cucumbers for further advice.

As I was taking that photograph, and in another demonstration of how the world is against me at the moment, I spotted a bee feeding on one of the all-female flowers of this variety.

Megachile on cucumber 20160713_103627

It spent some time there probing the centre with its tongue, so I think these flowers still produce nectar despite them not needing pollinators, a hang-over from their ancestry.  Plants have a whole range of mechanisms that ensure reproduction without the agency of insects and other animal pollinators, and this has been exploited by crop breeders who have selected crop varieties for their ability to self pollinate or to reproduce asexually via apomixis (as in the case of this cucumber).

The same bee then flew onto a tomato (Solanum lycopersicum) flower (another group which varies in its demands for pollination) and I got a better look – seems to be a Leaf-cutter Bee of the genus Megachile.

Megachile on tomato 20160713_103712

The final example of a crop which requires little or no insect pollination are the chillies (Capsicum spp.) all of which are self-pollinating, I believe.  This variety is a scrambling purple type called Orzoco*.

Orzoco chilli 20160713_102213

So, crops vary hugely in their need for pollinators and the presence of certain traits of animal pollination, such as large, brightly coloured flowers and nectar, is no guarantee that the crop really does have to be serviced by pollinators.  The only way to be certain is to experimentally test the plants, a topic I hope to come back to later in the summer.

Don’t worry, this grumpiness won’t last long, in no time at all I’ll be back to banging on about the importance of pollinators.  At least Monty, one of our two cats, still loves me.

 

*At least, that’s what it said on the seed packet; I’ve also seen it referred to as Orozco – does anyone know which name is correct?

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Six bees, one stone: recent pollinator-related talks and workshops

BBKA lecture April 2016As I write this I’m painfully conscious that (a) it’s a couple of weeks since I last posted on the blog; and (b) I have a long list of things to complete before I head off to Tenerife for ten days of field work on Friday.  The absence of posting has been due to my current work load, including the number of conferences, talks and workshops I’ve been involved with in the past month, which seems to have taken up a disproportionate amount of my time.  It’s all been interesting and useful, however, and reflects the rising activity stemming from the National Pollinator Strategy, and increasing interest in pollinators more broadly.  I’ve certainly learned a lot and hopefully my own expertise contributed to the success of these events.

In this post I thought I’d briefly summarise what I’ve been up to recently, in the process expanding the numerical and phylogenetic parameters of “killing two birds with one stone“:

16th March – took part in a workshop to map the latest phase of Buglife’s B-Lines across Bedfordshire, Northamptonshire, Buckinghamshire and Oxfordshire.  This was a really interesting exercise and I felt that we’d actually achieved rather a lot by the end of the day.  Once the final maps are completed I’ll post a link so you can see where the routes go through these counties and how they meet up.

23rd March – spoke at a one-day conference on “delivering biodiversity” organised by the Environmental Association of Universities and Colleges at the University of Worcester.  Although I was talking about our bird surveys on the University of Northampton’s new Waterside Campus, pollinators did receive some attention during a workshop on creating wildflower meadows.  I’ll post an update on the Waterside work once we’ve completed the next set of spring surveys.

30th March – spoke at the Bumblebee Working Group at the University of Sussex – have already posted an account of that.

6th April – took part in a”Pollinator Experts Elicitation” workshop at the University of Warwick, along with a group of nine other academics, and members of stakeholder groups such as FERA and the NFU.  Run as part of Warwick’s Food and Behavioural Science Global Research priority groups, the organisers, from the university’s Department of Statistics, used the Delphi Method to assess the likelihood of sustaining pollinator populations under different scenarios of disease, climate change, and habitat degradation.  It was a fascinating process and interesting to see how often experts’ views converged on the same opinion.  Also rather humbling to see the degree of our uncertainty in our forecasts.  The workshop garnered quite a bit of media attention including pieces on the BBC’s Midlands Today and the Farming Today programmes.

8th-9th April – delivered two lectures at the British Beekeepers Association’s Spring Convention at Harper Adams University.  Rather disconcerting to be the least-informed person in the room, given my limited knowledge of bee keeping, but they were a friendly and curious lot with good-sized audiences for my talks on the diversity of bees to be found in urban settings, and the global diversity and functional importance of pollinators.

13th April – spoke to a very receptive audience at the Friends of Linford Lakes Nature Reserve near Milton Keynes, on the topic of “Bees for dinner?  The importance of pollinators in a changing world“.  Great evening and lots of interesting questions afterwards, though my talk was a bit too long (must cut it for next time).

That’s it for now, hope to do some posts from Tenerife while we are there.

 

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Pollinators, Pollination and Food Production: IPBES gains momentum

Bee on apple blossom - 1st May 2015

The over-arching themes of this blog have been about understanding biodiversity; the science behind its study; why it’s important; how it contributes to human well being, (including both intangible and economic benefits); and how policy informed by science can support the conservation of species and ecosystems.  These are all issues that have a global perspective beyond the bounds of my home country (the United Kingdom), or even my continent (Europe) because species, ecosystems and the threats to them do not respect political borders.

Enter IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (sometimes shortened to Intergovernmental Platform on Biodiversity and Ecosystem Services).

IPBES is a United Nations body established in 2012 that in many ways is a parallel entity to the IPCC ( Intergovernmental Panel on Climate Change), bringing together scientists, policy makers and stakeholders, with a mission:

to strengthen the science-policy interface for biodiversity and ecosystem services for the conservation and sustainable use of biodiversity, long-term human well-being and sustainable development

Which has got to be a good thing: science informing policy, what’s not to like?

The first output from IPBES will be a Thematic Assessment of Pollinators, Pollination and Food Production, and it’s just been discussed (today) at the 4th Plenary meeting of IPBES in Kuala Lumpur – here’s a link to the press release.

In the coming weeks I’ll talk more about IPBES and its Thematic Assessment (for which I acted as a reviewer), but for now I’ll just repeat some of the headline figures from the report:

  • 20,000 – Number of species of wild bees. There are also some species of butterflies, moths, wasps, beetles, birds, bats and other vertebrates that contribute to pollination.
  • 75% – Percentage of the world’s food crops that depend at least in part on pollination.
  • US$235 billion–US$577 billion – Annual value of global crops directly affected by pollinators.
  • 300% — Increase in volume of agricultural production dependent on animal pollination in the past 50 years.
  • Almost 90% — Percentage of wild flowering plants that depend to some extent on animal pollination*.
  • 1.6 million tonnes – Annual honey production from the western honeybee.
  • 16.5% — Percentage of vertebrate pollinators threatened with extinction globally.
  • +40% – Percentage of invertebrate pollinator species – particularly bees and butterflies – facing extinction.

 

*They are quoting a figure that I calculated, and very proud of it I am too 🙂

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