Category Archives: Birds

Hunting the Chequered Skipper: an encounter with England’s latest species reintroduction project

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If you have been following recent conservation news on social media you’ll know that this week was an important one for invertebrates.  The Chequered Skipper, a butterfly last seen in England in 1976, has been reintroduced to the country as part of the Back From the Brink initiative.  The Chequered Skipper project is led by Butterfly Conservation and a team travelled to a site in Belgium earlier in the week where about 40 skippers were captured.  These insects were transported back to the UK where they were held overnight in mesh cages at a secret location in order to acclimatise them, then released into the wild.  The release was filmed as part of next week’s BBC Springwatch series – look out for it.

The exact location of the reintroduction is secret.  However I can tell you that it’s occurred in the Rockingham Forest area of north Northamptonshire, in habitat that (over the past couple of years) has been managed specifically for this reintroduction, in order to create a network of sites across which the species could disperse in the future.  This area was the last stronghold of the species in England prior to its extirpation.  No one knows why it went extinct here, but hung on and did well in Scotland, but it may relate to climate: 1976, as many of the middle-aged will remember, was a very hot, dry summer, and this butterfly likes it warm and humid.

Yesterday I had the privilege of seeing this reintroduction first hand when I visited the site with my colleague Dr Duncan McCollin.  Duncan and I are supervising a PhD student, Jamie Wildman, along with Prof. Tom Brereton, Head of Monitoring at Butterfly Conservation (BC), and the University of Northampton’s Visiting Professor in Conservation Science.  Jamie’s project will focus on understanding the habitat requirements for Chequered Skipper, and monitoring the success of the reintroduction.  I’m also hoping that it might be possible for Jamie to assess the role of this species as a pollinator of the plants it visits.  Butterflies as pollinators is a very under-researched area.

Here’s a shot of the Four Mus-skipper-teers* just before we set off to help BC volunteers to locate the skippers and record their behaviour:

Four Mouse-skipper-teers 2018-05-26 11.10.19.jpg

 

The day started unpromisingly.  It was cool and overcast, and little was flying except some hardy Common Carder Bees.  But around lunchtime things began to warm up and gradually the sun broke through and we started to see flying Lepidoptera that we excitedly chased, only to be disappointed by yet another Mother Shipton or Silver Y.  But no skippers.

As we encountered some of the BC volunteers who were also tracking the insects we were told that we had “just missed one” or that they “saw one down that ride, we marked the spot”.  One volunteer wanted to show me a photo of a Chequered Skipper that he’d just taken “so I could get my eye in”.  I politely refused; I wanted to see the real thing and didn’t want to jinx it with a digital preview.

Finally, our efforts were rewarded and we found the first skipper of several we later encountered.  The image at the head of this post is that butterfly, a sight that has not been seen in England in more than 40 years.  An exciting and privileged encounter.  The county Butterfly Recorder, David James (on the right in this next shot), is ecstatic that the reintroduction has occurred “on his patch” but also nervous at the responsibility it represents:

Skipper crew 2018-05-26 13.15.06

Later we spent time helping Jamie follow a female skipper who was showing egg-laying behaviour, moving slowly for short distances along a shrubby edge, occasionally nectaring on Bugle, and diving deep into the vegetation to (we hope) oviposit on grass leaves:

 

Skipper watching 2018-05-26 15.10.18

Although I’ve over-cropped this next image of the skipper on Bugle, I thought I’d leave it as I like the different textures and patterns, and the slightly blurry ambience:

Skipper nectaring 2018-05-26 13.06.08

The primary aim of Butterfly Conservation’s project is to return a small part of England’s lost biological heritage.  But it’s about more than just the Chequered Skipper.  It’s also about understanding how managing a network of sites for this flagship species can benefit other organisms.  The wide woodland rides that have been created are packed with plant species, amongst them at least five grasses that could be used as caterpillar food sources for the skippers, plus more than 20 nectar sources were flowering that they (and other flower visiting insects) could use.  Those other insects were plentiful too: over the day I spotted five species of bumblebees, several different day flying moths, lots of Dark-edged Bee Flies, and a few different solitary bees and syrphids flies.  We heard calling cuckoos, and four different warblers: chiffchaffs, garden warbler, whitethroats, and blackcaps.  Red kites (another incredibly successful species reintroduction) floated overhead skimming the treetops as they their cried to one another.

Rockingham Forest is a lovely part of Northamptonshire, well worth a visit.  The Chequered Skipper will be a wonderful addition to its biodiversity.  Of course there are no guarantees that the reintroduction part of the project will be a success, but if it isn’t it won’t be because of a lack of commitment from the people involved.  If the population does become established then in the future the location will be made public and butterfly enthusiasts will be able to come and pay homage to one of the few butterflies with a pub named after it.

 

*You get the puns you deserve on this blog…..

 

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Filed under Bees, Biodiversity, Birds, Butterflies, Pollination, University of Northampton

The explosion in orchids as houseplants: what does it tell us about how flowers evolve?

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One of the major trends in horticulture over the last 20 years or so has been the rise in popularity of orchids as house plants.  Orchids used to have a reputation as being delicate, choosy, costly things that needed expensive glasshouses, heating, and humidity systems to grow.  Some groups of orchids are certainly like that, but many are not (Orchidaceae is one of the two largest families of plants, after all).  These days it’s impossible to walk into any supermarket or department store and not see orchids for sale at a reasonable price, orchids that are tough and can withstand the relatively dry, centrally heated houses in which most of us in Britain live. 

The majority of these orchids are varieties of Phalaenopsis, the moth orchids.  Intensive hybridisation by commercial growers has meant that there is an almost inexhaustible range of flower colours, shapes, sizes and patterning available.  Take a look at this gallery of images and you’ll see what I mean, or go into a shop that sells such orchids and observe that almost no two are alike.

This is the stuff of natural selection: genetic variation in the phenotype that can be acted upon by a selective agent.  In this case it’s the growers of orchids who choose the most attractive types to sell and discard the others.  If this variation emerged in wild populations most of it would disappear over time, but some, just occasionally, would be selected for by a different group of pollinators and go on to form a new species.  This is much more likely to happen if the individuals with this variation are isolated from the rest of the population in time or space, for example if they flower later or have been dispersed to a distant valley or mountaintop (termed allopatric speciation).  But it can also happen within populations – sympatric speciation.

Back in 1996, near the start of this orchid explosion, one of my earliest papers was a speculative commentary in Journal of Ecology called “Reconciling ecological processes with phylogenetic patterns: the apparent paradox of plant-pollinator systems”.  It generated some interest in the field at the time and has picked up >250 citations over the years, mostly other researchers using it as supporting evidence for the discrepancies we see when trying to understand how flowers evolve within a milieu of lots of different types of potential pollinators selecting for possibly diverse and contradictory aspects of floral form.  In that paper I made a passing comment that I expected the reviewers to criticise, which they did not.  Once it was published I thought that perhaps other researchers in the field would critique it or use it as a jumping off point for further study, which has not really happened either.  This is what I wrote:

         “It appears that pollination systems are labile and may evolve quite rapidly….plant breeders can obtain a fantastic range of horticultural novelties through selective breeding over just a few generations.”

This is horticulture holding up a mirror to the natural world and saying: “This is how we do it in the glasshouse, look at the variety we can produce over a short space of time by selecting for flower forms; can nature do it as quickly, and if so what are the mechanisms?”  

I still believe that pollination ecologists could learn a lot from horticulture and there’s some fruitful (flowerful?) lines of enquiry that could be pursued by creative PhD students or postdocs.  Here’s one suggestion: part of the reason why these Phalaenopsis orchids are so popular as house plants is that they have very long individual flower life times, often many weeks.  Now we suspect that floral longevity is under strong selection; see for example research by Tia-Lynn Ashman and Daniel Schoen in the 1990s.  This showed that there is a negative correlation between rate of pollinator visitation and how long flowers stay open.  Plants with flowers that are not visited very frequently stay open much longer, for example the bird-pollinated flowers of the Canary Islands that may only be visited once or twice a day, and which can remain open for more than 20 days.  Is the floral longevity shown by these orchids (or other groups of plants that have been horticulturally selected) beyond the range found in natural populations?  If so, what are the underlying physiological mechanisms that allow such extreme longevity?  If not, does this mean that there is an upper limit to the lifespan of flowers, and if so, why?  

In the mean time I’m going to enjoy the orchids above that sit on our kitchen windowsill.  They actually belong to my wife Karin who has developed something of an interest in them in recent months.  The big spotty one is a late birthday gift for her that I picked up this morning from a local flower shop, and which stimulated this post as I was walking home.  I’d bet that we never see another one like it!

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Filed under Biodiversity, Biodiversity and culture, Birds, British Ecological Society, Evolution, Gardens, Personal biodiversity, Pollination

The flowers, the bees, and the tractor: a true story

Yesterday I was up and out early with colleagues and students to carry out the first of this season’s spring bird surveys of the University of Northampton’s new Waterside Campus – see my previous post on this topic.   We had finished one stretch of the survey and were walking back along the path next to Midsummer Meadow when I spotted a huge expanse of Red Dead-Nettle (Lamium purpureum), mixed in with some While Dead-Nettle (Lamium album):

Tractor 1 2018-04-18 08.21.14

Both species produce a lot of nectar; as kids we would often suck it from the flowers of White Dead-Nettle, and they are just as attractive to bees and other pollinators:

Tractor 2 2018-04-18 08.24.16

Sure enough, a quick survey showed that there were at least two species of bee working the flowers, Common Carder Bees (Bombus pascuorum), and male and female Hairy-footed Flower Bees (Anthophora plumipes) – here’s a shot of the female:

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Suddenly there was an exclamation from one of my colleagues: whilst I was focused on the bees he’d seen a tractor pulling a grass cutter coming towards us:

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It got closer…:

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…and closer…:

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…and we were sure it was going to mow this beautiful patch of wild flowers, and the bees, into oblivion:

Tractor 8 - 2018-04-18 08.25.46

But it didn’t!  The driver carefully mowed round the patch and headed back the way he’d come:

Tractor 9 - 2018-04-18 08.26.33

A big relief!

Urban recreational grasslands like this clearly need to be managed by regular cutting, but this should be done strategically as these sorts of wild flower patches are important nectar and pollen sources for urban pollinators.  They are especially critical at this time of year when resources are needed to build up colony numbers in the social species like Common Carder Bee.  I don’t know who manages Midsummer Meadow – presumably contractors working on behalf of Northampton Borough Council?  But I hope that this is a conscious strategy by them to conduct “smart mowing” whereby they cut around flower patches like this even when they are not planted.  The bees (and I) thank you for it.

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Trait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds – a new study just published

Hummingbird bowl from BM

Hummingbirds are fascinating creatures and important pollinators for a wide range of plants in the New World (and, historically, possibly in the Old World – see this post from 2014: There were hummingbirds over the White Cliffs of Dover).  During the last decade I have been involved in some hummingbird-related research with several colleagues, particularly Dr Bo Dalsgaard and Dr Stella Watts, and it’s generated some really interesting findings about the biogeography, macroecology, and interactions with plants of these most elegant of birds.

The latest installment of this work is a test of some ideas relating to the vulnerability of hummingbirds on islands to the extinction of their plant partners.  It’s just been published and the reference is:

Dalsgaard B., Kennedy J.D., Simmons B.I., Baquero A.C., Martín González A.M., Timmermann A., Maruyama P.K., McGuire J.A., Ollerton J., Sutherland W.J. & Rahbek C. (2018) Trait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds. Proceedings of the Royal Society series B (in press)

Here’s the abstract:

Species traits are thought to predict feeding specialization and the vulnerability of a species to extinctions of interaction partners, but the context in which a species evolved and currently inhabits may also matter. Notably, the predictive power of traits may require that traits evolved to fit interaction partners. Furthermore, local abiotic and biotic conditions may be important. On islands, for instance, specialized and vulnerable species are predicted to be found mainly in mountains, whereas species in lowlands should be generalized and less vulnerable. We evaluated these predictions for hummingbirds and their nectar-food plants on Antillean islands. Our results suggest that the rates of hummingbird trait divergence were higher among ancestral mainland forms before the colonization of the Antilles. In correspondence with the limited trait evolution that occurred within the Antilles, local abiotic and biotic conditions—not species traits—correlate with hummingbird resource specialization and the vulnerability of hummingbirds to extinctions of their floral resources. Specifically, hummingbirds were more specialized and vulnerable in conditions with high topographical complexity, high rainfall, low temperatures and high floral resource richness, which characterize the Antillean Mountains. These findings show that resource specialization and species vulnerability to extinctions of interaction partners are highly context-dependent.

As always I’m happy to send a PDF to anyone who drops me an email.

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Big Garden Birdwatch – our first six years of data

Big garden bird watch

This morning I spent an hour gazing out of our bedroom window with a coffee, a notebook, and a pair of binoculars.  Not sure what the neighbours opposite us thought I was doing but I was happy – this weekend is the RSPB’s Big Garden Birdwatch!  I’ve taken part in it every year since Karin and I moved into our present house in February 2012, and I thought it was time to show the results to date.

As you can see in the graph above, for the first couple of years there were relatively few birds (only 6 species in 2013, 8 in 2014).  Then in 2015 it jumped to 15 species, including some that I’ve not recorded in the garden since such as Lesser redpoll.  Two reasons for this sudden increase I think.  First of all, January 2015 was particualrly cold which meant that more birds were moving into urban areas looking for food and a little more warmth.  But secondly, and the reason why higher bird diversity has been maintained since then, is that we’ve been developing the garden and planting more shrubs, small trees, etc.

So since 2012 we’ve gone from this:

2012-02-22 10.19.23

To this:

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This planting and development of the garden has been good for other wildlife including bees, butterflies and other pollinators, as I’ve recounted a number of times.  So here’s a close up from last summer just to remind us that, on this grey, drizzly January day, spring is not so far away:

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Of course you don’t need to have a garden to take part in the Big Garden Birdwatch – the RSPB also accepts data from surveys of public parks and green space.  In fact tomorrow morning I’m leading a group of residents around our local park, The Racecourse, to do just such a survey.

Right, must go and upload this years data to the RSPB’s site.

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Pollinators, flowers, natural selection and speciation: a virtual conference

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It’s been a couple of years since I posted my previous “virtual conferences” on Pollinators, Pollination and Flowers and Ecology and Climate Change, a lapse that has largely been due to lack of time (my default excuse for most things these days….).  However Judith Trunschke at Uppsala University in Sweden has risen to the challenge of guest-curating her own virtual conference*.  The theme here is how pollinators impose (or sometimes don’t impose) natural selection on flowers that results in the formation of new plant species:

Timo van der Niet (IIASA 2010): Plant-diversification through pollinator shifts

Timo van der Niet (Congresos UCA 2014): Disentangling the contribution of pollinators in shaping angiosperm orchid genus Satyrium

Anne Royer (Evolution 2016): Plant-pollinator association doesn’t explain disruptive selection & reproductive isolation

Brandon Campitelli (Evolution 2016): Pollinator-mediated selection and quantitative genetics

Yuval Sapir (Evolution 2016): Rethinking flower evolution in irises: are pollinators the agents of selection?

Ruth Rivken (Evolution 2014): The mechanisms of frequency-dependent selection in gynodiocious Lobelia siphilitica

Gonzalo Bilbao (Botany 2017): Pollinator-mediated convergent shape evolution in tropical legumes

My grateful thanks to Judith for curating this great set of talks; if anyone else would like to do the same, please get in touch.

Feel free to discuss the talks in the comments section and to post links to other talks on the same topic.

 

*I’m assuming that, as all of these videos are in the public domain, none of the presenters or copyright owners objects to them being presented here.  If you do, please get in touch and I’ll remove it.

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Pollinator biodiversity and why it’s important: a new review just published – download it for free

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In a new review paper that’s just been published in the Annual Review of Ecology, Evolution and Systematics I have looked at the question of just how diverse the pollinators are, and why pollinator biodiversity is ecologically important and therefore worthy of conservation.  I’ve taken a deep time and wide space approach to this, starting with what the fossil record tells us about when animal pollination evolved and the types of organisms that acted as pollinators in the past (the answer may surprise you if you’re unfamiliar with the recent paleontological literature on this topic).  Some of the most prominent biogeographical patterns have been highlighted, and I have tried to estimate the global diversity of currently known pollinators.  A conclusion is that as many as 1 in 10 described animal species may act as pollen vectors.

As well as this descriptive part of the review I’ve summarised some recent literature on why pollinator diversity matters, and how losing that diversity can affect fruit and seed set in natural and agricultural contexts.  Extinction of pollinator species locally, regionally, and globally should concern us all.

Although I was initially a little worried that the review was too broad and unfocused, having re-read it I’m pleased that I decided to approach the topic in this way.  The research literature, public policy, and conservation efforts are currently moving at such a fast pace that I think it’s a good time to pause and look at the bigger picture of what “Saving the Pollinators” actually means and why it’s so important.  I hope you agree and I’d be happy to receive feedback.

You can download a PDF of the review entitled Pollinator Diversity: Distribution, Ecological Function, and Conservation by following that link.

Pollination ecologists should also note that in this same volume of Annual Review of Ecology, Evolution and Systematics there’s a review by Spencer Barrett and Lawrence Harder called The Ecology of Mating and Its Evolutionary Consequences in Seed Plants.  If you contact those authors I’m sure they’d let you have a copy.

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Hummingbirds have a sense of smell: so why do we keep saying that they don’t?

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One of the general features associated with specialised hummingbird-pollinated flowers in the New World is that they often have no scent perceptible to the human nose.  This is then interpreted as evidence that hummingbirds have no sense of smell, which strikes me as circular reasoning at best.  This “fact” is then frequently repeated in text books and on the web, for example at the Bird Watcher’s Digest site, at The Spruce site, and at the World of Hummingbirds.

However I know of only two research papers that have tested whether or not hummingbirds can smell, both of them short notes; and in both cases they found that the hummingbirds they tested could associate scents with food in artificial flowers.  Those studies (with links to the originals) are:

Goldsmith, K.M. & Goldsmith, T.H. (1982) Sense of smell in the black-chinned hummingbird. Condor 84: 237-238

Heringer, H. et al. (n.d. – c. 2006?) Estudo da capacidade olfatória em três representantes da subfamília Trochilinae: Eupetomena macroura (Gould, 1853), Thalurania furcata eriphile (Lesson, 1832) e Amazilia lactea (Lesson, 1832).  Unpublished manuscript – possibly a student project (?)

It surprises me that this has been so little studied, given how much research has otherwise been done on hummingbirds.  Have I missed any other studies?  Clearly vision is more important for hummingbirds when locating food, but that’s not the same as stating that hummingbirds have no sense of smell.  Seems to be one of those myths that won’t go away, of which there are many in pollination biology.

Comments welcomed, as always.

 

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

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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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Waxwings on my birthday!

waxwings-by-stephen-valentine

Waxwings (Bombycilla garrulus) may possibly be my favourite bird, and I’ve posted a couple of times about encounters with them – see: Waxwing winter and Waxwings in Northants.

So for my birthday last weekend I was stunned and delighted by a gift from my wife Karin: a specially commissioned illustration of waxwings by a very talented artist friend of ours, Stephen Valentine, who is based in Denmark.

I think Stephen has beautifully captured both the alert intelligence of these birds, always on the look-out for food and predators, and their subtle and striking colouration.  It’s such an honour to own a piece like this!

If you’re interested, Stephen regularly takes commissions; you can find him on Facebook by searching for “Studio Sejerø”, or I can put you in touch with him.

Thanks Karin, thanks Stephen! 🙂

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