Category Archives: Biodiversity

Celebrating Conrad Gesner Day 2017 (and Spiral Sunday #27)!

Gessner house Zurich March 2008 018

Happy Conrad Gesner Day!  Who is he, you may ask?  And why does he have a day?  Conrad Gesner (sometimes spelled Konrad Gessner) was a Swiss naturalist and polymath, born on this day (26th March) in 1516; he lived much of his life in Zurich, where he died on 13 December 1565.  Gesner was an extremely important figure in Renaissance science and scholarship, and when I visited Zurich in 2008 to give a seminar at the university, a tour of the old town revealed a number of references to the great man, including the memorial stone above.

Gesner’s Historia animalium (“History of Animals”)  is considered one of the founding texts of modern zoology, and for that reason he is memorialised in the name Gesneria Hübner, 1825; this is a genus of moths in the family Crambidae.

However Gesner was also a botanist and wrote a couple of books on the subject, though his Historia plantarum was not published until two centuries after his death.  To celebrate Gesner’s botanical achievements Linnaeus erected the genus Gesneria L. for a group of flowering plants.  Sounds odd to have the same name for two very different types of organism, but this cross-kingdom duplication of genera is allowable under the various codes of taxonomic nomenclature.

Gesneria in turn is the type genus for the family Gesneriaceae.  It’s quite a big family (about 3,450 species in 152 genera) and is ecologically important in the tropics and subtropics, where species may be pollinated by insects and birds, and are often epiphytic on trees.  It’s not a particularly economically important family, though a number of genera are widely grown as ornamentals, and there are specialist gesneriad growers and collectors.  The more familiar plants include those mainstays of Mothering Sunday (which by coincidence is also today) African Violets (Saintpaulia), Cape Primroses (Streptocarpus) and gloxinias (Gloxinia):

Gloxinias 20170325_105735

As I was looking through my photographs from the trip to Zurich in 2008 I spotted the following image of some wrought ironwork from the old city which may well be contemporary with Gesner.  This seems a fitting way to celebrate both the great man and this week’s Spiral Sunday:

Spirals in Zurich March 2008 119.png Happy Birthday Dr Gesner!

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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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Filed under Bees, Biodiversity, History of science, Pollination

Spiral Sunday #26 – a bumper crop from Birmingham Botanical Garden

Today Karin and I took a drive up to Birmingham to visit my daughter Ellen, who is studying applied performance and community theatre at Birmingham School of Acting.  After picking her up we went for lunch at Birmingham Botanical Gardens.  Now, I’m a bit of a botanic gardens collector; I love visiting them, and keep a life list of those I’ve visited and a wish list of those I’d like to visit.  So I was sure I had been to the Botanical Gardens as a PhD student during a British Ecological Society conference at the University of Birmingham.  But when we arrived there I had no recollection of the glasshouses or the layout, it was not familiar at all.  Odd how the memory plays tricks, one way or another.

I can recommend a visit, though – the Gardens looked stunning even this early in the season; lots of plants in flower and even a buzzard circling low overhead.  It being Spiral Sunday, of course, I was seeing spirals everywhere; in the unfurling fronds of a tree fern (Blechnum gibbum):

Blechnum gibbum 20170319_154939.png

On a cast iron garden seat:

Seat spiral 20170319_154601

In the flowers of a variety of camellia:

Camelia 20170319_150934.png

In the leaves and flower cones of Banksia grandis:

Banksia grandis.png

And in the design of a sun hat in the Gardens shop:

Sunhat 20170319_162432.png

 

 

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The Danish for garden is “haven”: five reasons why I love Gardeners’ World

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The latest series of the BBC’s flagship horticulture programme Gardeners’ World started on Friday, heralding its 50th year of broadcast – quite an achievement.  I’ve long been a fan, and a few years ago jumped at the chance to take part in one Science in the Garden special episode with Carol Klein (which I’ve posted about previously).  Since Friday I’ve given some thought as to what I get from the programme and have come up with a list of the main reasons why I love watching it:

1.  At its heart, Gardeners’ World is about the main subject of this blog and of my career: biodiversity.  Specifically the programme is centred on the biological richness of wild plants and the diversity of the horticultural varieties that we have created from them, for food and for ornament.  Spinning off from this is the acknowledgement that, although much of it is not native to Britain, this plant biodiversity (and the way in which we manage it in our gardens) can have important positive benefits for the wildlife of our country, including birds, amphibians and reptiles, and insects such as bees and butterflies.  This is particularly the case in urban settings and I’ve noticed a welcome trend in recent years for Gardeners’ World to include more features about city horticulture.

2.  Gardeners’ World has long championed a more environmentally friendly approach to horticulture, bringing in ideas about using peat-free compost, minimal use of biocides, recycling and upcycling, composting, and growing your own food, long before any of this became fashionable.  Indeed there’s a strong argument to be made that earlier presenters such as the late Geoff Hamilton were responsible for such fashions gaining mainstream exposure, influencing the habits of millions of people in Britain.  That kind of influence should not be under-estimated.

3. Gardeners’ World reminds me of my dad, who died in 1996.  I can recall him watching it back in the 1970s when Percy Thrower was the presenter and my dad had an allotment a short walk from our small terraced cottage house, with its tiny concrete backyard.  Some of my earliest memories of plants and nature relate to that allotment: a huge rambling rose along the fence; a greenhouse made from old window panes, filled with the rich scent of tomatoes; a toad that dad put in that greenhouse to eat the slugs; rainwater tanks hosting little communities of wriggling insect larvae.  After the allotment plots were cleared by the local council and sold for development my dad erected a greenhouse in the backyard, and grew shrubs and bedding in large pots.  In the early 1980s this was joined by a second small greenhouse for my cactus and succulent collection, many of which I still have.  Some of the best stories in Gardeners’ World are as much about people and their relationships with one another and with their gardens, as they are about plants and gardening per se (see also number 5, below).

4.  Despite having watched the programme for many years I still get new things from it.  Each season I gain inspiration for new plants and new ways of working with the garden that Karin and I are developing here in Northampton, which I’ve talked about quite a few time; see for example:  Renovating a front garden…, my post about Scientists and gardens, and the series I did on pollinators in the garden for Pollinator Awareness Week.  Gardeners never stop learning.

5. Being from the north of England I’m intrigued by the linguistic links between that part of our country and Scandinavia, particularly shared words such as “bairn”, and place-name elements such as “holm”.  Karin is Danish and these connections of language are something we often discuss.  Recently she pointed out that the Danish word for garden is “haven”.  Although it’s not pronounced in the English manner that word is probably the best single way of describing how I feel about our garden; it’s a haven from from the outside world, a place of rest and security, contemplation and physical activity, emotionally supporting us, and providing resources and space for the wildlife that uses it.  Although we don’t do much work in the garden during the winter, each year the start of a new season of Gardeners’ World reminds me of the pleasures to come in our own haven.

Of course there are sometimes things that irritate me about the programme: it can be a bit too cosily middle class at times, occasionally the advice offered can be simplistic or inaccurate, and some of the “scientific” trials of plant varieties lack rigour and replication.  Nonetheless, it’s a programme I have grown up with and one that I love to watch.  Happy Anniversary Gardeners’ World, here’s to 50 more years!

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Filed under Bees, Biodiversity, Biodiversity and culture, Gardens, Personal biodiversity, Urban biodiversity

Some upcoming public lectures

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Giving public lectures to special interest groups in and around Northamptonshire is always a pleasure as the audiences are usually very receptive.  Just been through my diary and realised that I’m giving five such lectures over the next few months, on pollinators, conservation,  ecosystem services, and so on:

8th March – “Bees for dinner?  The importance of pollinators in a changing world” – Long Buckby Women’s Institute – open to all and not just women!

22nd March – “A city without trees is like a bird without feathers” – Litchborough Gardening Club [title is slightly wrong on that link…]

5th April 2 – “Darwin’s Unrequited Isle: a personal natural history of Tenerife” – Friends of Linford Lakes (Milton Keynes)

27th June – “Pollinator diversity” – Chalfonts Beekeepers (Buckinghamshire)

12th July – “Plants & pollinators – more than just honey bees” – Cancer Research UK ladies lunch club fundraiser at Wellingborough Golf Club

Some of these will certainly be open to guests if you’re not a member and want to come along and hear what I have to say.

Happy to discuss giving a talk to other groups, please do get in touch, though I’m probably not available until after the summer as I’m also giving a keynote lecture at the PopBio conference in Germany in May and a couple of short talks at the International Botanical Congress in China in July.

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Filed under Bees, Biodiversity, Gardens, Honey bees, Pollination, Tenerife

Spiral Sunday #24 – a Roman snail

Roman snail cropped 20170303_123004.png

Although it is technically a non-native species, as it was almost certainly brought to Britain by the Romans, Helix pomatia (the edible or Roman snail) is nonetheless protected by the Wildlife and Countryside Act (1981), and in England it is an offence to sell, collect, kill or injure this species. That’s an unusual situation for an alien animal or plant in this country, and I’m struggling to think of another example – are there any?

Regardless of its status, the large shells of the Roman snail (several times bigger than the common garden snail Cornu aspersum when fully grown) form a beautiful spiral for today’s Spiral Sunday posting.

Thanks to Dr Tim Astrop for allowing me to photograph this dead specimen.

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Proposals to “sequence the DNA of all life on Earth” suffer from the same issues as “naming all the species”

Tanzania ichneumonid P1000757

There’s a short piece on the website of the journal Science this week entitled “Biologists propose to sequence the DNA of all life on Earth“.  I don’t propose to say much about it except to say to anyone interested: read that piece, then read my recent post entitled “The road to degradation: is ‘naming all the species’ achievable or even desirable?

In my view “naming all the species” and “sequencing the DNA of all life” suffer the same issues and flaws. At a time when research funding is becoming ever more difficult to obtain (in part because it’s becoming more concentrated on fewer institutions and individuals) such multi-billion dollar initiatives make great headlines, but are they value for money?

At the moment Science also has a series of stories on its conservation news web pages, and you can find others all over the web, that point to our inability to conserve even large, charismatic species such as elephants and the big cats, and how this in turn can impact on human survival and wellbeing.  Perhaps we should devote more funding and more research energy to fixing these issues before we attempt such large-scale projects?

As always, your opinions and comments are welcomed.

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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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What’s green, waxy and smells of cheese? The flowers of Deherainia smaragdina!

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A tweet this morning from Chris Howell at Birmingham Botanical Garden reminded me that for some time I’ve been meaning to post up images of an enigmatic flower that has intrigued me for over a decade, ever since I encountered it in the Palm House at Kew.

It was the smell that I first noticed: strong and pungent like a ripe blue cheese, or unwashed feet.  This drew me to a small, evergreen shrub with the wonderfully eliding name of Deherainia smaragdina, a Mexican member of the primula family (Primulaceae) though older sources put it in the Theophrastaceae, a family no longer recognised by most botanists.

cheese-tree-1

At first I couldn’t spot where the smell was coming from, then I saw the flowers: larger than I was expecting (a couple of centimetres across) given that they were not immediately obvious, and very waxy and stiff to the touch.  In fact (to the human eye) it was quite well camouflaged against the plant’s own leaves, not at all what one expects from a flower.  However camouflaged flowers that rely only on scent for attracting insects are not unknown in the plant kingdom, and probably under-recorded: see for example Adam Shuttleworth and Steve Johnson’s work on wasp-pollinated flowers of asclepiads (Apocynaceae) in South Africa, where the “cryptic colouring” is similar in reflectance to the background vegetation.  “Smaragdine” means emerald-like, so a very fitting species name.

The scent tends to come and go, perhaps affected by temperature or light levels.  Under the scanning electron microscope the surface of the petals has some intriguing bulbous cells (which I’d hypothesise produce the scent) and the wavy, waxy covering of the cuticle is clearly visible:

deherainia-close1

deherainia-close2

Another intriguing thing about Deherainia smaragdina is that the bisexual flowers are in a male phase when they first open, moving into female phase only after a day or two. Compare the two flowers below.  In the male phase (left) the pollen-bearing stamens are centered in the flower, hiding the female stigma (which is probably not receptive at this stage); over time the stamens move outwards to expose the stigma and the flower goes into female phase (the flower on the right):

cheese-tree-3

Why this plant should smell of cheese is a mystery, but it’s probably attracting a particular type of pollinator – though what they are no one knows !  It’s never been studied, as far as I’m aware.  We might predict from the scent that it’s flies, but I think that wasps are also a possibility.  If anyone is doing field work in the parts of Mexico where this plant grows, please look out for it and try to photograph flower visitors: I’d love to hear from you!

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