Monthly Archives: March 2017

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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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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Spiral Sunday #25 – a London Underground poster from the Osborne Robinson collection

Underground spiral 20170303_140031The University of Northampton is custodian of one of the best collections of posters in Britain.  The Osborne Robinson Collection now contains over 10,000 items and the university regularly displays them internally and at other venues.

This week’s Spiral Sunday shows a poster currently on display that caught my eye as I was passing.  The poster is by Edward McKnight Kauffer for London Underground (or Underground Electric Railways Co. of London, Ltd as it was), and dates from 1922.

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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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Some upcoming public lectures

2014-08-16 15.36.53

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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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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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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