Tag Archives: Bees

What’s wrong with the New Scientist story about “Bumblebees deployed to spray crops with pesticides”?

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Here’s a link to the story:

Bumblebees deployed to spray crops with pesticides

There’s at least three things wrong with this story:

The accompanying image is of a honey bee, not a bumblebee.
Bumblebees have nests, not hives.
It’s a dumb idea. For a whole set of reasons, some of which are mentioned by scientists who were interviewed for the story. I’d add another one: these bees will visit a lot of other flowers besides the ones that are being targeted, potentially spreading the bio-control fungus far and wide in the environment. Is that really a good idea?

Two of these things are within the control of New Scientist.

Thanks to my colleague Dr Wanda McCormick for pointing out the story.

Pollination syndromes: a brief update on recent developments, and news that Stefan Vogel has passed away

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In a recent post I discussed the current debates about “pollination syndromes”, which I described as “sets of flower characteristics that have repeatedly evolved in different plant families due to the convergent selection pressures applied by some groups of pollinators”.

The authors of the Ecology Letters paper that I discussed (Rosas-Guerrero et al. 2014) have now replied to our original critique of their approach and you can read that reply (Aguilar et al. 2015) in Journal of Pollination Ecology by following this link. Readers can make up their own minds as to whether the authors have responded adequately to our concerns, but I just briefly wanted to raise three points.

The first is that much of these authors’ response is focused on an earlier paper of ours (Ollerton et al. 2009) rather than on our critique per se. Nick Waser, Mary Price and myself have therefore written a second response that deals with some of the misunderstandings apparent in that piece; it’s available to download here.

The second point relates to the existing literature on pollination syndromes and pollinator effectiveness used by Rosas-Guerrero et al. (2014); as we demonstrated in our critique this is clearly a biased data set that is skewed towards groups of plants with relatively large flowers, “interesting” pollination systems, and text book examples of classical pollination syndromes such as bird and bat pollination. Researchers who study flowers and their pollinators choose their subjects based on a whole set of criteria, but random selection is not one of them. However as far as we can judge, Aguilar et al. (2015) seem to be arguing that drawing strong, “universal” conclusions about syndromes from this highly biased data set is perfectly acceptable because of the statistical rigour of formal meta-analysis. I’d re-iterate our main point that no amount of statistical rigour and exhaustive literature searching can take into account inherent biases within the primary data (i.e. the literature itself).

Finally, Aguilar et al. (2015) claim that “human disturbance of natural habitats has caused disruptions in patterns of mutualistic interactions that may partly explain the presence of the diverse pollinator assemblages that are frequently found in pollination studies”. It seems to us to be disingenuous to argue that pollination syndromes are universally valid and then to essentially concede that there are lots of wrong visitors (“secondary” pollinators), and to explain that with the idea that everything is disturbed in the Anthropocene. If this is really the case then we probably need to throw out a lot of our understanding of evolutionary ecology as a whole, not just studies of plant-pollinator interactions.

Clearly we don’t accept this argument and in fact it has echoes of arguments that have been going on since the 19th century (Waser et al. 2011): more than 130 years ago the Darwinian biologist Hermann Muller was criticising Federico Delpino (one of the original architects of the idea of pollination syndromes) for ignoring the “wrong” flower visitors. Interestingly, Delpino was a fundamentally a teleologist who saw purpose in nature, expressed through (as he perceived them) the highly ordered relationships between flowers and pollinators.

As we discuss in the Waser et al. (2011) paper, Stefan Vogel was another prominent pollination biologist, and advocate of the importance of pollination syndromes, who was also fundamentally teleological in his thinking. I was sad to learn that Stefan passed away very recently, in what I believe is his 90th year. I was fortunate enough to meet Stefan at a symposium in honour of his 80th birthday at the International Botanical Congress in Vienna in 2005. He graciously signed my copy of The Role of Scent Glands in Pollination and said, with a twinkle in his eye, “you and I have probably got a lot to discuss”. Unfortunately we never got the opportunity, but later I dedicated our 2009 paper on Ceropegia pollination to him “in honour of his pioneering work on pollination” in the genus. Stefan’s legacy of research, particularly in the tropical regions of South America, is a fitting tribute to his memory.

Pollination syndromes clearly continue to attract much interest in the scientific literature, and just this week I was intrigued to see a paper by John Benning showing that a species of Ericaceae that looks as though it “should” be pollinated by bees is actually moth pollinated. No doubt the discussion of the evolutionary extent and predictability of pollination syndromes will continue for some time to come.

A new bee for Northamptonshire!

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Back in the summer I produced a series of posts for Pollinator Awareness Week highlighting the pollinators to be found in our own urban garden in Northampton. One of those posts was of what I believed to be the Little flower bee (Anthophora bimaculata), a species which at the time I’d never previously seen. I noted that this was a new urban record for Northampton as my PhD student Muzafar Sirohi had not recorded it during his bee surveys, which I discussed earlier this year.

Some time later I checked the bee records on the National Biodiversity Network (NBN) Gateway site and realised that not only was this the first urban record of the species in Northampton, it was actually the first record for the county of Northamptonshire as a whole! The record has recently been accepted on iRecord and will be added to the NBN records.

Of course this is personally exciting (a new record for a large county found in our back garden) and it adds a significant regional record to the currently known distribution of the species. The map on the BWARS account of Anthophora bimaculata shows that the species is predominantly southern in its distribution, with a few eastern and western outliers. This new record places the species firmly in the centre of England, confirming that it is more widespread than previously assumed.

There are two possible explanations for the discovery of this bee in Northamptonshire. One is that it’s a very recent range expansion and the species is becoming more common and widespread, perhaps as a result of climate change. The second is that it’s always been present in Northamptonshire, but just never recorded. At the moment it’s impossible to decide between these two possibilities as there’s evidence to support both. Not only did Muzafar not record A. bimaculata in his surveys in 2012, neither did Dr Hilary Erenler, Dr Sam Tarrant or Kathryn Harrold in their pollinator surveys in the region between 2007 and 2015. Having said that, we do know that Northamptonshire is a historically under-recorded county for bees as it has no County Recorder for Hymenoptera, and both Hilary and Muzafar recorded species new to Northamptonshire, which I hope to report on at a later stage.

Differentiating between these two scenarios will be difficult and may be impossible unless we can discover previously unknown historical specimens of this bee that were collected in the county, or the species continues to expand in its range.

Understanding the distribution of pollinators such as bees is a key component of initiatives such as the National Pollinator Strategy – if we don’t know where the things we are trying to conserve actually are, how can we conserve them? So it’s very pleasing to be able to make a small contribution to that process from the comfort of our own garden!

Who is feeding the honey bee bullshit machine?

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This morning I received an email from Public Policy Exchange (PPE) inviting me to a conference in London in November entitled “Biodiversity and Local Partnerships: Halting the Decline of the Honey Bee in the UK”

The opening statement on the website and the official flyer convinced me that the organisers have been misinformed; all of it is wrong:

“Healthy honey bee populations are vital to food and crop production, and the natural environment. In the UK, honey bees are responsible for 80% of pollination, and a third of the food we eat is pollinated by bees.”

Where are they getting this information from? Who is feeding organisations like the PPE this kind of bullshit? Is it bee keeping organisations? I’d really like to know.

Honeybees are responsible for only one third of the crop pollination in the UK (Breeze et al. 2011), and a very small proportion of the wild plant pollination. Wild bees, hoverflies, butterflies, and other pollinators are much more important than honeybees, and collectively they are responsible for this pollination, not just managed honeybees. No one is denying that honey bees are important, but there is absolutely nothing to gain (and a lot to lose in terms of science credibility) by over-playing their importance, as I’ve argued in the peer-reviewed literature.

It’s not as if this is the only recent example, The Daily Express online has recently been equally ignorant of the facts, and didn’t even get the right bee in the accompanying image.

It’s interesting that the PPE website also uses the infamous not-Einstein quote, though they cite the author as “unknown”. With good reason, because that’s bullshit too.

I won’t be attending the conference.

By lifting the restriction on the use of neonicotinoid pesticides Defra throws a (bee) brick at its own National Pollinator Strategy

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Yesterday a brick arrived in the post. Not just any brick, but a Bee Brick, designed by the Green&Blue company in Cornwall as an architectural addition that can provide habitat for cavity nesting solitary species such as the Patchwork leaf-cutter bee that I discussed during Pollinator Awareness week. A representative of the company recently got in touch, after having read my blog, and asked if I’d like a sample to try out in the garden. In the absence of any planned wall building I’ve placed it a couple of metres up on the flat top of a south facing summer house window. It’s probably a bit late in the season to attract any nesting solitary bees this year, but we’ll see; expect a report back from me at some point.

I had actually encountered the Bee Brick earlier this year at the Chelsea Flower Show which Karin and I attended as a 50th year bucket-list day out. It was ok, I enjoyed it, the plants and (some of) the gardens were great. But it was too busy, too expensive and too full of ostentatiously wealthy people for my tastes.

As if to serve as a counter-point to all the good work being done during Pollinator Awareness Week and by companies such as Green&Blue, came the recent news that Defra has agreed to lift the restrictions on use of two neonicotinoid pesticides on oil seed rape across a “limited” area in the east of the country. It will apparently apply mainly to Suffolk, and cover an area of about 30,000 hectares. That’s 5% of the UK’s oil seed rape crop.

The decision was made at the behest of the National Farmers Union, and seems to make no farming sense whatsoever given that nationally yields of oil seed rape have not been affected by the restriction on neonicotinoids, with the harvest this year looking to be above average. Not surprisingly the decision has drawn furious fire from a range of environmental organisations including Buglife and the Wildlife Trusts. Meanwhile Friends of the Earth have threatened legal action, a move prompted by the fact that the Government has refused to allow its independent advisors to publish the details of the decision, including how it was made and what was discussed.

Aside from the lack of transparency, what particularly worries me is that this decision opens the door to further use of these restricted pesticides over the next 12 months, on a region by region basis, until we are back where we were prior to the restrictions being imposed. The two year restriction on use of neonicotinoid pesticides comes to an end in December, at which point no one outside (and possibly inside) of Defra knows what is going to happen.

The National Farmers Union is being very selective with their use of information about the scientific evidence base for the effects of these pesticides on pollinators. Dr Chris Hartfield, the NFU’s horticultural policy adviser and lead on bee health issues, was quoted as saying “The majority of the research that has fuelled this debate has been based on artificial dosing studies. The big question in this area is, does this accurately reflect what happens to bees foraging in and around neonicotinoid crops? We don’t know, but the field studies haven’t shown that they are causing population declines in pollinators”.

Dr Hartfield and the NFU know full well that all of the evidence so far published shows that even at very small (field realistic) doses, neonicotinoid pesticides have been demonstrated to have important, sub-lethal effects on pollinators that may ultimately affect populations of some species. Surely the wisest course of action is to further restrict their use until we have studied the situation.

This is not the only occasion when the NFU have been less than objective with their use of scientific evidence. In the past couple of weeks I’ve had a group email exchange with Dr Hartfield in which he talked about the study by Carvalheiro et al. (2013) that “shows these [pollinator] declines have slowed (or even reversed) in the last 2 decades”. I responded by pointing out that the current situation is not as straightforward as that. The recent paper that we published in the journal Science showed that the rate of extinctions of UK bees and flower-visiting wasps has in fact increased over the period when Carvalheiro et al. (2013) see a slow down in declines in abundance.

There are a number of reasons why our results may be in disagreement with those of Carvalheiro et al., which we discuss in the paper, including the large statistical confidence interval around the rate of extinction during this latter period. However as with all such data, one or two studies will not give a definitive answer. I provided Dr Hartfield with a link to our paper but I’m still waiting to receive a reply.

Initiatives such as the Bee Brick, reduced mowing on road verges, the RHS’s Perfect for Pollinators plant list, etc., etc. are important but they are tiny contributions compared to the role that must be played by British agriculture if we are to conserve pollinator diversity in the UK. Farming accounts for 70% of the land surface in this country and has by far the greatest part to play in reducing biodiversity loss.

Within 12 months of Defra launching the National Pollinator Strategy, the same Government department has decided to bow to pressure and allow some use of a group of pesticides that we know are causing problems, even if they are not the whole story. Defra is effectively hurling what may be the first of many bricks at itself, ultimately weakening the Strategy. From conversations with politicians I know that these large departments do not have good internal communication and dialogue, but this seems to be an outstanding example of Orwellian double-think on the part of Defra.

Garden pollinators for PAW no. 7 – Tree bumblebee (Bombus hypnorum)

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For my final post for Pollinator Awareness Week I’ve chosen another bumblebee, one with a fascinating history and ecology. The Tree bumblebee (Bombus hypnorum) is a relatively new arrival on our shores. It was first discovered near Southampton by Dave Goulson in 2001; since then has spread out through the country, as far north (currently) as central Scotland, and has recently been recorded from Ireland. It arrived in Northamptonshire in 2006. The Bees, Wasps and Ants Recording Society (BWARS) has been tracking its spread through a recording scheme: it’s very distinctive being the only one of our 25 bumblebees to have a ginger thorax, black abdomen and white tail.

All the evidence suggests that this was a natural range expansion for the species rather than a deliberate or accidental introduction by people. It’s what species do, they move around and change their distribution over timescales of decades to hundreds of years (there are lots of bird examples of this, including the Collared dove in the UK). There’s no suggestion that this was due to climate change, however: Bombus hypnorum has long been present in colder parts of Europe and Scandinavia.

That said, there is probably a human influence to its spread as the species is closely associated with houses and gardens, often nesting in bird boxes or roof spaces (we had one in our roof for three years running). The natural nesting habit for this bee is tree holes (hence the common name) which is why they are usually found in cavities above the ground. However, like the Buff-tailed bumblebee, they can also be found in compost heaps, as a recent posting on the Bees Knees Facebook group showed (if you’re not a member of that group I can recommend it as it’s full of friendly, practical gardening advice for those interested in how their garden can be beautiful, productive and wildlife-friendly).

Although the Tree bumblebee will take nectar and pollen from an assortment of garden plants it seems to be particularly associated with members of the rose family (Rosaceae) and is a frequent pollinator of rosaceous soft fruit such as raspberries and blackberries. I tried and failed yesterday to photograph the bee on our raspberries, so here’s a photograph of the outcome of that pollination.

The Tree bumblebee is rapidly becoming one of the commonest garden bumblebees. Is this likely to cause problems for our other bumblebees, by out-competing them for nectar and pollen, or even nesting sites? It’s too early to tell but I’d be surprised if it does.

Phew! That’s it! It’s been a bit of marathon preparing these posts on top of writing a large grant application and a thousand other jobs, but it’s been a lot of fun. Thanks to everyone who has viewed my posts For Pollinator Awareness Week and commented on them, either on the site or on Facebook. Hopefully they have raised a broader awareness of our amazing native pollinators.

Garden pollinators for PAW no. 6 – Buff-tailed bumblebee (Bombus terrestris)

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It would be impossible to write a series of blog posts about garden pollinators for Pollinator Awareness Week without considering the bumblebees (genus Bombus) and I intend to devote the last two posts to that group of bees. The bumblebees are arguably the UK’s most important pollinators of both wild and crop plants, certainly later in the season when colony numbers have increased. Earlier in the season it’s the solitary bees such as the Orange-tailed mining bee that are predominant.

Although common and widespread in gardens, the Buff-tailed bumblebee (Bombus terrestris) belongs to a group of bees in which the workers are rather variable in appearance and can be very difficult to distinguish from those in the Bombus lucorum group, which includes two other species (B. cryptarum and B. magnus).

This is a truly social species with an annual nest comprising workers and a queen. Nests are founded by queens that have mated the previous year and hibernated. They usually choose old rodent nests in which to begin their colonies, which is why they are sometimes found in garden compost bins. An interesting question that I’ve not seen answered is whether the queens actively displace mice or voles from such nests: does anyone know? This association between bumblebees and mice led Charles Darwin and Thomas Huxley into some speculation as to the role of spinsters in the British Empire.

In my garden the Buff-tailed bumblebee pollinates a range of crops including strawberries, squashes, courgettes, blackberries, runner beans, french beans, tomatoes, and raspberries. As the photo above shows they also visit the flowers of passion fruit, where they seem to be more effective than the smaller honey bees and solitary bees.

Garden pollinators for PAW no. 5 – Orange-tailed mining bee (Andrena haemorrhoa)

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The Orange-tailed mining bee (Andrena haemorrhoa) is also referred to as the Early mining bee due to its habit of emerging from over-wintered nests as early in the year as March. In truth, however, many Andrena species put in an early appearance, making them important pollinators of orchard fruit such as apples, which you can see from the photograph above, taken in my urban garden earlier this year. So “Orange-tailed” is a more descriptive name.

Thanks to the Orange-tailed mining bee and other early bees, this unnamed apple variety (which Karin and I rescued from the bargain area of a local garden centre) has gone on to produce a heavy crop of eating apples (see below). There’s considerable interest in the role of wild bees such as these as pollinators of fruit in commercial orchards, not just in Europe but in the USA too, where other Andrena spp. also pollinate apples.

The epithet “Mining bees” refers to the fact that these solitary species of the genus Andrena usually make their nests in soil, excavating deep tunnels in which to construct individual cells. It’s another generalist, taking pollen and nectar from a wide variety of garden and wild flowers. Dandelions are particularly important early in the year – so don’t over-manage your lawn and allow some to flower!

Garden pollinators for PAW no. 3 – Little flower bee (Anthophora bimaculata)

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There are only five Anthophora species in the UK and the Little flower bee (Anthophora bimaculata), as the name suggests, is one of the smallest. This is a fast moving little beast and my fairly bog standard cameras (and a generally impatient personality) struggle to capture it: Steve Falk’s images do it justice better than I ever could.

Once again, as with the Patchwork leaf-cutter bee, the flowers of Lamb’s ear are a real favourite in my garden. Also like that bee, this is a solitary species, though this is one that nests in dry, sandy soil. I’ve not been able to locate any nests in my own patch and I wonder whether it’s nesting in a nearby garden.

Another generalist species, I’ve seen this bee visit food crops with open flowers such as blackberry and raspberry in my garden. Despite its size it is likely to be quite a good pollinator of those fruit as it’s abundant, fast moving between flowers, and hairy, and can carry significant amounts of pollen.

Interestingly, Anthophora bimaculata was not recorded by Muzafar Sirohi during his surveys of bees in Northampton town centre, so it’s another species that we can add to that urban list.

Pollinator Awareness Week – 13th – 19th July 2015

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Next week has been designated Pollinator Awareness Week (PAW) by Defra and there are events and profile-raising activities going on all over the country.

The motivation behind the PAW is (quote) “to bring attention to the essential needs of pollinators and the simple actions that we can all take to help pollinators survive and thrive”.

With that in mind, next week I intend to produce one blog post a day that highlights, with photographs, a pollinator (or group of pollinators) that I’ve found in my own urban garden in Northampton. The purpose is to illustrate the diversity of pollinators that even a town garden can support, something about their fascinating life histories, and the different ecological requirements of these pollinators that our gardens can provide. For some of them I’ll even discuss the garden crops that they pollinate. First post will be on Monday.

If you, or the group you work with, are doing something for Pollinator Awareness Week feel free to share it in the comments section below.