Tag Archives: Wildlife

Do bumblebees make honey? Yes and no…and…maybe [UPDATED]

As kids, my friends and I did a lot of digging. We always seemed to be burrowing into slopes or excavating trenches, pretending to be archaeologists or treasure hunters. Indeed, there was a lot of ground treasure to be found in the part of Sunderland where I grew up. The area has a long history of pottery and glass making, and ship building, and the remnants of these industries could be uncovered every time we stuck a spade in the earth. Over time I developed my own small museum of interesting, unearthed fragments, including bits of hand-painted ceramics, glass bottles, and unidentifiable metal shards, alongside various animal bones I’d excavated. My parents quietly indulged this interest, and my muck-streaked face and clothes, even if they didn’t quite understand what I was doing.

Aged about 10, my first encounter with a bumblebee nest was during one such dig. On the waste ground behind a large advertising hoarding, we began digging into a low, grass-covered mound and accidentally excavated what was probably a small nest of Buff-tailed Bumblebees (Bombus terrestris). I can recall being fascinated by the waxy, odd shaped cells and by the sticky fluid that some of them were leaking. Being an adventurous sort of child I tasted the liquid: it was sweet and sticky, and that was my first encounter with bumblebee “honey”.

I’m going to leave those quotation marks in place because if you do an online search for “do bumblebees make honey?” you generally find that the answer is “no, only honey bees make honey”.

Now, defining honey as something made by honey bee strikes me as a circular argument at best. And it also neglects the “honey” made by meliponine bees that is central to the culture of stingless bee keeping by indigenous groups in Central and South America, and the long tradition pre-colonial tradition of honey hunting by Aboriginal Australians. So if we widen our definition of “honey” as being the nectar*-derived fluid stored in the nests of social bees, then Apis honey bees, stingless bees and bumblebees must all, by logic, make honey. And likewise there’s wasps in the genus Brachygastra from Central and South America that are referred to as “honey wasps” because, well, I’m sure you can work it out!

But this is where things become a little trickier, because turning nectar* into honey involves some complex evaporation and enzymatic activity, so that the resulting fluid is more concentrated and dominated by the sugars glucose and fructose. Although analysis of honey bee honey is commonplace, and there’s been some research conducted on the honey of stingless bees, I don’t know of any studies that have compared Bombus honey with that of other bees, or with what is stored in the nests of honey wasps**. If I’ve missed anything, please do comment and let me know, but this strikes me as an area of research demanding some attention.

So do bumblebees make honey? That very much depends on our definitions, but I’m happy to accept that they do because “honey” is not a single thing: it’s an insect-derived substance that can take a range of forms but serves the same broad purpose of feeding the colony. And although insects have probably been producing it for millions of years, I think I’ve known the answer to the question for almost 50 of them…

UPDATE: A couple of people have commented on social media that there are legal definitions of “honey” as a foodstuff. Here’s the definition according to UK law***:

“the natural sweet substance produced by Apis mellifera bees from the nectar of plants or from secretions of living parts of plants or excretions of plant-sucking insects on the living parts of plants which the bees collect, transform by combining with specific substances of their own, deposit, dehydrate, store and leave in honeycombs to ripen and mature”

So, legally, we can’t call anything that isn’t made by Apis mellifera “honey”, at least from a foodstuffs regulation perspective. But that’s clearly different to what we have been discussing above, which is about a biological definition of honey.

It’s also interesting to look at the compositional requirements of honey as a foodstuff (presented in Schedule one of that document, if you follow the link above). The lower limit for moisture content is 20%. Now if you consider that most nectar in flowers has a sugar content of between about 20% and 50%, clearly there’s been a lot of evaporative work done by the bees to reduce the amount of water in the honey. I would love to know how bumblebee (and other insect) “honey” compares to this: do they put the same kind of effort into evaporating the water from the stored nectar? Given that the purpose of reducing the water content is to prevent fermentation by yeasts when it’s stored for a long time, and that there are bumblebee species which have colonies that are active for more than one year, I imagine that at least some species in some parts of their range may employ similar tactics.

Thanks to everyone who has been commenting and discussing the topic. It never ceases to amaze me how much we still do not understand about some fundamental aspects of the natural history of familiar species!

*And honeydew to a greater or lesser extent.

**I’m going to ignore honey pot ants for now as this is complex enough as it is and they don’t store the “honey” in nest cells.

***From what I can gather definitions in other countries are similar.

Nature’s graffiti: lichens pattern clay tiles

Following on from my recent blog post about biological crusts, I was intrigued by the patterns formed by these lichens on the clay tiles capping the brick gate columns of our local cemetery. It looks as though they have been created by successive waves of growth, but I may be wrong about that. Any lichen experts out there who can tell me what’s going on?

I think the species is Xanthoria parietina, but again I’m happy to be corrected. Below is a cropped close-up from a slightly different angle.

A new study shows that even short-tubed flowers can specialise on hawkmoths as pollinators

Of all of the “classical” pollination syndromes, flowers that are hawkmoth pollinated have one of the highest levels of predictability. If a flower is pale in colour, opens at night, is highly scented, and possesses a long tube at the bottom of which is a supply of nectar, there’s a very high likelihood that it’s pollinated by long-tongued hawkmoths (Sphingidae).

Indeed, one of the foundational stories about the development of our understanding of how pollination systems evolve, relates to Charles Darwin, the long-tubed orchid Angraecum sesquipedale and the hawkmoth Xanthopan morganii praedicta.

Fast forward 160 years and we now know that pollination syndromes are more complex than 19th and early 20th century scientists imagined – see my recent book Pollinators & Pollination: Nature and Society for a discussion of this topic. That’s not surprising because, as I point out, we probably have data on the interactions between plants and their pollinators for only about 10% of the estimated 352,000 species of flowering plants. There’s still much to be discovered!

As an example of how our understanding of specialised flower-hawkmoth interactions is developing, consider this recent study that I’ve just published with my Brazilian colleague Felipe Amorim and other collaborators. In it we have shown that, contrary to expectations, a species of Apocynaceae (Schubertia grandiflora) with a relatively short floral tube can specialise on hawkmoths with much longer tongues than we might predict.

The full reference with a link to the study is shown below, followed by the abstract. If you would like a PDF, please drop me a line via my Contact page:

Amorim, F.W., Marin, S., Sanz-Viega, P.A., Ollerton, J. & Oliveira, P.E. (2022) Short flowers for long tongues: functional specialization in a nocturnal pollination network of an asclepiad in long-tongued hawkmoths. Biotropica https://doi.org/10.1111/btp.13090

Abstract:

Since Darwin, very long and narrow floral tubes have been known to represent the main floral morphological feature for specialized long-tongued hawkmoth pollination. However, specialization may be driven by other contrivances instead of floral tube morphology. Asclepiads are plants with a complex floral morphology where primary hawkmoth pollination had never been described. We detailed here the intricate pollination mechanism of the South American asclepiad Schubertia grandiflora, where functional specialization on long-tongued hawkmoth pollinators occurs despite the short floral tube of this species. We studied two plant populations in the Brazilian Cerrado and recorded floral visitors using different approaches, such as light-trapped hawkmoths for pollen analysis, direct field observations, and IR motion-activated cameras. Finally, using a community-level approach we applied an ecological network analysis to identify the realized pollinator niche of S. grandiflora among the available niches in the pollinator community. Throughout a period of 17 years, long-tongued hawkmoths were consistently recorded as the main floral visitors and the only effective pollinators of S. grandiflora. Flowers rely on highly modified corona and gynostegium, and enlarged nectar chambers, to drive visitors and pollination mechanism. Despite its relative short-tube, network analysis placed S. grandiflora in the module including exclusively long-tongued hawkmoth pollinators and the most phenotypically specialized sphingophilous plants in the community. These results represent the first example of functional specialization in long-tongued hawkmoths in an asclepiad species. However, this specialization is uncoupled from the long floral tubes historically associated with the sphingophily syndrome.

Deforestation grabs the headlines: but what about the grasslands?

Perhaps it’s because we don’t have a fancy name for it? “Deforestation” rolls off the tongue in a rather satisfying way that emphasises the importance of conserving old growth and ancient woodlands. But how do we describe destruction of grasslands? “Degrasslandation” doesn’t really work, even though at its root is trying to describe the same effect: the loss of important, carbon-storing and biodiversity-preserving ecosystems. Grasslands, remember, are the world’s largest single terrestrial ecosystem.

Of course it’s not just grasslands that are disappearing: shrublands and savannahs such as the Brazilian cerrado are being lost even faster than forests are being cut down. But again “deshrublandisation” or “decerradoisation” just don’t have the same ring. Nor the political clout: Boris Johnson cannot wax lyrical about the “cathedrals of nature” of chalk grassland on Salisbury Plain or the species rich flood meadows along the Thames. However Britain has lost far more of them than we have of ancient woodlands: over 90% of such species diverse grasslands have now gone according to some estimates.

It’s clear that forests have great PR, are highly photogenic, and are ecologically incredibly important. So today’s announcement at COP26 that world leaders have committed to stopping deforestation by 2030 is welcome news: if they come through with their promises, which they didn’t following a similar announcement in 2014. But I’m in agreement with Gill Perkins who has just published this opinion piece in New Scientist. A commitment to stop grasslands, and other types of habitat, being built on, ploughed up or agriculturally “improved” could go a long way towards ensuring that carbon remains locked up in the world’s soils and vegetation. It doesn’t all have to be about the forests.

UPDATE: for more about the importance of grasslands and how they are being degraded worldwide, see this recent piece by Richard Bardgett, James Bullock, and colleagues entitled “Combatting global grassland degradation“.

New article just published: ‘Pollinators and pollination: myths, misunderstandings and much more to discover’

My first (and hopefully not my last) article for the magazine British Wildlife has just appeared in the April issue. Entitled ‘Pollinators and pollination: myths, misunderstandings and much more to discover’ you can get a preview here: https://www.britishwildlife.com/article/volume-32-number-5-page-316-323

The article focuses on some of the myths and misunderstandings that I dealt with in my book Pollinators & Pollination: Nature and Society. It also points out that, even in a place like Britain with a long tradition of natural history study, there’s still much for the patient observer to discover. If you’re interested in a PDF, drop me a line via the Contact page.

Online talks and training: here’s a selection of what I offer

Over the past few months I’ve done a large number of online talks for a variety of audiences, including natural history and gardening societies, beekeeping groups, private companies, university estates departments, and ecological consultancies. I thought it would be useful to provide a list of what I offer, with a short description. All talks are accessible and understandable to a broad audience, and can be tailored to the individual needs of the group:

Pollinators & Pollination: Nature and Society is an introduction to the importance of pollinators and the pollination services that they provide to both wild and crop plants. The name, of course, reflects that of my recent book.

The Politics of Pollination is an account of how society (governments, organisations and individuals) has responded to the current “pollination crisis” (if that’s what it actually is…)

Bees in Cities: an Introduction to Urban Pollinators focuses on the positive roles that urban environments can play for pollinators, and the potential threats of city living.

Pollinators in Gardens gives practical advice on how to make your garden “pollinator friendly”.

Pollinator Conservation: Threats and Opportunities describes how and why pollinators are declining and what we can do about it at the individual and societal level.

Habitat Creation and Management for Pollinators gives an introduction to how NGOs, estates departments, consultancies, and so forth, can effectively support pollinators in ways that go beyond just planting flowers and putting up a few “bee hotels”.

To Be a Flower is an introduction to how flowers function and the ways in which they manipulate the behaviour of their pollinators to ensure reproduction.

Darwin’s Unrequited Isle: a Personal Natural History of Tenerife describes some of the field work that we’ve been doing on this most fascinating of the Canary Islands.

Biodiversity: What Is It and Why Should We Care? gives a very general overview of the topic of biodiversity and ecosystem services.

Talks typically last for around 50 minutes, following which I’m happy to answer questions and discuss any issues that have arisen. I also offer a half- or full-day of training for those organisations that need more depth, for example ecological consultancies. Note that I charge for all of my talks and training. If you would like to enquire about any of this, please use the form on the Contact page.

Why did I write the book? An interview with NHBS

The nice people at NHBS recently did a wide-ranging interview with me about my new book Pollinators & Pollination: Nature and Society and what led me to write it. It covers a lot of ground, including climate change, food security, the UK Pollinator Monitoring Scheme, and growing up in Sunderland.

Here’s the link:
https://www.nhbs.com/blog/jeff-ollerton-pollinators-pollination

Flowers can be assholes – quite literally!

2003-572 s G Bochum

WARNING: There’s a high yuck factor to this post, it’s not for the squeamish or easily offended!

One of my Twitter contacts, Traci Birge in Finland, has been reading Pollinators & Pollination: Nature and Society, and making some very nice comments about it. I had to laugh at this one in which she describes some plants as “assholes” because of the way in which they deceive pollinators into visiting their flowers but offer no reward in return:

If you follow that thread you can see that Traci was closer to the truth than perhaps she realised: there are some plants with flowers that appear to mimic the anuses of dead mammals, particularly in the families Apocynaceae and Araceae. By their smell, texture, colour and hairiness they are fooling flies into visiting the flowers, because assholes, like any mammalian orifice, provide an entry point for maggots of carrion-feeding flies. Sometimes the deception is so great that the flies lay their eggs on these blooms, though of course the maggots starve.

A great example of an anus-mimicking bloom is the Dead Horse Arum (Helicodiceros muscivorus). Check out the image above: if that doesn’t look like a horse’s ass, I don’t know what does!

Other examples might be found within the stapeliads, especially the genus Huernia which often have a thickened annulus to the centre of the flower. However that could also be interpreted as mimicking an open, inflamed wound on the side of an animal:

As I point out in the book, you might imagine that there would be strong natural selection against flies visiting these flowers if they lose fitness by laying eggs on such an unsuitable substrate. But the flowers are tapping into really deep-seated behaviours and clearly the flies can’t distinguish the flowers from the real thing.

This is flower pollination that is far removed from the deliciously perfumed, cute-and-cuddly, heart-warming world of bees and flowers. Isn’t nature wonderful?

All photos from Wikipedia, as follows:

Helicodiceros muscivorus: Göteborgs botaniska trädgård (photographer: Ingemar Johansson) – http://www.mynewsdesk.com/se/pressroom/goteborgs_botaniska_tradgard/image/view/dracunculus-muscivorus-128973, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19265330

Huernia zebrina: Enzo^ – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=10963668

Huernia schneideriana: Juan Carlos Fonseca Mata – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94705877

“Bee Together” with YDMT – pollinator online talks during January and February

As I write a slow haze of fine snow is falling, covering our garden with a thin white dusting. Spring feels a long way off, despite the emerging spears of daffodil leaves. But you can get a taste of what the new season will bring by signing up for a short series of free evening online talks on the topic of pollinators that has been organised by the Yorkshire Dales Millennium Trust – here’s the link for the Bee Together programme – and here’s more details of the talks:

Thursday January 28 at 7pm: Pollinators and Pollination: Nature and Society
An overview of the diversity of pollinators in Britain, why they are important, and the threats to that diversity with Jeff Ollerton.

Thursday February 18 (7pm): The B-Lines Project
Buglife’s B-Lines network is an imaginative solution to the problem of the loss of flowers and pollinators. B-Lines are a series of ‘insect pathways’ running through our countryside and towns, along which Buglife are restoring and creating a series of wildflower-rich habitat stepping stones. Catherine Jones talks about mapping the recently completed B-Lines map and some of the projects that have already created habitat for pollinators.

Thursday February 25 (7pm): The Hidden Lives of Garden Bees
Brigit Strawbridge Howard will explain some of the basic differences between bumblebees, solitary bees, and honeybees – including lifecycles and nesting behaviour; the problems they all face; and, most important, what we can do to help. Brigit is a wildlife gardener, amateur naturalist and advocate of bees. She writes and campaigns to raise awareness of the importance of native wild bees, and is the author of Dancing with Bees: A Journey Back to Nature.

I hope to see some of you there: Happy New Year everyone!

Pollinators, landscape and friends: our recent trip to the Danish island of Sejerø

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This is not the first time I’ve written about the beautiful Danish island of Sejerø – see my post “Why do bumblebees follow ferries?“.  It’s home to our friends Pia and Stephen Valentine (Stephen is the very talented artist who produced the fabulous study of waxwings that Karin commissioned for my birthday last year).  Earlier this month we traveled over to stay with them and to explore some more of the island.  Here are some photos and thoughts from that trip.

Despite the hot, dry weather that northern Europe has been experiencing recently there were pollinators aplenty.  Thistles and knapweeds (both groups from the daisy family Asteraceae) are well known to be drought tolerant and attract a lot of insect interest.  This is a Pantaloon Bee (Dasypoda sp.)  If it was Britain I’d say that it was D. hirtipes, but there are other species on the continent so I can’t be sure.  These bees are well named: the “pantaloons” are found only on the females and are used to collect pollen, especially from Asteraceae.

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I believe that this is the male of this species; note the absence of the pollen-collecting hairs on the rear legs and the yellow face, typical of many male bees:

The flower heads of the knapweeds were highly sought after; on this one, two different bumblebees (Bombus spp.) were competing with two Silver Y moths (Autographa gamma):

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Sometimes the bumblebees got an inflorescence to themselves, though the photobombing Silver Ys were never far away:

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It’s been a good year for the Silver Y, large numbers have migrated northwards from southern Europe and we’ve had lots in our garden too.  On Sejerø they were everywhere, on all kinds of plants: 

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The butterfly is one of the Blues (Lycaenidae), possibly Common Blue (Polyommatus icarus), but again this being Denmark they may have other species that I’m not familiar with.  Note the Silver Y photobombing once more…:

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Wild carrot (Daucus carota) was common on the island and always attracts a wide range of flies, wasps and beetles:

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Close to home we found a huge cherry tree laden with the fruits of pollination and collected a couple of kilos for Stephen to make into jam.  Stoning them was messy but fun and a nice opportunity to sit and chat about nature and people:

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I was very impressed with Stephen’s up-cycled general purpose baskets, made from plastic containers he finds on the beach, wire, and lengths of old hosepipe:

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Along the shore another edible plant, Sea Kale (Crambe maritima) was attracting a lot of attention from white butterflies (Pieridae) whose caterpillars feed on this and other members of the cabbage family (Brassicaceae):

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I tried a piece of raw leaf; it tasted ok, salty and a little bitter.  Apparently it’s very nice if you blanch the young leaves.  It’s a distinctive and impressive component of the beach flora:

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Amidst the greens, buffs and browns of the beach landscape we encountered the occasional scarlet of a patch of poppies (Papaver sp.):

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Everywhere on the island we saw evidence of the link between life on land and in the sea, and the cycles and processes upon which that life depends.  Sand martins (Riparia riparia – an apt name – “riparian” refers to the interface between land and water) are common and their nest excavations speed up the return of sediments back to the sea:

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Favoured rocks have been used by gulls and other sea birds for generations, their guano helping to enrich these coastal waters and fueling the primary production of seaweeds and diatoms, which in turn feed other shore life:

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Evidence of human activities was never far away, though, concrete and steel blending with nature:

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Wheat fields merging with the sky:

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Thanks to Pia and Stephen, and of course Zenja, for making this such a wonderful trip and allowing us to join them in exploring their home island:

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