Recently Phil Stevenson and I advised on an art/science project called Minus Pollinators which considered what a small café menu might look like if there were no pollinators to help produce the many, many fruits and vegetables and nuts that are animal pollinated.
The project is a collaboration between writer and consultant Max Fraser and artist Freddie Yauner. To quote Freddie’s description on his website, the project represents:
A dystopian future in the form of a drinks kiosk where the staples such as coffee, teas, juices, chocolate etc. are no longer available due to pollinator decline…the mobile drinks kiosk acts as an exhibition display, with artworks painted in pollen…and a take-away pamphlet…detailing the importance of insect pollinators for our collective future on this planet.
Minus Pollinators was commissioned as part of a summer-long event called Food Forever at the Royal Botanic Gardens, Kew, after which it goes to the Groundswell festival.
It was a pleasure to work with Max, Freddie and Phil on this because art/science projects are a great way of getting the message across about the importance of biodiversity and the current environmental crisis that we are facing.
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.
Cycling back from town this afternoon, Karin and I passed a hedgerow that was bursting with wild myrobalan or (cherry) plums (Prunus cerasifera). We had to stop and collect some, and soon filled a bag. What’s always intrigued me about these small, tart little plums is just how diverse they are: the image above shows the plums from six different trees. All of these are, in theory, the same species; but clearly there’s a lot of genetic diversity. In colour, the ripe fruits range from golden yellow through to dark purple, and vary in the amount of dark-contrasting streaking, lighter speckling, and waxy bloom. They are also variable in size, shape and taste.
All of this variation probably reflects the long history of cultivation of this European archaeophyte. The species is originally native to southeast Europe and western Asia, and was likely spread throughout Europe by the Romans. The local deer population is very fond of the fruit and we’re seeing a lot of deer droppings that are packed with seeds. We don’t usually think of these large mammals as seed dispersers, but I suspect that they are very successful in that ecological role.
As well as being a great source of wild fruit, for humans and wildlife alike, at the other end of the year these trees are important for pollinating insects. As I pointed out in my book Pollinators & Pollination: Nature and Society, Prunus cerasifera is one of the earliest flowering woody plants in northern Europe, and its flowers are an important nectar and pollen source for early emerging bumblebee queens, hoverflies, and honey bees.
Delicious, abundant fruit combined with a valuable role for pollinators: what’s not to like?
This week’s Spiral Sunday post features a couple of shots I took today in Milton Keynes where we spent a tiring day Christmas shopping. One of the outdoor stalls is selling a traditional baked sweet pastry from Transylvania, the name of which they have Anglicised to “Spiralicious”. It’s made with a very neat spiral-shaped dough cutter, which was just begging to be photographed.
This term we have started refreshing and reformatting our first year undergraduate modules, partly in preparation for the move to our new Waterside Campus, but also because they were beginning to feel a bit tired and jaded. We have begun with ENV1012 Biodiversity: an Introduction, a 20 CATSmodule which mainly services our BSc Environmental Science and BSc Biology programmes.
One of the changes has been to go from a “long-thin” delivery of 2 class hours per week over two terms, to a “short-fat” delivery of 4 hours per week in one term. The advantages of this, we think, are two-fold: (1) it provides students with a richer, more immersive experience because they are not mind-flitting between different topics; (2) it frees up longer blocks of time for academic staff to focus on programme development, research activities, etc.
For now we have opted to deliver the 4 hours in a single session. That’s quite a long time for the students (and staff) to be taught (teaching) but it’s punctuated by short breaks and includes a lot of practical work in the field, lab, and computer suite.
One of the aims of ENV1012 Biodiversity: an Introduction is to engage the students with the use of taxonomic names of species and higher groups, familiarise them with the principles of biological classification, why this is important (and why it underpins the rest of biology and much of the environmental sciences), and so forth. Building confidence in how scientific names are used, and the diversity of species that all of us encounter on a day-to-day basis, are important aspects of this, and I developed a couple of new exercises that we are trialling this term which are focused on these areas.
The first one is called “The Taxonomy of Gastronomy” and was partly inspired by a conversation I had with Steve Heard when he posted about The Plant Gastrodiversity Game. It works like this. I begin with an interactive lecture that sets out the basic ideas behind taxonomic classification and its importance. After a short break the students then begin the hands-on part of the exercise. Working in groups of three they use a work sheet that lists 10 culinary dishes, including: fried cod, chips, and mushy peas; spotted dick; spaghetti bolognese; Thai green curry with tofu & okra; chocolate brownies, etc. (this can easily be varied and adapted according to needs).
The students’ first task is to find a recipe online for each dish. For each biological ingredient in that dish, they list its common name and find its taxonomic family, genus, and species (italicising the latter two, as per taxonomic conventions). I emphasise that it is important to be accurate with names as they will be doing something similar in a later assessed exercise.
This takes a couple of hours and then they feedback their results in a debriefing session, including finding out who had the longest list of species in a meal – the winner was 17 species in a moussaka recipe, with a Jamie Oliver fish and chips recipe coming a credible second with 12! We also discuss particularly common taxa that turn up frequently, for example plant families such as Solanaceae – the relatedness of tomatoes, chillies, peppers, potatoes, and aubergine, the students found very intriguing.
By the end of this exercise the students will have gained familiarity with researching, understanding, handling, and writing scientific names of species and higher taxonomic groups. In addition they will have a better understanding of the taxonomic diversity of organisms that we consume, and their relatedness. It may also have encouraged them to try out some new recipes!
If anyone wishes to comment or add suggestions for improvements, please do. If you’d like to try this yourself with your own students feel free to adapt it to your own needs, though an acknowledgement somewhere would be polite.