Category Archives: Bees

Plant-based diets are a problem for bees! A new study of the significance of the ratio of food K:Na in bee ecology and evolution

Week-long Master’s course in Italy – March 2024 – on Pollination as an Ecosystem Service

A “weed” that you should be eating and an introduction to our new garden

It’s been a rather nomadic couple of years. After Karin and I sold our house in Northampton, we travelled around in the UK and then in Denmark, renting places as we needed them, plus we spent a month in Kenya. We’ve now become more settled in Sjælland and, after some deliberation about whether to buy a house or continue renting, we’ve reached a compromise and bought into an andelsbolig, one of the many Danish cooperative housing schemes – see this article in The Guardian for more details.

The development of twenty-eight small properties has been newly built to the highest standards of insulation and is plugged into the district heating system which uses a combination of solar warming and gas (in part using methane generated from food waste).

It’s nice to have a garden again. I hadn’t realised how much I’d missed having a space in which to plant and potter. All gardens present challenges, of course, and this one is no exception. Until about 600 years ago the area was under the shallow Kattegat sea. It’s now above sea level due to post-glacial rebound and in fact this whole region of Odsherred is a UNESCO Global Geopark because of the postglacial landscape.

What this means for us is that we are gardening on “soil” which has a very high sand content and is filled with stones, large and small.

Added to that, we’re in one of the driest parts of Denmark (certainly this year) and a persistent coastal wind rapidly strips the moisture from the soil. So as we dig up or find large stones we are using them around plants to retain water and mulching with the smaller stones that we find in abundance. As yet we don’t have any rain water butts so we’re using the kitchen water from washing up to supplement the hosepipe.

It’s not easy gardening here, but we like a challenge and we’re calling in favours from friends and family to provide us with cuttings and divisions of plants from their own gardens, which should mean that they are better adapted to the local conditions than most of the shop-bought plants. We’ve also started a small vegetable and fruit patch and planted apples and pears around a paved patio that over time we will train as self-supporting espaliers.

Gradually we’ll fill up the space and move things around as needed. But for now I’m also interested in seeing what plants come up spontaneously, especially the annual species that are benefitting from the disturbance. I don’t use the term “weed” to refer to these: weeds are just plants in the wrong place at the wrong time. Many such plants are ecologically important, especially as nectar and pollen sources for bees and other insects. This includes Common Bugloss (Anchusa officinalis) with its richly purple, velvet-textured flowers.

Another plant that we are tolerating is a fast-growing relative of spinach that’s variously called Goosefoot or Fat Hen (Chenopodium album). I’d long known that it was edible (it’s grown as a crop in parts of Asia) but until last night I’d not cooked with it.

In fact it’s delicious! I threw some roughly chopped leaves and stems into a mushroom omelette and I have to say that it was better than any commercial spinach I’ve bought or grown. In particular, the texture is much nicer as the leaves are very water-repellant which mean that they don’t absorb as much moisture during cooking. Highly recommended as an alternative to spinach but make sure you correctly identify the plant before you try it – there’s some good advice on this website: https://www.wildfooduk.com/edible-wild-plants/fat-hen/.

As well as Fat Hen we also have the close relative Tree Spinach (Chenopodium giganteum), with it’s beautiful magenta-tinged leaves, coming up in the garden. I’m looking forward to trying that too:

I’ll try to post more as the garden progresses, if I have time. But as I mentioned yesterday, even though the manuscript is complete and submitted to the publisher, there’s still lots to do on my next book! Have a good weekend.

Pesticides and pollinators: please sign this petition!

5 Replies

As part of our roles as ambassadors of the new conservation organisation Restore (more of which later this year), several of us including Dave Goulson, George McGavin, and myself, are promoting this online petition to get the government to take the issue of neonicotinoid pesticides seriously. Here’s some text from Dave explaining the situation with a link to a petition that you can sign:

“For three years in a row our government has granted farmers special permission to use banned neonicotinoid pesticides on sugar beet. This is contrary to the expert advice of their own Expert Committee on Pesticides, who specifically recommended that permission should not be granted. It also flies in the face of a huge body of scientific evidence showing that these chemicals are phenomenally toxic to all insect life, and that their use on any crop contaminates soils, hedgerow plants, and nearby streams and ponds for years to come. We are in a crisis, with insect populations in freefall. It is about time our government woke up to this, and acted accordingly. This petition https://petition.parliament.uk/petitions/631948 is a necessary means of holding the government to account. Please sign and share, as signing will ensure the issue is debated in Parliament.”

This petition now has more than 15,000 signatures which ensures that it gets a response from the Government. If it reaches 100,000 mark, it will trigger a debate in Parliament. Please sign and promote this important initiative!

Pollinators and the UN Sustainable Development Goals – free webinar on Monday!

2 Replies

There’s been a lot of discussion recently about how pollinators can contribute to the United Nations’ 17 Sustainable Development Goals. It’s a topic that I reflected on in Pollinators & Pollination: Nature and Society, and I’ve seen a few papers and articles that raise the subject – see here for instance. This free webinar on Monday 27th March is therefore very timely! To register, follow this link: forms.office.com\r\T5HrW0VZvS

Although I’m one of the speakers, I can’t make it in person as I’ve got teaching commitments at Roskilde University, so I’ve recorded my ten minute piece and I’m happy to answer questions via the Contact page on my website.

Join me tomorrow evening for an online talk about pollinators in the UK!

5 Replies

It’s been a couple of years since I last did a talk or workshop for the Wildlife Trust for Bedfordshire, Cambridgeshire & Northamptonshire. But I’m pleased to say that they’ve invited me back and you can join me tomorrow evening for an online introductory talk about pollinators and pollination in the UK.

The talk starts at 7pm UK time and full details of how to sign up are in the link below:

https://www.wildlifebcn.org/events/2023-02-22-online-pollinators-and-pollination-professor-jeff-ollerton

I look forward to seeing some of you there!

Soybean is more dependent on bee pollination in the tropics – a new study just published

1 Reply

It’s been an interesting start to the year in the world of pollinators and pollination. The European Union has revised its 2018 initiative for pollinator conservation with an update called “A New Deal for Pollinators“. At the same time the UK Government has released its plans for Post-Brexit farm subsidies, many of which focus on environmental action that can support pollinators, such as planting hedgerows. I think that it’s fair to say that there’s been a mixed response to these planned subsidies. There’s also mixed news in Butterfly Conservation’s State of the UK’s Butterflies 2022 report. The headline figure is that 80% of butterflies in the UK have decreased since the 1970s. However there are enough positive conservation stories in that report to demonstrate that this decline does not have to be irreversible, we can turn things around.

Against this wider backdrop of pollinator actions, I was pleased to have a new research paper published this week, which is an output from the SURPASS2 project with which I’ve been involved. Led by Brazilian researcher Nicolay Leme da Cunha, this paper assess the variability of soybean dependence on pollinators. Although soybean is one of the most widely grown crops globally, there’s still much that we don’t understand about which of the many different varieties have improved yields when visited by bees, and which are purely self-pollinating. One of our main findings was that for some varieties, especially in the tropics, an absence of pollinators results in a decline in yield of about 50%.

The paper is open access and you can download a copy by following the link in the reference:

da Cunha, N.L, Chacoff, N.P., Sáez, A., Schmucki, R., Galetto, L., Devoto, M., Carrasco, J., Mazzei, M.P., Castillo, S.E., Palacios, T.P., Vesprini, J.L., Agostini, K., Saraiva, A.M., Woodcock, B.A., Ollerton, J. & Aizen, M.A. (2023) Soybean dependence on biotic pollination decreases with latitude. Agriculture, Ecosystems & Environment 347, 108376

Here’s the abstract:

Identifying large-scale patterns of variation in pollinator dependence (PD) in crops is important from both basic and applied perspectives. Evidence from wild plants indicates that this variation can be structured latitudinally. Individuals from populations at high latitudes may be more selfed and less dependent on pollinators due to higher environmental instability and overall lower temperatures, environmental conditions that may affect pollinator availability. However, whether this pattern is similarly present in crops remains unknown. Soybean (Glycine max), one of the most important crops globally, is partially self-pollinated and autogamous, exhibiting large variation in the extent of PD (from a 0 to ∼50% decrease in yield in the absence of animal pollination). We examined latitudinal variation in soybean’s PD using data from 28 independent studies distributed along a wide latitudinal gradient (4–43 degrees). We estimated PD by comparing yields between open-pollinated and pollinator-excluded plants. In the absence of pollinators, soybean yield was found to decrease by an average of ∼30%. However, PD decreases abruptly at high latitudes, suggesting a relative increase in autogamous seed production. Pollinator supplementation does not seem to increase seed production at any latitude. We propose that latitudinal variation in PD in soybean may be driven by temperature and photoperiod affecting the expression of cleistogamy and androsterility. Therefore, an adaptive mating response to an unpredictable pollinator environment apparently common in wild plants can also be imprinted in highly domesticated and genetically-modified crops

Orchid pollen comes pre-packaged

6 Replies

The other day Karin bought a Miltonia orchid to add to the ever-expanding collection of orchids she’s accumulating. It’s nowhere near as large as the collection she accumulated in our old place in the UK – part of it is pictured in this old post of mine – but it’s only a matter of time. This morning I showed her how to extract orchid pollen from the flower and her squeals of delight were something to hear!

As you can see in the image above, these orchids package their pollen into discrete structures that we term “pollinia” – two of them in this case, though the form and number of pollinia vary between different groups of orchids. The pollinia plus the sticky organ that attaches them to a pollinator is collectively termed a “pollinarium”. The only other plants that present their pollen in this way are my beloved asclepiads in the family Apocynaceae. The orchids and the asclepiads are only very distantly related to each other so this is a clear example of convergent evolution, where both plant groups have come up with the same solution to a problem. In this case, the problem is probably that bees collect a lot of pollen which has a reproductive cost for plants. Packaging the pollen in this way prevents bees from stealing it, amongst other advantages.

If you want to look at this yourself, you’ll find the pollinaria tucked under the front of the central “column” of the flower, which comprises the fused male and female reproductive parts. Just take a fine needle and gently stroke the underside of the column. In the image below, taken just after we extracted the pollinarium, you can see the “anther cap” which covered them lying just below the column.

It’s possible to learn a lot about botany from studying even common houseplants such as these!

Plant-pollinator meta-network of the Kashmir Himalaya: a new study just published

The hidden potential value of woodland trees for wild bee assemblages – lead author Guthrie Allen introduces his recently published study

2 Replies

Note: This is a guest blog post by Guthrie Allen who is a PhD candidate at the University of East Anglia.

Though often overlooked, woodlands have great potential to support wild bees in farmed landscapes. Both the understory and canopy can provide large quantities of early-season nectar. The pollen of woodland-tree taxa such as Acer can form a large proportion of the early-season diets of bumblebees and solitary bees. Even the pollen from wind-pollinated trees such as Quercus can form a significant part of the diets of several common solitary bee species. Woodlands are also believed to provide ample nesting opportunities. These factors may explain why several studies have found positive correlations between bee abundance and/or diversity and woodland cover at the landscape scale. Despite this, a large-scale European study has shown that interior woodland understories support very few bees compared to exposed woodland edges.

Sampling the canopy – at heights of up to 20 metres – is not easy, but unlike the understory, this habitat remains sun-exposed after canopy closure and could be favourable for bees. In Europe, however, our knowledge of bee activity in the woodland canopy is very limited. Furthermore, whilst canopy-tree taxa have been identified as suitable food sources for many bees, we have little evidence that these trees are used for forage when located within woodlands. To explore the role of the canopy, we trapped bees in late spring in the understory and canopy – at the exposed edges and in the interiors – of 15 woodland sites across an English agricultural landscape.

A significant proportion of bee abundance was found in the canopy, represented by 23 of the 29 total sampled species. Interior canopy activity was much higher when nectar-producing Sycamore (Acer pseudoplatanus) trees were nearby. Communities differed between the canopy and understory: of the seven most common species sampled, three were more active in the understory, while the opposite was true of one species – Bombus lapidarius. Interestingly, we found the sex ratio of the most abundant species – B. pratorum – to be female-skewed in the canopy. For four of these species, and contrary to expectations, we found no evidence that understory activity was any higher at woodland edges compared to woodland interiors.

Further research is needed to understand community differences between the canopy and understory. Nonetheless, our results suggest that both these habitats have a significant role to play in supporting farmland bees. We demonstrate that a diverse bee community has the potential to exploit canopy resources, with nectar-producing trees in woodland interiors likely to provide forage for many bees. And we show the unexpected potential of interior woodland understories to support bee abundance.

Here’s the full reference with a link to the open access paper:

Allen, G. & Davies, R.G. (2022) Canopy sampling reveals hidden potential value of woodland trees for wild bee assemblages. Insect Conservation and Diversity. Available from: https://doi.org/10.1111/icad.12606

Here’s the abstract:

Woodlands can play an important role in supporting bee abundance and diversity in agricultural landscapes. However, in temperate-region studies, the canopy is rarely sampled, and our understanding of its contribution is limited. To explore this, we sampled bees in late spring with blue vane traps in the understory (n = 30) and crowns of mature Quercus robur (n = 35) at the exposed southern edges and in the interiors (ca. 25–75 m from woodland edges) of 15 woodland sites across an English agricultural landscape. A significant proportion of bee abundance and diversity was found in the canopy: canopy-trap catches were estimated to be a third as large as understory-trap catches, and 23 of the 29 sampled species were present in the canopy. Of the seven most common species sampled, four were equally abundant in woodland edge and interior traps; three were more abundant in understory traps, and a single species—Bombus lapidarius—was more abundant in canopy traps. The sex ratio of the most abundant species, B. pratorum, was female-skewed in the canopy. Additionally, the presence of nearby Acer pseudoplatanus trees in flower greatly increased canopy-trap catches in woodland interiors. These results suggest that both the woodland canopy and understory have a significant role to play in supporting farmland bee communities; they indicate the importance of nectar-producing trees in woodland interiors, opening avenues for canopy-based management; and they demonstrate that a diverse bee community has the potential to exploit canopy floral resources.