Monthly Archives: February 2019

Is pollination really an ecosystem service?

Ashy Mining Bee 2017-06-17 10.55.53

Yesterday on Twitter Prof. James Bullock from the Centre for Ecology and Hydrology posted a slightly provocative tweet asking: “why pollination is so often called an ecosystem service. To my mind it is an ecosystem process which can, in some circumstances (e.g. crop pollination), support services such as food provision”.

I confess to being a bit surprised to see this; I’d always referred to pollination (at least by animals) as an ecosystem service, and it’s classified in that way in large status-and-trend reports such as the Millennium Ecosystem Assessment and (more recently) the IPBES Assessment Report on Pollinators, Pollination and Food Production which describes animal pollination as “a regulating ecosystem service that underpins food production and its contribution to gene flows and restoration of ecosystems”.

The crux of James’s question is illustrated in this diagram from a paper by Prof. Georgina Mace and colleagues in 2012 entitled Biodiversity and ecosystem services: a multilayered relationship.  However note that even here, pollination straddles the line between ecosystem processes and services:

Mace ES image

My initial response to James’s tweet was that animal pollination is really a community process as the interaction, and its outcomes, between animal and crop plant is dependent mainly on species diversity and abundance.  Remember, an ecosystem is the sum of the biotic (i.e. community) plus abiotic (e.g. energy, water, mineral nutrients, etc.).  So as far as crop pollination is concerned, the abiotic components of an ecosystem don’t really come into it except in as much as they influence diversity and abundance of all life on Earth.  This is in contrast to more strictly ecosystem processes that link directly to the abiotic factors, such as primary productivity and soil formation, that then support ecosystem services.

It’s further complicated by the fact that many of the plants that perform ecosystem services, such as carbon capture by trees, are themselves dependent upon animal pollination to maintain their populations.  It’s the plants that are providing the ecosystem services but the animals are playing an important role in supporting that.

If you’d like to follow that discussion, which has some interesting contribution from a range of people, here’s the link:


But ultimately I feel that these are fairly arbitrary definitions across a continuum of causes and effects: we know what animal pollination of crops and wild plants is and why it’s important, so what we call it doesn’t really matter, does it?  Other things are much more concerning.  At the moment the UK is experiencing unprecedented weather: for the first time ever, earlier today, a temperature of in excess of 20 Centigrade has been recorded in winter.  It currently feels more like late April or early May than February.  I’m already seeing a lot of pollinator activity in the garden and beyond, and each day more plants come into flower, far earlier than expected.

The current and future effects of such changes in the climate are far more important than discussions of the semantics of processes versus services, however interesting that might be.



Filed under Bees, Biodiversity, Climate change, Ecosystem services, IPBES, Pollination

A poem for Valentine’s Day


I have to confess that I forgot completely about Valentine’s Day, it’s not a celebration that I generally pay much attention to, as expressions of love are something that everyone should be doing all the time, surely?

Anyway, this bastardised version of “Roses are red” is for my wife Karin:

Some bees are red
Others are blue
There’s twenty thousand species
Of every hue

Some flies are yellow
Some wasps are cerise
Many of them pollinate
Better than bees



Filed under Bees, Biodiversity, Poetry, Pollination, Wasps

Recent reviews in pollination biology: an annotated list: UPDATED x 3

2019-02-09 13.47.49

As it’s my birthday today, I thought I’d reward myself by completing a blog post that I started just after Christmas and never got round to finishing.  Review articles that summarise recent developments in a field are an important contribution to the scientific literature that allow us to pause and reflect on where a topic has been and where it is headed.  Having recently (co)authored a couple of reviews I can attest that they are useful in this respect for both the writers and for the readers.

In the past couple of years quite a number of critical and timely reviews have been published which are proving very useful to me: I’m currently writing a book and these reviews have been invaluable in summarising aspects of a field that is currently publishing in excess of 1000 research papers per year. So I thought I’d bring them together into a single listing with a short commentary on each.  No doubt I have missed many other reviews so please feel free to point out any gaps and I will update the list as I go along.

Each review is hot linked to the source; a good proportion of the reviews are open access, notably those from the recent special issue of Annals of Botany devoted to the ecology and evolution of plant reproduction.  Some reviews are very focused, but most are quite broad.  Several of these complement one another.  I hope you find them interesting and useful.

Barrett, S. & Harder, L. (2017) The ecology of mating and its evolutionary consequences in seed plants. Annual Review of Ecology, Evolution and Systematics 48: 135-157

Mating systems, i.e. who breeds with whom, are just as complex in plants as they are in animals.  However some features of seed plants, such as the fact that they don’t move, that most species have both male and female functions, and that their growth is modular and often indeterminate, represent significant challenges that have been overcome in a bewildering variety of ways.


Braun, J. & Lortie, C.J. (2018)  Finding the bees knees: A conceptual framework and systematic review of the mechanisms of pollinator-mediated facilitation.  Perspectives in Plant Ecology, Evolution and Systematics 36: 33-40

In a community, if one plant species positively affects another, we term this “facilitation”.  It can occur at a variety of life stages, including reproduction whereby the presence of one species increase the likelihood of another species being pollinated.  This review shows that it occurs fairly frequently at a variety of spatial scales, but there are still significant gaps in our understanding of the phenomenon.


Fuster, F., Kaiser‐Bunbury, C., Olesen, J.M. & Traveset, A. (2018) Global patterns of the double mutualism phenomenon. Ecography

When species provide benefits to one another in two different ways, for example an animal is both a pollinator and a seed disperser of a plant species, we refer to it as a “double mutualism”.  As this fascinating review shows, double mutualisms are very uncommon, but they are widespread, and probably under-recorded.


Minnaar, C., Anderson, B., de Jager, M.L. & Karron, J.D. (2019) Plant–pollinator interactions along the pathway to paternity. Annals of Botany 123: 225-245 

The male aspect of plant reproduction, i.e. pollen donation, is often neglected when we consider how pollination systems evolve.  This review provides as up to date account of where we are in understanding how paternity influences floral characters such as shape and colour.


Ollerton, J. (2017) Pollinator diversity: distribution, ecological function, and conservation. Annual Review of Ecology, Evolution and Systematics 48: 353-376

A very broad over view of our current understanding of the biodiversity of pollinators, taking a deep time and a wide spatial perspective to put current concerns about loss of pollinators into a wider perspective.


Parachnowitsch, A.L., Manson, J.S. & Sletvold, N. (2019) Evolutionary ecology of nectar. Annals of Botany 123: 247–261 

We often take nectar for granted – it’s just sugar and water, isn’t it?  As this review shows, nectar is dynamic and complex, and affects a range of ecological functions beyond just providing pollinators with a reward.  However there’s still a huge amount we don’t understand about how nectar traits evolve.


Toledo-Hernández, M., Wangera, T.C. & Tscharntke, T. (2017) Neglected pollinators: Can enhanced pollination services improve cocoa yields? A review.  Agriculture, Ecosystems and Environment 247: 137-148

Chocolate is most people’s favourite confectionery and is famously pollinated only by small midges.  Or is it? As this review shows, lots of other insects visit cocoa flowers, but their role as pollinators has not been well studied.


Vizentin-Bugoni J, PKM Maruyama, CS Souza, J Ollerton, AR Rech, M Sazima. (2018) Plant-pollinator networks in the tropics: a review. pp 73-91 In Dáttilo W & V. Rico-Gray. Ecological networks in the Tropics. Springer.

This book chapter that I co-authored with some very energetic and creative young Brazilian researchers summarises what’s currently known about plant-pollinator interaction networks in tropical communities.  One of the conclusions is that they are really not so different to those in temperate and subtropical biomes.


Wright, G.A., Nicolson, S.W. & Shafir, S. (2018) Nutritional Physiology and Ecology of Honey Bees. Annual Review Entomology 63:327-344

A review of how bees use nectar and pollen at the level of both the individual and the colony, focused on the most widespread of pollinator species.


As expected, several people have told me about reviews I’d missed, and in some cases ones that I had read but forgotten about!  I’ll list them below, though without annotations:

Bennett, J. et al. (2018) A review of European studies on pollination networks and pollen limitation, and a case study designed to fill in a gap, AoB Plants 10:

Knight, T. et al. (2018) Reflections on, and visions for, the changing field of pollination ecology. Ecology Letters 21: 1282-1295

Vallejo-Marin, M. (2018) Buzz pollination: studying bee vibrations on flowers. New Phytologist



I had deliberately restricted the reviews to 2017 onwards, but via email David Inouye kindly sent a few older ones through which are equally useful:

Brosi, B. J. (2016) Pollinator specialization: from the individual to the community. New Phytologist: 210: 1190–1194

Hahn, M. and C. A. Brühl (2016) The secret pollinators: an overview of moth pollination with a focus on Europe and North America. Arthropod-Plant Interactions: 1-8

Inouye, D. W., et al. (2015) Flies and flowers III: Ecology of foraging and pollination. Journal of Pollination Ecology 16



A more recent addition to this set of reviews was sent to me by Anne-Laure Jacquemart.  Although it’s focused just on one (rather variable) crop, I think it will be really useful for anyone interested in the pollination biology of crop plants:

Ouvrard, P. & Jacquemart, A.-L. (2019) Review of methods to investigate pollinator dependency in oilseed rape (Brassica napus).  Field Crops Research 231: 18-29





Filed under Bees, Biodiversity, Brazil, Honey bees, Mutualism, Pollination