I’ve been dreaming on writing a manuscript about who are the pollinators for a while, but it looks I’m not going to have the time soon, so here is an early draft of what the main figure should look like:
It’s surprisingly difficult to gather quantitative information on which animals are the main pollinators, and on which aspects of pollination they are good at. That figure can cover more aspects, or split the pollinator guilds in finer sub-groups, but this is just a first pass. As expected, bees are the clear winners!
I used guesstimates based on Winfree et al 2011 and the following articles:
Number of species: How many species of a given taxa are described based on different taxonomical resources. But not all species on a given taxa are necessarily good pollinators!
Efficiency: That one will vary a lot among species of the same group, but based on Sahli and Conner 2007, and other few cross taxa studies measuring pollen deposition I gave values from 1 to 10 to the different taxa.
Frequency of visits: This is based on Neff and Simpson 1993 descriptive work. An update to that with recent datasets is really needed! Values from 1 to 10.
Distribution: Some taxa are widespread, while others restricted to some areas, like to the tropics. Ranked from 1 to 10.
Number of plants pollinated: A complete guesstimate. Using Ollerton et al 2011 approach may give us better numbers.
Number of crops pollinated: Based on Klein et al 2007.
And as I know that the R code is what readers really want, here it is as a gist. I used function diamondplot{plotrix}, but I needed to edit the function first in order to scale the axes. The original function scale the groups (pollinators taxa, in my case) instead of the axes (pollination aspects) which was not desirable for my plot.
See you late January after a break!
I really like this approach! It chimes with some of my thinking over the past decade, though I’d not considered assessing it graphically in this way. Very neat! Some specific comments:
1. Many other groups of flies are flower visitors/pollinators, not just the syrphids. Information on those others is scarce but it does exist. See the Larsson et al. review of Diptera pollination and my Ceropegia paper in Annals of Botany 2009 for some leads.
2. I suspect that many bees are not good pollinators. The very small ones, in particular, are more often pollen robbers than pollinators. I’ve been talking about the size-pollinator effectiveness of bees recently with Andre Rech, my Brazilian PhD student who was at SCAPE.
3. Is abundance a better measure than visitation frequency? Harder to get good data on but gets over the problem that some individuals are chronically repeat visitors that come back to the same plants time and again (see work by James Thomson on this).
4. Distribution is problematical. For example, bees are relatively scarce (in relation to the size of the flora) in Southern Africa – see my chapter 13 in the Waser & Ollerton book. In this respect you should probably include other taxa such as beetles and wasps which are regionally important pollinators.
5. Regarding “Number of plants pollinated: A complete guesstimate. Using Ollerton et al 2011 approach may give us better numbers” – I actually have data that could help you in this regard – drop me an email in the New Year.
All the best for the holidays,
Jeff
Yes, many groups not represented, including lizards! I thought a too crowded graph will be difficult to read.
Curious about small bees… in temperate areas at least, small Lassioglosum are good tomato pollinators based on single visits pollen deposition.
This is a long term project, but eventually I’ll contact you to make a mega-review of existing data.
I don’t know if you received this but I thought I’d flag it up as one of your papers was cited in the report:
Click to access cop-11-inf-29-en.pdf
All the best for 2013,
Jeff
Very interesting…I have been thinking of doing something similar for a while too!