Pollinators make an awesome study system

I’ve told the story before about how I got into studying pollinators (you can read that here). I did a large, two year field study where I manipulated the presence or absence of a single plant species in a community of flowering plants and then I recorded the response of the insect community. After collecting more than 40,000 insect specimens, the only order of insects that responded significantly was Hymenoptera (ants, bees, and wasps). So I taught myself some taxonomy and identified all the hymenopterans to the family level and found that only the bee families responded (I later identified all of them to species).

So I got into studying bees because bees were the only insects out of a huge insect community to respond to my experimental treatment. And this is one of the reasons I still love studying them.

Pollinators (especially bees) are opportunistic, mobile, and selective in their food choices. They form labile interactions that change in response to plant phenology, resource availability, resource density, competition, predation, and, of course, experimental manipulations within a single season.

I did one experiment where all I did was slightly fertilize one group of plots and compare their pollinator visitation to another group of control plots (which received only water).  Within a single season, the bees had changed their visitation patterns, preferring the fertilized plants although I was unable to detect significant changes in biomass or floral display (i.e. the number of florets per plant).

Despite a short time scale and a small spatial scale, the bees were able to detect subtle changes in resource availability and quality and they changed their behaviour. Isn’t that exciting?

Of course, there are lots of other important reasons to study pollinators: they are responsible for the diversity and colour in our diets, they are necessary for the exchange of genetic information in the vast majority of flowering plants, and they are threatened by anthropogenic impacts. Pollinator declines have both important economic and ecological implications and should be taken seriously.

At the same time, we still know very little about wild populations of pollinators (especially bees). These populations change dramatically over short temporal and spatial scales in ways that we don’t totally understand. For example, one study showed that bee diversity and abundance changed more within a single orchard between two different years than between two different orchards in the same year (Russo et al 2015, open access).

We’re still scratching our heads as to how to measure population dynamics in these small, highly mobile, highly cryptic, solitary species that refuse to be reared in the lab, and it is clear that it would require an intense sampling effort (Lebuhn et al 2012). (In the apple orchard paper mentioned above, one site that was sampled almost 80 times across 6 years was still not well described in terms of bee species richness!)

So, in sum, I hope I have convinced you that pollinators are an excellent study system because:

  1. they are important
  2. they are interesting
  3. there is still a lot to learn about them
  4. they respond to experimental treatments on short time scales and over small spatial scales
  5. they are dynamic, mobile, and picky
  6. they are adorable*

*Just kidding on that last one…or not….decide for yourself

Colletes inaequalis

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11 thoughts on “Pollinators make an awesome study system

    • I think it is a synergistic effect of 1) low genetic diversity which makes honeybees more susceptible to 2) impacts from heavy pesticide usage and 3) our migratory beekeeping practices, which also make honeybees more vulnerable to 4) pathogens and parasites. Haha how’s that for a short answer?

      • Pretty good. I heRd yesterday that bees are bouncing back in Europe after banning certain pesticides. Care to comment?

      • Pesticides are almost certainly a major component of bee declines (and other insect declines) on a broad scale. The things that are designed to kill insects also kill bees (because they are insects).

      • Because there is such high pressure and demand to get incredible yields out of smaller and smaller areas of land. Working in apple orchards, you really get to see how the farmers are constantly battling against one pest or another, or different pathogens in the crops.

      • Another thing is that pesticides that are safer for bees (eg. organophosphates) are very very bad for humans, and vice versa. Neonics are safer for humans, but very dangerous for bees.

  1. Your studies sound super interesting and relevant. I study pollination too, but more from the plants’ perspective and in natural systems (Arctic and alpine).

    Out of curiosity, may I ask how you interpreted the results regarding bees preferring fertilized plants without significant changes in plant size?

    I totally agree that pollinators are adorable, especially the fuzzy bees 🙂

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