Saturday, July 5, 2014

Bees on Corn

Melissodes bimaculata collecting corn pollen
Maricopa corn, image from Native Seeds/SEARCH
This year I experimented with growing my own sweet corn for the first time. I bought a multi-colored 'Maricopa' cultivar from Native Seeds/SEARCH- they no longer have it available in their online store, but it's a very popular product so I'm sure they'll restock in the fall. Native Seeds/SEARCH is a Tucson-based non-profit that specializes in North American vegetable seeds locally adapted to the southwest. I went to them for my corn, beans, tomatoes, and squash this year because I figured if it can handle Arizona, it can deal with the Texas drought. In addition to preserving these native varietals of common garden crops, Native Seeds/SEARCH also donates seed to tribes that have lost their cultural food ways.  At any rate, it's a neat project, and I've had a remarkably trouble-free garden this year. Even my little corn patch is going gangbusters.

Another M. bimaculata, hard at work.

This morning I was watering my garden, and I noticed something quite unexpected: the Melissodes bimaculata that had been so busy pollinating my squash were now collecting pollen from my corn! As most people are aware, corn is wind pollinated, so it certainly doesn't require the services of our native bees. That said, the native bees aren't hurting anything and they are doing remarkable work increasing my squash yields. Anything that keeps them healthy increases the productivity of my garden.

So: why do I care that my neighbor-bees are eating corn pollen? Well, I've heard the argument that corn pre-treated with pesticides (i.e., neonicitonoids) is harmless because corn isn't insect pollinated. After watching the bees in my garden, I feel pretty safe making the statement that there is still a high potential for exposure.

I also worry that these fuzzy little bees are exploiting the corn pollen because there isn't much else available. I know the local bee populations took a real hit when the vacant-lot prairie was scraped clear to the bed-rock. I hope they are eating the corn pollen because it's convenient, and not because they are starving!

M. bimaculata are named for their two white spots, one on either side of their abdomen


  1. Thanks for noticing this - and for your important observation about how native bee populations may, indeed, by affected by neonics on/in corn, even though corn is wind-pollinated. I hadn't thought of this possibility.

    1. A number of my colleagues have also seen bees gathering pollen from corn and other grasses- they have pictures of bumblebees exploiting this resource too. It seems like bees that are polylectic (ie, not at all picky) will collect grass pollen. Bumblebees and honeybees are both examples of polylectic bees.