Natural History Observations: Wasps on Red Maple

While kayaking in Holland, Massachusetts, I paddled under the branches of a tree that had fallen into the river, and realized too late that it was completely covered in wasps. I made it through unstung, but paddled back for a second look.

There were several wasps, but no obvious nest. Something interesting was that there were several different kinds of wasps; not just vespids like yellow jackets (Vespula spp.) and bald-faced hornets (Dolichovespula maculata), but also some pompilids. What were they doing?

The Red maple I paddled under, before realizing too late that it was covered in wasps. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

I watched one Vespula spp. crawl across the top of a leaf, buzz over to the next to repeat the process, then so on and so forth, working its way up the branch. It was systematic in its efforts, covering every single leaf on that branch before moving onto the next. The other wasps did the same, as if searching the leaves for something (see video below).

I later identified the tree as a red maple, Acer rubrum, also known as swamp or water maples (fitting for where I found it). A quick online search revealed that many others have seen wasps crawling on leaves of red maple that were infested with scales, psyllids, aphids, and other insects that produce honeydew, which attract wasps like vespids and pompilids.

Natural history observations tend to be underplayed in our research, but simple observations such as these can generate important questions about behavior, ecology, and more. The day I made these observations was cloudy and cool (about 70°F), and I observed this behavior around 3:00PM. I passed by the same branch again on a few sunnier, warmer days (about 80°F) but did not see as many wasps. Did the wasps forage until they exhausted the supply of honeydew? Did they have greater energetic needs on a cooler, cloudier day than on a sunnier one, and change their foraging behavior in response?

As a new fall semester starts and a new session of ENT 432: Insect Biodiversity and Evolution begins, we have our students do an activity called “Your Inner Darwin”. Students are instructed to watch a small patch of nature for an hour, record their observations and collect the insects they see. In doing this activity, we hope to show our students how much can be gained from observation, even if it’s something as simple as watching wasps on branch.

This entry was posted in Fieldwork/Collecting, news. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *