On the second floor of Insectarium Center at Tama Zoo, next to the bee model, you can see water striders. Currently, there are about 10 adult water striders, and many recently hatched larvae, about 2 mm in length.

Water striders, like stink bugs and cicadas, belong to the order Hemiptera (hemipterans). One characteristic of Hemiptera is that they have a straw-like mouthpart. It may be difficult to see because they are small, but if you observe carefully, you will see that water striders also have such a mouthpart. They pierce the bodies of small insects with this mouthpart, inject digestive fluids, dissolve the internal organs, and then suck them out.


When most people hear the word "stink bug," the first thing that comes to mind is probably its smell. But actually, water striders also emit an odor. The name "water strider" itself offers a clue to what that smell is like.

There seem to be several theories about the origin of the name "amenbo" (water strider), but one of them is that it's called "ame"bo because it emits a candy-like smell. Apparently, if you actually catch one and disturb it, it does emit a candy-like smell. It's not an unpleasant smell like that of a stink bug, but rather a rather pleasant smell.

I wanted to smell it too, so I pinched it with my fingers and stimulated it. However, no matter how many times I tried, I couldn't smell the candy. Is my nose insensitive, am I doing it wrong, or is it because it was an individual that had been bred for generations? It's a mystery.

I'd love to try this with a wild specimen, but you can't see water striders near the water's edge at this time of year. During the winter, they move away from the water's surface and hibernate on land, under fallen leaves or in the crevices of fallen trees. As it gets warmer, they'll wake up and return to the water's edge. In this area of Tokyo, that's probably around the time the cherry blossoms bloom. If I find a water strider around that time, I'd like to try again with a wild specimen.

[Keiichi Kusano, Animal Care and Exhibition Staff, Insectarium Tama Zoo]

(March 18, 2016)