A trio of biologists from the University of Connecticut; the Organization for Tropical Studies, in Costa Rica; and the University of Bristol, has found that hummingbird flower mites use hummingbirds to carry them from flower to flower.

In their paper published in Proceedings of the National Academy of Sciences, Carlos García-Robledo, Diego Dierick, and Konstantine Manser describe how they tested sensitivity to the type of electric field that hummingbirds generate when their wings rapidly flap next to a flower, and what they learned by doing so.

Prior research has shown that hummingbird flower mites spend their lives eating pollen and sipping nectar from flowers. But to do so, and to procreate, they must move from flower to flower. Since they cannot fly, or even hop, how they do so has been somewhat of a mystery.

In this new effort, the research trio suspected that the mites hitched a ride on hummingbirds. They also suspected that the means for doing so had something to do with the electric field hummingbirds create as they flutter their wings during their approach to a flower.

To determine whether that might be the case, the research team tested several specimens in their lab. Each was exposed to different types of electric fields via copper plate electrode. The researchers found that the mites only responded to a modulated field, one very close to that produced by the hummingbirds—a form of electroreception.

They also found that if they cut off the front legs of a mite, it no longer responded to the field, proving that the electricity-sensing organs were located there. An even closer look showed the mites had hairs on their legs similar to those found on spiders that also respond to an electric field.

Next, the researchers looked into how the mites climbed aboard a hummingbird. They found that moving the electrode close to the mite resulted in the mite being pulled (due to electrostatic force) through the air and landing on the electrode. Thus, for a mite to catch a ride, all it needed to do was move a few steps closer to the arriving hummingbird. Once it landed, it would remain in the bird’s nostrils to prevent being blown off as the bird flew. It could then simply jump down onto a flower as the hummingbird fed.