Everyone knows you have to be delicate with insects. Most of us have probably made the mistake of handling the wings of butterflies or moths, accidentally removing some of their “dust,” which is actually comprised of the scales that they need to fly. Who hasn’t, as a child, been a little too careless and mauled a ladybug? Or, among those of us who were lucky enough to grow up in regions they populate, let curiosity get the better of us when handling a lightning bug or firefly? You have to be delicate with insects.
Well, here’s some insect news requiring a slightly different brand of delicacy. As Science put it in a story last week: “Tiny Bug Makes a Riot With Its Privates.” Or, in the words of the BBC: “‘Singing penis’ sets noise record for water insect.”
That’s right. From the BBC story:
Scientists from France and Scotland recorded the aquatic animal “singing” at up to 99.2 decibels, the equivalent of listening to a loud orchestra play while sitting in the front row.
The insect makes the sound by rubbing its penis against its abdomen in a process known as “stridulation”.
Researchers say the song is a courtship display performed to attract a mate.
On average, the songs of M. scholtzi reached 78.9 decibels, comparable to a passing freight train.
First off, let’s note that “stridulation” is not actually defined as “rubbing genitalia against belly.” Mark Denny and Alan McFadzean explain in their book Engineering Animals: How Life Works, in a chapter on animal communication:
Sound is just a vibration: to make it you have to move things. Most insects and other noisy arthropods achieve this by stridulation—rubbing one body part against another. Generally this action involves a body part that acts as a file and another that acts as a pick: ideally the pick is connected to some sort of resonant structure, such as wing panels. The file is dragged across the pick (or vice-versa) and a noise is generated.
So this bug, the Micronecta scholtzi, a freshwater insect that measures just 2mm, is stridulating its way to the rumble of a freight train. The scientists who made the discovery say that if body size is taken into account then the M. scholtzi are the loudest animals on earth. The fact that the bug makes this call underwater explains why scientists are just now noting its extraordinary volume, as 99% of the sound is lost when transferring from water to air.
In his recent book Cricket Radio: Tuning In the Night-Singing Insects, John Himmelman explains everything about the calling of crickets and katydids, the singing insects we’re likely most familiar with. Crickets and katydids stridulate with their legs, a more common variation than is practiced by the M. scholtzi. In crickets the file and pick, or scraper, are together referred to as the “stridulary organ,” but in the case of the M. scholtzi that begins to sound like a bit of a euphemism. Himmelman also explains that some grasshoppers engage in a different kind of noisemaking, known as “crepitation,” in which the rapid opening of the hind wings creates a crackling sound.
We built a web page that lets you hear the different calls of some of Himmelman’s crickets. Have a listen to them, and then go hear what the M. scholtzi sounds like, courtesy of the BBC. It’s sort of like a maraca. Not so delicate after all.