A small water boatman of the species Micronecta scholtzi is seen in this photo from the University of Strathclyde Glasgow. The insect has been found to use its penis to perform a very loud mating call. Scientists say the "singing penis" -- relative to its body size -- is the loudest animal on Earth.

Singing Penis Insect Proves Size Does Matter

Courtship never sounded so sweet -- at least in the insect kingdom. It appears that a tiny bug known as the singing penis (also, water boatman, or Micronecta scholtzi) -- is the loudest creature on Earth, relative to its body size and the way in which it uses its penis.

BBC Nature News reports that French and Scottish scientists have determined that the male variety of the 2mm freshwater insect "sings" so loud -- at almost 100 decibels -- it's like sitting in the front row of a concert hall while a loud orchestra plays.

Here's where the penis comes into play: the male bug attempts to beguile a prospective mate by rubbing its penis against its abdomen -- something called "stridulation," which insects do all the time when they rub body parts together to produce sounds.

The scientific team was caught off guard at the volume of the insects, which are found all over Europe.

"We were very surprised. We first thought the sound was coming from larger aquatic species," said James Windmill of the University of Strathclyde, Glasgow.

"When we identified without any doubt the sound source, we spent a lot of time making absolutely sure that our recordings of the sounds were calibrated correctly," he said.

Their findings, published in the science journal PLoS One, indicate the bewitching song of the insect designated M. scholtzi can be compared to the sound of a passing freight train.

Despite the tiny dimensions of the insects, their penis is apparently what gives them their deafening roar.

"If you scale the sound level they produce against their body size," explained Windmill, "Micronecta scholtzi are the loudest animals on Earth."