Insect Songsnoise or Music?

You’ve undoubtedly heard many insects making sounds, and maybe you find certain noises of theirs annoying, such as flies and bees buzzing. There are some true musicians in the insect world: namely, orthopterans (grasshoppers, katydids, and crickets) and cicadas. There are countless scientific studies on insect songs, ranging from descriptive studies that detail the particular song of a species, to how temperature affects insect songs. If you’re interested, there is a blog dedicated solely to the music of nature, which discusses insect songs much more in-depth than I will here.

I started thinking more about the songs of these insects when I started working at my current field site at the University of Houstons Coastal Center, a remnant of rare tallgrass coastal prairie along the Gulf Coast of Texas. You can hear different orthopterans (grasshoppers, katydids, and crickets) calling at different times of the day. The softer thrills of southeastern crickets while it’s dark, and loud calls of katydids during the heat of the day, which to me often sound like those sprinklers with rotating heads.

Not knowing too much about these different insect calls, I started looking for a good resource on the subject and stumbled across this wonderful book by Lang Elliott and Wil Hershberger. It describes 72 species of orthopterans and cicadas that produce songs in east/central North America. The best part, for an insect geek like me, is the CD it contains that provides sound clips of many of these insects singing, and if you’re particularly interested, you can learn to identify many species of these singing insects by learning their calls.

Most of these songs are produced to find a mate, and it’s more often the males calling to attract females than visa versa. Sometimes calls let another male, potentially rivaling for females know not to get too close, that this area is claimed. A few band-winged grasshopper species (characterized most simply by bright, colorful wings) produce a clicking sound both in an attempt to scare off a potential predator, and, again, to attract mates.

So, are people affected by these insect musicians? My guess would be if you asked this question to the average urban or suburban American, they would say no. In these settings, we hear fewer insects simply because there isn’t much habitat for them in cities, and even where there is grass, it’s often a lawn that is mowed or treated with pesticides. If they happen to be observant and live in the areas of certain annual cicadas whose calls are harbingers of summer, they may say yes. Maybe folks in rural areas would be inclined to admit a nostalgia for or distinct feeling of summer upon hearing insect songs, as this is when many of these singing insects are active.

David Attenborough talks about what is considered one of the most spectacular gatherings of insect musicians globally, the songs of 17-year cicadas in the midwestern US in the BBCs Life in the Undergrowth (which, as a side note, is a must watch series for anyone that appreciates insects).

The first time I experienced this phenomenon was as a child in 1987, growing up in Northern Kentucky. Once they emerged, cicadas appeared to be dripping off plants. You could not walk down the sidewalk without stepping on one. My mom and I made cobblers from blackberries we’d picked. My aunt bit into something crunchy, and sure enough, a cicada had snuck into the cobbler. Either way, the major thing I remember was people complaining about them. In places with many old trees where the ground has not recently been tilled, the screeching can, as Attenborough says, be deafening. This large emergence of cicadas has other important effects on ecosystems, including effects nutrient cycles (Yang 2004), and providing huge pulses of food for predators, which often causes a boom in predator populations, such as red-winged blackbirds that also have distinctive calls (Strehl and White 1986). Although not everyone appreciates this phenomenal spectacle, it is certainly a wonder of nature.

Apparently, in certain areas of Asia, however, singing insects are revered. In Japan, people sell insects as a profession (and are called mushiya; there is a book chapter about this here).  People keep them in their houses in the winter time so they can hear their songs year-round, and plan vacations to places where certain insects are known to call. Calling insects are also important to people in China: there has even been recent press about this (although, the title is misleading the insects are not singing for their food). One man, who apparently carries around a singing orthopteran in his pocket is quoted as saying, During the winter it is dry and cold and you cannot hear any birdsong. The sound of bush crickets makes me happier. That would make me happy in the cold, gray winter, too!

But now there is evidence that singing insects are affected by our noise as well.  A forthcoming study in Functional Ecology has gotten a lot of public press recently (Lampe et al 2012) provides evidence that male grasshoppers near German roadsides alter their songs to be better heard by potential female mates. This is the first evidence that insect musicians must now compensate for human noise. I wonder what other insects may be changing their songs because were a noisy species?

Human feelings about these singers may range from annoyance to appreciation to reverence. I’d like to do more research but haven’t seen any studies that attempt to quantify how humans feel about the sounds of different insects. Although Japanese and Chinese cultures are certainly influenced by insect songs, their economies must be affected in some small way, I haven’t yet found any studies that quantify this.

I, for one, have gained a fondness for insects songs, and a desire to be able to identify insects by their songs since my time working in prairies. Do you notice these singing insects? Do they affect your life in any appreciable way?

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