Wednesday, June 15, 2022

Answer: Why do gnats DO that?

  With my head in the clouds... 

... of gnats... I learned a few fascinating things by asking a few simple questions.   

As I mentioned, one of the defining features of being great at doing SearchResearch is having a deep curiosity.  In my work, I'm paid to be professionally curious, so I've developed a kind of permanently curious outlook on life.  As I'm reading, or as I'm walking around in the world, I constantly ask myself questions:  Is what I'm seeing actually what's going on?  What caused that to happen?  Why is this phenomenon taking place?  

And so it was when I was walking on the beach.  I saw the cloud of gnats circling around in a fairly tight swarm and wondered Why do they do that?  

One great strategy for thinking about Why questions is to think of similar situations.  In this case, What else flies in tight swarms, circling around a fixed point, rather than wandering off to another location?  

That thought is what made me think of starlings and their murmuration flights.  

So my Challenge was: 

1. Why do gnats and starlings murmurate?  (Is that even the right language to use?)  What's a good search strategy to find the answer?  Do they murmurate for the same reason?  

I have to admit that I've only ever read of starlings in a murmuration, but I specifically chose that word to break you, my dear SRS readers, out of a habit.  The obvious word would have been a "cloud of gnats" or a "swarm of gnats."  But one of the traits of doing good research is to have a wide-ranging vocabulary--it's important to be able to ask a question in a different way, if only to get a different view onto a common topic.  

"Murmuration" usually refers to starlings, but other birds (and animals) fly (and swim) in large groups in tightly coordinated turns, with different groups sometimes moving in synchrony, but in multiple directions, often forming lobes of groups staying more-or-less in one location.  This is not giant groups of animals migrating--those are flocks or herds or schools.  

While the starling murmurations are impressive, I wanted to see if it was ONLY starlings that murmurated, so I did a search for: 

     [ "murmuration of *" -starling ] 

to look for other kinds of murmurations, finding that red-wing blackbirds, pelicans, sanderlings, robins, flamingos, and many other kinds of birds murmurate as well.   (Pro Search Tip:  Note that I'm using the star operator as a kind of fill-in-the-blank search, along with the minus sign to avoid results with the word starling in them.)  

And of course, fish often do something very similar when they form "bait balls" to escape predators.  (See this great video from Blue Planet--watch at 1:05 to see a remarkable bait ball murmuration.)  

A bait ball of sardines. Large bait balls also murmurate. P/C OpenStax College

What about gnats?  

(BTW, what IS a gnat anyway?  It's important to know your terms when you start a search!  A quick definition search told me that gnat is a collective word for many species of small flies that do not bite. In some areas, gnats are also called midges. Gnats only live long enough to mate and lay eggs.) 

If you fell into my suggestion and did a search for: 

    [ gnats murmuration ] 

you probably saw some wonderful videos of gnats flying in clusters, BUT by looking down the SERP, you'll quickly learn that "swarm" is the preferred term for gnats (just as "murmuration" is the preferred term for starlings and birds, while "bait ball" is preferred for fish).  

So I'm going to modify my query to be: 

     [ why do gnats swarm ] 

and find a bunch of results, the first four which look to be from credible sources (a nature conservancy website, two science journal sites, and the U. Kentucky department of entomology), each of these with articles about "why do gnats swarm?"   

All of the sites agree: it's all about mating.  

The science news site tells us that 

"The swarms make it easier for the male and female gnats to find each other and mate..." and that "Gnats will often congregate around objects or other visual markers that contrast the landscape, such as fence posts...This helps the females more easily see in the swarm. [Turns out that] ...0nly male gnats swarm. The females then identify the swarm and enter it to mate."

Since gnats don't live very long, it's important to have a fast and easy way to find a mate.  Swarming is one very visible and simple way to do that.  Think of it as speed dating for tiny insects.  

But gnats are long-lived compared to mayflies: they live in the mud of a riverbed for up to three years before hatching.  After reaching hatching and growing to adulthood before emerging on the water’s surface, adult mayflies only have about three hours to mate. As you can imagine, this makes for a pretty frantic mayfly swarm. In these swarms, frenzied insects create a dramatic (and to some, dramatically revolting) congregation. One was so large that it appeared as a rainstorm on weather radar.  (For a video of a mayfly swarm, see this NatGeo video.) 

Interestingly, starlings seem to murmurate as a kind of group defense mechanism; it's difficult for a predator to track an individual when they're swirling around in a giant mob.  

By contrast, when gnats swarm, it's easier for some predators to fly through the cloud and pick up multiple meals at once.  (That's the way dragonflies will sometimes feed in swarms of gnats. This is so common that it's got a specific term: swarm feeding.)  

So what works as defense for the birds, doesn't work out so well for the little insects.  Well, if you're a mayfly, you're time limited, so procreation beats out your survival instincts!  

SearchResearch Summary 

1. Curiosity matters. It's not hard to develop the practice of being curious--it's just a matter of asking questions and then doing your SRS to find the answers.  It's a great way to learn about the world (and develop that little twinkle in your eye that leads you to ask, "I wonder if...")  

2. Be sure to check definitions.  I hope murmuration is now in your vocabulary, and that you know it usually refers to starlings (but not exclusively).  

3. Check for near-misses: What else is like this thing?  Up above I used the * operator along with the minus operator ( - ) to search for alternatives ("other things that murmurate, but don't tell me about starlings").  Once you know what else is nearby, you'll understand the large concept space--the specific answer to your question along with other things that tell you what's nearby or closely associated with it.  

As always... Search On!  

(And in Dan's addendum:  Stay Curious!!)  


  1. Just curious - Is that gnat video rated R NSFW?

  2. the gnats just won't leave… (btw, the cat said gnat movie rating/(MPAA) curiosity is not good… still scarred from "the Last Tango in Paris, Finland*")
    regarding the Google that laid the Golden Egg:
    tl;dg… (too long;didn't google… or giggle)
    what does the atlantic know?
    SE decay
    evolutionary culling
    dying Space X
    true or false - Marie Haynes
    a theme?
    even the stones die