The Jekyll and Hydes in Our Backyards

Turns out, they’re neither! Fireflies are beetles. This is one of many

Fireflies have a delicate set of flight wings, and a second pair of wings that act as hardened covers that fold over their flight wings like Their second pair of wings act as hardened covers that fold back when the firefly isn’t flying, to protect the delicate flight wings. It’s characteristics of all kinds of beetles, like ladybugs.

“So worldwide, there’s more than two thousand different kinds of fireflies, and they have a suprising  diversity of lifestyles and morphology and behaviors.

“One of the ways of getting a hand on that diversity is to break them up into three major groups. In one group are the lighting bug fireflies. And the lightning bug fireflie- both the male and female fly around and are capable of making light. They’re actually talking to each other so they’re communicating with one another using very quick bright flashes.”

So when you look out into your backyard – those flashes that you see? Are males and females communicating with one another trying to find a mate. You’re basically witnessing a speed dating scenario – where the males are trying to strut their stuff, flashing their best light – and the females flash back if they like what they see. 

Way more on that later…... But on to the next category of fireflies…. The glow worms. 

“There’s another group of fireflies that light up as an adult, but it lights up in a really different way. Those are called glow worm fireflies.And in glow worm fireflies, it’s often only the female that makes light that can light up and as their name implies they don’t flash, but they glow. So they emit a really long lasting – you know, several minutes long glow and the worm part of the glow worm refers to the fast that these females look really different. They don’t have wings and they can’t fly. 

And so the glow worm females for example in Europe and northern Europe, they are the main firefly species there –they are called the common European glow worm. The females are plump and flightless and don’t have wings. So every night those females climb up onto perches in the low grass or bugs and they have their light lantern, swing it back and forth, back and forth, hoping to attract a male of their species that’s flying around not capable of producing light and is flying around in the forest. So the glow worm is a really different kind of courtship. 

3.    Third kind is the daytime fireflies…..

And for the third and final myth bust - - - - - 

“The third myth about fireflies is that every body associates fireflies with summertime… and you never stop and think honesty – I never stopped to think – where do they go when they’re not out flying around and flashing? And so it turns out that what we think of as the lightning bug and summertime, is just the tip of the firefly iceberg.”

The truth is – when we see lighting bugs flashing – that’s really their swan song. There’s about two weeks out of the year when the fireflies become adults and are capable of flashing. Those two weeks – fireflies rarely eat – they are just out there for the sole purpose of finding a mate, doing the deed, and then dying.

Before that, they spent nearly two years as a juvenile. And that world is quite different than you would expect.  

“And so we kind of think of fireflies as these sort of ethereal fairy like creatures that you know silently very romantic looking for mates using lights out at night very genetle. But the juevenile stage is called larva, and the larva of a firefly is a very different beast. They live underground and they spend about two years living underground in this past of New England, and they are carnivaorous and they are voracious predators on earthworms and other soft bodied insects. And they pretty much only focus on eating and growing and eating and growing. They are kind of like a firefly teenager.” 

“so for the common fireflies in North America – one group is called preternis fireflies. And those guys when their larva actually turn out to be earthworm specialists. So pretty much that’s all they eat. And when you see a firefly larva it’s pretty small, compared to when you see an earthworm. … earthworms can be pretty big. And so what these larva tend to do is they hang up on earthworms and they have very, very sharp sick shaped jaws and they bite the earth worm. And when they gang up on the earthworm there’s a lot of larva that line up among the earthworm biting it and at the same time injecting the earthworm with paralyzing neurotoxins. So it’s alive, but it’s paralyzed at that point. The firefly then switches over to secreting digestive enzymes from the inside of it’s body out through these same hollow jaws and it basically is basically digest the earthworm externally and then suck it up as a liquid. It’s kind of an earthworm smoothie.”

“So you, it’s kind of a gory lifestyle, and it’s hard to reconcile that juvenile lifestyle with the ethereal lifestyle that we’re thinking about.”

Fireflies are one of the special creatures on the planet that are capable of biolumiscene – producing their own light – some species make light that’s more yellow, some more green, and some even orange. But fireflies aren’t the only critters that can produce light. There’s a lot of ocean animals that can do it too – like jelly fish and deep sea critters. It also occurs in some bacteria and fungi too. They’ve all independently evolved to produce their own light. 

So how do fireflies do it?  

There’s a specialized tissue area located on their abdomen called the lantern. Within that area, are cells that have a high concentration of a particular enzyme called Luciferace. 

**** A chemical reactions occurs within the firefly cells – the firefly is able to give off energy in the form of a light photon. It is also able to recyle that energy so that nothing is wasted – and it’s constantly able to fire and re-fire light photos.

Think about it – they’re like their own zero-waste energy plant – producing light long before humans ever thought about electricity. And it’s inspired humans to harness the technology. Recently, scientists have used properties of firefly biolumesence to study all sorts of things. 

“So they’ve been used in the food testing for food safety to detect microbial contaminants in soft drinks and food…. they’ve been used to detect life on other planets. So firefly chemicals were sent to Mars on one of the earliest Viking missions. And several decades ago when the genes for that produce the enzyme Luceriferace were isolated and cloned, we now use the luciferasece in many different genertic reporting contexts in biomedicine. So firefly lucerface genes can be hooked up to other genes and then light production can be used as the readout to tell you when certain genes are turned on and off……so firefly luciferase is used in high throughput screening for detecting things that might be effective against cancer.”

But what’s in it for them? Why do fireflies produce light?

“So fireflies produce light for a couple of different purposes. One purpose that we’re more familiar with is that the adults fly around flashing in order to find and to attract mates. So in common North American fireflies different species have different flash patterns that they use kind of like Morse Code and the males fly around emitting a particular flash signal, repeating that flash signal again and again and it’s that particular combination of flashes and pasues that allows females of their species to identify hey there’s a male of the right species, I’m going to flash back a respnse to him. So males and females keep up pretty much constant feedback back and forth – it’s called a flash dialogue. And that’s how they find each other in the dark.”

Male fireflies strut their stuff by making light, and hoping to get a female to flash back. But out to each other in the dark so that they can find one another. Unable to find eachother in the vast darkness, the males and females flash to each other to communicate – hey I like you, come on over – and keep flashing until they eventually find each other. 

But fireflies won’t mate with just any firefly. They have to be the same species - they have to flash the right way. Each firefly has it’s own particular dialect - both the male and female have to speak the same language. 

I know that this is audio, so it’s going to be a little hard. But can you give me two examples of different patterns that people might understand.” 

“In one really common firefly in the eastern United States is called the big dipper firely. It’s body is pretty large and it’s called the dipper firefly because of a particular flash gesture that it makes as it’s flying along. So males will fly early in the evening. So still when it’s qiute light out you can still reada newspaper, and they fly along and pretty low, at around t feet, and fly fly along and begin to flash. Up and as they flash they dip down and lift up, and as they’re flying they doing this buueeep making a J shaped flash gesture – and that’s a really distinctive big dipper firefly. 

There are other fireflies that closely related but have an entirely different signal. So these males give off a pair of quick bright flashes so that the males might fly along and then they’ll go pip. Pip. So a pair of flashes, separated by an interval of several seconds and then the same flash pair were repeated.

And a female sitting down below is looking up and she seen a flash pattern she’ll say oh yes there’s a male of my species. So males are advertising, not just that they’re hey I’m really attractive, but here I’m really attractive for a big dipper male. 

It’s very specific advertising. A very specific audience.”

And when she likes what she sees? 

“When she finally responds to the males, if you watch them closely it’s astounding thing because the males basically when they see a female response he’ll stop in his tracks. I mean really just suddenly he’ll just drop out of the air down onto the ground and then they will carry on a dialogue you know flashing back and forth and that can go on for you know sometimes it’s just a few inutes but it can be as long asn hour or more before he finally finds the blade of grass that has the female on it and mates with her.”

Let’s just say I’m a female firefly. What am I looking for in father material? How picky am I? Professor Lewis and her students developed what she liked to call firefly opinion polls  - they would create a species specific flash pattern to the females – and wait to see which versions a female would flash back to. 

“And so by doing lots and lots of experiments in the lab testing female fireflies in the field, testing different species, with different kinds of signals… after I don’t know hundreds and hundreds of hours of flashing fireflies and analyzing the data, we discovered that females like males who are more conspiscious. 

Turns out, a female firefly is looking for a flashy guy. 

“So sometimes that was males that gave slightly longer flashes than average for their species. Sometimes it was males that flashed a higher rate of flashing than other males of their species. And so it looks like females are trying to pick out the brightest flashiest males.”

But firefly light isn’t all just about finding love…. It can also serve another purpose.

“All baby fireflies can light up, and they’re definitely not using their light as a courtship si gnal. They’re much too young to be looking for love. So they are doing something else. We think fireflies first evolved in the larval form as a warning signal to warn off predators .And we’ve discovered that juvenile firelies use their light as a warning signal. ] They are extremely bad tasting. And so it’s an advayage for them to advertise that they are really nasty to predators with some kind of conspicuous signal. It’s nighttime or it’s dark underground and so they needed something that’s visible to predatos, so they use light. 

Fireflifes don’t just taste bad – they’re actually dangerous to eat. Fireflies produce toxins that are poisonous to most predators… in fact, birds, frogs, and bats stay clear of eating them. So, fireflies have nothing to worry about, right? They’re not on anyone’s menu? 

So, pretty nifty right? They have biolumiscnee to find their perfect mate – and they warn off anyone who might want to eat them. It sounds like they got it all figured out. They have a complex language system – speaking in code to each other. They taste so bad that no one wants to eat them. I don’t know. This sounds pretty ideal. Fireflies aren’t on anyone’s menu, right? 

Well, this is where the story gets really interesting…. 

“SO in one of the most fascinating twists of firefly biology… most fireflies don’t eat at all. So they’re doing all of their eating and growing in their larval stage, once they ecome adults the majority of fireflies don’t eat anything. They only live for about two weeks. They’re all about flying all their courtship flashing everything theyr’re doing during their adult lives is fueled by reserves that they accusumulated during their juevenile stages.

One group of fireflies, and they’re called……. I like to use the neumonic deveices… it’s ahrd to remember. Many of them are predatory. So during their adult tlives they actually have different strategies that they use to hunt and eat other fireflies. They don’t eat other things. They only go after fireflies. And in the late 1990s a scientist at Cornell Tom Eisner discoverey why they have developed these many different methods of hunting. 

..This one group of firelies somehow lost their metabolic machinery that they need to make their own protective toxins. And so in order to protect themselves against their own predators like birds or spiders or small mamells – other things that eat insects – they actually need to consume other fireflies to hijack their toxins. And that’s the only way they can protect themselves and their offspring against predators. 

“So these fireflies actually have a whole bunch oftricks up their sleeve, or under their wings I guess you could say. One of the things they can do is they can fly around the field where the other fieflies are active. Just simply hawk these male fireflies just catching them on the wing and consuming them. 

“The other thing that you see is these so called femme fatals is mimic the flash patterns that are normally used by the prey species. And they can do it so convincingly that they canlure in the males getting them lured closely enough that they can reach out, grab them, and eat them.

Yeah. That’s right.

I can’t wrap my head around that. A predatory female firefly will actually switch lanagueges to match the flash pattern of her victim. She’ll switch to whatever flash pattern he uses. 

She switches HER CODE to DECEIVE Him into coming closer…the trap is set and bam. 

 She tricks him into thinking that she’s into him – lures him in – and then bam. It’s like a stealthy hitman move.   

The predator firefly will specifically change her language pattern to mimic the firefly she wants to eat and trick the male into thinking that she was an interested female.

That’s pretty clever… and shady. 

 “Anothr really cool thing that they do is these predatory fireflies hang out sometimes next to spider webs – and they wait until a freifly has been caught be a spider and wrapped up by the spider and then these fireflies actually jump into the web and steal those spiders prey. They take the wrapped firefly and run off with it and they consume that firefly sequestering the toxins and then graining protections for themselves.”

“I find that out of this world incredible. That one firefly species could actually change their language in order to deveive another.”

“Yeah it’s a really incredible thing to think about the next time for example next summer when you’re out watching fireflies in a field. You know you think you know it’s not just all sweetness and light out there. But a lot of flashes that you might be seeing could be these predatory fireflies that are actually out there mimicking the flahes of other species in order to grab them and eat them.”

See, I told you! Deception, stealing. More drama than a soap opera!

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“So worldwide, there’s more than two thousand different kinds of fireflies, and they have a suprising  diversity of lifestyles and morphology and behaviors,”