Tuesday, August 17, 2010

Lightning Bugs, Singing Insects, and Nostalgia


I just got home from a long weekend in the Ozarks with Mom and Dad down at the lake.
Bull Shoals Lake, Arkansas

I flew in to the brand new Branson airport, which was hilarious. It was like walking into Silver Dollar City - the terminal is a cavernous wooden-paneled room with hillbilly hand-painted signs, an artificial creek, and wood-bark rocking chairs. There's also a big sign that says, "Welcome to the Ozarks."

Anyhow, the first thing that hit me when I got to Missouri was a blast of heat and the singing insects.

That's one of the things I miss the most from the Ozarks - the ever-present sound of insects singing and hmmming and shushing and chk-chk-chking and bzzzzing. They are especially cacophonous down at the lake, where the trees are full of cicadas and katydids.

I miss the singing insects so much that Mom got me a CD of them for Christmas this last year. The nights in Seattle are sooooo quiet! There are no singing insects here at all, and I don't believe I've ever heard any in Oregon or California either. What's up with that?

Question #1: Why are there no singing insects on the West Coast?

And then there were the lightning bugs. I just stood outside the first night at the lake looking into the field behind Mom and Dad's trailer watching the little blinking yellow lights. How awesome is a bug that LIGHTS UP?! I remember when we were little girls and we used to spend almost every summer evening running barefoot through the grass catching as many lightning bugs as we could, making sure to catch them with cupped hands so they wouldn't get squished. We'd put them into a glass jar with ventilation holes poked into the metal top to bring to our rooms for the night. Or sometimes we'd just catch and release all evening, until Mom made us go inside and take baths and put calomine on our chigger bites.

Anyway, lightning bugs are also absent from Seattle. :(

Question #2: Why aren't there any lightning bugs on the West Coast?

While I was at the lake, I intended to take a bunch of pictures of bugs for you, but I got side tracked by my general plan of relaxation. I did a lot of swimming with Mom and scuba diving and spearfishing with Dad, although I didn't shoot any fish because the walleye have all but mysteriously vanished this year (another topic for another day).

But I did get a great picture of a green walking stick. Dad found the walking stick in a barn and brought it out for me. It's one of those creatures that seems like a cartoon rather than a real living thing. It's upside down in the picture, so you kinda have to look at it the other way. It has these goofy orange eyeballs that look sort of like eyeglasses, two gangly arms and two legs, and a tall head that is topped by what looks like the hairs on Waldo from "Where's Waldo".

I keep expecting it to say hello and confess its ambition to become a stage comedian with a top hat.

Question #3: Are walking sticks the entertainers of the bug world?

Hehehe . . .


You are a dork. A cute dork. But a dork.


Answer 1: Singing Bugs
Ahhhh. I miss cicadas. When we're talking in the summer, sometimes mom takes the phone outside so I can hear them.

I don't know why you don't have any singing insects. We have some crickets here. I can tell you why you don't have the loudest and prettiest "singers," though.

I used to call every singing insect a katydid (unless it was obviously a cricket). There are katydids in Missouri, but tons of other species sing as well. Cicadas veritably roar. I called them locusts when I saw them, until my first entomology course. I love them so much. In fact, I brought a cicada carcass with me when I left for Denver. Unfortunately, I kept it on the dashboard of my car, so it fell apart. So did my frozen dragonflies, because something crushed them in the freezer. I had awesome room mates in that they didn't mind bugs in the freezer, but they weren't very careful with them either. But I digress. Cicadas make the really loud buzzing noise at night.

Periodic cicadas show up in the news every once in a while (every 13 or 17 years). Cicadas are xylem feeders - that's the water system of plants. Aphids and others feed on the sugar/food system of the plant, otherwise known as phloem. I've already touched on how inefficient phloem is as a food source. (Wow, this blog is probably bad for my reputation with strangers. I've admitted to tasting aphid poop/phloem and keeping bugs in my freezer!) Anyway. Xylem has even fewer nutrients than phloem, so it takes a long time for cicadas to mature. They spend most of their lives as immatures (or nymphs) feeding underground on the roots of deciduous trees. They don't have any specific hosts, but they need to be deciduous. They also engage in some pretty dangerous practices. Singing is very costly to an insect, because your mate isn't the only thing that can find you. You're also broadcasting your location to predators and parasites. And insect parasites (parasitoids) are pretty nasty things. It's not like getting hair lice. They'll kill you just as dead as a bat, only slowly and sometimes including venom that makes you unable to move while their babies eat you. I'm not just getting gruesome because it's a cool story. This actually pertains to your question.

So cicadas have a strategy to overcome this problem. It's called predator satiation (or saturation). The nymphs are relatively protected, because they hang out underground. The adult males, however, have to literally sing it from the treetops. So they come out in large enough numbers that they can't all get eaten. The predators eat so many cicadas that they're too full to eat anymore. Probably not much consolation to the ones that get eaten, but each individual has a higher chance of survival. The periodic cicadas really go for it. They only come out once every 7, 13 or even 17 years in HUGE numbers. But the dog day (or annual) cicadas do it too. They can live for around 3 years if they aren't killed. And there are tons of them. They're called dog day cicadas because they emerge for the dog days of summer.

And here's why you don't have cicadas. The strategy depends on these large numbers for a given population to survive. And they need a large number of deciduous trees to do it. Cicadas don't do well in coniferous forests. In fact, the don't make it very far into the grasslands of Kansas and Oklahoma, relatively speaking.

I'm going to talk about cicada speciation, so skip to the next paragraph is this topic makes you yawn: Cicadas stretch through most of eastern America, up into Canada. So we know it isn't a problem with climate. You'll also find cicadas through Central and South America, and temperate Europe. Cicadas have interesting speciation patterns in that the North American species seem to be more closely related to those in France than those in South America. It's an old order of Hemipterans. I have had many the argument with an entomologist telling someone that only hemipterans are "true bugs." Personally, I don't think scientists have any right to determine common names. These patterns have something to do with plate tectonics that's beyond me (I get lost after Pangaea). Oddly, there are some species that are extant here and also on islands that have never touched North America (at least, since the dispersal event). This means they must have flown/blown there. Anyway, there hasn't been much change to the songs of species that diverged a long long time ago. There's a good amount of work that goes into studying cicada songs.

Katydids are easy to explain. They don't live in Seattle because it's too cold for too long. They like it tropical, and I guess Missouri is warm and humid enough. Even though it gets colder in the winter. They can hibernate (which we call overwintering, because it's very different from what mammals do). There are several other singing insects in Missouri that need tropical-like conditions. These two are the major players, though.

I don't know why you don't have many crickets. And I just deleted a really long explanation of insect hearing. I don't think anyone (other than entomologists) probably cares why crickets have ears in their knees. My students didn't care when I TA'd the course.

Question 2: Lightning Bugs
I miss fireflies almost as much as singing bugs. There's this really cool trick I'm going to do as soon as I get a group of kids together, collecting lightning bugs. Here I usually take them to streams. Remember how you'd see the occasional bug lighting up in the grass? I always assumed that was a tired firefly. Actually, those are the females. The ones flying around are the males, and they light up in a specific pattern - like Morse Code. If the female is open to mating, she'll respond in another pattern. So if you take out a pen-light, and you flash it the way a female would, you can get a male to land on your hand. No chasing required. Have I mentioned I really want to try this? No kids, even, required.

Lightning bugs require warm, moist climates. The moist part is particularly important. They need damp grass for the female to hang in, waiting for the right guy. You have that there. But. They can't get across the Rocky Mountains. When we were younger, they hadn't made it into the front range of Colorado. It was too dry. There are a few populations that have made it - for the first time - to Fort Collins in the last few years. We can thank global warming coupled with development. Doug remembers a time when no one had air conditioning and the lake froze every winter. Now, everyone needs AC and people water their lawns. So they can support a lightning bug population. It's not in back yards yet - still out in the fields. But the kids can find them if they have parents who know where to look.

I don't think they'll ever make it over the Rockies, unfortunately. Someone might be able to transplant a population there, but I'm pretty sure there are restrictions for that. And they aren't an anthropophilic species, so they won't end up accidentally in someone's luggage.

Answer 3: Stick Bugs
Once again, you are a dork.

They'd be pretty slow moving clowns, as their entire defensive strategy revolves around pretending to be a stick. But they are pretty funny-looking, I'll give you that. I remember thinking they were poisonous, when we were really young and we'd see them hanging out on the bathroom wall at the lake. Funny. That's kind of like that old wives' tale that Daddy Long Legs have the most potent venom, but their mouths are too small to bite you. Pretty silly, all told.

But, yeah, they're pretty funny looking.

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