Otto: There’s really no such thing as ‘just a bug’
When was the last time you, or someone you know, uttered those fateful words, “Oh, it’s just a bug,” then proceeded to spray, swat or stomp to smithereens some unfortunate member of Class Insecta?
It’s true, insects’ generally small sizes make them seem insignificant. The cecropia moth, which happens to be the largest insect native to Illinois, seems miniscule when compared to, say, an African Goliath beetle larva, which can weigh as much as a Quarter Pounder. But even a Double Quarter Pounder with cheese is small and inconsequential when compared to a mighty human being. (Now, a mighty hungry human being would beg to differ, but we’re not going there right now.)
Something I like to call The Yow Factor plays a role, too, when it comes to public perception of insects. We tend to think that two legged creatures are “like us,” while four leggeds are at the very least “familiar” – all the more so if we can work them, eat them or keep them as pets.
But when the leg-count total starts to creep higher, so too do people’s heebie jeebies. Six legs can cause uneasiness; eight legs, unrest; and when the number hits 10 or more, a primal “Yow!” often results. I can’t help but remember the day a giant desert centipede, Scolopendra heros, appeared rather suddenly in the bookstore at Carlbad Caverns in New Mexico. “Yow!” doesn’t begin to describe the sounds tourists and staff alike uttered as the eight-inch creature scuttled its way cross the floor and beneath a bookcase.
I know it’s asking too much for everyone, everywhere, to appreciate all arthropods, all the time. But if we dial back the number of legs to six, and focus – for today – on just one family, we may find the Yow factor changing to Wow, as in “Wow, insects are amazingly important. In the future I will consider putting down my spray/swatter/shoe away and allow these fascinating animals to perform the job to which they have been assigned.”
Meet “Sandy,” an extraordinary beetle that literally dropped into our lives here in the naturalist department one sunny day last week.
Native Illinois, our natural history program for third-graders, was winding down out in the Hickory Knolls Natural Area, when one of our instructors, Kim Haag, happened to look down. Hooked onto her leg was not, thankfully, a third-grader, but rather an insect that measured about an inch long – big enough to notice, yet not so large as to elicit a “Yow!”
Mostly brown, with a black pronotum, its coloring was attractive but not remarkable. Its antennae, though, were nothing short of spectacular. Wow!
Jeanette Joy, who had been playing the role of a Potawatomi Native in the program, came over and agreed that the beetle was unlike any she had seen before. Although surrounded by artifacts that dated back hundreds of years, she also had a smartphone, and proceeded to snap several pictures of the decidedly unique critter.
From there, the race was on to identify the little bugger.
Thanks once again to our favorite online field guide, BugGuide.net, it wasn’t too hard to track down the beetle’s family, Rhipiceridae, the cedar beetles. As beetle families go, this one’s pretty small, with only one genus, Sandalus, and five species occurring in North America.
I’m hesitant to try to identify this insect down to species, since very little is known about the family. But to me, the exact name doesn’t matter as much as its ecological niche or job is.
Sandalus beetles parasitize cicada nymphs. Female beetles are gifted with the ability to track down the slits in tree branches where female cicadas laid their eggs. The female beetles lay their eggs in or near the same location, and when the eggs hatch the little larvae – which, astoundingly, have legs, but only until they advance to their next stage of development – dig down and latch onto the young cicadas.
Sandalus larvae go through what is known as hypermetamorphosis. Whereas most baby beetles spend much of their juvenile lives as lumpy grubs, young Sandalus larvae start out as triungulins – silverfish-like creatures with well-developed legs, which they use to get them where they need to go – down, down underground, to where the cicada nymphs are feeding, on tree roots.
Nobody really knows what happens after that, but the presumption is that the beetle larvae feeds and molts several times, then pupates and emerges as an adult. Then it’s the common adult insect drill of mate-and-die. No feeding is necessary, as nutrient needs were met by the cicada nymph.
Besides, at least in our area, there really isn’t time for food.
Adult Sandalus beetles conduct their business late in the year – October is typical – and there are some reports of mating activity even after snow has fallen. The beetles are known for congregating on tree trunks, probably near where they emerged from the ground. Males fly about, relying on those fantastic antennae to detect female chemical cues.
Once mating occurs, it’s all over for the adults. It’s up to their progeny to carry on the important work of helping to control cicada populations.
The next time you, or someone you know, is tempted to whack a bug (or spider, or centipede, or ...) stop for just a second to consider just why that creature exists here on Earth. You’ll soon see, there’s really no such thing as “just a bug.”
If you’re a fan of things like cicada parasite beetles, you may be interested in meeting others who share that special sort of enthusiasm.
If so, mark your calendars for this coming week. The coordinating partners of Kane County Certified Naturalists, a year-long, adult-level nature education program, are ramping up for another fun-filled session that will begin in January.
We will be holding KCCN information meetings at 6:30 p.m. Tuesday and again at 10 a.m. Nov. 16 at the Hickory Knolls Discovery Center located within the James O. Breen Community Park at the corner of Peck and Campton Hills roads in St. Charles. I’ll be there; hope you will too!
• Pam Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or firstname.lastname@example.org.