Wednesday, October 22, 2014

Another Worry for Cicadas: Cedar Beetles

Kermit the Frog always said, "It's not easy being green."  Well, I've decided that it's not easy being a cicada either.

My dogs absolutely love to munch cicadas and have been known to catch them in mid-air.  If they find one on the ground, they'll often hold it in their mouth for a little bit to get it to buzz before they chomp down and eat it.  A canine "Fizzy", I guess.

Then there are more "normal" predators like birds and, especially, the huge wasps known as cicada killers.  Female cicada killers hunt down a cicada, sting it to paralyze it (but keep it alive), drag it back to their nest in the ground, carry it below ground, lay an egg on it and seal the brood cell off.  When the egg hatches, the larval wasp eats out the paralyzed, living cicada, pupates, and emerges the next year to repeat the cycle.  An effective population control mechanism for cicadas, although it's extremely unsettling to think about.

I suspect that moles eat a fair number of cicada nymphs, too, as the nymphs feed and mature underground.

Now, I've learned about another animal that feasts on cicadas, specifically on the nymphs while they are still underground - the cedar beetle, Sandalus niger, also descriptively known as the cicada parasite beetle.  I've been observing these large beetles all around the yard over the last few days.  Most often, I'm seeing them on honeylocust trees.


These are fairly large beetles - many are close to an inch in length.  I first noticed one when I saw a big brown beetle being eating by 2 wheelbugs.  I've never seen TWO wheelbugs eating the same beetle before!  I took photos and tried to identify the beetle, but I couldn't quite make it out.  It looked somewhat like a longhorn beetle, but I didn't see long "horns" (antennae) on it.

While I was photographing this interesting vignette, Greg called me over to a nearby lacebark elm, saying that he'd just seen a big black beetle fly into it.  He showed me where she had landed and I took several photos of her;  she appeared to be laying eggs on the underside of a dead limb.

I started to go back to taking photos of pollinators on asters, when I felt something on my shoulder.  Looking down, it was a large black beetle with one of the elytra (thickened wing covers) missing.  I brushed her to the ground, where I photographed her, wondering how she had lost her elytra.  Then I picked her up and put her in the elm tree, thinking she probably got interrupted during egg laying.

Only when I edited the photographs this evening did I notice that all the white "innards" showing were actually larvae(?) or pupae(?) of some other insect that were massed inside her.  I have no idea what they are...but I'm submitting the photo to BugGuide to see if anyone there can help identify what was going on with her.  (Parasites eating parasites.  Sometimes the natural world is really complex in its creepiness.)  Did the larvae have anything to do with how she lost her wing cover?  I have no idea.

Next, I noticed another, similar looking beetle being eaten by a wheelbug on a nearby honeylocust trunk.  As I stood and took photos, I heard and felt yet another big beetle - the 5th one - fly by my head.  It was a male, judging by its smaller size and more slender body, and it landed on the tree trunk right in front of me and starting searching all around.  Its antennae were really interesting, especially when the beetle fanned them all the way out.

While all of these beetles were grabbing my attention, I was also hearing a clicking noise that sounded very much like the rhythmic pattern of a field sparrow, which is often likened to the sound of a bouncing ball.  This noise, however, was more "insect-like" than a bird call, if there is such a thing.  I never did find out what was creating the sound, but I don't recall having heard it before and I wonder if it was some sort of mating call between the cedar beetles.

Before I went in for the evening, I took several more photos of each of the different beetles I'd observed, and  I also found a 6th beetle on the underside of a honeylocust branch. This was another female, based on the size and shape, but I didn't get any clear photos of her.

Looking through Insects in Kansas, by Glenn A. Salsbury and Stephan C. White, I found the tentative identification of my beetles, which I confirmed on BugGuide.net.   They were all the same species, Sandalus nigerInsects in Kansas had noted that males often had blackish-brown wing-covers, rather than black, and on BugGuide, I saw the difference in antennae between the males and females.  There wasn't a lot of information given about the species on its information page at BugGuide, but it was noted that the adult beetles are very short-lived.

I've gone back and picked up the "empty" beetles discarded by the wheelbugs after they were through eating them so that I could examine them more closely, plus I've been able to find a couple more dead specimens.  Sunday, October 19th, was the only day that I saw so many living individuals, although I've seen one or two more each day since then.  I have not heard the clicking noise again.

I have seen one more instance where two wheelbugs were eating the same cedar beetle.  Do wheelbugs do this with any large insect, or is it only with cedar beetles?  I'll be keeping my eyes open to see what I observe in the future.

Isn't the complexity of life fascinating?! 


4 comments:

Corner Gardener Sue said...

I love this post! I was right there with you as you were looking at the beetles, and in awe of the wheel bugs eating at the same time, and trying to figure out what was what with all of it. Yes, nature can be quite amazing!

Debra said...

Great post. A bug's life is pretty brutal. I often find arthropods with missing limbs or other serious trauma and wonder about their adventures.

Gardener on Sherlock Street said...

So much happening at your place. Those wheel bugs look so cool. Interesting that they were sharing a meal. I really like the antennae on the beetle. Reminds me of those headbands with springs and some shape at the end of each spring like a star or something that kids sometimes wear. Again your photos are great.
I was thrilled to find several praying mantis egg cases yesterday as I surveyed around the outside of the house for places that need caulk before winter. Still enjoying some butterflies too.

katob427 said...

I was also right there with you, but wasn't too thrilled about the beetle on the shoulder and all the parasites! You sure are right about the creepiness factor, creepy yet fascinating. Things were busy indeed in your yard that afternoon, it is amazing what all goes on around our feet.
Frank