Monday, August 22, 2011

One thing leads to another

The other evening as I was putting the dog to bed, I came across a cicada laying belly up on the ground. It's white abdomen was easy to see, otherwise I never would have known it was there. It was obviously injured, as it made no attempt to flutter or put up a fight when I poked at it lightly with a stick to see if it was even alive. I picked it up and laid it on the deck railing, thinking I would take pictures of it the next morning if it had not managed to fly away by that time.


As luck would have it, the cicada was still there the next morning, where it had somehow managed to hang on through a mild rain storm. Unfortunately, it was not in good shape, and only it's front two legs seemed to show much movement.


I believe this to be a Swamp Cicada, Tibicen tibicen. This is an example of a perfect treat for the young Mississippi Kite I saw last weekend. (Did you miss that post? If so, click HERE to get more info about Ohio's only current breeding family of Mississippi Kites!)


The Swamp Cicada, along with a myriad of other cicadas, gets lumped into the category of annual cicada, which is a bit of a misnomer. The "annual" designation refers to the fact that there are adults out and about each year; their entire life cycle, however, lasts several years, most of which is spent underground. Alternately, there are the periodical cicadas, such as the 13-year or 17-year cicadas. These cicadas spend MANY years underground to emerge as adults synchronously (i.e. all in the same year) on a 13- or 17-year cycle. (The 17-year cycles are mostly in midwest and northern states, whereas the 13-year cycles are mostly in the southern states). For more information and brood maps showing when the next hatching of periodical cicadas is scheduled to hit your area, click HERE.


When I was a kid, I remember coming across the exoskeleton of a recently emerged adult of some cicada species, attached to a tree, and I was quite terrified. Who knew that so many years later I would nonchalantly hold one in my hand? I can attest to the grabbing power of the "feet" of this cicada. Here you can see how it was latched onto my finger by just these two little feet. While this poor swampie was in no condition to be "singing," I remember the song of the Swamp Cicada as THE cicada song of the hot summer days of my childhood. You can listen to it HERE.

After the photo shoot was over I was looking for someplace to put the cicada other than our deck railing when my attention was shifted to another odd-looking insect altogether. Actually, a LOT of odd-looking insects. There was quite a swarm of these blue-black beetles in my flower bed, and they were making short work of the leaves of my hellebore!


After determining that these are a type of blister beetle, I read that most of them feed on flower nectar or flowers themselves, but some species, like this one, feed on foliage. Hopefully the plant will recover, but honestly, it doesn't look good for the hellebore.


Okay, they might look odd, but they are also kind of handsome. I believe this is Meloe impressus. This turns out to be one insect species that is sexually dimorphic, meaning that there is a visible way for my human eyes to discern male from female. (di- meaning "two" and morph meaning "form" or "shape") Those funny looking "c"-shaped kinks in the middle of the antennae indicate that this is a male.


Here's where things get weird (at least to my non-beetle brain!), and fascinating. The males use that kink in their antennae as part of the courtship process. From what I was able to personally observe over a limited amount of time with these beetles, the male would mount the female from behind and use that portion of his antennae to stroke the antennae of the female. To make matters more interesting, I observed several mated pairs where male and female are going about their conjoined business, but then I also observed just as many TRIOS where a male and female were already joined, but a second male was on the female's back, doing the antennae-to-antennae tango! What on earth is THAT all about?! In the photo just above, the male on her back is the extraneous male (you can barely make out her actual mate, who's out of focus directly beyond her in this shot). Bet you never guessed you were going to get a discourse on beetle sex when you started reading this post, did you?!


In addition to the antennae giving away gender, the relative size is also an indication of sex. In general, the females are larger than the males, both in length and girth. In these side-by-side photos, the male (at left) and female (at right) are roughly the same length, but you will notice the much more swollen abdomen of the female, who is very likely gravid (carrying eggs).

In my next post, I'll talk briefly about how I came to identify this as a blister beetle in the first place. Stay tuned!

2 comments:

Kathiesbirds said...

Though they have a pretty color I do not want blister beetles around my yard. When I lived in Tucson they flew into my yard each summer and starting nipping all the leaves off my velvet mesquite tree. I battled them back with bursts of water and drown them in buckets to save my tree. I did not want to use pesticides for many reasons. they seemed to come in hordes for one day or even one morning and then they were gone, so it made it easier for me to manually deal with them. don't know what I would have done if they were persistent. Very interesting post.

Heather said...

Hi Kathie. It's always hard when some creature of nature messes with the things that we hold near and dear. I'm glad you were able to keep them at bay by simply hosing down the tree. One thing the Kaufman guide mentioned was that, typically, blister beetles are locally abundant for a short period of time, which matches what you describe. Two days after I took my photos of these guys, I only saw one or two of them remaining. Makes me wonder where they come from, and where they went, and will I see them again?