The much-loved min-min zemi (2011.12.1[Thu.])

“If you can show me hard evidence of min-min zemi living on this island, I’ll apologize standing on my head!”
Masatoshi Takeichi; Sannomiya, August 17, 2011

 

After one particularly powerful typhoon this summer, temperatures fell and, enjoying the weather one morning, I decided to sit in the shade by a fountain in a park on the way to the CDB for a while and read for a spell. As I read, I noticed to my surprise that, mingled in with the calls of the tsuku-tsuku boushi cicada (Meimuna opalifera), was the equally distinctive cry of the min-min zemi (Hyalessa maculaticollis) – something that had never happened until as late as last year (2010).  This, after all, is Port Island; how unexpected to hear that plaintive song on this landfill isle. This cicada is found all over the Kanto Plain, but the flatlands of the Kinki Region are generally too hot a habitat, and any Kansai bug fancier will agree that they are nowhere to be found in these parts. If you see a TV drama or manga set in or around Tokyo, the droning miiiin-miiiin is a familiar bit of Foley art. Even for someone like me, born and raised in Osaka, I grew up thinking of the min-min zemi as the cicada archetype.  Not only is its voice instantly memorable, but its curvilinear form is shaded a lovely hue of green. It stands out among the cicadas of Japan not only for its beauty but for its diversity as well, and I would spend hours catching dozens to find a brilliant green specimen. Indeed, the only cicadas really worth bothering over are the min-min and the Ezo-zemi (Lysristes japonicas) around here. So when I saw one so close by, I instinctively reached for my camera. A pair of male Lesser Emperor dragonflies flitted, vying for territory, nearby....

Truth to tell, I had first encountered a male min-min zemi two weeks prior in mid-August. I could hear another male crying from deeper in the trees, suggesting that this was not just a lonely individual that had errantly found itself on the island, but that they had established themselves in residence. When I mentioned this to Takeichi-sensei, he said, “That can’t be right. If we were in Kanto, I could understand it, but around here min-min zemi are only up in the mountains. Either it was a mistake or one somehow wandered down here.” That’s a tough hypothesis to exclude, but I felt sure about ruling out the possibility of an error in identification. I said, “This is me. I may make mistakes about a lot of things, but I know a min-min zemi when I see one!” to which Takeichi-sensei replied, “All right then, If you can show me hard evidence of those cicadas living on this island, I’ll apologize to you while standing on my head!”

Now, this presents a problem. How am I supposed to react to our Center Director doing a headstand? But we scientists like our answers clear and well-defined. Most of use grew up chasing after bugs and arguing stubbornly over what species was what, so I felt compelled, if nothing else by force of habit, to get to the bottom of this question as well. But in my mind, I already knew the answer.  But how could I prove it? What would constitute convincing hard evidence that an insect is in habitat? A close-up photo of one drinking sap, with the CDB in the background? Such a shot might be possible for a kuma-zemi (Cryptotympana facialis), which swarm all over the island,

but this was a different story altogether. The princely min-min zemi is elusive quarry, not something the causal photographer would just stumble across and snap away at. In fact, as seen above, I already had a photo of one of Port Island’s male min-min in mid-song. But this image lacks a clear context. So I set out with my camera determined to make a definitive case.

I could hear their cries as I trod into the forest. They seemed to cease in response to my footsteps, only to be taken up by another individual off in the distance. They seemed to sense I was tracking them; no doubt they would have gone on singing contentedly if I was just some uninterested passerby, but they went silent when confronted with an fanatic enthusiast such as myself. I stalked them for some time, when only a few meters distant I heard one begin its call. The tone was slightly different from before – a different individual.  When it stopped, another cicada called out from the wood on the other side of the Port Liner track to the west. They were engaging in the call-and-response behavior known as nakiwake! Short of hearing many individuals singing together in symphony, this was the strongest evidence yet of their residency. Questions may remain about how exactly it happened, but I can say without a doubt that as of 2011, the min-min zemi joined the sylvan fauna of the Port Island Stage I – II industrial zone ecosystem.

In Japan, cicadas are the reference point for children starting out in insect collecting; one of the things to look forward to in summer vacation is running around all day filling your insectarium with cicadas, then getting yelled at by your parents for bringing them into the house, as your pet cat munches happily away on them. Where I grew up in Toyonaka, not just min-min, but kuma-zemi were also rare, so for us semi (cicada) really meant either abura-zemi (Graptopsaltria nigrofuscata) or nii-nii zemi (Platypleura kaempfer), and like children everywhere, we felt wistful distress at hearing tsuku-tsuku-boushi signal summer’s end.  Back then, catching a kuma-zemi was something of an achievement. In the regional dialect, I’ve also heard them called katabira. The image of the bright orange breastplate of the male was burned into my mind as kind of natural wonder. But recently, spotting one is no more than a commonplace.

Changes in species distribution can’t fail to make one think on the passage of time. What will the Port Island biota look like in the future? Its diversification to date has been wonderful, and we can only imagine how this environment will evolve going forward. I can only hope that people restrain their urges to spray insecticides and weed-killers. These will only drive off birds that feed on insects in the long run. Important problems, but more immediately, what to do about that headstand?