Misery loves company, an old saying goes. And with earthquakes, tsunami and now nuclear radiation creeping into our food supply, you'd think things were bad enough. But Aera (Aug 1) has discovered a peculiar side-effect of the government's "Cool Biz" campaign to promote setting of thermostats at 28 degrees Celsius: that temperature also happens to be the most hospitable for the odious "gokiburi" (cockroach).
Last April Varsan, a maker of insecticides, even launched a cockroach forecasting service on the web called "Gokiburi Tenki Yoho" or "Gokiten" for short, at gokiten.varsan.jp/ -- and up to mid-July, it had received over 1.8 million page views.
The site categorizes cockroach activities around Japan on a scale of four, based on temperature and other factors. The highest, Level 4, is issued on days when the temperature peaks over 30 degrees Celsius and the low remains above 25 degrees.
Apparently cockroaches, like humans, also suffer from "natsu-bate" (heat exhaustion), according to Hiroki Kamezaki, a researcher at Lion Corporation.
"They become sluggish over 30 degrees and become debilitated over 35. And 40 degrees is enough to kill them," he says, adding that the 25 to 30 degree range is the most hospitable for the repulsive bugs.
Unfortunately, the government-recommended thermostat setting of 28 degrees provides "gokiburi" with the coziest of conditions.
"We recently received a request from someone on the 12th floor of a building, who suffered from a large infestation," relates Hisashi Sato of Albatross, a Tokyo-based 24-hour extermination service. "I thought it was a bit strange to have them so high up, but when we checked things out, there were a large number of decorative plants.
"If water is present, roaches can survive. Water present in soil also contains nutrients. The "kuro gokiburi" (Oriental cockroach) was originally a species that thrived in the wild, and it will often nest in the soil of potted plants," says Sato.
In households obliged to summon the exterminator, a number of common factors can be found. One is that they tend not to open their windows. Recently, fears over airborne radiation may be one reason, but in any case this serves to create a moist, fetid environment that the "goki" find particularly inviting.
"A lot of people believe that the roaches fly into their house, but in most cases they invade buildings via crevices," says Sato. "They instinctively sense that places lacking air currents are safe. In human habitations, this is a necessary condition for harboring them."
It's therefore effective not only to keep windows open, but to set up an electric fan to circulate air into "oshiire" (closets).
The two most common species in Japan are the "chabane gokiburi" (German cockroach) and "kuro gokiburi" (Oriental cockroach). When population density of the latter becomes too high, they move on in search of food and more hospitable habitations. The reason they are more noticeable in summer is because that's also the time when they engage in reproductive activities and their population rises further.
The oriental cockroach has another interesting characteristic. "When they begin moving around and their activity intensifies, their feet part from the floors or walls and they take wing," says Kamezaki.
Makio Takeda, a professor of entomology at Kobe University, has observed the "goki" in flight, and notes that while takeoffs from the floor tend to be infrequent, it's been known to happen.
In any event, as the summer heat persists you can expect to be hearing more screams of terror, Aera predicts.© Japan Today