The steep decline of the autumn darter -- a species of red dragonfly -- in Japan is linked to neonicotinoid insecticides

The autumn darter -- a species of red dragonfly -- is making it onto the "red list" of endangered species in many local municipalities in Japan. The data point to a possible link with the use of pesticides. According to the Nature Conservation Society of Japan (NACS-J), the autumn darter (Sympetrum frequens) has been confirmed as being on endangered species lists in the six prefectures of Osaka, Hyogo, Mie, Toyama, Nagasaki and Kagoshima. Their numbers have dropped dramatically from the late 1990s onward. According to Tetsuyuki Ueda, an animal ecology expert and professor emeritus at Ishikawa Prefectural University, autumn darters were confirmed to have emerged from their chrysalises at 80 percent of rice paddies in the prefecture in 1989, while the figure was down to 19 percent in 2009. Tests found that using neonicotinoid insecticides, which have become widespread since their emergence in the 1990s, led to a 70-percent drop in the autumn darter's eclosion rate than when such insecticides were not used.

In fiscal 2014, the Environment Ministry looked through scientific literature to determine the effects of eight kinds of pesticides. The ministry said that the literature suggested the chemicals affected autumn darters, but this could not be confirmed. This fiscal year, Hyogo, Hiroshima and Saga prefectures are investigating the number of autumn darters, whether pesticides are used, and the concentration of residual pesticides in relevant areas.

"Farmers often don't know what kind of negative impacts pesticides have on the natural environment," says Ueda. "It's necessary to create a framework in which the risks can be clearly communicated to farmers."

August 23, 2015 (Mainichi Japan)…