The research team established a method of environmental DNA analysis and succeeded in perceiving the presence or absence of endangered species aquatic insects "Pleurotus thunbergii" simply by drawing water. Since the method was also applicable to small aquatic insects living at low density, it is expected to be applied to monitoring various endangered species or exotic species inhabiting water.
◆Title of paper
Detection of an endangered aquatic heteropteran using environmental DNA in a wetland ecosystem
◆Authors
Hideyuki Doi, Izumi Katano, Yusuke Sakata, Rio Souma, Toshihiro Kosuge, Mariko Nagano, Kousuke Ikeda, Koki Yano, Koji Tojo
◆ Background of research
The habitat of Pleurotus thunbergii is rapidly decreasing or deteriorating, and it is designated as an endangered species in Hyogo prefecture and Tokai region. Moreover, it is designated as a protected species in Kuwana city, Mie prefecture. As its body length is around 23 mm and catch survey is difficult , it remains an issue to spend a great deal of time and cost to confirm the habitat.
Since DNA fragments (environmental DNA) derived from feces or epidermis of aquatic organisms are floating in the water environment such as wetlands, the research team verified the effectiveness of environmental DNA analytical method by conducting a field work using "real-time PCR (polymerase chain reaction) method" which can amplify and quantify DNA fragments of Pleurotus thunbergii species-specifically, judging the presence or absence of Pleurotus thunbergii, carrying out a catch survey in the field in parallel.
◆ Research method
The research team surveyed Pleurotus thunbergii in Hyogo prefecture and Aichi prefecture. In 2014 and 2016, 1 liter of water was sampled at each of 14 wetlands and trickle streams, and analyzed the presence or absence of Pleurotus thunbergii's DNA derived from feces, epidermis or body mucosa floating in water by real-time PCR method. At the same time, we investigated the inhabitation of Pleurotus thunbergii in regular catch survey.
◆ Research achievements
In all 5 places where Pleurotus thunbergii was captured, specific DNA of Pleurotus thunbergii was detected from 1 liter of water, and inhabitation was confirmed from environmental DNA. In addition, we were able to confirm the inhabitation through environmental DNA at 4 places that were not found in the catch survey. It will take several hours in catch survey, but sampling will be completed in a few minutes, so it is to investigate in less time than before.