A paper on the population structure of giant water bugs in southern Kyushu has been published.

The valleys between mountains are called "sako." Many of these sakos were once rice paddies (sakota), but now many of them have been abandoned. We are investigating whether these abandoned sakos can be used to store water and prevent runoff, or to restore wetland ecosystems that are deteriorating and decreasing worldwide, while examining the technical methods and social systems involved.

In order to conserve the ecosystem, it is important to investigate the current situation, such as what organisms live in each abandoned rice paddy and what the relationships between the populations are between the rice paddies, in order to consider which rice paddies to regenerate and their placement.

The giant water bug is an aquatic insect about 6 cm long that was once widely distributed in rice paddies. It can only survive in wetlands, where many other creatures live, and is now found in only a small area. We use it as an indicator for rice paddy conservation because it is an endangered species and the species itself is a conservation target, protecting the giant water bug leads to protecting a set that includes many other species, and it is large and easy to survey the population.

Recently, a paper was published that used DNA to analyze the characteristics of several populations remaining in Sakota, Kuma region. It was revealed that one population has low genetic diversity (probably due to the population being small), and that there is almost no interaction between different Sakotas in the same watershed. Given these results, it was thought that it would be necessary to enlarge the population at an early stage (improving the quality and increasing the area of the wetlands so that the population can increase) and to enable the species to move between suitable wetlands (ensuring that suitable wetlands are available within flight range).

Paper information

Journal Name : Entomological Science

Title of the paper : Discovery of a new population of the endangered giant water bug Kirkaldyia deyrolli (Heteroptera: Belostomatidae) in Kyushu and evaluation of their genetic structure

Author : Tomoya SUZUKI, Hidetaka ICHIYANAGI, Shin-ya OHBA

Link to paper (DOI) : https://doi.org/10.1111/ens.12564