No.179 研究課題 / Project
鯉川に生息するゲンジボタルの発生とその生活環境の研究Study of population and habitat of Luciola cruciata in Koikawa| 一般研究 General Research |
No.179 |
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| 代表研究者 Principal Investigator |
浅原 俊宏 Toshihiro Asahara |
| 所属（採択当時） Affiliation |
自然の学校 校長 Principal of the Nature School |
| 研究内容要約 Research Summary |
会員の子ども達とともに鯉川のゲンジボタル成体の発生と分布域の調査および６つのポイントで環境調査を行った。鯉川の水質は生活排水が入り込む箇所もあるが、湧水や砂州の植生の浄化作用により全体として良好に保たれ、餌となるカワニナが生息しやすい川底になっていた。法面や法面上部の植生、川岸や中州に堆積した土など、ゲンジボタルが幼虫期から成虫になるまでの環境が整った川であることが確認できた。ゲンジボタル成体の探雌行動(飛翔)について、今回の調査範囲では多数最大98頭のゲンジボタルの飛翔は確認できたが、公道に設置された街路灯等からの光の影響を受けやすいエリアではあまり見られなかった。外灯にカバーを設置してLED照明(3mm大)を点滅させたところゲンジボタルを呼び寄せることができたことからも、探雌行動が光に影響されることが推察された。 調査を行った子ども達は照明の有無でゲンジボタルの飛翔に違いが出ていることを感じ、昼間のゲンジボタルの観察や環境調査にも積極的に参加しており、都会ではなかなかできない体験をすることができた。 Along with the children who are members of this group, we conducted a six-point environmental survey and a study of the emergence and areas of distribution of Genji fireflies (Luciola cruciata) in the Koi River. There are some places where household wastewater is discharged into the Koi River, but the water quality is generally good, due to springs and the cleansing action of plants on the sandbars, and the riverbed is a good habitat for the freshwater snails on which fireflies feed. We were able to ascertain that it is a river with a good environment for Genji fireflies from the larval stages through to adulthood, with vegetation on the slopes and at the top of the slopes, and with soil having accumulated on the riverbank and the sandbars. With regard to the mate-seeking behavior (flight) of adult Genji fireflies, we were able to observe the flight of as many as 98 Genji fireflies around the area surveyed, but we were unable to find many in areas that tended to be affected by the light from street lights placed on public roads. When outdoor lights were covered and an LED (3mm in size) was flashed, we were able to attract Genji fireflies, so it was inferred that light had an impact on mate-seeking behavior. The children who conducted the survey noticed a difference in the flight of the Genji fireflies depending on the presence or absence of light, and actively participated in daytime observation of Genji fireflies and environmental surveys, so they had an experience that it is not often possible to have in an urban area. |
| 共同研究者 Collaborators |
青木 雅之、宿谷 珠美、田中 彰（自然の学校） Masayuki Aoki, Tamami Shukuya, Akira Tanaka(The School of Nature: Shizennogakkou) |
| 研究全文 Full Text |
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