西南日本における海産ユスリカの生態に関する研究

西南日本において海産ユスリカの生態に関わる研究を行った。その結果，計20種が採集され，垂直分布では，潮間帯上部あるいは中部域のみに分布する種は少なかったが，下部域のみに分布する種は多かった。基質については岩石面や泥中のみに棲む種は少なかったのに対し，海藻類のみに棲む種は多かった。また，地理的分布では南西諸島や本土外洋沿岸域のみに分布する種は少なかった。一方，数種は，瀬戸内海沿岸と本土外洋沿岸域，本土外洋沿岸域と南西諸島，あるいは全地域に分布することが分かった。また，羽化時期については，Dicrotendipes enteromorphaeは夏季・秋季のみ，S. endocladiaeは周年出現し，他種は秋季・冬季のみあるいは冬季・春季のみに出現した。これらのことから，潮間帯には様々な生活様式を持つ多くの種のユスリカが棲息し，生態系において重要な役割を果たしていることが示唆された。Ecological studies were conducted on marine chironomids in south-western Japan. A total of 20 species was collected. For vertical distribution, only a few species was distributed only at high or middle intertidal zone while many species were distributed only at low zone. For substrate preference, some species were collected only on rocks or in mud while many species were collected only in seaweeds. For geographical distribution, a few species was collected only in the southwestern islands or in the oceanic coast in the Japanese main islands. In contrast, some species were collected in the Seto Inland Sea and the oceanic coast in the main islands, in the oceanic coast in the main islands and the southwestern islands, or in all areas. For seasonal emergence, Dicrotendipes enteromorphae was collected only in summer and autumn, and Semiocladius endocladiae was collected in all seasons. Other species were collected only in autumn and winter, or only in winter and spring. These results suggest that many chironomid species with a variety of lifestyles dwell in intertidal zones and have some important roles in the ecosystems

海産ユスリカ種の形態学的系統樹と遺伝学的系統樹の関係

海産4属，Clunio，Semiocladius，TelmatogetonおよびThalassosmittiaと陸生のSmittia，淡水性のCricotopus属のエリユスリカ亜科と近縁亜科の形態学的系統樹と遺伝学的系統樹の関係を調べた。遺伝学的系統樹では3系統，すなわちSmittia，SemiocladiusとClunioを含む他の4属に分かれた。さらに，TelmatogetonとThalassosmittiaは別亜科にも拘わらず小さなクラスターを形成した。形態学的系統樹ではSemiocladiusとClunioは小さなクラスターを形成したが，TelmatogetonとThlassosmittiaはこれらだけではクラスターを形成しなかった。Cricotopusは最後に大きなクラスターに加わった。これらの結果は，Clunio，TelmatogetonとThalassosmittiaは淡水種の祖先から派生したこと，そして形態学的形質の中にいくらかの平行進化が存在することを示唆する。Relationships between morphological and genetic trees of 4 marine orthoclad and related genera, Clunio, Semiocladius, Telmatogeton and Thalassosmittia, of the dipteran family Chironomidae as well as a terrestrial genus Smittia and a freshwater genus Cricotopus were examined. In the genetic tree, there were 3 lineages; Smittia, Semiocladius and other 4 genera, comprising Cricotopus. Telmatogeton and Thalassosmittia formed an intimate clade in spite of their different affiliations to the subfamily. Semiocladius and Clunio made a small clade in the morphological tree, whereas Telmatogeton and Thlassosmittia did not form a clade by themselves. Cricotopus participated in the largest cluster. These results suggest that Clunio, Telmatogeton and Thalassosmittia have derived from a freshwater ancestor and there be some morphological parallelisms

Relationship between morphological and genetic trees of marine chironomid species

Abstract Relationships between morphological and genetic trees of 4 marine orthoclad and relate