土壌バンピレラ科アメーバによる植物寄生性線虫の捕食 Predation on Larvae of Plant Parasitic Nematodes by Soil Vampyrellid Amoebae

土壌から分離した数種のパンピレラ科アメーバが, 植物寄生性線虫の幼虫を捕食する過程を観察した。<I>Arachnula impatiens</I>と同定した分離株No.1の栄養体は, 細い糸状の仮足で<I>Meloidogyne incognita</I>の2期幼虫を捕え, その体壁に直径2.5-5.5μmの丸い穴を多数あけて内容物を摂取し, 2～3時間で完全に空にした。これに対し<I>Vampyrella vorax</I> と同定した分離株No.3は栄養体の細い仮足で幼虫を捕えて後, 全体を包囲してシスト化し, 12～24時間で捕食し終えた。このような捕食習性の違いは, <I>Aphelenchoides besseyi</I> および<I>Helicotylenchus dihystera</I> の幼虫または成虫に対しても同様であった。

The stages of feeding on larvae of plant parasitic nematodes by soil vampyrellid amoebae were sequentially observed to determine the mechanism of predation. A trophozoite of an isolate identified as <I>Arachnula impatiens</I> captured an active larva of <I>Meloidogyne incognita</I> with fine filopodia, made several holes of 2.5 to 5.5μm in diameter in the wall of cuticular sheath, and completely emptied the contents of the larva within 2 to 3 hr in the aquatic cultures at 25 C. In contrast, another isolate tentatively identified as <I>Vampyrella vorax</I> encysted after surrounding the whole body of larva and 12 to 24 hr were required for completion of feeding. Similar feeding behavior by the two isolates was observed with larvae or adults of <I>Aphelenchoides besseyi</I> and <I>Helicotylenchus dihystera. Jpn. J. Nematol</I>. <B>14</B>: 1-7 (1984).