Heterotrophic nanoflagellates are ubiquitous in natural waters, and most heterotrophic nanoflagellates are known to grow on bacteria. Recently, the heterotrophic nanoflagellate Katablepharis japonica has been reported to be an effective predator of diverse toxic or harmful algal prey. To date, 7 Katablepharis species have been identified, and therefore important questions arise as to whether other Katablepharis species can feed on algal prey, and further whether the types of prey of other Katablepharis species differ from those of K. japonica. To answer these important questions, feeding by Katablepharis remigera on diverse algal prey was examined. Specific growth and ingestion rates of K. remigera feeding on the raphidophytes Heterosigma akashiwo and Chattonella subsalsa were determined. Furthermore, the abundance of K. remigera at 28 stations along the coastline of Korea from January 2015 to October 2017 was quantified using qPCR method and newly designed specific primer-probe sets. Among 25 potential algal prey tested, K. remigera fed on only H. akashiwo and C. subsalsa; however, it did not feed on a diatom, a prymnesiophyte, a prasinophyte, cryptophytes, dinoflagellates, Mesodinium rubrum, a mixotrophic ciliate, and another raphidophyte Fibrocapsa japonica. The number of prey types on which K. remigera could feed (2 species) was considerably smaller than that of K. japonica (14 species). With the increase in the mean prey concentration, the specific growth rates of K. remigera on H. akashiwo and C. subsalsa increased as well before becoming saturated. The maximum specific growth rates of K. remigera on H. akashiwo and C. subsalsa were 0.717 and 0.129 d⁻¹, respectively. In addition, the maximum ingestion rates of K. remigera on H. akashiwo and C. subsalsa were 0.333 and 0.661 ng C predator⁻¹ d⁻¹ (3.33 and 0.23 cells predator⁻¹ d⁻¹), respectively. The results of this study clearly indicate that K. remigera is an effective predator of 2 red tide-causing raphidophyte species, and additionally, the feeding activity of K. remigera differs greatly from that of K. japonica. The abundance of K. remigera was ≥0.1 cells mL⁻¹ at 24 stations located in the East, West, and South Sea of Korea. Thus, K. remigera has a nationwide distribution in Korea. The highest abundance of K. remigera in Korean waters was 24.9 cells mL⁻¹ in March 2017, when there was no red tide caused by H. akashiwo or Chattonella spp. In most regions where red tides caused by H. akashiwo or Chattonella spp. occurred in 2000–2017, K. remigera was detected. Thus, the abundance of K. remigera may increase during red tides caused by H. akashiwo and Chattonella spp.

异养纳米鞭毛虫在自然水中普遍存在，并且已知大多数异养纳米鞭毛虫都在细菌上生长。最近，据报道，异养纳米鞭毛Katablepharis japonica是各种有毒或有害藻类猎物的有效捕食者。迄今为止，已经鉴定出7种石able属植物，因此，关于其他石able属植物是否能以藻类猎物为食，以及其他石Kat属植物的猎物类型是否不同于日本粳稻，提出了重要的问题。为了回答这些重要问题，请使用Katablepharis remigera喂养在各种藻类猎物上进行了检查。确定了以斜纹藻类杂种Akashiwo和盐沼沙门氏菌为食的雷氏克雷伯菌的特定生长和摄食率。此外，使用qPCR方法和新设计的特异性引物探针组对2015年1月至2017年10月沿韩国海岸线28个站点的雷曼氏梭菌的丰度进行了定量。在经过测试的25种潜在藻类捕食物中，雷米K.仅以H. akashiwo和C. subsalsa为食；然而，它没有以硅藻，褐藻类植物，草类植物，隐生植物，鞭毛藻，中生红豆为食。，一种混合​​营养的纤毛虫，和另一种斜纹植物Fibrocapsa japonica。在其猎物类型的数目K. remigera可以养活（2种）比小得多K.粳稻（14种）。随着平均猎物浓度的增加，雷克氏假单胞菌在akashiwo和C. subsalsa上的比生长率也在达到饱和之前就增加了。的最大比生长速率K. remigera上H.弯藻和C.盐泽为0.717和0.129 d ^-1，分别。此外，最大摄食率K. remigera上H. akashiwo和C. subsalsa分别为0.333和0.661 ng C捕食者^-1  d ^-1（3.33和0.23细胞捕食者^-1  d ^-1）。这项研究的结果清楚地表明，K. remigera是2赤潮-导致raphidophyte物种的有效捕食，以及另外地，摄食活动K. remigera大大从不同的K.粳稻。丰K. remigera为≥0.1细胞毫升^-1在位于东，西，和韩国的南海24个车站。因此，K。remigera在韩国分布全国。最高丰度2017年3月，韩国水域的雷克氏杆菌为24.9细胞mL ^-1，当时没有因赤子克氏杆菌或查通氏菌引起的赤潮。在大多数地区，赤潮H. akatsuwo或查通氏菌spp引起。发生在2000– 2017年，检测到了雷克氏菌。因此，在由akashiwo和Chattonella spp引起的赤潮期间，remigera K. remigera的丰度可能会增加。