武陵洞蛭对洞顶壁吸蝠血行为的生态适应

Ecological Adaptation of Sinospelaeobdella wulingensis to the Batblood-Sucking Behaviors on the Ceiling of Karstic Caves

摘要: 中国洞蛭属是2019年发表的一个新属，其模式种武陵洞蛭(Sinospelaeobdella wulingensis)终生生活在溶洞的顶壁，在洞顶壁完成全部生活史，面临着“倒悬身体”栖息和运动的选择压力。项目组经过野外观察、现场试验和实验研究发现，在长期的进化过程中，武陵洞蛭衍生出了对洞顶壁吸蝠血行为的适应性特征：(1) 身体的伸展性较弱，但吸盘非常发达，具有较强的吸附力，其吸附力约为日本医蛭(Hirudo nipponia)的6.7倍和天目山蛭(Haemadipsa tianmushana)的1.4倍；(2) 洞蛭可通过超声波信号探测蝙蝠的方位，以吸食蝙蝠的血液；通过宿主发出的超声波信号寻觅宿主，这在环节动物门甚至在无脊椎动物中都是首次发现；(3) 冬季蝙蝠迁出或个体稀少时，洞蛭会因食物缺乏而呈现“半冬眠”状态。本文为洞蛭适应性进化的深入研究提供了基础资料，创建的蛭类活体形态测量法可用于比较蛭种之间的活体量度及伸展性。将来可望从形态结构、生理生化、遗传变异、基因组学、转录组学等方面对洞蛭的行为生态进行系统研究，以促进蛭类觅食行为生态学和进化生物学的新发展。

Abstract: Sinospelaeobdella is a new genus of leeches first discovered in China and published in 2019, with the type species, S. wulingensis, which carries on entire life cycle on the ceiling of Karstic caves and experiences the selection pressure of “Upside-down hanging” for resting and movement. Combined with years of field observations, on-site experiments, and laboratory researches, the project team found that S. wulingensis has developed adaptive characteristics for feeding on bat’s blood on the cave ceiling during its evolutionary process. These characteristics include that: (1) It’s a little less stretchable, but has well-developed suckers of strong adhesion force, which is about 5.8 times than that of Hirudo nipponia and 1.6 times of Haemadipsa tianmushana; (2) This species of cave leeches can found the locations of bats by ultrasonic signals from bats for sucking batblood. Foraging a host by means of its ultrasonic signals is the first account for annelids and even for invertebrates; and (3) In winter, when bats migrate out or their individuals are scarce, cave leeches will appear “semi-hibernation” possibly due to lacking of food. This paper provided some basic data for further researches of adaptive evolution of leeches. Our in-vivo morphometry method for leeches could be used to compare morphological measurements and extensibility among leeches and even among other small-type animals. In the future, it will be expected to systematically investigate behavioral ecology of leeches from morphology, physiology, biochemistry, genetics, genomics, and transcriptomics to promote new development of foraging behavioral ecology and evolutionary biology.