Social trematodes: What factors determine the caste ratio in their colonies?

Research Project

Project/Area Number	25840160
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Ecology/Environment
Research Institution	Kochi University
Principal Investigator	Miura Osamu 高知大学, 教育研究部総合科学系複合領域科学部門, 准教授 (60610962)
Project Period (FY)	2013-04-01 – 2016-03-31
Project Status	Completed (Fiscal Year 2015)
Budget Amount *help	¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000) Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000) Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2013: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywords	社会性 / 二生吸虫 / カースト比率 / 寄生虫
Outline of Final Research Achievements	Social trematodes effectively maintain their colonies by reproductive division of labor between reproductive and soldier individuals. I conducted a series of ecological analyses to evaluate which ecological factors determine the caste ratio in their colonies. I found that the caste ratio of trematodes was fairly constant irrespective of the strength of competitive pressure against other trematodes, demonstrating that competitive pressure is not the factor which affects the caste ratio. I suggest that density of colony members and/or amount of nutrients available for a colony are other potential candidates determining the caste ratio in trematode sociality.