Knowledge of dietary compositions is essential to the recovery of the dwindling populations of horseshoe crabs in China.The feeding habits of Tachypleus tridentatus and Carcinoscorpis rotundicauda of Pearl Bay in southwestern China were studied by stable isotope analysis.Hemolymph samples of the two species were obtained from two age groups living in different habitats(inner,central,and outer Bay).In addition,their potential food source samples were collected in May 2019.Results showed that the mean values of δ13C and δ15N in C.rotundicauda individuals ranged from-19.01‰ to-16.47‰ and from 10.49‰ to 13.5‰,respectively,and those of T.tridentatus ranged from-19.12‰ to-14.96‰ and from 8.78‰ to 13.48‰,respectively.These values indicated that the horseshoe crabs have a wide variety of food sources and therefore are highly omnivorous.No remarkably correlations were found between δ13C and δ15N values and individual widths in the two species.Thirteen potential food sources were selected,in which Sipunculus nudus,Batillaria zonalisi,and Ulva lactuca contributed largely to the dietary compositions of the two species of horse-shoe crabs.No significant correlation was found between the feeding habits and habitat geochemical characteristics of the horseshoe crabs.All these results possibly indicate the high diversity of their food sources and the indiscriminate dietary compositions of the two Asian horseshoe crabs.

LI Yuhong;FENG Jianxiang;KWAN Kit Yue;TAN Yiran;WENG Bosen;JIA Ruiling

Department of Environmental Science and Engineering,Huaqiao University,Xiamen 361021,China;School of Marine Sciences,Sun Yat-sen University,Zhuhai 519082,China;College of Marine Sciences,Beibu Gulf University,Qinzhou 535011,China

中国海洋大学学报（自然科学英文版）

[1]LI Yuhong;FENG Jianxiang;KWAN Kit Yue;TAN Yiran;WENG Bosen;JIA Ruiling-.Indiscriminate Dietary Compositions of Two Asian Horseshoe Crabs,Tachypleus tridentatus and Carcinoscorpius rotundicauda:Evidence from Hemolymph Stable Isotopes)[J].中国海洋大学学报（自然科学英文版）,2022(03):583-590

Indiscriminate,Horseshoe,Crabs,Carcinoscorpius,rotundicauda,Hemolymph,dwindling,Carcinoscorpis,Batillaria,zonalisi

Dietary,Compositions,Two,Asian,Tachypleus,tridentatus,Evidence,from,Stable,Isotopes,Knowledge,dietary,compositions,essential,recovery,populations,horseshoe,crabs,China,feeding,habits,Pearl,Bay,southwestern,were,studied,by,stable,isotope,analysis,samples,two,species,obtained,age,groups,living,different,habitats,inner,central,outer,addition,their,potential,food,collected,May,Results,showed,that,mean,values,13C,15N,individuals,ranged,respectively,those,These,indicated,have,wide,variety,sources,therefore,are,highly,omnivorous,No,remarkably,correlations,found,between,widths,Thirteen,selected,which,Sipunculus,nudus,Ulva,lactuca,contributed,largely,significant,was,geochemical,characteristics,All,these,results,possibly,diversity,indiscriminate

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