| Summary: | 碩士 === 國立臺灣大學 === 生態學與演化生物學研究所 === 92 === Diet of three sympatric shrew species, Anourosorex yamashinai, Crocidura attenuata tanakae, and Soriculus fumidus from the Mei-feng Farm in Nantou County were investigated between October 2001 and July 2002. Shrews were trapped seasonally from seven sites, which belong to three habitat types, i.e. forest, orchard, and grassland. Contents of their digestive tracts were collected and analyzed to examine the variation of their diet in different seasons and habitat types and their potential foraging strategies. Relationship between body size of shrews and their dietary segregation was also examined.
All three species of shrew took a wide range of invertebrates, and oligochaetes, insect larvae, and insect adults as their major preys. Gastropoda and Chilopoda were also important preys for A. yamashinai and C. attenuata, respectively, while S. fumidus consumed a greater proportion of arthropods than the others. Diets of A. yamashinai and S. fumidus were more variable in different seasons and habitats than that of C. attenuata。Although the trend of their dietary variation between habitat types was similar, A. yamashinai took a higher proportion of dipteran larvae in winter, whereas S. fumidus fed more evenly on different arthropods in winter. Larger shrews tended to use wider range of prey size and more tougher preys, such as Gastropoda and Diplopoda, and smaller species consumed more arthropods. However, the relationship between body sizes of shrews and the proportion of earthworm they consumed was not significant. The relationship between food niche breadth or niche overlap and body size was also insignificant.
All three species of shrews were generalist insectivores. Dietary segregation of these species was not significantly related to differences in their body size, but might be related to differences in their foraging strategies and behaviors. Because trapping results revealed the pattern of habitat use maybe different among these species, more studies are needed to clarify the relationship of dietary segregation and habitat use in these species and invertebrate availability in the future.
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