HOST SEX AND ECTOPARASITE INFECTIONSOF PLATEAU PIKA (OCHOTONA CURZONIAE, HODGSON)ON THE QINGHAI-TIBETAN PLATEAU

摘要

A total of 449 plateau pika(Ochotona curzoniae Hudgson) individuals weresampled with rattraps from 21 plots (size 1 ha)randomly scattered over the area of the speciesdistribution at the altitude 3275-4807 m a.s.l. inthe Qinghai-Tibetan Plateau (West China). Twomain ectoparasite species Hypoderma satyrusBrauer and Ixodes crenulatus Neumann of plateaupika were surveyed, and the relations betweenhost sex and parasitism were analyzed. The resultswere: (i) although not significantly, the infectionrate of female young was close to zero and lowerthan that of male young (6%), while the infectionrate of female sub-adults (19%) was contrarily- higher than that of male sub-adults (11%);adult females had significantly higher (41%) in-fection rate than that of males (18%) (P <0.001);(ii) the parasite infection rates for both males andfemales increased with increasing age, but femaleage-groups had obviously steeper slope. We sug-gested that the differences of body mass, growthrate and home range between males and femaleshad mainly caused the sex-biased parasitism(SBP) of plateau pika at each age stage. Also, dueto the higher increases of body mass and maybeas well as of the home range differences betweenconsecutive age-groups, the parasite infections offemales became more sensitive to the influencesof age than that of males.