2013 Volume 18 Issue 3 Pages 99-105
Relationships between the abundance of two morphs of an species of abomasal nematodes, Spiculopteragia houdemeri, in sika deer, Cervus nippon, from the Ashoro District, Hokkaido Island, Japan, and relevant factors such as individual host traits (sex, age, and body weight) were examined using a generalized linear model, with AIC (Akaike’s Information Criterion) for selection of optimal models. Many main and interactive effects significantly affected “morph houdemeri” abundance. As one of the main effects, abundance of this morph was significantly lower in male hosts; this result was attributable to sexual differences in habitat use (habitat segregation) by the hosts. Yearling hosts were parasitized by significantly fewer “morph houdemeri” than other age groups, probably because of the lack of some increasing factors such as maternal infection in fawns and large body mass in adults (age, ≥2 yr-old). Host body weight and “morph andreevae” presence - absence showed other main effects that significantly affected “morph houdemeri” abundance. The abundance of S. andreevae was higher in hosts with more “morph houdemeri”, and other than this tendency, only host age significantly affected “morph andreevae” abundance. Various factors including individual host characteristics affected the abundance of “morph houdemeri”, the dominant species, whereas the abundance of the subdominant S. andreevae was affected by fewer factors, such as “morph houdemeri” abundance. Some interactive effects were difficult to interpret, and further studies that include additional factors such as the seasonal dynamics of nematode abundance are needed.
