Splenic mass of masked shrews, Sorex cinereus, in relation to body mass, sex, age, day of the year, and bladder nematode, Liniscus (=Capillaria) maseri, infection.

The spleen is an important organ of vertebrates. Splenic mass can change in response to a variety of factors. We tested whether splenic mass of masked shrews. Sorer cinereus, was related to sex, age, time of the year, or intensity of bladder nematode (Liniscus [;=Capillaria] maseri) infection, after controlling for host body mass. For females, body mass was a strong predictor of splenic mass. For males, splenic masses were greater later in the year and in more heavily infected males. The latter appeared to represent a threshold response wherein only the most heavily infected individuals had enlarged spleens.