ABSTRACT
This research is the first published study to report a relationship between climate variables and plastron growth increments of turtles, in this case the endangered Nova Scotia Blanding's turtle (Emydoidea blandingii). We used techniques and software common to the discipline of dendrochronology to successfully cross-date our growth increment data series, to detrend and average our series of 80 immature Blanding's turtles into one common chronology, and to seek correlations between the chronology and environmental temperature and precipitation variables. Our cross-dated chronology had a series intercorrelation of 0.441 (above 99% confidence interval), an average mean sensitivity of 0.293, and an average unfiltered autocorrelation of 0.377. Our master chronology represented increments from 1975 to 2007 (33 years), with index values ranging from a low of 0.688 in 2006 to a high of 1.303 in 1977. Univariate climate response function analysis on mean monthly air temperature and precipitation values revealed a positive correlation with the previous year's May temperature and current year's August temperature; a negative correlation with the previous year's October temperature; and no significant correlation with precipitation. These techniques for determining growth increment response to environmental variables should be applicable to other turtle species and merit further exploration.
ABSTRACT
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, Sorex 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.
