Natality in Peromyscus polionotus Populations

Abstract
Populations of the old-field mouse (Peromyscus polionotus) were snap-trapped in fields of the Savannah River Project, South Carolina, from 1955 through 1961. Litter size of 172 pregnant females was 3.13 (SD=0.86). Total length was chosen as the statistic best representative of body size. The 126-135 mm mature females were pregnant more frequently (34%) and had larger embryo counts (3.47, ISE=0.17) than the 98-115 mm mature females (21% and 2.95[plus or minus] 0.10). Breeding peaks occurred in spring and fall for all size classes with 50% less activity in the summer and virtually none in the winter. Summer litters were significantly smaller (2.76, ESE=0.19) than litters of spring and fall (3.48[plus or minus]0.20). The observed effect of body size on natality could cause a 12% recruitment difference between natural populations.

This publication has 2 references indexed in Scilit: