Reproductive biology and population structure of the western red-backed salamander, Plethodon vehiculum (Cooper)

ABSTRACT—Certain aspects of the life history of Plethodon vehiculum from Benton andLincoln Cos., Oregon, were studied. Mating occurs primarily from November through Januarywith oviposition in the spring. The number of yolky ovarian ova is a function of body size; themean for all sizes was 10.4/female, Incubation is in the summer, with hatching in the fall at 13to 15 mm SVL. Growth rates for both sexes are about 10 mm SVL/year for the first 3 years.Both sexes mature between their second and third years: males at 42 mm SVL and females at44 mm SVL. Females have a biennial gonadal cycle as has been described for other species ofPlethodon, and males have an annual cycle. Spermatogenesis begins in the spring and culminatesin the fall. Mature females are larger (mean SVL = 49.1 mm) than mature males (meanSVL -45.7 mm). In general, P. vehiculum, a western plethodon, has a life history similar to thatof eastern small and eastern large plethodons.