Diet and Reproductive Cycles of an Allegheny Population of the Red-Spotted Newt, Notophthalmus viridescens viridescens (Rafinesque, 1820)

The diet, gonadal cycles, and clutch characteristics of an Allegheny population of the red-spotted newt, Notophthalmus viridescens viridescens (Rafinesque, 1820), were studied from a wetland matrix in southwestern Pennsylvania. Mean adult body size was similar between males and females, and collectively, adults ate 14 categories of prey with Daphnia, mosquito larvae, and amphibian eggs figuring most prominently. Dietary overlap was high between the sexes with respect to frequency of prey in the diet (r = 0.91, P < 0.000) and frequency of stomachs common to prey types (r = 0.87, P < 0.000). Only variance differed in prey size (F = 2.3881, P = 0.003) and number (F = 0.1189, P < 0.000) between the sexes, and no significant relationships existed between these variables and body size of either sex. Monthly incidence of testis size and presence of secondary sexual characteristics indicated that males were in breeding condition throughout much of the year. Oviposition was inferred to have taken place from at least March through June from condition of the ovaries and oviducts. Clutch sizes ranged 126–186 eggs (mean = 151.3 eggs) and mean ovum diameter was 1.44 mm. No significant relationships were evident among female body size, clutch size, and egg size. Our results show a strong overlap in diet between the sexes. Importance of amphibian eggs, a protein-rich resource, was greater in the diet of females, the inclusion of which coincided primarily with much of their egg-laying season. Our study revealed meaningful differences in seasonal variation and in the overlapping diet between the sexes, and a reproductive phenology and clutch characteristics, little studied in Pennsylvania, that typified those of this species found elsewhere in the mid-Atlantic and northeast.