Pygmy Salamander - Life History and Behavior

Life History and Behavior

D. wrighti courtship differs from other members of Desmognathus in the phenology of oviposition which is in late summer into autumn. Males reach sexual maturity by their second or third year while females reach their sexual maturity by their third year. Males normally have two testes lobes but this number can increase with body size. In courtship males use their vomerine teeth to bite the female which in turn allows pheromone secretion to enter directly into the female circulation. D. wrighti and D. aeneus are the only two desmognathine salamanders that exhibit the courtship that which the male bite and seizes its partner before behaviors exhibited to accomplish sperm transfer. The male approaches the female quickly, bites, and tugs as he begins to undulate his tail. The female in return turns towards the male and places her chin on his laterally undulating tail so that they rotate in full circle. Typically in courtship behavior a Plethodontidae characteristic tail-straddling walk follows. In the tail-straddling walk, the male release the female and slides his head under her chin, then her forelimbs straddle the male’s tail and the pair then move forward. The male then deposits a spermatophore on the ground which is followed by the female picking up a sperm cap with her cloacal lips as she moves forward undulating her pelvic area.

Desmognathus wrighti females have an average clutch size of 8 to 9 eggs which are suspended by a single attachment stalk and develop between 4 to 25 oocytes. Females lay eggs in banks of streams in areas of saturated gravel. The females also typically remain close to their egg mass and coil their bodies around the mass. Eggs change from spheroid shape to ovoids when hatching conditions occur. The embryo then thrusts itself against the capsule and rotates within the egg until it escapes from the egg fluid. D. wrighti hatchlings are not larvae and have gills in late embryonic stages. At hatching the ventral side is unpigmented and the characteristic ‘V’ pigmentation is found on the dorsal side. The characteristic stripe from the eye to the jaw is also present in late embryo and hatching stages.