The Consequences of Within-Year Timing of Breeding in Ambystoma maculatum

Abstract

Embryonic and adult mortality, as a function of within-year timing of breeding, was studied in the spotted salamander, A. maculatum. Separate groups of salamanders bred at 3 different times in 1978 between Jan. 26 and March 28. Embryonic survival associated with the earliest breeding salamanders (wave 1) was very low (23%) compared to the later 2 waves (93% and 98%). The number of eggs/egg mass was greater in wave 1 egg masses than in wave 2 or 3 egg masses. Adult mortality caused by a pond freeze occurred among the earliest breeding salamanders (wave 1). Adults killed by the freeze had significantly larger snout-vent lengths than did survivors. Within-year variation in timing of breeding can have a major effect on reproductive success.