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Successful reproduction in salamanders is driven by behavioral, environmental, and temporal interactions among adults. While much of our understanding of salamander mating systems is based upon either courtship behavior of both sexes or aspects of female choice, the decisions made by males regarding where to place spermatophores is much less quantified. In this study, we mapped male spermatophore placement in the spotted salamander (Ambystoma maculatum) with respect to ecological and spatial locations within a vernal pool complex in Charles City County, Virginia. The overall goal was to use the spatial and ecological placement of spermatophores to determine if individuals deposit spermatophores randomly within the vernal pool or if males exhibited specific preferences for deposition. Using comprehensive surveys of the vernal pools and individual spermatophores within a 0.5m2 grid and terrestrial LIDAR, a total of 218 spermatophores were identified and mapped. We repeated these surveys for two successive breeding seasons. Placement occurred at an intermediate depth and an intermediate distance to the edge. Males also preferred to place spermatophores on leaf substrate as opposed to sticks or conifer needles. The physical placement of spermatophores exhibited autocorrelation in space during single reproductive events as well as across breeding seasons. These results suggest that males actively select for specific locations within a pool for spermatophore placement-a proverbial Goldilocks zone-which may be consistent with increased reproductive success. This information is key to understanding salamander mating system parameters in this species and may contribute to developing more effective management strategies.

The aim of this study was to investigate the basis to male mating decisions in two related species of bitterling: Rhodeus ocellatus and R. amarus. Bitterling have a resource-based mating system; females lay eggs in the gills of live freshwater mussels and males fertilize the eggs by releasing sperm into the inhalant syphon of the mussel. Male bitterling perform courtship behaviour and aggressively defend mussels in a territory from which they exclude other males. Using laboratory and field experiments it was shown that male aggressive behaviour is inherited through additive maternal genes. Male aggression is also influenced by the number of conspecific males encountered in competition for a mussel, and by the degree of clustering of mussels. Limited availability of mussels results in stronger selection on traits males use in mating context: hence they are more aggressive, larger and more colourful. The differences in mating behaviours in different environments may indicate a conflict between male dominance and female choice, but have not led to reproductive isolation. Resource availability during ontogenesis and male density during embryogenesis, however, do not exert an effect on male aggressive behaviour. Red carotenoid-based nuptial coloration functions as an inter- and intra-sexual signal and undergoes rapid variation in response to changes in mating context. Male bitterling do not modulate their courtship and aggressive behaviour in response to variation in female size, and their choice of mussel species is influenced by, and consistent with, female oviposition choice.