Diet of the Southern Appalachian Salamander, Plethodon teyahalee, and Red-legged Salamander, Plethodon shermani, across their hybrid zone in the Southern Appalachians

Background/Question/Methods

Stomach contents from 242 Plethodon teyahalee and Plethodon shermani hybrids at the Coweeta Long-Term Ecological Research site were collected and identified to examine differences in diet across the P. teyahalee x P. shermani hybrid zone. Individuals were collected across the vertical hybrid gradient at three elevations (2950m, 2850m, and 2750m), scored for hybrid characteristics, and lavaged before being released at their original capture location.

Results/Conclusions

A wide variety of prey were found in the stomachs of P. teyahalee x P. shermani hybrids although Aphaenogaster spp. (Hymenoptera: Formicidae) comprised 48% of items consumed and was present in 94% of samples collected. The level of dependence on Formicidae was not continuous across the hybrid gradient. Individuals at middle and low elevations displaying more P. teyahalee characteristics are significantly more likely (p<0.0004 and p<0.0009, respectively) to consume Formicidae than individuals at high elevations displaying more P. shermani characteristics. The Formicidae dependence at lower elevations appears to climate driven with consumption positively associated with warmer, drier nights. Aphaenogaster spp. is the primary seed disperser within the Southern Appalachians, indicating that P. teyahalee x P. shermani hybrids are crucial components of a complex terrestrial food web.