Avoidance of alarm chemicals by plethodontid salamanders (genus Eurycea): Importance of phylogeny, ecology, and methodology

Variation among vertebrates in the response to alarm chemicals released from injured conspecifics and heterospecifics may be caused by differences in phylogeny and/or ecology. To investigate the relative importance of phylogeny and ecology in the evolution of alarm responses, we tested five species of plethodontid salamanders (genus Eurycea) for whether they avoid chemicals from injured conspecifics and congeners of sympatric and allopatric populations. We also examined whether different methods of data collection and analysis produce equivalent results. All methods indicate that E. guttolineata, E. multiplicata multiplicata, and E. quadridigitata do not avoid chemicals from injured conspecifics or congeners. Some methods indicate that E. longicauda melanopleura avoids alarm chemicals from conspecifics and sympatric E. lucifuga and that E. wilderae avoids alarm chemicals from conspecifics and allopatric E. m. multiplicata. However, other methods indicate that these species do not avoid chemicals from injured conspecifics. We conclude that (1) only some species may avoid areas with alarm chemicals, (2) ecological factors may be more important than phylogenetic affinities in determining responses to alarm chemicals, and (3) differences in methodology can lead to disparate conclusions about the response of a species to alarm chemicals