SEASONAL CHANGES OF PRIMARY AND SECONDARY SEXUAL CHARACTERISTICS IN THE SALAMANDERS EURYCEA AQUATICA AND E . CIRRIGERA

—Eurycea aquatica and E. cirrigera are closely-related plethodontid salamanders with overlapping geographic ranges in the southeastern United States. These species generally occupy separate habitats: E. aquatica occurs primarily in springs, while E. cirrigera occurs in and around streams and swamps. To test whether these environments influence reproduction in these salamanders, we analyzed seasonal variation of putative secondary sexual characteristics, such as cirri length and head width. To explore whether relationships exist between these characteristics and reproductive anatomy, we also analyzed seasonal variation in testis size and vas deferens diameter (i.e., primary sexual characteristics), and determined the relationship between these primary and secondary sexual characteristics within each species. For E. cirrigera, testis size was largest in summer and fall, followed by enlargement of the vas deferens and simultaneous lengthening of the cirri in winter and early spring. Eurycea aquatica becomes difficult to locate during the non-breeding season, precluding a thorough seasonal analysis and comparison of the reproductive cycle between the two species. However, the secondary sexual characteristics of E. cirrigera and E. aquatica exhibit different temporal relationships to testis size, and testis size and vas deferens size (standardized by body size) differ between the two species, suggesting that these features may represent adaptations for different male reproductive strategies.

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