Biological, Environmental, and Earth Sciences
A substantial body of work exists examining courtship in lungless salamanders (family Plethodontidae), but there are many species and population pairs that have not been tested for sexual isolation. Spotted (Desmognathus conanti sensu lato [SL]) and Southern Dusky Salamanders (D. aff. auriculatus) occur sympatrically within drainages in South Mississippi. I crossed individuals from three populations of D. aff. auriculatus (n = 6 individuals) and seven populations of D. conanti (SL) (n = 10) occurring in the Pascagoula and Pearl River basins. I alternated homospecific (n = 23) and heterospecific (n = 23) trials across nights in the spring and summer of 2014 and 2015, and I used GoPro™ HERO3 cameras and time-lapse photography to record the behaviors of a random subset of these pairs, as well as to determine the stage of courtship reached. Seventeen of the 23 homospecific trials resulted in spermatophore deposition and 14 in insemination. None of the 23 heterospecific trials (D. aff. auriculatus ♂ x D. conanti [SL]♀; or D. conanti [SL]♂ x D. aff. auriculatus ♀) reached this stage of courtship, but ten of the 14 photographed, heterospecific pairs exhibited pursuit and/or persuasive behaviors (i.e., pheromone transfer). These results suggest that D. aff. auriculatus and D. conanti (SL) are completely sexually isolated and that isolation is likely chemically mediated. I used a total of eight polymorphic microsatellite loci to genotype offspring from two clutches oviposited by a single female D. aff. auriculatus and one clutch oviposited by a female D. conanti (SL). Strict exclusion suggested that each clutch was sired by a single male, and that female D. aff. auriculatus and female D. conanti (SL) were capable of storing sperm for at least 4 mo 5 days and 3 mo 3 days, respectively. The data presented here further our understanding of the reproductive ecologies of Desmognathus in the historically understudied Gulf Coastal Plain.
Lamb, J. Y.
(2017). Sexual Isolation between Two Sympatric Desmognathus in the Gulf Coastal Plain. Copeia, 105(2), 261-268.
Available at: https://aquila.usm.edu/fac_pubs/17689