Frequency of interspecific mating in salamanders of the plethodontid genus Desmognathus: different experimental designs may yield different results

Abstract

With 1 figure in the text)Heterosexual courtship trials were staged between dusky salamanders of two species (Desmognuthus fuscus and D. sanfeefluh) from two allopatric populations in the southern Appalachian Mountains of eastern North America. Two experiments were conducted in order to test for effects of experimental design on estimates of the strength of sexual isolation between these species. In Experiment I, frequencies ofinterspecific mating were determined when: (I) a male was presented with a conspecific and a heterotypic female successively; and (2) both types of females were presented simultaneously to a male. The frequency of interspecific mating by male D. fusci was greatest when females were presented successively. The frequency of interspecific mating by male D. santeetluh was not influenced by method of female presentation. An index of sexual isolation of +0.29 was obtained between D. fuscus and D. sunfeefluh when females were presented successively, and of +0.63 when females were presented simultaneously. In Experiment 2, interspecific mating frequencies were determined in courtship arenas of two different sizes. No significant effect of arena size on frequency of interspecific mating was found for D. ficus. In D. santeetlah, a trend towards greater mating frequency in small arenas was almost significant. These results suggest that interspecific mating frequencies (and thus estimates of the strength of sexual isolation between populations or species) may be sensitive to the experimental design employed. The validity and generality of this conclusion for other animals is an urgent, empirical issue.

Male and female contributions to behavioral isolation in darters as a function of genetic distance and color distance

“…Furthermore, males were presented with a no‐choice situation in which they could only choose whether or not to pursue the female. No‐choice mating assays are thought to underestimate levels of behavioral isolation (Foote and Larkin ; Verrell ; Coyne ; Hatfield and Schluter ). How these high levels of behavioral isolation evolved among recently diverged, allopatric taxa is unclear.…”

Sympatry with the devil: reproductive interference could hamper species coexistence

“…Recent studies suggest that vibrational communication might also play a role in the communication of Tetrigidae (Benediktov 2005). It has often been doubted that results from laboratory behavioural experiments are comparable with field situations, as heterospecific sexual interactions have been detected more often in the laboratory (Coyne & Orr 1989;Verrel 1990;Ficetola & De Bernardi 2005). In the field, the frequency of heterospecific encounters can be substantially lower than in small arenas with unnaturally high abundance.…”

Interspecific Social Interactions and Breeding Success of the FrogRana latastei: A Field Study

“…The strong interspecific differences in calls of males and the existence of releasing calls likely play an important role in the selection of conspecific mates (Nollert & Nollert 1992; Roesli & Reyer 2000 and references therein). Secondly, the limited space available to the males in the experimental containers (in the laboratory conditions) may increase the rate of interactions between species (Verrel 1990). In natural conditions, tens of R. latastei females frequently lay their eggs on the same submerged wood (Pozzi 1980).…”