Our study appears to represent the western-most report of autumn breeding within this species' range, the first report of potential environmental cues stimulating the occurrence of fall breeding, and the first examination of egg clutches and spermatogenesis from fall breeding populations. We conducted calling surveys throughout the year over a 4 year period extending from 1999–2002 to determine the frequency of fall breeding in this species. Southern Leopard Frogs bred 20 September 2002 during heavy rains. Although we observed sporadic individual calling males in other years, lack of rain seemed to suppress breeding activities despite the presence of flooded agronomic fields and ditches in the region. We characterized 11 egg masses and the testicular condition of three males during years when fall breeding was observed. The number of eggs per mass in the fall was similar to that observed during the spring, but mass-per-egg was nearly twice that observed in studies of spring breeding frogs. The hatching rate for subsamples from these clutches varied between 91 and 100% hatched. Spermatozoa, spermatids, and spermatogonia were evident in nearly all spermatic cysts. The mean maximum spermatic cyst diameter of the three males was 61.24 µm (s = 0.0125). Spermatic cyst diameter was significantly different among specimens (ANOVA, F = 20.71, df = 92, p = 0.001) suggesting they were not all expressing the same level of reproductive condition. A Tukey's pairwise comaparisons test indicated all three specimens had significantly different spermatic cyst diameters from each other. We suggest that clutch size may vary geographically and may be related to multiple clutching in this species.
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1 September 2004
Fall Breeding of the Southern Leopard Frog (Rana sphenocephala) in Northeastern Arkansas
Malcolm L. McCallum,
Stanley E. Trauth,
Michelle N. Mary,
Charles McDowell,
Benjamin A. Wheeler
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