Sex-Related Differences in Somatic Stored Energy Reserves of Pseudacris crucifer and Pseudacris triseriata during the Early Breeding Season

Sexual Dimorphisms in Metabolism, Organ Mass, and Reproductive Energetics in Pre-breeding American Toads (Anaxyrus americanus)

“…Similarly, carcass nonpolar lipid content correlated positively with dry carcass mass only in males. Duffitt and Finkler (2011) found similar differences between the sexes in Pseudacris crucifer and P. triseriata. These differences may reflect the fact that at the time of sampling females had already completed their primary energetic investment in reproduction (oogenesis), whereas males would not have yet commenced the breeding activities that constitute their primary energetic investment (Jönsson et al, 2009).…”

“…Moreover, our approach to evaluating reproductive investment relative to the dry mass and energy contents of the females indicate that in many studies of anurans the magnitude of female reproductive investment may be underestimated. Many examinations of female reproductive investment use the wet masses of the ova and the females as the bases of gonadalsomatic indices, relative clutch masses, or similar measures of reproductive investment (e.g., Shine, 1980;Prado and Haddad, 2005;Duffitt and Finkler, 2011). The problem with this approach is that the relative water content of the ova may be substantially lower than that of the rest of the female's body.…”

“…In contrast, males likely invest little energy into gametogenesis (e.g., Guha et al, 1980), but may expend considerable amounts of energy searching or calling to attract a mate, or engaging in interference behavior with other males while competing for females (Gatz, 1981;Howard, 1988;Sullivan, 1992). Such differences in energy expenditure could, plausibly, promote the evolution of differences in relative non-reproductive organ mass (particularly organs used for energy storage and for supporting activity) and physiological performance between the sexes in anurans (e.g., Long, 1987;Zimmitti, 1999;Duffitt and Finkler, 2011), but the presence of such dimorphisms in A. americanus has heretofore not been investigated.…”

Life history traits and reproductive ecology of North American chorus frogs of the genus Pseudacris (Hylidae)

“…Reproductive investment and fecundity are associated with body size in several frog species, including those in the families Hylidae, Leptodactylidae, Microhylidae, Ranidae and Rhacophoridae [ 173 – 176 ]. Duffitt and Finkler [ 177 ] found that, prior to reproduction, larger males and females of P. crucifer and P. triseriata allocate more energy to courtship activity and gamete production, respectively, than smaller individuals. Ovarian mass is positively correlated with body size in both species, and the gonadal-somatic index is positively correlated with body size in P. crucifer [ 177 ].…”

“…Duffitt and Finkler [ 177 ] found that, prior to reproduction, larger males and females of P. crucifer and P. triseriata allocate more energy to courtship activity and gamete production, respectively, than smaller individuals. Ovarian mass is positively correlated with body size in both species, and the gonadal-somatic index is positively correlated with body size in P. crucifer [ 177 ].…”