scholarly journals Reproduction and growth of the Southern Leopard Frog, Lithobates sphenocephalus utricularius (Harlan, 1825), in Virginia: implications for seasonal shifts in response to global climate change

Author(s):  
Daniel Frederick Hughes ◽  
Walter Meshaka Jr. ◽  
Pablo R. Delis

An examination of 750 museum specimens of the Southern Leopard Frog (Lithobates sphenocephalus) collected during 1938‐1989 from eastern Virginia (USA) provided comparative life‐history data from the northeastern portion of this species geographic range. Individuals were collected in all months except December. Testis size was largest and incidence of gravid females was highest during fall and spring. In both sexes, fat storage was lowest during late‐winter‐spring, which is indicative of increased activity and commencement of breeding. Incidence of food in stomachs was lowest in late winter and relatively high thereafter, especially in males. Geographic trends in five lifehistory traits were corroborated for the Southern Leopard Frog in this study, including breeding season, egg size, mean adult body size, sexual size dimorphism, and larval metamorphosis season. In response to hotter summers and milder winters, as predicted to occur with climate change, the reproductive characteristics for this species in Virginia will likely shift to resemble contemporary reproductive patterns of southern populations.


2018 ◽  
Author(s):  
Daniel F. Hughes ◽  
Walter E. Meshaka

ABSTRACTWe ascertained various life-history traits from an examination of 310 museum specimens of the Rio Grande leopard frog (Lithobates berlandieriBaird, 1859) collected during 1907–2016 from Texas, USA.Lithobates berlandieriwas captured during every month of the year except November, and adults were most frequently encountered during January–September with a distinct peak in May. Mean body size of adult males (69.5 mm) was smaller than that of adult females (77.5 mm), and both sexes were larger in mean body sizes than those of New Mexico populations (M = 64.4 mm; F = 73.5 mm). Females were gravid during January–September, and most gravid females were captured from late-winter to early-summer. Gonadal enlargement in males was generally high throughout January–September with no detectable seasonal increase. Feeding became widespread in both sexes during May–June shortly after a spring breeding bout. Spent females were common in July and lipid deposition increased in June/July, signaling oogenesis for breeding in the fall. From 15 gravid females, we estimated a mean clutch size of 3,107 eggs which was correlated with female body size, yet egg diameter was not related to clutch or body size. Age to metamorphosis was likely 2 to 4 months depending upon whether eggs were laid in the winter/spring or late fall. If metamorphosis occurred in May/June, the minimum size at sexual maturity in adult males (50.1 mm) could have been reached in 3–4 months and in 6–7 months for adult females (57.2 mm). Mean adult body sizes, however, may have taken 12 to 17 months to reach. A synthesis across Texas populations suggests that the breeding season extends almost continuously from the fall through the winter and spring until mid-summer and is interrupted by winter and summer peaks in seasonal temperatures.





2009 ◽  
Author(s):  
Marci Culley ◽  
Holly Angelique ◽  
Courte Voorhees ◽  
Brian John Bishop ◽  
Peta Louise Dzidic ◽  
...  




2010 ◽  
pp. 115-132 ◽  
Author(s):  
S. Agibalov ◽  
A. Kokorin

Copenhagen summit results could be called a failure. This is the failure of UN climate change policy management, but definitely the first step to a new order as well. The article reviews main characteristics of climate policy paradigm shifts. Russian interests in climate change policy and main threats are analyzed. Successful development and implementation of energy savings and energy efficiency policy are necessary and would sufficiently help solving the global climate change problem.



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