Herpetology Notes, volume 13: 187-189 (2020) (published online on 27 February 2020)

Egg counts of Southern Leopard , sphenocephalus, egg masses from southern Louisiana, USA

Brad M. Glorioso1,*, Lindy J. Muse2, and J. Hardin Waddle3

Southern Leopard , Lithobates sphenocephalus lay several masses of relatively large eggs in a season, (Cope, 1889), lay eggs year-round in their southern range, a hypothesis also suggested by Bragg (1944). To our including Louisiana, but their peak breeding season is knowledge, only Dundee and Rossman (1989) have the cooler months from late fall through early spring reported data for Louisiana on the number of embryos (Mount, 1975; Caldwell, 1986; Dundee and Rossman, per egg mass for Southern Leopard Frogs, stating only a 1989). Double-enveloped eggs in globular masses are general range of 1,000–1,500 eggs per mass. typically deposited in shallow water, but deeper waters We examined egg masses of Southern Leopard Frogs are used when temperatures are warmer (Dodd, 2013). in Louisiana within the Sherburne Complex in the Egg masses are often attached to vegetation when Atchafalaya Basin, the largest forested wetland in the present but may also lie free on the substrate (Dundee United States (Piazza, 2013). The Sherburne Complex and Rossman, 1989; Dodd, 2013). Egg masses may be occurs to the east of the Atchafalaya River north of deposited singly, but are often found communally, with Interstate 10 between the metropolitan cities of Baton hundreds of egg masses in a small area (Dundee and Rouge and Lafayette (Fig. 1). The Sherburne Complex Rossman, 1989; Trauth, 1989). Communal laying in includes the Sherburne Wildlife Management Area Southern Leopard Frogs may be an adaptative response (WMA), the Atchafalaya National Wildlife Refuge to cold temperatures (Caldwell, 1986), as has been noted (NWR), and the Bayou des Ourses Area. Two sites, Site in congeners (Waldman and Ryan, 1983). A (30.460°N, 91.735°W, WGS84) and Site B (30.529°N, The number of eggs laid by Southern Leopard Frogs 91.732°W, WGS84), both located in Sherburne WMA, in a single mass is variable across its range, with means were surveyed eight times in late 2013 and early 2014 to up to about 1,000 eggs per mass (e.g., Brown, 1956; locate Southern egg masses (Fig. 1). We Ruthig, 2008) to several thousand eggs per mass reported found twenty-eight egg masses, with the majority (n = (e.g., Mitchell, 1986; Trauth, 1989; Lance et al., 2012). 24) observed on 31 Jan 2014 from Site B. The remaining It appears that Southern Leopard Frogs may deposit more than one egg mass during the breeding season, as Trauth (1989) found clutch sizes of sacrificed females far exceeding observed counts of laid egg masses from the same general area. He posited that small to medium sized adult females may lay their full complement of smaller eggs all at once whereas larger females may

1 U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, Louisiana 70506, USA. 2 Cherokee Nation Businesses, contracted to the U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, Louisiana 70506, USA. 3 U.S. Geological Survey, Wetland and Aquatic Research Figure 1. Sites A and B denote the locations where Southern Center, Gainesville, Florida 32653, USA. Leopard Frog egg masses were observed in the Sherburne * Corresponding author. E-mail: [email protected] Wildlife Management Area, Louisiana, USA. 188 Brad M. Glorioso et al. four masses came from Site A on 21 Nov 2013 (n = 1) and 24 Feb 2014 (n = 3). To accurately count the number of embryos in egg masses, we removed each egg mass from the water and placed it on top of a lined, hard- plastic tray. We placed an additional clear tray on top of the eggs and applied gentle pressure to spread eggs out in a monolayer while still retaining each egg in the mass (Glorioso et al., 2012). We photographed each egg mass and then placed the mass back into the water where it was found. The time spent out of the water for each egg mass was 2-3 minutes. In the office, we partitioned the photographs of the egg masses for ease of counting and

Figure 2. An example of how egg masses were photographed, Table 1. Site, date, and egg count of Southern Leopard Frog partitioned, and counted. egg masses observed in Sherburne Wildlife Management Area, Louisiana,Table 1. Site, USA. date, and egg count of Southern Leopard Frog egg masses observed in Sherburne Wildlife Management Area, Louisiana, USA.

Mass # Site Date Egg Count tallied the total egg count for each mass (Fig. 2). The 1 A 21-Nov-13 1857 mean number of eggs per mass was 1,649 (SD = 499.5, 2 B 31-Jan-14 856 range = 529–2,612; Table 1). 3 B 31-Jan-14 1541 Comparing our results to those of others in the region, 4 B 31-Jan-14 2031 we found a larger mean number of eggs per mass for Southern Leopard Frogs from the Atchafalaya Basin 5 B 31-Jan-14 1238 than the general estimates of <1,000 eggs from Alabama 6 B 31-Jan-14 1598 (Brown, 1956) or 1,000–1,500 eggs reported by several 7 B 31-Jan-14 529 authors (Dundee and Rossman, 1989; Cash, 2008; 8 B 31-Jan-14 2343 Dorcas and Gibbons, 2008). In northeastern Arkansas, 9 B 31-Jan-14 2168 however, the mean number of eggs per mass in two 10 B 31-Jan-14 2315 studies was 2,106 (Trauth, 1989) and 1,828 (McCallum 11 B 31-Jan-14 1315 et al., 2004). It is likely that the number of eggs per mass 12 B 31-Jan-14 1734 varies both geographically and temporally, due to a suite 13 B 31-Jan-14 1417 of biotic and abiotic factors. 14 B 31-Jan-14 1946 Acknowledgments. We thank J. Hefner for field assistance. 15 B 31-Jan-14 1704 were captured under Louisiana Department of Wildlife 16 B 31-Jan-14 2095 and Fisheries Scientific Collecting Permits LNHP-13-037 and 17 B 31-Jan-14 2500 LNHP-14-071. Any use of trade, firm, or product names is for 18 B 31-Jan-14 1635 descriptive purposes only and does not imply endorsement by the U.S. Government. This is contribution number 722 of the 19 B 31-Jan-14 1852 U.S. Geological Survey Research and Monitoring 20 B 31-Jan-14 1369 Initiative (ARMI). 21 B 31-Jan-14 1483 22 B 31-Jan-14 1810 References 23 B 31-Jan-14 2612 Bragg, A.N. (1944): Egg laying in leopard frogs. Proceedings of the 24 B 31-Jan-14 1538 Oklahoma Academy of Science 24: 13–14. 25 B 31-Jan-14 1315 Brown, J.S. (1956): The toads and frogs of Alabama. Unpublished 26 A 24-Feb-14 1211 PhD thesis, University of Alabama, Tuscaloosa, USA. Caldwell, J.P. (1986): Selection of egg deposition sites: a seasonal 27 A 24-Feb-14 929 shift in the southern leopard frog, sphenocephala. Copeia 28 A 24-Feb-14 1242 1986: 249–253.

Egg counts of Southern Leopard Frog egg masses from southern Louisiana, USA 189

Cash, W.B. (2008): Southern Leopard Frog: Rana sphenocephala Mitchell, J.C. (1986): Life history patterns in a central Virginia frog (Lithobates sphenocephalus). In: and Reptiles of community. Virginia Journal of Science 37: 262–271. Georgia, p. 121–123. Jensen, J.B., Camp, C.D., Gibbons, W., Mount, R.H. (1975): The Reptiles and Amphibians of Alabama. Elliott, M.J., Eds., Athens, USA, University of Georgia Press. Auburn, USA, Auburn University Press. Cope, E.D. (1889): The Batrachia of North America. Washington Piazza, B.P. (2013): The Atchafalaya River Basin: History and D.C., USA, United States National Museum Bulletin 34. Ecology of an American Wetland. College Station, USA, Texas Dorcas, M., Gibbons, W. (2008): Frogs and Toads of the Southeast. A&M University Press. Athens, University of Georgia Press. Ruthig, G. (2008): The influence of temperature and spatial Dodd, C.K., Jr. (2013): Frogs of the United States and Canada. distribution on the susceptibility of southern leopard frog eggs Baltimore, USA, Johns Hopkins University Press. to disease. Oecologia 156: 895–903. Dundee, H.A., Rossman, D.A. (1989): Amphibians and Reptiles Trauth, S.E. (1989): Female reproductive traits of the southern of Louisiana. Baton Rouge, USA, Louisiana State University leopard frog, Rana sphenocephala (Anura: Ranidae), from Press. Arkansas. Proceedings of the Arkansas Academy of Science 43: Glorioso, B.M., Waddle, J.H., Hefner, J. (2012): Ambystoma 105–108. maculatum (Spotted Salamander). Reproduction. Herpetological Waldman B., Ryan M.J. (1983): Thermal advantages of communal Review 43: 627–628. egg mass deposition in wood frogs (Rana sylvatica). Journal of Lance, S.L., Erickson, M.R., Flynn, R.W., Mills, G.L., Tuberville, Herpetology 17: 70–72. T.D., Scott, D.E. (2012): Effects of chronic copper exposure on development and survival in the southern leopard frog [Lithobates (Rana) sphenocephalus]. Environmental Toxicology and Chemistry 7: 1587–1594. McCallum, M.L., Trauth, S.E., Mary, M.N., McDowell, C., Wheeler, B.A. (2004): Fall breeding of the southern leopard frog (Rana sphenocephala) in northeastern Arkansas. Southeastern Naturalist 3: 401–408.

Accepted by Yunke Wu