Herpetology Notes, volume 13: 1017-1019 (2020) (published online on 10 December 2020) Oophagy by larval Red Salamanders, Pseudotriton ruber (Sonnini de Manoncourt and Latreille, 1801) (Caudata: Plethodontidae: Spelerpinae) from the state of Tennessee, USA Brian T. Miller1,* The Red Salamander, Pseudotriton ruber (Sonnini delined Salamander was beneath the clutch, presumably Manoncourt and Latreille, 1801), is a moderately-sizedguarding her eggs. I also found several Red Salamander spelerpine (Plethodontidae: Spelerpinae) that occurs larvae in the vicinity of the eggs, including one beneath throughout much of the eastern United States, where the nest stone. To chronicle development of the eggs, I it inhabits relatively small, low-order streams, seeps, replaced the rock in its original position and returned and bogs, and the terrestrial habitats adjacent to these a day later (21 March) to again photograph the clutch, wetlands (Petranka, 1998). As with other members of which then consisted of only 35 eggs (Fig. 2b). Although this subfamily, Red Salamanders have a complex life some brooding female plethodontids eat their own eggs history that includes a prominent larval stage, which following a disturbance (Forester and Anders, 2000), I lasts two to three years (Bishop, 1941; Bruce 1972). could not see ingested eggs through the abdominal wall Larval Red Salamanders are robust (Fig. 1), and older of the attending female or of other adult Southern Two- individuals often exceed 45 mm snout to vent length lined Salamanders in the vicinity. Eggs were, however, before undergoing metamorphosis (Bruce, 1972; visible through the abdominal wall of at least three Semlitsch, 1983). As larvae, Red Salamanders are larval Red Salamanders that were near or underneath the dietary generalists that eat a variety of invertebrate prey egg-bearing stone (Fig. 3). Although I neither preserved (Bishop, 1941; Cecala et al., 2007); however, larger nor dissected the salamanders, I am confident that the larvae at least occasionally eat smaller salamander larvae eggs visible through the body wall were ingested and (Cecala et al., 2007). Although adult females have been in the digestive tract rather than eggs developing in observed attempting to eat eggs of conspecifics (Miller the oviducts of a mature female. Although common in et al., 2008), oophagy by larvae of this species has not other spelerpine lineages, including Gyrinophilus and been reported. Here, I document larval Red Salamanders Eurycea, paedomorphosis has never been documented eating eggs of another spelerpine plethodontid, the Southern Two-lined Salamander, Eurycea cirrigera (Green, 1831). On 20 March 2019, I found and photographed a clutch of 72 eggs (Fig. 2a) of the Southern Two-lined Salamander attached to the under surface of a stone embedded approximately 6 cm in the gravel bed of an unnamed intermittent stream in southern Cannon County, Tennessee, which is located in the south- eastern USA. An attending adult female Southern Two- Figure 1. A larval Red Salamander (Pseudotriton ruber) found 1 Department of Biology, Middle Tennessee State University, in a small intermittent stream on 20 March 2019 in southern Murfreesboro, Tennessee 37132, USA. Cannon County, Tennessee, USA. (Photograph by Brian T. * Corresponding author. E-mail: [email protected] Miller) 1018 Brian T. Miller Figure 2. A clutch of eggs of the Two–lined Salamander (Eurycea cirrigera) located on the under–surface of a stone embedded about 6 cm into the gravel bed of a small, intermittent, unnamed tributary to Carson Fork Creek in southern Cannon County, Tennessee, USA. The number of eggs in the clutch decreased from 72 on 20 March 2019 (A) to 35 on 21 March 2019 (B). (Photographs by Brian T. Miller) in any species of Pseudotriton. Furthermore, oviposition reduces competition for their young (Kuzmin, 1991). occurs during the fall, rather than the spring, in Furthermore, ingestion of either heterospecific or populations of P. ruber that inhabit middle Tennessee conspecific eggs provide nourishment required for (Miller et al., 2008). mating, egg-production, and seasonal movements Although female plethodontid salamanders apparently (Kaplan and Sherman, 1980; Denoël and Demars, are loath to abandon nests after disturbance (Juterbock, 2008). Aquatic paedomorphs of some salamander 1987), I suspect that by initially uncovering the nest site, species also eat eggs of conspecifics, e.g., the Lesser I inadvertently facilitated the relatively rapid predation Siren, Siren intermedia Barnes, 1826 (Scroggin and of the eggs, either by prompting the female to at least Davis, 1956) and the Mudpuppy, Necturus maculosus temporarily abandon her eggs, or by allowing the Red Salamander larvae better access to the eggs suspended on the under surface of the stone. Although female spelerpines are known to physically defend their eggs (Miller et al., 2008), they might not always be successful in their efforts, particularly when marauding larvae are larger than attending females. Oophagy has been reported for diverse lineages of salamanders (Polis and Myers, 1985; Kuzmin, 1991). Most reports are of terrestrial adult salamanders, particularly brooding female plethodontids that remove Figure 3. The under–surface of a larval Red Salamander unhealthy eggs to reduce disease spread within their (Pseudotriton ruber) found on 21 March 2019 near a clutch clutch, and perhaps also to acquire nutrients thereby of eggs of the Southern Two–lined Salamander (Eurycea reducing their need to forage away from the nest (Kaplan cirrigera) in an unnamed intermittent stream in southern and Sherman 1980; Kuzman, 1991). Also, adults of Cannon County, Tennessee, USA. At least eight ingested eggs many species of newts eat aquatic eggs of amphibians, are visible through the body wall. (Photograph by Brian T. including eggs of conspecifics, which potentially Miller) Oophagy by larval Red Salamanders from the state of Tennessee, USA 1019 (Rafinesque, 1818) (Eycleshymer, 1906), but reports Juterbock, J.E. (1987): The nesting behavior of the Dusky of oophagy by free-living aquatic salamander larvae Salamander, Desmognathus fuscus. II. Nest site tenacity and are scarce, e.g., the Marbled Salamander, Ambystoma disturbance. Herpetologica 43:361–368. Kaplan, R.H., Sherman, P.W. (1980): Intraspecific oophagy in opacum (Gravenhorst, 1807) (Walters, 1975) and Cope’s California Newts. Journal of Herpetology 14:183–185. Giant Salamander, Dicamptodon copei Nussbaum 1970 Kuzmin, S.L. (1991): The ecology and evolution of amphibian (Kaplan and Sherman, 1980). Nonetheless, oophagy cannibalism. Journal of Bengal Natural History Society 10: by larval salamanders is likely more common than the 11–27. scarcity of records implies, particularly by species in Miller, B.T., Niemiller, M.L., Reynolds, R.G. (2008): Observations the plethodontid subfamily Spelerpinae in which the on egg–laying behavior and interactions among attending larval stage can last for years and the larvae grow to female Red Salamanders (Pseudotriton ruber) with comments on the use of caves by this species. Herpetological Conservation relatively large size prior to undergoing metamorphosis. and Biology 3: 203–210. Amphibian eggs are nutrient rich (Denoël and Demars, Petranka, J.W. (1998): Salamanders of the United States and 2008) and potentially serve as an excellent energy Canada. Washington, D.C., USA. Smithsonian Institution resource for larger larvae nearing metamorphosis, which Press. is an energetically costly process. Polis, G.A., Myers, C.A. (1985): Predation among reptiles and amphibians. Journal of Herpetology 19: 99–107. References Scroggin, J.B., Davis, W.B. (1956): Food habits of the Texas Dwarf Siren. Herpetologica 12: 231–237. Bishop, S.C. (1941): Salamanders of New York. New York State Semlitsch, R.D. (1983): Growth and metamorphosis of larval Red Museum Bulletin 324: 1–365. Salamanders (Pseudotriton ruber) on the Coastal Plain of South Bruce, R.C. (1972): The larval life of the Red Salamander, Carolina. Herpetologica 39: 48–52. Pseudotriton ruber. Journal of Herpetology 6: 43–51. Walters, B. (1975): Studies of interspecific predation within an Cecala, K.K., Price, S.J., Dorcas, M.E. (2007): Diet of larval Red amphibian community. Journal of Herpetology 9: 267–279. Salamanders (Pseudotriton ruber) examined using a nonlethal technique. Journal of Herpetology 41: 741–745. Denoël, M., Demars, B. (2008): The benefits of heterospecific oophagy in a top predator. Acta Oecologia 34: 74–79. Eycleshymer, A.C. (1906): The habits of Necturus maculosus. The American Naturalist 40: 123–136. Forester, D.C., Anders, C.L. (2000): Contributions to the life history of the Redback Salamander, Plethodon cinereus. In: The Biology of Plethodontid Salamanders, p. 407–416. Bruce, R.C., Jaeger, R.G., Houck, L.D., Eds., New York, USA, Kluwer Academic / Plenum Publishers. Accepted by Saeed Yunke Wu.