Pseudacris nigrita

Geographic Range

Southern chorus frogs, Pseudacris nigrita , inhabit the southeastern coast of the United States including Florida, the southern half Georgia, and the eastern halves of South Carolina and North Carolina. The range extends westward to the far southern reaches of Alabama and Mississippi. These frogs' range includes the Gulf Coastal Plain, northward to the Tar and Pamlico Rivers of North Carolina. There is a disjunct population in far southeastern Virginia. Southern chorus frogs are vacant from the Everglades and the Florida Keys.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

As juveniles, southern chorus frogs inhabit wet meadows and forested wetlands. Froglets tend to stay near their natal ponds for several weeks. As southern chorus frogs mature, they move away from the wetlands and meadows and towards pine ( Pinus ) forests. Adult southern chorus frogs can also be found near limestone sinkholes, especially bordering wet prairies in southern parts of Florida. They can also be found where the soil is sandy in Alabama.

Southern chorus frogs breed in wet seasons in otherwise xeric habitats. During the breeding season, they inhabit a wide variety of waterbodies, including ponds, bogs, marshes, and, rarely, floodplains. They also use temporary waterbodies like open-canopied vernal pools, roadside ditches, woodland ponds, Carolina bays, and flooded fields. Additional habitats include weedy margins of shallow flatwoods ponds and flooded pine-hardwood ditches.

Elevation has not been reported for this species.

• Habitat Regions
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• forest forest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools

• Wetlands
• marsh marsh
• bog bog

• Other Habitat Features
• riparian riparian

Physical Description

Adult southern chorus frogs' skin is brown, gray, or tan. These frogs have three distinguishable, longitudinal stripes or linear rows of spots on their dorsum. There is also a white line that runs along their pointy snout and upper lip, and they have dark bands along their eyes. Male chorus frogs have an olive color or a rusty orange throat; females’ throats are lighter. The skin of these frogs is mainly smooth except for some granular bumps on their dorsum. Male and female southern chorus frogs differ slightly in size; males range in SVL from 21 mm to 30 mm and females are slightly larger, 22 mm to 33 mm SVL.

As tadpoles, they possess a light stripe that begins at the eye and continues to their tail. They have brown tails on the dorsal side, often with black spotting, but tails are lighter on the ventral side. Bodies are darker, either brown or black, and they have yellow or spotting throughout the dorsum. Like the tail, the ventral side of the body is lighter in color. At hatching, southern chorus frogs' total length averages 4.5 mm. They continue to grow as tadpoles until they reach a total length of 35 mm. Post-metamorphosis, young frogs have a SVL that ranges from 8.5 mm to 15 mm.

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• male more colorful

Development

Southern chorus frogs go through metamorphosis. After 30-90 days after hatching, the tadpole stage ends, and metamorphosis begins. The length at hatching for the southern chorus frog is approximately 4.5 mm long. After 1-4 months, the tadpoles metamorphose into juvenile froglets. After the tadpoles undergo this process, they can grow between 9-15 mm in length in the juvenile stage. The froglets remain near the shallow water in which they hatched for several weeks. After approximately a year (range: 8-14 months), the froglets reach sexual maturity. The males can range from 21-30 mm in length, and the females can range from 22-33 mm in length. Like all frogs, their growth is indeterminate.

• Development - Life Cycle
• metamorphosis metamorphosis
• indeterminate growth indeterminate growth

Reproduction

Southern chorus frogs can be described as polygynandrous, males and females mate with multiple pairings. Like their name suggests, male southern chorus frogs call in large choruses in temporary or shallow permanent waterbodies. Males call to attract female southern chorus frogs, and choruses are more pronounced immediately after heavy rains. Calling allows the female chorus frogs to determine the quality of a potential mate, while it allows the male chorus frogs to determine the quality of their competitors. Males call, but choose call sites that are heavily vegetated to avoid predation.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

The breeding season for southern chorus frogs varies greatly by geographic location. For example, in Florida, the season is the longest, lasting 9 months from January until September; however, most breeding here occurs mid-summer. In Alabama and South Carolina, these frogs breed December through May, and are considered winter breeders.

Males and females breed via amplexus, using external fertilization. Female chorus frogs lay up to 160 eggs, in clusters of 15 up to 150. However, total reproductive efforts are estimated at 500-1500 eggs per season. The females place the eggs in clusters near vegetation of shallow water. The eggs typically hatch within a week of being laid; Lannoo (2005) reported that in Florida, they hatched in 2.5 days. Tadpoles are independent at hatching.

Tadpoles are in the larval stage for 28-90 days before metamorphosis commences. Froglets also take a few months to develop into adult frogs. Egg and tadpole development is affected by factors such as water temperature, predation levels, and other environmental conditions. Caldwell (1987) studied these chorus frogs in South Carolina, and found that sexual maturity was reach between the ages of 11.5 to 14 months for both sexes. Dodd, Jr. (2013) suggests that maturity is reached in 8 to 10 months.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external
• oviparous oviparous

There is no parental investment reported for southern chorus frogs beyond the act of mating.

• Parental Investment
• no parental involvement

Lifespan/Longevity

The longest recorded lifespan for southern chorus frogs was three years. The typical lifespan for these frogs is one year.

Breeding sites influence the longevity of adult southern chorus frogs, with survival rates ranging from 15% to 34% for males and 27% to 55% for females in Caldwell's (1987) study in South Carolina. Generally, congregating in large numbers at breeding sites increases the risk of predation. Dodd Jr. (2013) reported that less than 3.2% of adults reproduce in 2 consecutive years (suggesting high mortality).

These frogs are not kept in captivity.

Behavior

Southern chorus frogs are saltatorial (which means they are specialized for jumping and hopping), nocturnal, and social (which means they live mainly in a group) - but only when breeding.

Like many other frog species, southern chorus frogs concentrate activity at night, but male frogs in chorus may begin to call during the daytime, around dusk. They are also a migratory species because they move in between the wetlands and other shallow waters during the breeding season to upland pine ( Pinus ) forests for the remainder of the year. Southern chorus frogs are also a social, polygynandrous species.

These chorus frogs are active during the winter, even beginning the breeding season in December or January in some parts of their range. Male chorus frogs call to find mates, but call mainly while hidden in thick vegetation or nearly underwater. They form large choruses and are especially active after heavy rainfall events. Depending on the year (influenced by rainfall and temperature), both sexes stay at a breeding pond from 1 to 61 days. When they leave breeding areas, most movement occurs nocturnally (likely to avoid visual predators).

• Key Behaviors
• saltatorial saltatorial
• natatorial natatorial
• nocturnal nocturnal
• motile motile
• migratory migratory
• social social

Home Range

Home range and territory size has not been reported for southern chorus frogs. In non-breeding periods, they are not known to defend an area. During heavy breeding times, males may occupy a small area in the pool but aggressive encounters have not been reported.

Communication and Perception

Southern chorus frogs communicate by an advertisement call. Males’ advertisement calls can be described as a slow trill (called "ik-ik-ik" by Dodd, Jr.) which on average have 6-12 pulses per second, with 1 to several seconds of break between trills. The pneumonics of the call are reported by Dodd, Jr (2013) as 3.325 kHz lasting, on average 0.39 seconds.

In most locations, except Florida, the months of December through April are when the chorus frogs are actively calling to mate, even in crepuscular hours. Male chorus frogs call to mate while remaining hidden in thick grasses or nearly underwater. Female southern chorus frogs are able to accurately discern calls between their own species and other sympatric frogs that belong to the same genus, such as spotted chorus frogs ( Pseudacris clarkia ). This stands true even when confronting varying environmental conditions, such as changes in ambient air and water temperatures, which affect the duration and trill rates of calls.

These frogs mate via amplexus, so they use visual and tactile senses to communicate. Color differences between sexes also suggest a reliance in visual mate recognition.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• choruses choruses

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Food habits of southern chorus frogs are not well-studied, limited to two studies that address the issue. Dodd, Jr. (2013) suggests they are opportunistic insectivores. Duellman and Schwartz (1958) examined 10 stomachs in southern Florida and reported finding ants (Order Hymenoptera, family Formicidae) and beetles (Order Coleoptera). Another anecdotal report says the adults consume grasshoppers (Order Orthoptera). In their tadpole phase, they mainly feed on algae.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
• herbivore herbivore
  • algivore

• Animal Foods
• insects

• Plant Foods
• algae

Predation

Southern chorus frogs are eaten by species of birds (especially owls) and snakes. Tadpoles fall prey to predacious aquatic insects, and tiger salamander ( Ambystoma tigrinum ) larvae. To avoid daytime, visual predators, adult southern chorus frogs concentrate breeding activity at night. Further, these frogs may hide in tall grasses to avoid risk of detection.

Southern chorus frogs’ survival rates range from 15% to 34% for males and 27% to 55% for females in Caldwell's (1987) study in South Carolina. Much of the mortality is a direct result of predation.

Ecosystem Roles

Southern chorus frogs fit into the food web as predators and as prey. They consume algae as tadpoles and insects as adults. As prey, in the tadpole stage they are eaten by salamander larvae and aquatic insects. As adults, they are eaten by species of birds, owls, snakes, and aquatic insects.

Trematodes ( Glypthelmins pennsylvaniensis ) have been found parasitizing southern chorus frogs. There were oral deformities found in the southern chorus frogs in South Carolina, which are often a sign of trematode parasites.

Economic Importance for Humans: Positive

The economic impact of southern chorus frogs is minimal, as their commercial value is set at $0.50.

Economic Importance for Humans: Negative

There are no negative economic impacts of southern chorus frogs on humans.

Conservation Status

Southern chorus frogs are listed as species of “Least Concern” on the IUCN Red List. They also have no special status for the US federal list, CITES, and State of Michigan lists.

A major threat to southern chorus frogs is habitat loss. As a species that relies on pine ( Pinus ) forests and wetlands across their range, loss of both habitats for urban and commercial development has the potential to cause significant harm. For example, compared to historical land coverage, longleaf pine ( Pinus palustris ) forests have declined by more than 99%. The conversion of these lands to commercial pine plantations, suppression of fire on which longleaf pines depend, and changing of wetland placement on the landscape all pose threats to these frogs. Development of roads and railroads also make it more difficult for southern chorus frogs to reach a suitable habitat.

Southern chorus frogs lack federal- and state-specific protections. Although there are no active conservation measures in place, protection of mature forests and wetlands would benefit this and other species.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Ashley Welch (author), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.

References

Altig, R., R. McDiarmid. 2015. Handbook of Larval Amphibians of the United States and Canada . Ithaca, New York: Cornell University Press.

Banker, S., A. Lemmon, A. Hassinger, M. Dye, S. Holland, M. Kortyna, O. Ospina, H. Ralicki, E. Lemmon. 2020. Hierarchical hybrid enrichment: Multitiered genomic data collection across evolutionary scales, with application to chorus frogs (Pseudacris). Systematic Biology , 69/4: 756-773.

Burger, J., J. Snodgrass. 2000. Oral deformities in several species of frogs from the Savannah River Site, USA. Environmental Toxicology and Chemistry , 19/10: 2519-2524.

Caldwell, J. 1987. Demography and life history of two species of chorus frogs (Anura: Hylidae) in South Carolina. Copeia , 1987/1: 114-127.

Crenshaw, J., F. Blair. 1959. Relationships in the Pseudacris nigrita complex in southwestern Georgia. Copeia , 1959/3: 215-222.

Degregorio, B., J. Willson, M. Dorcas, J. Gibbons. 2014. Commercial value of amphibians produced from an isolated wetland. The American Midland Naturalist , 172/1: 200-204.

Dodd Jr, K. 2013. Frogs of the United States and Canada . Baltimore, Maryland: Johns Hopkins University Press.

Dorcas, M., W. Gibbons. 2008. Frogs and Toads of the Southeast . Athens, Georgia: University of Georgia Press.

Duellman, W., A. Schwartz. 1958. Amphibians and reptiles of southern Florida. Bulletin of the Florida State Museum: Biological Sciences , 3/5: 181-324.

Ethier, J., A. Fayard, P. Soroye, D. Choi, M. Mazerolle, V. Trudeau. 2021. Life history traits and reproductive ecology of North American chorus frogs of the genus Pseudacris (Hylidae). Frontiers in Zoology , 18: 40. Accessed September 07, 2021 at https://doi.org/10.1186/s12983-021-00425-w .

Gartside, D. 1980. Analysis of a hybrid zone between chorus frogs of the Pseudacris nigrita complex in the southern United States. Copeia , 1980/1: 56-66.

Gates, W. 1988. Pseudacris nigrita (Le Conte) southern chorus frog. Catalogue of American Amphibians and Reptiles , 416: 1-3.

Gosner, K., D. Rossman. 1959. Observations on the reproductive cycle of the swamp chorus frog, Pseudacris nigrita. Copeia , 1959/3: 263-266.

IUCN SSC Amphibian Specialist Group, 2014. "Pseudacris nigrita" (On-line). The IUCN Red List of Threatened Species 2014: e.T55894A64733885. Accessed December 09, 2021 at https://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T55894A64733885.en .

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species . Los Angeles, California: University of California Press.

Lemmon, E., A. Lemmon. 2010. Reinforcement in chorus frogs: Lifetime fitness estimates including intrinsic natural selection and sexual selection against hybrids. Evolution , 64/6: 1748-1761.

Martof, B., E. Thompson. 1958. Reproductive behavior of the chorus frog, Pseudacris nigrita. Behavior , 13/3: 243-258.

Michaud, T. 1964. Vocal variation in two species of chorus frogs, Pseudacris nigrita and Pseudacris clarki, in Texas. Evolution , 18/3: 498-506.

Whitaker Jr., J. 1971. A study of the western chorus frog, Pseudacris triseriata, in Vigo County, Indiana. Journal of Herpetology , 5/3,4: 127-150.

Wilson, L. 1995. The Land Manager's Guide to the Amphibians and Reptiles of the South . Chapel Hill, North Carolina: The Nature Conservancy, Southeastern Region.

Witczak, L., M. Dorcas. 2009. What are frogs and snakes worth? The economic value of reptiles and amphibians inhabiting the Charlotte-Metropolitan area of North Carolina. Journal of the North Carolina Academy of Science , 125/4: 131-137.

Wright, A., A. Wright. 1949. Handbook of Frogs and Toads of United States and Canada, Third Edition . Ithaca, New York: Comstock Publishing Associates.