Pseudacris triseriata

Geographic Range

Midland chorus frogs (formerly known as striped or western chorus frogs) are now considered to be found solely east of the Mississippi River. The range extends from Michigan, southern Ontario, and western New York south through western Pennsylvania, Ohio, and Indiana to southern Illinois and north-central Tennessee. Midland chorus frog eastern distribution appears to be limited by the Appalachian Mountains (Lemmon et al. 2007; Green et al., 2013).

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Midland chorus frogs live largely in open, damp areas including marshes, meadows, forest edges, fallow farm fields, bottomland swamps, floodplains and damp woodland areas (Powell, Conant, and Collins, 2016). They are rarely seen outside of the breeding season (early spring) but can sporadically be spotted under logs or boards, among dead vegetation, leaf litter, in cracks in the ground, or in crayfish burrows mostly in damp places (Harding and Holman, 1992; Green et al., 2013). Due to an ability to tolerate the partial freezing of body water, these frogs can overwinter buried shallowly in soil and leaf litter near breeding sites, typically temporary bodies of water such as vernal ponds, flooded fields, ditches, marsh edges and wooded swamps (Harding and Holman, 1992).

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Aquatic Biomes
• temporary pools

• Wetlands
• marsh marsh
• swamp swamp
• bog bog

• Other Habitat Features
• suburban suburban
• agricultural agricultural
• riparian riparian

Physical Description

Midland chorus frogs range from 1.9 to 3.2 cm (.75 to 1.25 inches) in snout to vent length. Dorsal coloration can vary from light or dark brown to gray or greenish (or very rarely rust orange). They have a white line along the upper lip which can extend to the shoulder. There also may be a dark triangle or other figure between the eyes. A dark stripe runs from the snout through the eyes and eardrums and can continue along side of the groin. They have 3 dark brown or gray longitudinal stripes down their backs. These stripes are rarely broken into streaks or spots or absent. They have a whitish belly with dark stippling on the chest. Males have dark throats during the breeding season. The length of the tibia (lower hind limb) is approximately half the head-body length. Also, the ends of the toes slightly expand into small discs (Harding and Holman, 1992; Powell, Conant and Collins, 2016). They exhibit slight sexual dimorphism, as females tend to be a bit larger than males.

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

• Sexual Dimorphism
• female larger

Development

Midland chorus frogs breed in shallow waters in late winter or early spring. Males call to attract females. During amplexus (where the male grips the female from above with his front legs), the female lays from 500 to 1500 eggs in small gelatinous masses, while the male fertilizes them externally. As with most amphibians, the rate of development of eggs and larvae can depend on water temperature. Colder temperatures can increase development time. Once eggs are laid, tadpoles hatch in anywhere from 3 to 14 days and will metamorphose into small versions of their adult form in another 40 to 90 days (Harding and Holman, 1992). Maximum length of the tadpole before metamorphosis is about 3 cm.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Midland chorus frogs breed, sometimes in small to large congresses, in shallow pools and temporary waters in or adjacent to marshes, swamps, and swales. During axillary amplexus, males externally fertilize the eggs as they are laid by the female in a pattern typical of most hylids (Halliday and Adler, 2002). Over most of the range, amplexus and egg laying takes place from late March to early April, but breeding occasionally extends into May in the north (Harding and Holman, 1992).

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

Midland chorus frogs are often the first frog species to call in the spring (Harding and Holman, 1992). In the north this is typically in mid to late-March, but further south it may be even earlier. Breeding is initiated by favorable temperatures and rainfall to create the required temporary bodies of water (Landreth and Furguson, 1966). Amplexus and egg laying takes place mostly in April but will occasionally continue into May. Females produce between 500 and 1500 eggs that are laid in small gelatinous masses of 20 to 100 or more eggs. Females attach the mass to grasses or twigs underwater. Eggs hatch in 3 to 14 days and metamorphose in 40 to 90 days (Harding and Holman, 1992).

• 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 known parental involvement once the female has laid her eggs.

• Parental Investment
• no parental involvement

Lifespan/Longevity

Typical for frogs that lay a large number of eggs, most of the offspring will die before reaching adulthood, though the exact numbers are unknown. However, once these frogs reach maturity, they may live for 2 to 5 years.

Behavior

Despite being in the treefrog family ( Hylidae ), midland chorus frogs rarely climb. They are not often seen outside of the breeding season but are occasionally found in damp retreats (Harding and Holman, 1992). Additionally, they are largely solitary outside of breeding congresses (Kramer, 1974). They can tolerate partial freezing of body water in the winter and use glucose as an antifreeze mechanism to preserve important critical organs (Pough et al., 2004). Overwintering sites are typically near breeding sites and are in shallow soil and leaf litter. This allows these frogs to quickly emerge and start breeding as soon as breeding sites are thawed and flooded (Harding and Holman, 1992). Tadpoles are active feeders relative to other frogs that breed at the same time, allowing faster growth and shorter time to metamorphosis, and thus may be able to escape from the temporary pond before it dries up. However, predators may be attracted to this increased activity (Pough et al., 2004).

• Key Behaviors
• terricolous
• natatorial natatorial
• crepuscular crepuscular
• motile motile
• migratory migratory
• sedentary sedentary
• hibernation hibernation
• aestivation
• solitary solitary

Home Range

Midland chorus frog home ranges average 2116 square meters, including the breeding pond. They migrate long distances in order to breed (Kramer et al., 1974; Landreth and Ferguson, 1966)

Communication and Perception

The call of midland chorus frogs is a short, rising, squeaky trill which sounds like “cree-ee-ee-ee-eek." It can be roughly imitated by strumming the teeth of a small, stiff pocket comb from middle to end with a thumbnail (Harding and Holman, 1992). Their calls are used mainly to attract females to breeding sites during their breeding season. They create a chorus of their calls during their breeding congresses. They also use visual and auditory cues for migration and breeding and rely on their keen vision for capturing prey.

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

• Other Communication Modes
• choruses choruses

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

Food Habits

Like most small frogs, the diet of midland chorus frogs includes a variety of small invertebrates, such as spiders, ants, flies, and moths. Younger, smaller frogs will feed on smaller prey: mites, midges and springtails. Tadpoles are herbivorous feeding mostly on algae (Harding and Holman, 1992).

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
• herbivore herbivore
  • algivore

• Animal Foods
• insects
• terrestrial worms

• Plant Foods
• algae

Predation

Typical predators on adult midland chorus frogs would include birds (herons, grackles, etc.), small mammals (raccoons, mink, skunks), snakes, and larger frogs. Young metamorphs and tadpoles are eaten by salamander larvae, crayfish, fish (if present), turtles, and aquatic insects such as water scorpions, diving beetles, and dragonfly larvae.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Midland chorus frogs serve as a food source for their predators and help keep prey populations under control. Both adult and larval forms (tadpoles) have different but important ecological roles. In both environments these frogs and their larvae serve as predator and prey and do not compete with their parents or offspring. Water-breeding amphibians such as midland chorus frogs can channel nutrients from the aquatic to the terrestrial environment.

Economic Importance for Humans: Positive

As with other amphibians, midland chorus frogs can act as a critical indicator of environmental health. Their permeable skin makes them susceptible to many contaminants, external stimuli and toxins that they are exposed to in both aquatic and terrestrial portions of their life cycle. Since their larval and adult forms occupy very different habitats, a decline in frog numbers or population health could signify problems in either environment or both.

• Positive Impacts
• research and education
• controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of Pseudacris triseriata on humans.

Conservation Status

This species is considered to be mostly stable. Although listed as "vulnerable" in Quebec (Green et al.,2013), it has no special status in the United States. It is common in much of its large range. The IUCN indicates there has been a decline but the degree is uncertain. Like other frogs, they are very susceptible to agricultural chemicals and to baitfish and gamefish introduction into breeding wetlands. Their breeding habitat is also vulnerable to destruction due to urban and suburban development (Green et al., 2013).

Other Comments

There has been much change in recent years in the taxonomy and species delimitation of chorus frogs ( Pseudacris ). Until recently, what is called the Pseudacris triseriata complex (including Upland, Cajun, New Jersey, Boreal and Midland chorus frogs) were considered a subspecies of northern chorus frogs (Powell, Conant, and Collins, 2016). Now, they have all been promoted to species status. Recent findings show mitochondrial DNA is similar to that of the boreal chorus frogs but the species status hold due to the differences in range and calls (Green et al., 2013).

The many names of this species can also be confusing. The common name "striped chorus frogs" comes from the characteristic 3 stripes down its back. Until recently, this species was called western chorus frogs. Due to the restricted range east of the Mississippi, though, the proper common name is now midland chorus frogs.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Kelsey Landry (author), Michigan State University, James Harding (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Encyclopedia of Life, 2016. "Pseudacris triseriata, Striped Chorus Frog" (On-line). Encyclopedia of Life. Accessed November 10, 2017 at http://eol.org/pages/1048370/details .

Green, D., L. Weir, G. Casper, M. Lannoo. 2013. North American Amphibians Distribution and Diversity . Berkeley and Los Angeles, California: University of California Press.

Halliday, T., K. Adler. 2002. Firefly Encyclopedia of Reptiles and Amphibians . Toronto, Ontario; Buffalo, New York: Firefly Books Ltd.

Harding, J., J. Holman. 1992. Michigan Frogs, Toads, and Salamanders: A Field Guide and Pocket Reference . East Lansing, MI 28824: Michigan State University Museum.

Kramer, D. 1974. HOME RANGE OF THE WESTERN CHORUS FROG PSEUDACRIS-TRISERIATA-TRISERIATA. Journal of herpetology , 8/3: 245. Accessed November 08, 2017 at http://za2uf4ps7f.search.serialssolutions.com.proxy1.cl.msu.edu/?url_ver=Z39.88-2004&url_ctx_fmt=info:ofi/fmt:kev:mtx:ctx&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.atitle=HOME%20RANGE%20OF%20THE%20WESTERN%20CHORUS%20FROG%20PSEUDACRIS-TRISERIATA-TRISERIATA&rft.aufirst=D&rft.aulast=KRAMER&rft.date=1974&rft.epage=246&rft.genre=article&rft.issn=0022-1511&rft.issue=3&rft.jtitle=Journal%20of%20Herpetology&rft.pages=245-246&rft.spage=245&rft.volume=8&rfr_id=info:sid/www.isinet.com:WoK:UA&rft_id=info:doi/10%2E2307%2F1563171 .

Landreth, H., D. Ferguson. 1966. Behavioral Adaptations in the Chorus Frog, Pseudacris Triseriata. Journal of the Mississippi Academy of Sciences , 12: 197-202.

Lemmon, E., A. Lemmon, J. Collins, J. Lee-Yaw, D. Cannatella. 2007. Phylogeny-based delimitation of species boundaries and contact zones in the trilling chorus frogs ( Pseudacris ). Molecular Phylogenetics and Evolution , 44: "1068-1082".

Pough, F., R. Andrews, J. Cadle, M. Crump, A. Savitzky, K. Wells. 2004. Herpetology Third Edition . New Jersey: Pearson Prentice Hall.

Powell, R., R. Conant, J. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America Fourth Edition . Boston, New York: Houghton Mifflin Harcourt Publishing Company.

Stuart, S., G. Hammerson, D. Sharp, L. Hoblin. 2015. "Pseudacris triseriata" (On-line). IUCN Redlist. Accessed November 08, 2017 at http://www.iucnredlist.org/details/55899/0 .