The western chorus frog is found in the middle to eastern portions of the North American continent. Its range extends from southern Quebec and northern New York west to South Dakota, then south to Kansas and Oklahoma (Harding 1997).
Western chorus frogs can be found in a variety of habitats, including marshes, meadows, swales, and other open areas. Less frequently they can be found in fallowed agricultural fields, damp woods, and wooded swamps. These areas of less permanent water offer reduced risk of egg and tadpole predation by other animals such as fish. There is a trade-off, however, as these temporary bodies of water can dry up in years of drought, resulting in reproductive failure for that year (Harding 1997).
- Terrestrial Biomes
The western chorus frog is characterized by a white or cream colored stripe along the upper lip, bordered by a dark brown stripe running through the eye from the nostril to the groin. There are usually 3 dark stripes running down the back, although these may be broken into rows of spots in some specimens. Background color ranges from brown to gray or olive. The underside is white or cream colored, possibly with dark spots on the chin and throat (Conant and Collins, 1991). Males have a yellow colored vocal sac that appears as a dark, loose flap of skin when not calling. The skin of the western chorus frog is typically moist and bumpy, and the toes end in slightly expanded toepads. Adult length is typically 1.9 to 3.9 cm (.75" to 1.5"), with males usually smaller than females.tadpoles have gray or brown bodies round in shape. Their tail fins are clear, often with dark flecks. The intestinal coil can be seen through the bronze belly skin. Maximum length before metamorphosis is about 3cm (1.2 inches)(Harding 1997).
- Sexual Dimorphism
- female larger
- Range length
- 19.0 to 39.0 mm
- 0.75 to 1.54 in
The rate of development of the eggs and larvae is dependent on water temperature, with specimens in colder water requiring more time for development. Maximum length before metamorphosis is about 3cm.
- Development - Life Cycle
- Mating System
In Michigan, the breeding season ofbegins in mid-March and runs through late May, although most activity occurs in April. These periods can vary, with breeding taking place earlier in the southern end of its range and later in the northern end. (Conant and Collins, 1991). Breeding sites include the edges of shallow ponds, flooded swales, ditches, wooded swamps, and flooded fields. Breeding choruses early in the season can be heard on clear, sunny days, but shift to evenings or cloudy, rainy days as the season progresses. Picking the small end of a high quality fine tooth comb with a fingernail can reproduce the call of the western chorus frog. The call sounds like "Cree-ee-ee-ee-eek", rising in speed and pitch as it progresses.
During amplexus, the female will lay 500-1500 eggs in several loose, gelatinous clusters attached to submerged grasses or sticks. Each cluster will typically have 20 to 300 eggs. Hatching generally occurs in 3 to 14 days and tadpoles transform into tiny froglets 40 to 90 days thereafter. The rate of development of the eggs and larvae is dependent on water temperature, with specimens in colder water requiring more time for development. Western chorus frogs can mature and breed in less than one year (Harding 1997).
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- Breeding interval
- Striped Chorus Frogs breed each year in the spring.
- Breeding season
- Breeding occurs from March to May.
- Range number of offspring
- 500.0 to 1500.0
- Range time to hatching
- 14.0 (high) days
- 40.0 to 90.0 days
After laying their eggs in clusters on vegetation there is no further parental care in Striped Chorus Frogs.
- Parental Investment
- no parental involvement
Most Striped Chorus Frogs will probably die as tadpoles or froglets. Once they reach adulthood, Striped Chorus Frogs may live for about 5 years.
- Average lifespan
- 5.0 years
- Average lifespan
Western chorus frogs tend to remain close to their breeding grounds throughout the year. They often hide from predators beneath logs, rocks, leaf litter, and in loose soil or animal burrows. They will typically hibernate in these places as well (Harding 1997).
Communication and Perception
Picking the small end of a high quality fine tooth comb with a fingernail can reproduce the call of the western chorus frog. The call sounds like "Cree-ee-ee-ee-eek", rising in speed and pitch as it progresses. Striped Chorus Frog males use these calls to attract females to breeding sites during the breeding season. Striped Chorus Frogs also use their keen vision to capture prey.
Western chorus frogs eat a variety of small invertebrates, including ants, flies, beetles, moths, caterpillars, leaf hoppers, and spiders. Newly formed froglets feed on smaller prey, including mites, midges, and springtails. Tadpoles are herbivorous, foraging mostly on algae (Harding 1997).
- Primary Diet
- eats non-insect arthropods
Striped Chorus Frogs help to control insect populations where they live, they also act as an important food source for their predators.
Economic Importance for Humans: Positive
The western chorus frog (and most other frogs) acts as a critical indicator species. Because the larval and adult forms of this species occupy different levels of the food chain, anomalies (such as deformities) or a reduction in reproductive success can be linked to either aquatic or terrestrial ecosystems, depending on the life stage of the animal. This makes this species valuable in determining the overall health of both ecosystems. The permeable skin of the western chorus frog also makes it susceptible to contaminants and other external stimuli. Changes in morphology or ecology of this species might indicate high levels of pollution or other activity detrimental to their well being.
The western chorus frog can be common to locally abundant, although some areas have shown a decline. The subspecies Pseudacris triseriata maculata is listed as special concern in the state of Michigan. This species appears to be quite tolerant of human activities, considering its presence in agricultural and suburban areas. Caution must be exercised during agricultural practices, as runoff containing pesticides, herbicides, and fertilizers often fills breeding ponds, making eggs and larvae susceptible to detrimental effects (Harding 1997).
Kevin Gardiner (author), Michigan State University, James Harding (editor), Michigan State University.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- bilateral symmetry
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
active at dawn and dusk
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- external fertilization
fertilization takes place outside the female's body
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
mainly lives in water that is not salty.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
having the capacity to move from one place to another.
- native range
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
having more than one female as a mate at one time
- seasonal breeding
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
Conant, R., J. Collins. 1991. Peterson Field Guides: Reptiles and Amphibians of Eastern and Central North America. New York: Houghton Mifflin Company.
Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, MI: The University of Michigan Press.