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. P. triseriata 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).
Range length: 19.0 to 39.0 mm.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: female larger
Striped chorus frogs are preyed on by large birds, small mammals, and snakes. Tadpoles and froglets can be preyed on by other frogs, crayfish, fish, turtles, and dragonfly larvae.
Known Predators:
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.
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
Status: wild: 5.0 years.
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).
Habitat Regions: temperate ; terrestrial ; freshwater
Terrestrial Biomes: forest
Wetlands: swamp
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).
Biogeographic Regions: nearctic (Native )
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: carnivore (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.
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 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: metamorphosis
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).
US Federal List: no special status
CITES: no special status
State of Michigan List: special concern
IUCN Red List of Threatened Species: least concern
Mating System: polygynous
In Michigan, the breeding season of Pseudacris triseriata begins 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).
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.
Range : 40.0 to 90.0 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
After laying their eggs in clusters on vegetation there is no further parental care in Striped Chorus Frogs.
Parental Investment: no parental involvement
The western chorus frog (Pseudacris triseriata), also known as striped chorus frog,[2] or midland chorus frog[3] is a species of frog found in Canada and the United States.
Western chorus frogs are small 40 mm (1.6 in), smooth skinned, and greenish-grey, reddish, olive, or brown in color. Differences in color can occur locally and should not be confused for range-specific populations. Typically, these frogs have three dark-brown or grey stripes which extend down the entire dorsal side. The dorsal stripes can be broken up, reduced, or even absent in certain specimens. The white or cream-colored underside or ventral side of the frog typically has dark, scattered flecks. A single white stripe runs along the upper lip, and a heavy dark stripe runs across the eye and along each side from the snout to the leg. A dark triangular spot on the head may also be seen in some individuals. These frogs have small, round toes without pads and very little webbing between each toe.
Typically, males are smaller than females, and can be told apart from the females by their yellow vocal sacs when calling. When not calling, this sac looks like a dark, loose flap of skin beneath the throat.
Tadpoles of the western chorus frog have gray or brown bodies. Their body shape is round with clear tail fins and dark flecks. The intestinal coil reportedly can be seen through the belly skin if closely observed. Their lips are black.
P. triseriata was once considered a subspecies of the southern chorus frog, P. nigrita, but was reclassified as its own species with four subspecies: P. t. triseriata,[3] P. t. kalmi, P. t. maculata,[2] and P. t. feriarum. These have since been granted species status, meaning P. triseriata as described here has no subspecies.[4]
This chorus frog has a huge distribution, from Canada to the Gulf of Mexico, and New Jersey to central Arizona. The frogs lives from near sea level to about 12,000 ft (3,700 m) above sea level, and are capable of surviving temperatures as low as –8 °C.[5]
Western chorus frogs live in a variety of different habitats, but areas of more permanent water increase the risk of predation on eggs and/or tadpoles. To compensate for this, chorus frogs stick to mostly ephemeral freshwater areas, such as marshes, river swamps, meadows, grassy pools, and other open areas found in mountains and prairies. The western chorus frog remains close to these ephemeral aquatic habitats, since they provide excellent mating, breeding, and hibernation grounds. Since these areas tend to dry out, these frogs can be, but are less commonly, found in fallowed agricultural fields, damp woodlands, roadside ditches, and wooded swamps.
Both males and sometimes females call in large choruses. Males use a special call to attract several potential mates to breeding sites. The western chorus frog call can be heard from half a mile away. The call is a very distinct "cree-ee-ee—eeek", but can be confused with the upland chorus frog. Calling can occur for 0.5–2.0 seconds and can occur 18–20 times in a minute. The higher the temperature, the more frequent calls occur in a minute, (30–90 calls per minute). The western chorus frog relies heavily on secrecy to keep themselves safe from predators. Any disturbances to the frog's environment causes them to stop calling and dive into the depths of whatever water source they reside near, under leaf litter, logs, rocks, or loose soil, for minutes. These terrestrial hiding spots serve not only as hiding places, but also as hibernation places for the frogs during the winter.
The diet of an adult consists of small invertebrates and arthropods, such as small flies, mosquitoes, ants, small beetles, moths and caterpillars, grasshoppers, and spiders, only if they are small enough. Froglets (the transition or metamorphic phase between tadpole and frog) will feed on smaller prey, such as mites, midges, and springtails. Tadpoles feed on periphyton, filamentous algae, diatoms, and pollen in or on the surface of the water. They will scavenge if given the opportunity.
Breeding occurs at different times throughout the various states where this frog resides. Typically, western chorus frog's breeding season starts in March through May, with April being the most active month. However, breeding takes place earlier in southern parts and can vary through the frogs entire range. The earliest sign of western chorus frog breeding occurs with choruses heard on sunny days. Males call to potential females over the course of several days to months. As the season continues, these competing male choruses move to the evenings and cloudy, rainy days. The lifespan of these frogs averages five years. After mating has occurred, females can lay between 500 and 1500 eggs during the entire breeding season. The female lays one cluster at a time, which can contain 20–300 eggs. The eggs are retained in a loose, gelatinous cluster, submerged below the water and stuck to weeds or grasses found along the edges of shallow ponds, flooded swales, roadside ditches, flooded fields, open areas, and swamps. The eggs will hatch into tadpoles between three and 14 days after being laid. However, water temperature can be a limiting factor in the growth of both eggs and tadpoles. Colder water temperatures prevent the tadpoles and eggs from growing. Tadpoles metamorphose into froglets 40–90 days afterwards.
Although quite adaptable and tolerant to human activity, western chorus frog populations are declining in certain areas. Labeled as in least concern on the IUCN list, the US Federal List has the species labeled as no special status. In Canada, the western chorus frog is listed as threatened in the Great Lakes/St. Lawrence - Canadian Shield under the Species at Risk Act (SARA).[6][7] The western chorus frog is currently the subject of a legal dispute over compensation between a landowner and the Government of Canada[8]
The western chorus frog plays an important role as an indicator species. Deformities, reduction in reproductive success, or changes in morphology in either the larval or adult forms could indicate pollution or toxic substances in the environment, sometimes trematodes. Therefore, the health of these frogs are valuable in determining the health of ecosystems and whether agricultural practices have leaked any pesticides, herbicides, or fertilizers into the environment.
The western chorus frog (Pseudacris triseriata), also known as striped chorus frog, or midland chorus frog is a species of frog found in Canada and the United States.
