Rana Pretiosa Research Articles

Comparative Escape Behavior of Sympatric Rana aurora and Rana pretiosa

The escape behavior of Rana aurora and R. pretiosa from sympatric populations is compared. In the field, when given a choice between land and water as escape routes, R. aurora prefer land and flee with long jumps about 45 0 off the ground. If water is used, R. aurora tend to remain on the surface, swimming along the bank away from danger. Rana pretiosa almost always seek escape by immediately diving and submerging in the nearest water, from which they seldom wander. When water is not available, R. pretiosa tend to jump in a circular fashion with short weak jumps ca. 200 off the ground. In laboratory tests with garter snakes as predators, both frog species used escape behavior seen in field studies. The overall morphology, including length of hind limbs, degree of webbing on hind feet, eye placement and body coloration, is consistent with the escape patterns used by the two species.

Food and feeding behavior of sympatric Red-legged Frogs, Rana aurora, and Spotted Frogs, Rana pretiosa, in southwestern British Columbia

Food and feeding behavior of sympatric Red-legged Frogs, Rana aurora, and Spotted Frogs, Rana pretiosa, in southwestern British Columbia

Host-induced variations in Haematoloechus buttensis (Trematoda: Haematoloechidae)

The life cycle of Haematoloechus buttensis was maintained in the laboratory by using the usual natural hosts: Rana pretiosa, Physa nuttalli, and Ischnura perparva. Morphological variations in important taxonomic characters were studied and compared with those found when one of the usual hosts was replaced by a sympatric, but usually uninfected, host. In all, six species of Amphibia, three of Insecta, and three Mollusca were used.The effect of host size, sex, and ambient temperature was also studied using R. pretiosa as definitive host.The most reliable taxonomic characters were determined to be the sucker ratio, egg size of 21-day-old and older worms, position of the testes, and the anterior extent of the extracaecal uterine loops.The unreliability of other characters and their prior use as species-specific features suggests that many of the currently recognized species of Haematoloechus are not valid.

Plasma aldosterone concentrations in wild and captive western spotted frogs ( Rana pretiosa)

Plasma aldosterone concentration (1.33 ± O.10 ng/ml) was substantially lower in a wild population of Rana pretiosa than in frogs from the same population held in captivity for three weeks (4.48 ± 0.55 ng/ml). The aldosterone value for the wild population was much lower than circulating levels previously reported for laboratory amphibians but higher than those reported for other vertebrates.

Comparative life history features of the western spotted frog, Rana pretiosa, from low- and high-elevation populations

Comparisons are made of life history features of the western spotted frog, Rana pretiosa pretiosa, living at 70 m in southwestern British Columbia, and 2600 m in Yellowstone Park, Wyoming.Lowland tadpoles remain longer as larvae and transform at twice the body size as highland tadpoles.Growth rates of juveniles and adults are rapid in the lowland population and the same amount of growth achieved by them in 2–3 years takes 8–10 years for highland frogs.Body size at sexual maturity is the same for frogs from both populations, but B.C. frogs breed at half the age of Wyoming frogs. Female fecundity, the number of eggs at spawning, is the same, but lowland females breed annually, while high-elevation females breed only every 2 or 3 years.Various explanations are put forth to account for observed differences.

Survival of embryos, tadpoles, and adults of the frogs Rana aurora aurora and Rana pretiosa pretiosa sympatric in southwestern British Columbia.

Field survival of embryos, tadpoles, and adults of Rana aurora and Rana pretiosa sympatric in marshes near Vancouver, British Columbia, was studied.Embryonic survival for R. aurora was 90% and better, whereas for R. pretiosa it was about 70%. As well, in dry periods during breeding, R. pretiosa embryos face the danger of desiccation and extensive or complete mortality.Survival of tadpoles of both species in a pond breeding site studied was less than 1% in 1968. By the end of the season of transformation, there was about 5% survival of young-of-the-year frogs of both species from the initial number of eggs deposited in river breeding sites.After the end of the first full year of life (1969), there was a minimal survival of 2.5% for R. aurora and 3.5% for R. pretiosa from the eggs laid the year before. By the end of 1969, there was a 52% survival of R. aurora and 67% of R. pretiosa which metamorphosed in 1968.For R. pretiosa adults, there was a 64% survival between 1968 and 1969; males suffered higher mortality than females. The survival of adult R. aurora was 69% between 1968 and 1969.Factors influencing mortality are discussed, and the conclusion is reached that predation (and chance climatic events for R. pretiosa embryos) on all life-history forms is the strongest factor limiting frog population numbers.

The Life Cycle of Cephalogonimus salamandrus sp. n. (Digenea: Cephalogonimidae) from Ambystoma tigrinum (Green) from Eastern Washington

Mother and daughter sporocysts and xiphidiocercariae develop in Helisoma trivolvis. Cercariae penetrate tadpoles of Rana pretiosa and small A. tigrinutm larvae in which they encyst. The adult develops in the anterior small intestine of A. tigrilnum after ingestion of an infected 2nd intermediate host. The life cycle of C. salamandrus is compared with C. americanus from Rana clamitans. C. salamandrus is described as a new species on the basis of cercarial and adult morphology, and the failure to achieve cross-infections in the respective definitive hosts for C. americanus and C. salamandrus. Cephalogonimus Poirier, 1886, is the only genus of the family Cephalogonimidae in amphibians. Rai (1961) listed Cephalogonimus brevicirrus (Ingles, 1932), C. amphiumae (Chandler, 1923), C. letusus Dujardin, 1845, and C. am?ericanus (Stafford, 1902) from amphibians of North America. Premvati (1969) described C. sireni from Florida mud eels. The only life cycle reported is for C. americanus from Rana clamitans Latreille (Lang, 1968). This parasite has also been reported from R. catesbeiana Shaw (Rankin, 1945), and R. pipiens Schreber (Brandt, 1936; Najarian, 1955). An undescribed cephalogonimid is a common intestinal parasite of neotenic and adult Ambystoma tigrinum (Green) of eastern Washington. Of the other species of Cephalogonimus, this parasite most closely resembles C. americanus. Comparison of the life cycle stages of this parasite with those of C. americanus and the demonstrated specificity of these two parasites to their respective definitive hosts establishes the validity of this new species to which the name Cephalogonimus salamandrus is assigned. MATERIALS AND METHODS Eggs were teased from adult flukes and stored in filtered spring water at 5 C until used. Fully embryonated eggs were fed to young laboratoryreared Helisoma trivolvis (Say). Exposed snails were crushed and examined at intervals after Received for publication 9 April 1973. *A portion of this study was conducted at the University of Michigan Biological Station. tPresent address: Department of Biology, New Mexico State University, Las Cruces, New Mexico 88003. exposure. Naturally infected H. trivolvis were collected for cercarial study and laboratory infection of the second intermediate host. Cercariae were studied alive with and without vital stains. Cercariae were placed wvith various aquatic invertebrates, small salamander larvae, tadpoles, and small frogs. Penetration and encystment occurred only in amphibian skin. Metacercariae were studied at 2 hr, 1 day, 5 days, 10 days, 12 days, and 21 days after infection. Tadpoles and salamander larvae used as intermediate hosts were laboratory-reared. Large neotenic A. tigrinum for use in laboratory infections were collected from a lake where no trematode or cestode parasites were found in 150 A. tigrinum and no Helisoma spp. have been found in over 6 years of study. Salamanders were maintained in filtered spring wrater on a diet of earthworms. Before exposure 13 neotenic salamanders (20 to 30 cm in length) were starved for 2 weeks. Feeding was resumed the day after exposure. Each of 11 salamanders was permitted to ingest two infected tadpoles, each containing 20 to 30 metacercariae which were 12 days old at exposure. Salamanders were necropsied at 52 hr, 5 days, 10 days, 15 days, 20 days, and 48 days after exposure. Also each of two salamanders was permitted to ingest two infected salamander larvae, each containing 20 to 30 metacercariae which were 12 days old at exposure. These were necropsied at 5 days. Recovered flukes were studied alive, measured, heat-killed, stored in AFA, and stained in Semichon's Carmine. To determine if A. tigrinum and R. pretiosa of eastern Washington could be infected with C. americanus, hosts were transported to the University of Michigan Biological Station. Methods for handling C. americanus and collection of Cephalogonimus-free R. clamitans have been reported (Lang, 1968). Two salamanders were exposed to 10-day-old metacercariae of C. americanus. Each salamander received 50 to 70 metacercariae and was necropsied 10 or 30 days after exposure. During this experiment two A. tigrinum

Effects of cytochalasin B on the ultrastructure of Rana pretiosa tadpole epidermis.

AbstractImmersion of Rana pretiosa tadpole tail integument in 1 μg/ml of cytochalasin B (CCB) for 45 minutes disrupted various cell structures of the two‐squamous cell‐layered epidermis including macromolecular components within microvilli and subjacent to the apical plasmalemma, the unit membrane which bounds mucinogenic vesicles and various other supranuclear structures. Surface cells exhibited the greatest degree of organelle disorganization when pieces of excised tail fin (“discs”) were treated with the antibiotic. This may indicate a differential response to the drug by various regions of the cytoplasm or that the concentration of CCB and/or exposure period was only adequate to penetrate the most superficial layers of this epithelium. The effect(s) of the penetrate the most superficial layers of this epithelium. The effect(s) of the antibiotic on filaments and filament related kinetic processes is discussed and the possibility of dissimilarities in CCB‐sensitivity between immature and differentiated plasmalemma and among unit membrane of various organelles is considered.

Breeding Habits and Embryonic Thermal Requirements of the Frogs, Rana Aurora Aurora and Rana Pretiosa Pretiosa, in the Pacific Northwest

Embryonic thermal adaptations of the frogs, Rana aurora aurora and Rana pretiosa pretiosa from the Pacific Northwest, are described. Limits of temperature tolerance of young R. aurora embryos are about 4—21 degrees C, both the upper and lower lethals being the lowest for any North American ranid frog. For R. pretiosa, the lethal thermal limits of young embryos are approximately 6—28 degrees C. The tolerance limits broaden as embryos become older, and embryos of both species can survive short—term exposure to normally lethal chronic cold temperatures. The developmental rates for embryos of both species at a wide range of constant temperatures are given. Egg masses of both species are compact and globular. The ova of R. aurora average 3.03 mm, those of R. pretiosa 2.31 mm. R. aurora embryos hatch at stage 21, and R. pretiosa embryos hatch at stage 19, a difference that may reflect the O2 needs of the hatching embryos. The O2 consumption by R. aurora embryos between developmental stages 12—15 at 18.5 degrees C averaged 0.59 cmm O2/egg per hour. R. pretiosa embryos at the same stage and temperature averaged 0.57 cmm O2/egg per hour. Field observations of breeding frogs indicate a correlation between breeding habits–such as initiation of breeding season, time of daily sexual activity, male calling behavior, and spawning site–and embryonic thermal requirements. High mortality of R. pretiosa embryos in the field often results from freezing temperatures at night and desiccation of egg masses. These factors do not greatly affect R. aurora embryos. These thermal adaptations of the two western species of Rana are compared with those of species from eastern North America, as an aid in broadening our understanding of the evolutionary strategies within the genus in North America.

Comparative breeding behavior of the red-legged frog (Rana aurora aurora) and the western spotted frog (Rana pretiosa pretiosa) in southwestern British Columbia

The breeding behavior of Rana aurora aurora and R. pretiosa pretiosa from an area of sympatry in southwestern British Columbia is described and compared. A 7-ac field near White Rock, B.C., was closely observed during the 1968 and 1969 breeding seasons.Both species arrived at breeding sites and began breeding activities within 2 weeks after emergence from hibernation in February and March. They both used the same temporary pond and slow-moving stream, and breeding occurred simultaneously.Male pretiosa gather into small groups with individuals vocalizing within inches of each other. The mating call is given in air as the frogs float on the surface of water only a few inches deep at the margins of the pond and river. Male aurora call several feet apart while completely submerged in 2 ft or more of water, and 3 ft or more from the pond and river edges. Descriptions of the mating calls of both species, as well as a call peculiar to amplectic male aurora, are given.Female pretiosa spawn mainly during daylight and the eggs are placed on top of, or immediately adjacent to, the first mass present. As many as 26 separate masses were laid on top of one another in the same place, unattached to vegetation in only a few inches of water. Female aurora spawn only at night and deposit their eggs attached to submerged vegetation in a minimum of 12 in. of water, and at least 3 ft from the pond and river shore; masses are several feet apart. The eggs of both species are laid in those areas where conspecific males vocalize.Peculiar aspects of both species' breeding behaviors are discussed, as well as those factors leading to successful reproductive isolation. Observations of breeding aurora in allopatry indicate no major differences from those on aurora sympatric with pretiosa.

The ecology of the western spotted frog, Rana pretiosa pretiosa Baird and Girard, a life history study.

The ecology of the western spotted frog, Rana pretiosa pretiosa Baird and Girard, a life history study.

Effects of renin and ACTH on adrenal steroid secretion in the American bullfrog.

Effects of renin and ACTH on adrenal steroid secretion in the American bullfrog.

The Life History of Haematoloechus breviplexus Stafford, 1902 (Trematoda: Haplometridae McMullen, 1937), with Emphasis on the Development of the Sporocysts

Embryonated eggs of Haematoloechus breviplexus Stafford, 1902 were fed to laboratoryreared specimens of Gyraulus similaris (F. C. Baker, 1919). Miracidia hatch in the snail intestine, then invade the intestinal epithelium, many penetrating only as far as the basement membrane, but some passing through to the hemocoel of the snail. In either location they metamorphose to the mother sporocyst which enlarges gradually as the germinal cells multiply. Those mother sporocysts that are enclosed by basement membrane soon become pedunculate and detach from the intestine when the basement membrane ruptures. By the 12th day, the limiting membrane of many mother sporocysts ruptures, freeing the germinal cells which continue multiplying in the hemocoel of the snail. Between the 12th and 22nd days, the germinal cells give rise to many daughter sporocyst embryos which also undergo their development in the hemocoel. There is no host cellular response to the parasite, and consequently, paletots do not develop around the sporocysts. Xiphidiocercariae of the Omatae group are produced within 31 days and encyst in the branchial basket of naiads of the dragonfly, Aeschna multicolor Hagen, 1861. Metacercariae were fed to newly metamorphosed specimens of Rana pretiosa (Baird and Girard, 1853), and young adults of H. breviplexus were recovered 22 and 23 days later. The development of sporocysts of H. breviplexus is compared to that of several other species of plagiorchioid trematodes formerly studied by the author. Sporocyst development of H. longiplexus Stafford, 1902 and H. parviplexus (Irwin, 1929) was also observed and found to be identical to that of H. breviplexus. New host and distribution records are given for H. longiplexus and H. breviplexus. The present report represents part of the results of a long-range investigation of sporocyst and paletot development of plagiorchioid trematodes. The work was done during the summers of 1963 and 1964. Knowledge of the life cycle of Haematoloechus variegatus (Rud., 1819) was contributed by van Thiel (1930), who fed metacercariae, from anopheline larvae, to frogs and recovered adults of H. variegatus. Krull (1930 and 1931) reported on the life histories of H. medioplexus Stafford, 1902 and H. parviplexus (Irwin, 1929). The host snail for the latter species is Gyraulus parvus (Say, 1817), whereas, Planorbula armigera (Say, 1818) serves as host for H. medioplexus. He observed all stages except the mother sporocyst, and found that dragonfly naiads of the genus Sympetrum Newman, 1833 serve as second intermediate hosts for both species. The definitive host for H. parviplexus is Rana clamitans Latreille, 1802, while R. pipiens Schreber, 1782 serves as host for H. medioplexus. Krull (1932) found metacercariae of H. longiplexus Stafford, 1902 in the damselfly, Lestes vigilax Hagen, 1862, fed some to bullfrogs, and recovered adults of this species. The host snail was unknown. Krull Received for publication 24 November 1964. (1933 and 1934) observed the daughter sporocysts and cercariae of H. complexus (Seely, 1906) in Pseudosuccinea columella (Say, 1817). Naiads of three species of dragonflies serve as second intermediate hosts, and Rana clamitans serves as definitive host. Ingles (1933) investigated the life cycle of H. oxyorchis Ingles, 1932 from Rana aurora (Baird and Girard, 1852) and found that Gyraulus parvus and G. vermicularis (Gould, 1847) serve as first intermediate hosts. Ingles observed a 50-dayold daughter sporocyst and found that the cercariae encyst in dragonfly naiads of the genus Sympetrum. None of the above authors observed the mother sporocyst of any species. MATERIALS AND METHODS Second and third generation laboratory-reared specimens of Gyraulus similaris (F. C. Baker, 1919) were used throughout the investigation. Snails were maintained in enameled pans of aquarium water to which was added powdered calcium carbonate and an abundance of aquatic plants. The thick basal parts of lettuce leaves were added as food. As the lettuce decayed, the snails fed on it readily. Only young snails, having a shell diameter of 1.5 to 2 mm, were used. Mature specimens of H. breviplexus were obtained from the lungs of Rana pretiosa (Baird and Girard, 1853). The trematodes were placed in dishes of aquarium water for release of eggs.

The Status of Records of the Western Spotted Frog, Rana pretiosa, in Saskatchewan

The Status of Records of the Western Spotted Frog, Rana pretiosa, in Saskatchewan

A Revision of the Genus Haplometrana Lucker, 1931 (Trematoda: Plagiorchiidae), with Notes on Its Distribution and Specificity

While examining specimens of Rana pretiosa Baird and Girard from Idaho, the author recovered a number of helminths of the genus Haplometrana Lucker, 1931. In attempting to identify the species involved, the variability of the individuals and the similarities of the 2 described species became apparent. After studying the distribution of the host, it appeared that the 2 described species of Haplometrana were sampled from hosts at 2 ends of a cline, in the center of which was Idaho. It seemed reasonable to assume that the parasites as well were 2 ends of a cline and the 2 species were synonymous. In order to prove or disprove these suppositions, a wide-spread collection was made and a large number of worms were studied. The results of this study are presented in this paper. The genus was named and described by Lucker (1931) the type species being H. intestinalis from the small intestine of Rana pretiosa from Bothell, Washington. Olsen (1937a) described a new species, H. utahensis, from the small intestine of Rana pretiosa from Springville, Utah, and studied its life cycle. Olsen (1937b), in his study of the subfamily Plagiorchiinae, revised the generic diagnosis and again differentiated between the 2 species in a key.

Pigmentation of the Western Spotted Frog, Rana p. pretiosa, in Yellowstone Park, Wyoming

Information on the amount of variation in the pigmentation of Rana pretiosa has usually been scanty and based on subjective appraisals of a small number of individuals (Dickerson, 1920; Blanchard, 1921; Patch, 1922; Tanner, 1931; Logier, 1932; Gordon, 1939). All these color descriptions are perfectly valid as generalizations but were not intended to serve as expressions of the variation existing in natural populations. Color and pattern differences are useful characteristics in attempting to assess inter- and intraspecific relationships but the proper evaluation of pigment variation depends upon adequate understanding of the differences exhibited by the species as a whole, and hence by its component populations. For example, in her description of the new race Rana pretiosa luteiventris Thompson (1913) contrasted, among other characteristics, the yellow ventral pigmentation of the new form with the red or salmon coloring of the nominate subspecies. One may wonder whether such a difference is actually of taxonomic significance or whether ventral coloration varies so greatly over the entire range, or even within adjacent populations, of Rana pretiosa as to negate its diagnostic value. Slevin (1928) did not recognize Rana pretiosa as a polytypic species and there are others (Stebbins, 1951) who are at least skeptical as regards the validity of R. p. luteiventris. However, the purpose of this study is not to attempt to settle this taxonomic issue but rather to gain some conception of the amount of variation that may be expected in several localized populations of Rana p. pretiosa in Yellowstone Park, Wyoming. The expansion of this approach to embrace other populations in other parts of the range of Rana pretiosa will eventually permit a decision as to the status of R. p. luteiventris. A similar study of pigmentation has already been carried out in Oregon by Dunlap (1955). His remarks are based largely on preserved material (at least for melanin distribution) with additional notes on ventral color differences based on field observations. In this study a more restricted geographic area was chosen for

Descriptions of Four Salientian Eggs

There exist, so far as we know, no descriptions of the eggs of Bufo alvarius, Rana aurora aurora, Rana boylii sierrae, and Rana pretiosa luteiventris. In the collection of the Cornell University Museum there are specimens of eggs of each of these species. Unfortunately the individual eggs were not measured when freshly collected. Hence, the measurements given below were obtained from material preserved in seven per cent formalin. However, so far as can be determined, the preservative has caused no appreciable change in the specimens. The measurements were made with the aid of an ocular micrometer. Unless stated otherwise, data appearing under the sections on field notes are from the records of A. H. Wright.