Pipiens Schreber Research Articles

Nematode parasites and leukocyte profiles of Northern Leopard Frogs,Rana pipiens: location, location, location

Globally, amphibians face a variety of anthropogenic stresses that include exposure to contaminants such as agricultural pesticides. Pesticides may negatively affect amphibian immune systems, concomitantly increasing susceptibility to parasitism. We quantified nematodes and evaluated leukocyte profiles of Northern Leopard Frogs (Rana pipiens Schreber, 1782) collected from five wetlands in southwestern Quebec, Canada, that spanned a gradient of pesticide exposure. Three taxa of nematode parasites (Rhabdias ranae Walton, 1929, genus Oswaldocruzia Travassos, 1917, and genus Strongyloides Grassi, 1879) were sufficiently numerous for detailed evaluation. When all frogs were pooled, frog size was negatively correlated with nematode species richness, abundances of each of the three nematode species, and densities of three different leukocytes. When all frogs were pooled, there was strong evidence of both negative and positive associations between pairs of parasite species. However, none of the previous relationships was significant within wetlands. Our results reveal strong spatial organization of amphibian–parasite communities and illustrate the importance of controlling for sampling locale in evaluating host–parasite associations. Finally, although several response variables varied significantly among wetlands, causes of this variation did not appear to be related to variation in nematode parasitism or pesticide exposure.

Does exposure to cues of fish predators fed different diets affect morphology and performance of Northern Leopard Frog (Lithobates pipiens) larvae?

Phenotypic plasticity allows animals to change their morphological and life-history traits when exposed to predator cues, which modifies performance and can enhance survival but engender costs. Thus, the extent of plastic changes should vary in relation to the perceived risk of predation. We tested the hypothesis that plastic changes in morphology (and their effect on performance) and life history of developing Northern Leopard Frog (Lithobates pipiens (Schreber, 1782)) larvae vary when exposed to cues of fish predators fed different diets. During development, we exposed tadpoles to control cues, cues from brown bullhead (Ameiurus nebulosus (Lesueur, 1819)) fed trout pellets, or cues from A. nebulosus fed L. pipiens tadpoles. Tadpoles exposed to predatory fish cues had smaller bodies, deeper tail fins, slower growth and development rates, and better turning performance than tadpoles that were not exposed to predatory fish cues, but we found limited evidence that the predator’s diet had an effect on phenotypic plasticity. Predator diet affected tail morphology and activity, but the latter effect was only marginally significant. Lithobates pipiens tadpoles clearly respond to predatory fish cues, but it remains unclear whether their response is modulated by the predator’s diet.

Opossums and Leopard Frogs Consume the Federally Endangered American Burying Beetle (Coleoptera: Silphidae)

The American burying beetle (ABB), Nicrophorus americanus Olivier, has disappeared from more than 90% of its historic range and has been listed as federally endangered since 1989. Prior to its listing, relatively few studies existed documenting ABB ecology and interactions with other animals, including its potential vertebrate predators. Bedick et al. (1999) documented a predation event by a blue jay, Cyanocitta cristata L. Walker and Hoback (2006) presented circumstantial evidence of predation by a bat of a beetle that was equipped with a radio transmitter. Shrews that fall into pitfall traps occasionally eat American burying beetles (W. W. Hoback, personal observation). Further evidence of potential predation by shrews was found in an illustration of a masked shrew consuming an American burying beetle (Zim and Hoffmeister 1955). Herein, we document video surveillance of predation of American burying beetle by Virginia opossum, Didelphis virginiana (Kerr), and pronota and elytra of ABB in feces of the northern plains leopard frog, Lithobates pipiens Schreber. We conducted two studies in the northeastern region of Nebraska’s Sandhills utilizing camcorders to record carrion beetle activity at night on rat (Rattus norvegicus Berkenhout) carcasses. The rat carcasses (approximately 300 g) were secured and could not be buried or removed from the site; however, beetles and some other animals could freely enter or exit the bait stations. Similar stations were used in 2010, but cages were used to eliminate access by opossums. The cages kept opossums out, but did not deter northern plains leopard frogs. Over 230 hrs of video were captured in 2009 and over 500 hrs in 2010, providing novel ABB footage and the opportunity to make behavioral observations. American burying beetle mortality caused by an opossum was confirmed by a video recorded on the

Genetic diversity and structure in Canadian northern leopard frog (Rana pipiens) populations: implications for reintroduction programs

The northern leopard frog ( Rana pipiens Schreber, 1782) underwent a large decline in the western portion of its range and only occurs in 20% of historically occupied sites in Alberta. Its absence may reflect an inability to disperse to these sites because of habitat fragmentation, and human-mediated translocation has been proposed. In this study, we used three criteria to examine the genetic suitability of potential translocation sources: diversity, similarity to area of reintroduction, and evolutionary history. We genotyped 187 samples and sequenced 812 bp of the mitochondrial NADH dehydrogenase 1 gene from 14 Canadian northern leopard frog populations. Nuclear and mitochondrial diversity were highest in Manitoba and western Ontario and declined westward. There was no significant relationship between genetic and geographic distance, suggesting that genetic drift is a driving force affecting the genetic relationships between populations. Regions separated by more than ~50 km were quite differentiated. Therefore, source populations similar to the original inhabitants of an area for reintroduction may be uncommon. Mitochondrial analyses revealed that all populations share a close evolutionary history, belonging to the western haplotype group. While genetic criteria support the use of Manitoba and Ontario as sources, the desirability of environmental similarity to the reintroduction site suggests that ecologically exchangeable Alberta populations should also be considered.

Antipredator behavior of chytridiomycosis-infected northern leopard frog (Rana pipiens) tadpoles

We investigated the effects of Batrachochytrium dendrobatidis Longcore, Pessier & Nichols, a pathogen implicated in global amphibian population declines, on antipredator behavior of northern leopard frog (Rana pipiens Schreber, 1782) tadpoles in response to visual and chemical cues of a fish predator, bluegill sunfish (Lepomis macrochirus Rafinesque, 1819). We placed infected and uninfected tadpoles in containers partitioned with a transparent divider and measured tadpole activity and distance from the center. Infected tadpoles had significantly lower activity levels across all treatments. When exposed to only visual cues, uninfected tadpoles positioned themselves farther from the center divider (and thus the predator) than infected animals. All tadpoles were at similar distances from the center when exposed to chemical cues only, likely because chemical cues alone do not provide spatial information on the location of predators. Infected tadpoles were significantly farther from the center divider than uninfected ones when exposed to visual and chemical cues together, suggesting that, although the mechanism is unknown, both cues are necessary to stimulate predator avoidance behavior for infected animals. In a second experiment, infected tadpoles experienced lower mortality than uninfected ones in the lethal presence of fish. Thus, effects of infection on behavioral antipredator responses are complex, but lower host susceptibility to predation, low activity, and greater distance from predators when both chemical and visual predator cues are present likely benefits B. dendrobatidis, which relies on host survival for transmission.

Landscape resistance to frog movements

An animal's capacity to recolonize a patch depends on at least two components: its ability to detect the patch and its ability to reach it. However, the disruption of such processes by anthropic disturbances could explain low animal abundance patterns observed by many investigators in certain landscapes. Through field experiments, we compared the orientation and homing success of northern green frogs (Rana clamitans melanota Rafinesque, 1820) and northern leopard frogs (Rana pipiens Schreber, 1782) translocated across disturbed or undisturbed surfaces. We also monitored the path selected by individuals when presented with a choice between a short distance over a disturbed surface and a longer, undisturbed route. Finally, we measured the water loss and behaviour of frogs on substrates resulting from anthropogenic disturbances and a control. When presented with a choice, 72% of the frogs avoided disturbed surfaces. Although able to orient towards the pond of capture when translocated on disturbed surfaces, frogs had a lower probability of homing successfully to the pond than when translocated at a similar distance on an undisturbed surface. Frogs lost the most water on substrates associated with disturbance and in the absence of cover. Our data illustrate that anthropically disturbed areas devoid of cover, such as mined peatlands and agricultural fields, disrupt the ability of frogs to reach habitat patches and are likely explanations to their reduced abundance patterns in such environments.

Differences in size, pigmentation, and fluctuating asymmetry in stressed and nonstressed northern leopard frogs (Rana pipiens)

We compared a range of anatomical features of northern leopard frogs (Rana pipiens Schreber) collected from areas where deformity rates were low (-2% in nonstressed regions) and high (-40% in the stressed region) to determine if one or more of these characters might be useful in detecting developmental stress. Deformed individuals from the stressed region were significantly lighter than normal frogs both from the same region and from nonstressed regions. Body length, head width, femur length, and forelimb length were also significantly shorter in deformed and normal individuals from the stressed region than in individuals from nonstressed regions. Despite being smaller, deformed individuals had significantly larger pigment spots. Fluctuating asymmetry in femur length, femur spot area, femur spot number, and tibio-fibula length was significantly greater in deformed frogs than in normal frogs from the stressed population and the nonstressed group. Of these characters, however, only femur spot number provided a data set suitable for fluctuating asymmetry analysis (R - L values have a normal distribution, no directional asymmetry, no size-dependent asymmetry). There were no significant differences found among the three groups for fluctuating asymmetry in forelimb length, eyespot area, lateral spot number, and lateral spot area.

Controlled anaesthesia of Rana catesbeiana (Shaw) and Rana pipiens (Schreber 1792) using xylocaine delivered by spray

Controlled anaesthesia of <i>Rana catesbeiana</i> (Shaw) and <i>Rana pipiens</i> (Schreber 1792) using xylocaine delivered by spray

A Skeletochronological Assessment of Age and Growth in the Frog Rana pipiens Schreber (Amphibia, Anura) from Southwestern Quebec

The number of hematoxylinophile resting lines (RL) in diaphyseal cross-sections of phalanges was used to assess individual ages in 53 Rana pipiens, mostly males, from a southwestern Quebec population. The RL ranged from zero in underyearling frogs to a maximum of four in the largest specimen. Endosteal resorption may have eroded away the first RL in a significant number of frogs. In adults, most of the osseous crown thickness was made up of parallel fibered bone deposited during the second growing season. The results indicate that frogs experience a rapid growth rate and reach sexual maturity at 2 yr of age; frogs older than 4-5 yr old represent only a tiny fraction of the population. KELETOCHRONOLOGY, which uses var

Trypanosoma chattoni Mathis &amp; Leger, 1911 in Rana pipiens of southern Ontario: morphometrics and a description of the division process

Trypanosoma chattoni Mathis & Leger, 1911 was detected in stained kidney impressions in eight of 41 Rana pipiens Schreber, 1782. It is distinguished from Trypanosoma rotatorium (Mayer, 1843) Laveran & Mesnil, 1901 by being round and having a much shorter flagellum with no obvious undulating membrane. Body width and cell area of dividing and non-dividing forms are similar. However, the nuclear area of dividing forms is greater than in non-dividing forms. The ratio of nuclear area to cell area of T. chattoni is the same for both isolates in this study and for specimens from previous studies. T. chattoni divides by binary fission during which daughter kinetoplasts migrate to opposite poles of the nucleus before nuclear division. Cell division follows nuclear division. ac]19860207

The biology of Trypanosoma andersoni n. sp. and Trypanosoma grylli Nigrelli, 1944 (Kinetoplastida) from Hyla versicolor LeConte, 1825 (Anura)

From May 1979 to July 1980, the blood of 196 mature Hyla versicolor LeConte from six sites in southern Ontario and southeastern Manitoba was examined for trypanosomes using the haematocrit centrifugation technique. Trypanosoma andersoni n. sp. and Trypanosoma grylli Nigrelli were found in 5.2 and 5.6% of the frogs examined. Three frogs (1.5%) were infected with both species of trypanosomes. Blood trypomastigotes of both species were monomorphic. Blood trypomastigotes of T. andersoni n. sp. were long and slender, tapering at both ends, whereas those of T. grylli were pyriform with a rounded posterior and tapered anterior.Both blood and culture forms of these trypanosomes were infective to laboratory-raised H. versicolor and Hyla crucifer Wied. Trypanosoma grylli was also infective to a field-collected Acris gryllus (LeConte). Neither trypanosome was infective to laboratory-raised Rana catesbeiana Shaw, Rana clamitans Rafinesque tadpoles, Rana pipiens Schreber, Rana sylvatica LeConte, or Xenopus laevis Daudin. Trypanosoma andersoni n. sp. was also not infective to laboratory-raised Bufo americanus Holbrook, Pseudacris triseriata (Wied), or to field-collected Hyla cinerea (Schneider) and Osteopilus septentrionalis Dumeril and Bibron. Neither species was infective to field-collected Notophthalmus viridescens (Rafinesque).

The genetic basis of a dorsal color polymorphism in Rana pipiens.

Leopard frogs (Rana pipiens Schreber) from Colorado were used in laboratory matings to investigate the mode of inheritance of green-brown, dorsal background color polymorphism. A total of 624 F1 progeny were produced in 18 successful matings. The results support the hypothesis that the control of dorsal color in Rana pipens is a two-allele, one-locus system with the allele for green color dominant to the allele for brown color.

Development of the urostyle during metamorphosis in five species of anurans.

Normal development of the urostyle is described during late stages of metamorphosis in five species of anurans: Xenopus laevis (Daudin), Bufo americanus Holbrook, Pseudacris triseriata (Wied), Hyla chrysoscelis Cope, and Rana pipiens Schreber. The developing urostyle of all five species is composed of essentially the same cartilaginous elements: one pair of basidorsals above the notochord and the subtended hypochord. Among the five species there is variation in such details as the number of spinal nerve foramina and the degree of fusion of the basidorsals; however, both the hypochord and basidorsals are very similar in all five genera examined. Consideration of the literature suggests that contradictory descriptions of the developing urostyle result from (1) varied methods of study (alizarin-staining of whole specimens or serial cross-sections), (2) the variety of species examined, and (3) the particular stage of development of the tadpole described by an investigator.

A Model of the Dynamic Exchanges of Water and Energy between a Terrestrial Amphibian and Its Environment

Mechanistic models of the H2O and energy dynamic interrelationships between a terrestrial amphibian and its environments were developed and applied in a study of the temperature and water relations of the northern leopard frog Rana pipiens Schreber. The models illustrate the relative importance of air temperature, relative humidity, wind speed, absorbed solar and thermal radiation, substrate temperature, and soil H2O potential on the core temperatures, hydration levels, and rates of hydration level change during desiccation and rehydration for leopard frogs of different size. Leopard frogs' core temperatures are influenced most by ambient air and substrate temperatures, whereas absorbed radiation has a subordinant effect. Evaporative H2O loss rates are strongly influenced by absorbed radiation and virtually not influenced at all by substrate temperature (relative humidity, air temperature, and wind speed were also shown to be strongly influential on evaporative H2O loss). Water uptake from wet soils (ψsoil &gt; —150 mb) is determined primarily by the properties of the frog, whereas H2O uptake from relatively drier soils (ψsoil &lt; —300 mb) is determined by the conductive properties of the soil. Results of computer simulations suggest that leopard frogs in southern Wisconsin environments should not be found at great distances from standing H2O or soils with H2O potentials &lt; —150 mb. Data taken from the literature and viewed in context of the theory of H2O exchange between an amphibian and soil, suggests that leopard frogs may rarely venture from saturated soils (ψ soil = 0). Results of simulations also imply that leopard frogs in most natural environmental circumstances will not generally have core temperatures greatly different from ambient air temperatures; thus, implying that any behavioral thermoregulatory ability would likely be crude. The modeling approach provides an extremely practical technique to study mechanistic interactions of the many environmental variables involved in the temperature and water relations of terrestrial amphibians.

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

Under-Ice Observations of Wintering Sites of Leopard Frogs

Leopard frogs (Rana pipiens Schreber) hibernating in an ice-covered pond in Ontario, Canada, were found to rest in small pits apparently excavated by the frogs. Frogs were sometimes lightly covered with silt and all were capable of some movement including swimming. This habit keeps the frogs from being buried in anoxic mud, but increases their exposure to predation by fish, such as trout. Observations were made using SCUBA under the ice.

Androgens of the leopard frog, Rana pipiens Schreber

It was determined by paper chromatographic methods that the principal steroids produced by the testes of Rana pipiens S. are testosterone and androstenedione.

Studies on the Helminth Fauna of Iowa. I. Trematodes of Amphibians

A survey of 542 amphibians collected during 1953-1967 from 40 areas of northwest Iowa reveals an incidence of 52.8% infection with digenetic trematodes. Almost all represent new locality records. Hosts examined include Ambystoma tigrinum (Green), Bufo americanus Holbrook, Bufo cognatus Say, Acris crepitans Baird, Hyla versicolor LeConte, Pseudacris triseriata (Wied), Rana catesbeiana Shaw, and Rana pipiens Schreber. Fifteen species of flukes are included in the collection, 14 of which are harbored by Rana pipiens (leopard frog), the most abundant host in the region. A summary of pertinent literature relating to each species of trematode. is presented, together with 20 illustrations. The trematode fauna of amphibians of the United States is quite varied and has been the subject of numerous investigations. Early compilations by Stiles and Hassall (1894) and by Pratt (1900, 1904) were followed by the first comprehensive systematic accounts of Stafford (1902a,b, 1905), who published several reports on helminths of North American vertebrates. Later studies on amphibian helminths from the United States include those by Cort (1912, 1915a), Harwood (1932), Brandt (1936), Ingles (1936), Rankin (1937), Manter (1938), Kuntz (1940), Parker (1941), Kuntz and Self (1944), Rankin (1945), Bouchard (1951), Lehmann (1954, 1956, 1960), Odlaug (1954), Najarian (1955), Frandsen and Grundmann (1960), Waitz (1961) and Campbell (1967). Pratt and McCauley (1961) compiled an annotated catalogue of the trematodes of the Pacific northwest. A series of abstracts and papers published by Walton (1942-1962)1 included a worldwide compilation of amphibian hosts, parasites and their geographic distribution. This information, together with a comprehensive bibliography, was published in microcard form in 1964. The herculean effort of Yamaguti (1958) to bring together an account of all genera of digenetic trematodes of vertebrates has provided a useful summary of the literature up to 1955. Published accounts of the helminth fauna of Iowa are regrettablv meager. Since 1953, an extensive survey of helminths of vertebrates within the state has been under way and has resulted in the examination of several thousand hosts. This report, the first in a series devoted to the helminths of Iowa vertebrates, is concerned with trematodes of amphibians, particularly those from the lakes region of northwestern Iowa. 1 For a listing of these reports, see the U.S. Dep. Agriculture Index Catalogue of Medical and Veterinary Zoology, Part 17 (1952) (Authors) and subsequent supplements.

The Life Cycle of Cephalogonimus americanus Stafford, 1902 (Trematoda: Cephalogonimidae)

Mother and daughter sporocysts and xiphidiocercariae of Cephalogonimus americanus develop in the snails Helisoma antrosa and H. trivolvis. Following emergence, cercariae penetrate tadpoles in which they encyst. Cephalogonimus americanus develops in the anterior small intestine of Rana clamitans which acquires the parasite by eating infected tadpoles. It is suggested that young frogs may also become infected during metamorphosis. Stafford (1902) described adult Cephalogonimus americanus from the intestine of Rana clamitans Latreille. It has also been reported from R. pipiens Schreber by Brandt (1936) and Najarian (1955). Rai (1961) listed 20 species for the genus. To date no complete life history has been reported for any member of the genus. Cephalogonimus americanus is a common intestinal parasite of R. clamitans found in certain areas near Douglas Lake,

Spring Movements of Leopard Frogs, Rana pipiens Schreber, in Northern Michigan

In spring, adult leopard frogs precede the young out of hibernation. During and for several weeks after breeding, frogs of all ages are confined to bodies of water and do not occupy the fields as in summer. Some movement occurs between ponds, involving mainly, perhaps entirely, postbreeding frogs. In 1962, 39% of the adult leopard frogs in one study area were occupying their home ranges within a week after emergence from hibernation in late April; this was possible because extensive spring flooding permitted breeding in normally less wet regions where many animals had summer ranges, and because many animals had summer home ranges adjoining ponds. In contrast, in a second study area where spring flooding was less extensive and where few animals resided near water, frogs did not abandon the ponds and begin moving to their home ranges until late May and early June; movements to the summer ranges in the fields continued throughout June and, for a few stragglers, into early July. Two adult females were trailed as they moved to their home ranges 150 and 400 m from the ponds. Details of their routes are given.