| growth and behavior of thyroid-deficient lizards (sceloporus undulatus). | this study investigates thyroid control of growth and energy metabolism plus growth-dependent and growth-independent behavioral effects of thyroid manipulation in lizards. experiments were done on surgically thyroidectomized (tx) and sham-operated (sh) yearling sceloporus undulatus enclosed in their natural habitat. lizards were placed in an outdoor enclosure in early august. growth rate was measured and behavior was observed until mid-october. subsequently, lizards were returned to the lab for ... | 1992 | 1398024 |
| the western fence lizard sceloporus occidentalis: evidence of field exposure to borrelia burgdorferi in relation to infestation by ixodes pacificus (acari: ixodidae). | the role of the western fence lizard sceloporus occidentalis in the enzootiology of the lyme disease spirochete borrelia burgdorferi was evaluated in the hopland and ukiah areas of mendocino county, california. in 1989, half of 74 lizards collected monthly from april to october at hopland were infested by the immature western black-legged tick ixodes pacificus at a mean intensity of 6.0 ticks per lizard. the prevalence of infestation of lizards by immature i. pacificus (36 of 73) at ukiah was si ... | 1992 | 1524146 |
| interactive effects of thyroxine and experimental location on running endurance, tissue masses, and enzyme activities in captive versus field-active lizards (sceloporus undulatus). | this study investigates the effects of exogenous thyroxine (t4) on running endurance, tissue masses, and the activities of citrate synthase (cs), pyruvate kinase (pk), cytosolic alpha-glycerophosphate dehydrogenase (alpha-gpdh), and beta-hydroxyacyl coenzyme a dehydrogenase (hoad) in sceloporus undulatus (eastern fence lizard). the enzymes were assayed to indicate maximal catabolic activities that support exercise. parallel experiments were done on captive and field-active groups to determine wh ... | 1991 | 2026310 |
| virulence of lizard malaria: the evolutionary ecology of an ancient parasite-host association. | the negative consequences of parasitic infection (virulence) were examined for two lizard malaria parasite-host associations: plasmodium agamae and p. giganteum, parasites of the rainbow lizard, agama agama, in sierra leone, west africa; and p. mexicanum in the western fence lizard, sceloporus occidentalis, in northern california. these malaria species vary greatly in their reproductive characteristics: p. agamae produces only 8 merozoites per schizont, p. giganteum yields over 100, and p. mexic ... | 1990 | 2235062 |
| survey of birds and lizards for ixodid ticks (acari) and spirochetal infection in northern california. | a total of 138 birds (24 species) was captured in an oak woodland between december 1988 and june 1989 at the university of california, sierra foothill range field station, yuba county, calif. ticks were not found on 71 birds captured between december 1988 and march 1989. five subadult ixodes pacificus cooley & kohls were removed from 3 of 67 birds caught between april and june 1989. these three birds, an orange-crowned warbler (vermivora celata (say], a lazuli bunting (passerina amoena (say], an ... | 1990 | 2280384 |
| thyroid regulation of resting metabolic rate and intermediary metabolic enzymes in a lizard (sceloporus occidentalis). | this study investigates the effects of physiological increments in plasma thyroxine (t4) at three levels of biological organization in thyroid-intact and thyroidectomized captive western fence lizards, sceloporus occidentalis. two doses of t4-loaded pellets elevated plasma t4 in thyroid-intact lizards from 4.8 +/- 0.47 to 10.7 +/- 2.25 and 20.4 +/- 5.77 ng/ml (mean +/- se). surgical thyroidectomy reduced t4 to 1.8 +/- 0.23 ng/ml, and subsequent t4 pellet implantation raised t4 to 14.8 +/- 4.30 n ... | 1990 | 2295423 |
| susceptibility of the western fence lizard (sceloporus occidentalis) to the lyme borreliosis spirochete (borrelia burgdorferi). | attempts to infect juvenile and adult western fence lizards (sceloporus occidentalis) with the lyme borreliosis spirochete (borrelia burgdorferi) were largely unsuccessful. spirochetes could not be isolated from the blood and various tissues of 14 lizards 21-32 days after they had been inoculated ip (n = 8) or sc (n = 6) with 10(6) or 10(8) b. burgdorferi representing 3 tick isolates, although 1 lizard apparently developed a transitory spirochetemia lasting 2 days. similarly, spirochetes could n ... | 1990 | 2301709 |
| lyme disease in california: interrelationship of ixodes pacificus (acari: ixodidae), the western fence lizard (sceloporus occidentalis), and borrelia burgdorferi. | the relationship of immature western black-legged ticks, ixodes pacificus cooley and kohls, to the western fence lizard, sceloporus occidentalis baird and girard, and to the lyme disease spirochete, borrelia burgdorferi, was investigated in chaparral and woodland-grass habitats in northern california from 1984 to 1986. immature ticks were found on lizards in spring and summer, but the prevalence and abundance of ticks on this host were considerably greater in spring. the peak of larval abundance ... | 1989 | 2769705 |
| the sex ratio of plasmodium gametocytes. | sex ratio theory usually predicts an equilibrium sex ratio and equal proportions of males and females in a population, including the progenitors of the reproductive cells of protozoans. this proposal was tested with three species of malarial parasites of lizards, plasmodium mexicanum of the western fence lizard, and p. agamae and p. giganteum of the african rainbow lizard, using single samples from naturally infected lizards, repeated samples from free-ranging lizards (p. mexicanum only), and re ... | 1989 | 2771445 |
| larval nematodes (ascarops sp., spirurida, spirocercidae) in liver granulomata of the western fence lizard, sceloporus occidentalis (iguanidae). | prevalence of larval nematodes (ascarops sp., spirurida, spirocercidae) and associated granulomata are reported from livers of wild populations of the western fence lizard, sceloporus occidentalis. granulomata were circumscribed by layers of fibrocytes. the encysted nematode was surrounded by masses of histiocytes, cellular debris and cells with pyknotic nuclei. | 1988 | 3411718 |
| experimental transmission of plasmodium mexicanum by bites of infected lutzomyia vexator (diptera: psychodidae). | lutzomyia vexator is an efficient experimental vector of plasmodium mexicanum, infecting 69.2% (9/13) of the sceloporus undulatus lizards with as few as one bite. sporozoites were present in the salivary glands by day 6.5 postfeed and infective by day 8 postfeed at 27 degrees c. the prepatent period was relatively long, ranging from 23 to 40 days for bite-induced infections and appears to be related to the number of sporozoites injected. the acute phase of the infection is initially exponential ... | 1987 | 3504905 |
| the occurrence and development of plasmodium mexicanum in the western fence lizard sceloporus occidentalis. | | 1970 | 5420333 |
| lizards infected with malaria: physiological and behavioral consequences. | in northern california, western fence lizards, sceloporus occidentalis, are frequently parasitized by plasmodium mexicanum, which causes malaria. animals with this naturally occurring malarial infection are anemic: immature erythrocytes in peripheral blood become abundant (1 to 30 percent), and blood hemoglobin concentration decreases 25 percent. maximal oxygen consumption decreases 15 percent and aerobic scope drops 29 percent in infected lizards; both correlate with blood hemoglobin concentrat ... | 1982 | 7112113 |
| diel activity of nymphal dermacentor occidentalis and ixodes pacificus (acari: ixodidae) in relation to meteorological factors and host activity periods. | relation of diel activity and questing behavior of nymphal dermacentor occidentalis marx and ixodes pacificus cooley & kohls to meteorological factors was investigated in a shaded versus a sun-exposed outdoor arena. oak-woodland soil covered partially with leaf litter and small rocks, and 24 vertically oriented grass stems 2.5, 5.0, 10.0, and 20.0 cm tall were provided as substrate and potential questing sites. tick activity and weather conditions were monitored bihourly during 15 diel (24-h) ex ... | 1995 | 7616519 |
| immature ixodes scapularis (acari: ixodidae) parasitizing lizards from the southeastern u.s.a. | preserved museum specimens of 13 lizard and 3 snake species common in the southeastern u.s.a. were examined for immature ixodes scapularis say ticks. five eumeces and 4 ophisaurus lizard species yielded an infestation prevalence of 17.8% for species of eumeces and 29.0% for species of ophisaurus. mean intensity of larvae and nymphs was 7.1 and 2.7, respectively, for species of eumeces, and 6.3 and 1.4, respectively, for species of ophisaurus. collection dates of the lizards ranged from january t ... | 1993 | 8410539 |
| characterization of the clinical and anatomical pathological changes associated with hepatozoon mocassini infections in unnatural reptilian hosts. | laboratory-reared aedes aegypti mosquitoes were employed in the successful transmission of hepatozoon mocassini from a cotton-mouth moccasin (agkistrodon piscivorus leucostoma) to 3 lizard species (sceloporus undulatus, eumeces obsoletus and sceloporus poinsetti). marked to severe lethargy and anorexia developed in the s. undulatus, e. obsoletus and s. poinsetti at 15, 38, and 96 days postinfection (pi), respectively. all 3 lizards developed a leukocytosis and had increased plasma aspartate amin ... | 1996 | 8690537 |
| borreliacidal factor in the blood of the western fence lizard (sceloporus occidentalis). | in some populations of the western black-legged tick, ixodes pacificus, the prevalence of infection with lyme disease spirochetes (borrelia burgdorferi) in nymphal ticks exceeds those in adult ticks by 3-4-fold. experiments were conducted to determine if the reduced spirochetal prevalence in adult ticks is due to the presence of anti-borrelial antibodies or to another borreliacidal factor in the blood of the western fence lizard, sceloporus occidentalis, a primary host of subadult i. pacificus, ... | 1998 | 9488334 |
| abundance of ticks (acari: ixodidae) infesting the western fence lizard, sceloporus occidentalis, in relation to environmental factors. | we examined the impact of environmental characteristics, such as habitat type, topographic exposure and presence of leaf litter, on the abundance of ixodes pacificus ticks infesting the western fence lizard (sceloporus occidentalis) at the university of california hopland research and extension center (hrec), mendocino county, california. a total of 383 adult lizards were slip-noosed and examined for tick infestation in april and may 1998. at least 94% of the lizards were infested by ticks and a ... | 1999 | 10581712 |
| oxygen consumption by mitochondria from an endotherm and an ectotherm. | comparisons of metabolic properties of mitochondria from an endothermic and an ectothermic vertebrate were performed. oxygen (o2) consumption rates of liver mitochondria from laboratory mice and western fence lizard (sceloporus occidentalis) were determined over a range of temperatures (10, 20, 30 and 37 degrees c) and in the presence of a variety of substrates. at 37 degrees c the o2 consumption rate of mouse mitochondria was 4-11 times higher than lizard mitochondria in the presence of five of ... | 1999 | 10582317 |
| seasonal activity and host associations of ixodes scapularis (acari: ixodidae) in southeastern missouri. | based on tick collections recovered from wild vertebrates and by dragging, the seasonal occurrence of adult blacklegged ticks, ixodes scapularis say, extended from october through may in southeastern missouri. adult activity was bimodal with the higher peak occurring in november followed by a lower peak in february. the activity of immature i. scapularis had the general pattern of that found in the northeast where lyme disease is hyperendemic, with larval activity (july) peaking after that of ny ... | 1999 | 10593072 |
| phenotypic effects of leptin in an ectotherm: a new tool to study the evolution of life histories and endothermy? | leptin is a hormone that regulates energy expenditure and body mass in mammals, and it has attracted considerable attention because of its potential in treating human obesity. comprehensive data from both pathological and non-pathological systems strongly support a role for leptin in regulating energy metabolism, in thermoregulation and in regulating the onset of puberty. we report here that daily injections of recombinant murine leptin in fence lizards (sceloporus undulatus) produce phenotypic ... | 2000 | 10607539 |
| life history of a malaria parasite (plasmodium mexicanum) in its host, the western fence lizard (sceloporus occidentalis): host testosterone as a source of seasonal and among-host variation? | the course of infection of a malaria parasite (plasmodium mexicanum) is highly variable in its host, the fence lizard (sceloporus occidentalis). however, a seasonal trend is superimposed on this variation such that gametocyte production is intensified during mid- to late summer. host testosterone levels follow a similar seasonal fluctuation and are variable among individual lizards. we sought to determine if testosterone levels affect seasonal and among-host variation in 11 p. mexicanum life his ... | 2000 | 11128477 |
| transmission success of the malaria parasite plasmodium mexicanum into its vector: role of gametocyte density and sex ratio. | the life-cycle of plasmodium depends on transmission of the parasite from the vertebrate host into its vector when the insect takes a bloodmeal. transmission success may depend in part on the parasite's gametocyte density and sex ratio in the blood. p. mexicanum, a parasite of fence lizards in california, usa, exploits the sandfly lutzomyia vexator as its vector. in experimental transmissions using naturally infected lizards as donors of blood, transmission success (measured as percentage of vec ... | 2000 | 11155927 |
| a comparative study of mammalian and reptilian alternative pathway of complement-mediated killing of the lyme disease spirochete (borrelia burgdorferi). | the potential bactericidal activity of the alternative complement pathway of mammalian and reptilian sera to borrelia burgdorferi sensu stricto (s.s.) was evaluated in vitro. complement-mediated killing was observed when cultured spirochetes were inoculated into sera from the western fence lizard (sceloporus occidentalis) and from the southern alligator lizard (elgaria multicarinata), but not when they were inoculated into serum from either the deer mouse (peromyscus maniculatus) or from humans. ... | 2000 | 11191895 |
| landscape features associated with infection by a malaria parasite (plasmodium mexicanum) and the importance of multiple scale studies. | in a 3-year study, we examined landscape features (aspect, slope, sun exposure, canopy cover, type of ground cover, and nearest water source) that were potentially related to prevalence of infection with plasmodium mexicanum in fence lizards (sceloporus occidentalis) within a 4.5 ha study area in northern california, usa. logistic regression analysis showed that ground cover type was the primary mediator of the probability of p. mexicanum infection. infected lizards were captured more often in r ... | 2001 | 11393823 |
| birds and their ticks in northwestern california: minimal contribution to borrelia burgdorferi enzootiology. | birds and their attendant ticks were surveyed for infection with the lyme disease spirochete borrelia burgdorferi, in chaparral and woodland-grass habitats in northwestern california from march to july, 1998 to 1999. in total, 234 birds were captured and recaptured (15%); nearly 2.5 times more birds were captured in chaparral than in woodland-grass. overall, 34 species representing 15 families were collected during this study; of these, 24 species were caught in chaparral, 19 in woodland-grass, ... | 2001 | 11534638 |
| prevalence and abundance of ixodes pacificus immatures (acari: ixodidae) infesting western fence lizards (sceloporus occidentalis) in northern california: temporal trends and environmental correlates. | the prevalence and abundance of immature ixodes pacificus ticks on western fence lizards (sceloporus occidentalis) were examined in relation to time of year, host attributes (i.e., age, gender, and presence or absence of blood parasites), and 5 environmental characteristics, including topographic exposure and ground cover substrate, over a 2-year period in northern california. lizards were infested with subadult ticks from early march until late july or early august, with peak median numbers of ... | 2001 | 11780813 |
| nymphs of the western black-legged tick (ixodes pacificus) collected from tree trunks in woodland-grass habitat. | nymphs of the western black-legged tick, ixodes pacificus, were found on the trunks of trees during spring and summer in northwestern california. in a woodland-grass habitat, large- and medium-sized (> 130 cm and 80-130 cm in circumference, respectively), moss-covered oak (quercus spp.) trees supported ticks significantly more often than trees without these characteristics. additionally, trees with basal leaf-litter and lacking shade (at time of sampling) were significantly associated with the p ... | 2001 | 11813653 |
| molecular systematics of the eastern fence lizard (sceloporus undulatus): a comparison of parsimony, likelihood, and bayesian approaches. | phylogenetic analysis of large datasets using complex nucleotide substitution models under a maximum likelihood framework can be computationally infeasible, especially when attempting to infer confidence values by way of nonparametric bootstrapping. recent developments in phylogenetics suggest the computational burden can be reduced by using bayesian methods of phylogenetic inference. however, few empirical phylogenetic studies exist that explore the efficiency of bayesian analysis of large data ... | 2002 | 11943092 |
| gametocyte sex ratio of a malaria parasite: experimental test of heritability. | the gametocyte sex ratio of plasmodium mexicanum, a malaria parasite of western fence lizards, was studied in a modified garden experiment. each of 6 naturally infected lizards was used to initiate 20 replicate-infections in naive western fence lizards. a significant donor effect was observed for the sex ratios of recipient infections at their maximal parasitemia, and this effect was associated with the sex ratio of the donor infection. in 20 infections in which sex ratio was followed during the ... | 2002 | 12099417 |
| relative importance of lizards and mammals as hosts for ixodid ticks in northern california. | abstract lizards and mammals were trapped and examined for ticks from august 1992 to june 1993 in two habitat types, chaparral and woodland-grass, in northern california. five tick species were collected from mammals (dermacentor occidentalis, haemaphysalis leporispalustris, ixodes pacificus, i. spinipalpis, i. woodi), but only i. pacificus was found on lizards. dermacentor occidentalis, i. pacificus, and i. woodi occurred in both habitats, whereas h. leporispalustris and i. spinipalpis were fou ... | 2002 | 12475082 |
| manipulation of the vertebrate host's testosterone does not affect gametocyte sex ratio of a malaria parasite. | gametocyte sex ratio of the malaria parasite plasmodium mexicanum is variable in its host, the western fence lizard (sceloporus occidentalis), both among infections and within infections over time. we sought to determine the effect of host physiological quality on the gametocyte sex ratio in experimentally induced infections of p. mexicanum. adult male lizards were assigned to 4 treatment groups: castrated, castrated + testosterone implant, sham implant, and unmanipulated control. no significant ... | 2003 | 12659329 |
| development of a terrestrial vertebrate model for assessing bioavailability of cadmium in the fence lizard (sceloporus undulatus) and in ovo effects on hatchling size and thyroid function. | in the terrestrial environment, standardized protocols are available for measuring the exposure and effects of contaminants to invertebrates, but none currently exist for vertebrates. in an effort to address this, we proposed that developing lizard embryos may be used as a terrestrial vertebrate model. lizard eggs may be particularly susceptible to soil contamination and in ovo exposure may affect hatchling size, mortality, as well as thyroid function. toxicant-induced perturbations of thyroid f ... | 2004 | 14675843 |
| bacteriolytic activity of selected vertebrate sera for borrelia burgdorferi sensu stricto and borrelia bissettii. | an in vitro assay to evaluate the bacteriolytic activity of the complement pathway was applied to 2 strains of borrelia bissettii, co501 and dn127, and compared with that of b. burgdorferi sensu stricto b31. sera from mule deer (odocoileus hemionus) and the western fence lizard (sceloporus occidentalis) were completely borreliacidal for b. burgdorferi and for both strains of b. bissettii. serum from bobwhite quail (colinus virginianus) was nonlytic for b. burgdorferi and partially lytic for b. b ... | 2003 | 14740924 |
| observations on the natural occurrence of plasmodium floridense, a saurian malaria parasite, in sceloporus undulatus undulatus. | | 1951 | 14824938 |
| the course of natural and induced infections of plasmodium floridense thompson and huff in sceloporus undulatus undulatus (latreille). | | 1952 | 14952700 |
| life-history studies on two molecular strains of mesocestoides (cestoda: mesocestoididae): identification of sylvatic hosts and infectivity of immature life stages. | life-cycle studies were conducted on 2 molecular strains of mesocestoides tapeworms that represent different evolutionary lineages (clades a and b). wild carnivores, reptiles, and rodents were examined for tapeworm infections at 2 enzootic sites: (1) san miguel island (smi), a small island off the coast of southern california and (2) hopland research and extension center (hrec), a field station in northern california. results indicate that deer mice (peromyscus maniculatus) and coyotes (canis la ... | 2004 | 15040675 |
| natriuretic peptides are negative modulators of adrenocortical cell function of the eastern fence lizard (sceloporus undulatus). | elucidation of the role of natriuretic peptides (nps) in vertebrate adrenal steroidogenesis has been facilitated by the use of freshly dispersed adrenocortical cells. our recent characterization of lizard adrenocortical cells [carsia, r.v., john-alder, h.b., 2003. seasonal alterations in adrenocortical cell function associated with stress-responsiveness and sex in the eastern fence lizard (sceloporus undulatus). horm. behav. 43, 408-420] provided the opportunity to examine the influence of atria ... | 2006 | 16212963 |
| bacteriocidal activity of lizard and mouse serum for borrelia lonestari, putative agent of a lyme-like illness (aka stari or masters disease) in missouri. | to determine responses of borrelia lonestari and borrelia burgdorferi to eastern fence lizard (sceloporus undulatus) and swiss-webster mouse (mus musculus) sera. | 2005 | 16259394 |
| convergent evolution of embryonic growth and development in the eastern fence lizard (sceloporus undulatus). | theory predicts that cold environments will select for strategies that enhance the growth of ectotherms, such as early emergence from nests and more efficient use of resources. we used a common garden experiment to detect parallel clines in rates of embryonic growth and development by eastern fence lizards (sceloporus undulatus). using realistic thermal conditions, we measured growth efficiencies and incubation periods of lizards from five populations representing two distinct clades. in both cl ... | 2006 | 16817545 |
| refractoriness of the western fence lizard (sceloporus occidentalis) to the lyme disease group spirochete borrelia bissettii. | the western fence lizard, sceloporus occidentalis, is refractory to experimental infection with borrelia burgdorferi sensu stricto, one of several lyme disease spirochetes pathogenic for humans. another member of the lyme disease spirochete complex, borrelia bissettii, is distributed widely throughout north america and a similar, if not identical, spirochete has been implicated as a human pathogen in southern europe. to determine the susceptibility of s. occidentalis to b. bissettii, 6 naïve liz ... | 2006 | 16995383 |
| incubation temperature and phenotypic traits of sceloporus undulatus: implications for the northern limits of distribution. | cold environmental temperature is detrimental to reproduction by oviparous squamate reptiles by prolonging incubation period, negatively affecting embryonic developmental processes, and by killing embryos in eggs directly. because low soil temperature may prevent successful development of embryos in eggs in nests, the geographic distributions of oviparous species may be influenced by the thermal requirements of embryos. in the present study, we tested the hypothesis that low incubation temperatu ... | 2007 | 17102996 |
| hybridization between multiple fence lizard lineages in an ecotone: locally discordant variation in mitochondrial dna, chromosomes, and morphology. | we investigated a hybrid zone between two major lineages of fence lizards (sceloporus cowlesi and sceloporus tristichus) in the sceloporus undulatus species complex in eastern arizona. this zone occurs in an ecotone between great basin grassland and conifer woodland habitats. we analysed spatial variation in mtdna (n=401; 969 bp), chromosomes (n=217), and morphology (n=312; 11 characters) to characterize the hybrid zone and assess species limits. a fine-scale population level phylogenetic analys ... | 2007 | 17305859 |
| detection of borrelia burgdorferi dna in lizards from southern maryland. | lizards serve as hosts for ixodes ticks in the western and southeastern united states and may affect the transmission cycles of borrelia burgdorferi in these regions. in maryland, the role of lizards in the maintenance and transmission cycle of this pathogen has not been examined. we tested 29 lizards (sceloporus undulatus and eumeces spp.) and 21 ticks from these lizards for the presence of b. burgdorferi. eight lizards were positive by polymerase chain reaction (pcr) for at least one b. burgdo ... | 2007 | 17417956 |
| ability of transstadially infected ixodes pacificus (acari: ixodidae) to transmit west nile virus to song sparrows or western fence lizards. | the hypothesis that ixodes pacificus cooley & kohls (acari: ixodidae) may serve as a reservoir and vector of west nile virus (family flaviviridae, genus flavivirus, wnv) in california was tested by determining the ability of this tick species to become infected with the ny99 strain of wnv while feeding on viremic song sparrows, to maintain the infection transstadially, and then to transmit wnv to recipient naive song sparrows and western fence lizards during the nymphal stage. the percentage of ... | 2007 | 17427704 |
| experimental test for premunition in a lizard malaria parasite (plasmodium mexicanum). | premunition in plasmodium spp. is the prevention of superinfection by novel genotypes entering an already established infection in a vertebrate host. evidence for premunition was sought for the lizard malaria parasite, p. mexicanum, in its natural host, the fence lizard, sceloporus occidentalis. clonal diversity (= alleles for the haploid parasite) was determined with the use of 3 microsatellite markers. both naturally infected lizards (n = 25) and previously noninfected lizards (n = 78) were in ... | 2007 | 17539410 |
| clonal diversity of a lizard malaria parasite, plasmodium mexicanum, in its vertebrate host, the western fence lizard: role of variation in transmission intensity over time and space. | within the vertebrate host, infections of a malaria parasite (plasmodium) could include a single genotype of cells (single-clone infections) or two to several genotypes (multiclone infections). clonal diversity of infection plays an important role in the biology of the parasite, including its life history, virulence, and transmission. we determined the clonal diversity of plasmodium mexicanum, a lizard malaria parasite at a study region in northern california, using variable microsatellite marke ... | 2007 | 17594442 |
| ascertainment bias in spatially structured populations: a case study in the eastern fence lizard. | despite increased interest in applying single nucleotide polymorphism (snp) data to questions in natural systems, one unresolved issue is to what extent the ascertainment bias induced during the snp discovery phase will impact available analysis methods. although most studies addressing ascertainment bias have focused on human populations, it is not clear whether existing methods will work when applied to other species with more complex demographic histories and more significant levels of popula ... | 2007 | 17611259 |
| the role of lizards in the ecology of lyme disease in two endemic zones of the northeastern united states. | we examined the role of lizards in the ecology of lyme disease in new york and maryland. we collected data on vector tick infestations, measured lizard "realized" reservoir competence for the lyme disease spirochete borrelia burgdorferi, and estimated lizard population density. these data were incorporated into a model that predicts a host's ability to influence the prevalence of b. burgdorferi in the tick population, a primary risk factor in the epidemiology of lyme disease. published data on o ... | 2007 | 17626342 |
| clonal diversity within infections and the virulence of a malaria parasite, plasmodium mexicanum. | both verbal and mathematical models of parasite virulence predict that genetic diversity of microparasite infections will influence the level of costs suffered by the host. we tested this idea by manipulating the number of co-existing clones of plasmodium mexicanum in its natural vertebrate host, the fence lizard sceloporus occidentalis. we established replicate infections of p. mexicanum made up of 1, 2, 3, or >3 clones (scored using 3 microsatellite loci) to observe the influence of clone numb ... | 2008 | 18937882 |
| patterns of infection of the lizard malaria parasite, plasmodium floridense, in invasive brown anoles (anolis sagrei) in southwestern florida. | plasmodium floridense is a saurian malaria parasite common in the anolis lizards of the northern caribbean islands and the se usa. in the latter area, it is found in two native lizards (sceloporus undulatus and anolis carolinensis) and in the introduced anolis sagrei, which is native to cuba. we measured parasite prevalence and parasitemia in the introduced anole at a single site in north port, florida over 5 years. prevalence, based on microscopic examination of blood smears, was high year-roun ... | 2009 | 19085004 |
| feeding preferences of the immature stages of three western north american ixodid ticks (acari) for avian, reptilian, or rodent hosts. | larval and nymphal ixodes pacificus cooley and kohls, i. (ixodes) jellisoni cooley and kohls, and dermacentor occidentalis marx were tested for host preference when simultaneously presented with a deer mouse (peromyscus maniculatus wagner), california kangaroo rat (dipodomys californicus merriam), western fence lizard (sceloporus occidentalis baird and girard), and california towhee (pipilo crissalis vigors) in an experimental apparatus. differences were observed in the preferences among the thr ... | 2009 | 19198525 |
| reptile infection with anaplasma phagocytophilum, the causative agent of granulocytic anaplasmosis. | granulocytic anaplasmosis (ga) is a potentially fatal tick-borne rickettsial disease that occurs sporadically in the far western united states. we evaluated the prevalence of anaplasma phagocytophilum in multiple species of lizards and snakes from enzootic sites in northern california, described the infestation prevalence of its tick vector ixodes pacificus on reptiles, and conducted an experimental challenge of western fence lizards (sceloporus occidentalis) and pacific gopher snakes (pituophis ... | 2009 | 19281295 |
| clonal diversity of a malaria parasite, plasmodium mexicanum, and its transmission success from its vertebrate-to-insect host. | infections of the lizard malaria parasite plasmodium mexicanum are often genetically complex within their fence lizard host (sceloporus occidentalis) harbouring two or more clones of parasite. the role of clonal diversity in transmission success was studied for p. mexicanum by feeding its sandfly vectors (lutzomyia vexator and lutzomyia stewarti) on experimentally infected lizards. experimental infections consisted of one, two, three or more clones, assessed using three microsatellite markers. a ... | 2009 | 19523471 |
| sublethal effects of invasive fire ant venom on a native lizard. | invasive species can impose novel selection pressures on natives, such as toxins to which native taxa are not adapted. native species may survive such invasions by evolving mechanisms to avoid toxin exposure or increase toxin tolerance. red imported fire ants (solenopsis invicta) employ an alkaloid-based venom to defend their colonies and capture prey. in this study we aim to characterize the sublethal effects of invasive fire ant venom on a native vertebrate, the eastern fence lizard (sceloporu ... | 2010 | 19722273 |
| geographic genetic differentiation of a malaria parasite, plasmodium mexicanum, and its lizard host, sceloporus occidentalis. | gene flow, and resulting degree of genetic differentiation among populations, will shape geographic genetic patterns and possibly local adaptation of parasites and their hosts. some studies of plasmodium falciparum in humans show substantial differentiation of the parasite in locations separated by only a few kilometers, a paradoxical finding for a parasite in a large, mobile host. we examined genetic differentiation of the malaria parasite plasmodium mexicanum, and its lizard host, sceloporus o ... | 2010 | 19916631 |
| toxicity of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (hmx) in three vertebrate species. | the explosive, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine or high-melting explosive (hmx), has been found in soils in areas used for testing and training by the military. many of these areas contain habitat for valued wildlife species. in an effort to better understand the environmental consequences from exposure, a reptilian (western fence lizard [sceloporus occidentalis]), an amphibian (red-backed salamander [plethodon cinereus]), and a mammalian species (rabbit [oryctolagus cuniculus]) ... | 2010 | 20012743 |
| bayesian species delimitation using multilocus sequence data. | in the absence of recent admixture between species, bipartitions of individuals in gene trees that are shared across loci can potentially be used to infer the presence of two or more species. this approach to species delimitation via molecular sequence data has been constrained by the fact that genealogies for individual loci are often poorly resolved and that ancestral lineage sorting, hybridization, and other population genetic processes can lead to discordant gene trees. here we use a bayesia ... | 2010 | 20439743 |
| effects of an invasive forest pathogen on abundance of ticks and their vertebrate hosts in a california lyme disease focus. | invasive species, including pathogens, can have important effects on local ecosystems, including indirect consequences on native species. this study focuses on the effects of an invasive plant pathogen on a vertebrate community and ixodes pacificus, the vector of the lyme disease pathogen (borrelia burgdorferi) in california. phytophthora ramorum, the causative agent of sudden oak death, is a non-native pathogen killing trees in california and oregon. we conducted a multi-year study using a grad ... | 2010 | 20941513 |
| impact of the experimental removal of lizards on lyme disease risk. | the distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. lizards (such as the western fence lizard; sceloporus occidentalis) play a unique role in lyme disease ecology in the far-western united states. lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks (ixodes pacificus-the vector for lyme disease in that region) but are not competent reser ... | 2011 | 21325326 |
| relative clonal proportions over time in mixed-genotype infections of the lizard malaria parasite plasmodium mexicanum. | vertebrate hosts of malaria parasites (plasmodium) often harbour two or more genetically distinct clones of a single species, and interaction among these co-existing clones can play an important role in plasmodium biology. however, how relative clonal proportions vary over time in a host is still poorly known. experimental mixed-clone infections of the lizard malaria parasite, plasmodium mexicanum, were followed in its natural host, the western fence lizard using microsatellite markers to determ ... | 2011 | 21396372 |
| invader danger: lizards faced with novel predators exhibit an altered behavioral response to stress. | animals respond to stressors by producing glucocorticoid stress hormones, such as corticosterone (cort). cort acts too slowly to trigger immediate behavioral responses to a threat, but can change longer-term behavior, facilitating an individual's survival to subsequent threats. to be adaptive, the nature of an animal's behavior following elevated cort levels should be matched to the predominant threats that they face. seeking refuge following a stressful encounter could be beneficial if the pred ... | 2011 | 21549122 |
| changes in oviducal vascularity during the reproductive cycle of three oviparous lizards (eumeces obsoletus, sceloporus undulatus and crotaphytus collaris). | histologically derived estimates and ink suspension vascular casts were used to examine oviducal vascular changes. vascularity peaked during gravidity and was correlated with maximal plasma progesterone concentrations. the vascular increase in the oviducal tissue was attributed exclusively to increased capillary densities. the greatest change occurred in the anterior uterus where incubation and egg shell secretion occur. similar patterns of change in vascularity occurred in the infundibulum, alt ... | 2013 | 3656274 |
| impacts of an introduced forest pathogen on the risk of lyme disease in california. | global changes such as deforestation, climate change, and invasive species have the potential to greatly alter zoonotic disease systems through impacts on biodiversity. this study examined the impact of the invasive pathogen that causes sudden oak death (sod) on the ecology of lyme disease in california. the lyme disease bacterium, borrelia burgdorferi, is maintained in the far western united states by a suite of animal reservoirs including the dusky-footed woodrat (neotoma fuscipes) and deer mo ... | 2012 | 22607076 |
| eco-epidemiological factors contributing to the low risk of human exposure to ixodid tick-borne borreliae in southern california, usa. | little is known about the eco-epidemiology of lyme disease in southern california, a region where the incidence is much lower than it is in northern california. here, we sought to discover the previously unknown microhabitats of nymphs of the primary vector, the western black-legged tick (ixodes pacificus), in 3 moderately to heavily-utilized state parks in the santa monica mountains in los angeles county; to elucidate the seasonal distribution and abundance of adults of i. pacificus and another ... | 2013 | 23643357 |
| effects of temperature on feeding duration, success, and efficiency of larval western black-legged ticks (acari: ixodidae) on western fence lizards. | the western black-legged tick (ixodes pacificus) is a common tick species throughout the western usa and is the major vector for borrelia burgdorferi, the lyme disease causing bacterium. western fence lizards (sceloporus occidentalis) are a major host for juvenile i. pacificus, but are incompetent hosts for b. burgdorferi, which makes this host-parasite relationship of particular interest. in order to shed further light on this complex host-parasite relationship, we investigated the effects of t ... | 2015 | 26188858 |
| minimal role of eastern fence lizards in borrelia burgdorferi transmission in central new jersey oak/pine woodlands. | the eastern fence lizard, sceloporus undulatus , is widely distributed in eastern and central north america, ranging through areas with high levels of lyme disease, as well as areas where lyme disease is rare or absent. we studied the potential role of s. undulatus in transmission dynamics of lyme spirochetes by sampling ticks from a variety of natural hosts at field sites in central new jersey, and by testing the reservoir competence of s. undulatus for borrelia burgdorferi in the laboratory. t ... | 2014 | 24871138 |
| how do duration, frequency, and intensity of exogenous cort elevation affect immune outcomes of stress? | stress is typically characterized as "acute" (lasting from minutes to hours) or "chronic" (lasting from days to months). these terms are of limited use as they are inconsistently used and only encompass one aspect of the stressor (duration). short and long duration stress are generally thought to produce specific outcomes (e.g. acute stress enhances while chronic stress suppresses immune function). we propose that aspects of stress other than duration, such as frequency and intensity, are import ... | 2015 | 26209864 |
| immune responses of eastern fence lizards (sceloporus undulatus) to repeated acute elevation of corticosterone. | prolonged elevations of glucocorticoids due to long-duration (chronic) stress can suppress immune function. it is unclear, however, how natural stressors that result in repeated short-duration (acute) stress, such as frequent agonistic social encounters or predator attacks, fit into our current understanding of the immune consequences of stress. since these types of stressors may activate the immune system due to increased risk of injury, immune suppression may be reduced at sites where individu ... | 2014 | 24852352 |
| leukocyte profiles for western fence lizards, sceloporus occidentalis, naturally infected by the malaria parasite plasmodium mexicanum. | plasmodium mexicanum is a malaria parasite that naturally infects the western fence lizard, sceloporus occidentalis , in northern california. we set out to determine whether lizards naturally infected with this malaria parasite have different leukocyte profiles, indicating an immune response to infection. we used 29 naturally infected western fence lizards paired with uninfected lizards based on sex, snout-to-vent length, tail status, and the presence-absence of ectoparasites such as ticks and m ... | 2014 | 24945903 |
| establishment efficiency among clones of the malaria parasite, plasmodium mexicanum, for mixed-clone infections in its natural lizard host. | within genetically diverse infections of malaria parasites ( plasmodium spp.), the relative proportions of genetic clones in the vertebrate host's blood can influence clonal competition, transmission success, gametocyte sex ratio, and virulence. clonal proportions depend on establishment success of each clone when they enter a new host and on subsequent differences in rates of asexual replication and clearance. both of these life history traits could be influenced by clone genotype. to assess ge ... | 2013 | 23841469 |
| multiple environmental stressors elicit complex interactive effects in the western fence lizard (sceloporus occidentalis). | evaluation of multiple-stressor effects stemming from habitat degradation, climate change, and exposure to chemical contaminants is crucial for addressing challenges to ecological and environmental health. to assess the effects of multiple stressors in an understudied taxon, the western fence lizard (sceloporus occidentalis) was used to characterize the individual and combined effects of food limitation, exposure to the munitions constituent 2,4,6-trinitrotoluene (tnt), and plasmodium mexicanum ... | 2012 | 22975894 |
| parasites and showy males: malarial infection and color variation in fence lizards. | hamilton and zuk (1982) proposed that the quality of male showy traits reflects genetically-based resistance to parasites and can be used by females to select mates that are less prone to parasitic attack. the hypothesis requires that a particular state of a variable showy trait should be associated with parasite infection. we tested this idea with a population of western fence lizards, sceloporus occidentalis, infected with the malarial parasite, plasmodium mexicanum. ventral color pattern is s ... | 1989 | 28312354 |
| malarial parasitism and male competition for mates in the western fence lizard, sceloporus occidentalis. | the effect of malarial parasitism on the ability of male western fence lizards, sceloporus occidentalis, to compete for access to females was assessed experimentally. pairs of male lizards, one infected with the malarial parasite, plasmodium mexicanum, and the other not infected, were matched by size and color and placed in large seminatural outdoor enclosures along with an adult female lizard. infected males displayed to females and to other males less often than did noninfected male lizards. n ... | 1987 | 28311520 |
| transmission, host specificity, and seasonal occurrence of cyrtosomum penneri (nematoda: atractidae) in lizards from florida. | experimental infections and field-collected lizards were used to investigate issues of transmission, host specificity, and seasonal occurrence in the nematode cyrtosomum penneri (cosmocercoidea: atractidae). anolis sagrei (87 males, 42 females) were captured from the florida southern college campus, polk county, florida, from october 2010 to september 2011, and 8,803 c. penneri were collected from their intestines. during the breeding season all sexually mature (svl ≥ 34 mm) a. sagrei were infec ... | 2013 | 23020090 |
| an electrophoretic study of inter- and intrapopulation genetic variation within the northern fence swift, sceloporus undulatus hyacinthinus. | | 1976 | 1000935 |
| direct and indirect effects of petroleum production activities on the western fence lizard (sceloporus occidentalis) as a surrogate for the dunes sagebrush lizard (sceloporus arenicolus). | the dunes sagebrush lizard (sceloporus arenicolus) is a habitat specialist of conservation concern limited to shin oak sand dune systems of new mexico and texas (usa). because much of the dunes sagebrush lizard's habitat occurs in areas of high oil and gas production, there may be direct and indirect effects of these activities. the congeneric western fence lizard (sceloporus occidentalis) was used as a surrogate species to determine direct effects of 2 contaminants associated with oil and gas d ... | 2016 | 26456391 |
| permeability of roads to movement of scrubland lizards and small mammals. | a primary objective of road ecology is to understand and predict how roads affect connectivity of wildlife populations. road avoidance behavior can fragment populations, whereas lack of road avoidance can result in high mortality due to wildlife-vehicle collisions. many small animal species focus their activities to particular microhabitats within their larger habitat. we sought to assess how different types of roads affect the movement of small vertebrates and to explore whether responses to ro ... | 2013 | 23772966 |
| evaluation of western fence lizards (sceloporus occidentalis) and eastern fence lizards (sceloporus undulatus) as laboratory reptile models for toxicological investigations. | a need is recognized for one or more laboratory reptile models for use in ecotoxicological studies and risk assessments. maintenance of breeding populations of most reptile species under laboratory conditions is not practical because of their size and slow maturation rate. however, a number of species of spiny lizards (sceloporus sp.) are small, mature quickly, and reproduce under laboratory conditions. we evaluated three populations of western fence lizards (s. occidentalis) and four population ... | 2002 | 12013135 |
| tick microbiome and pathogen acquisition altered by host blood meal. | lyme disease, a zoonotic disease, is the most prevalent vector-borne disease in the northern hemisphere. diversity of the vector (tick) microbiome can impact pathogen transmission, yet the biotic and abiotic factors that drive microbiome diversity are largely unresolved, especially under natural, field conditions. we describe the microbiome of ixodes pacificus ticks, the vector for lyme disease in the western united states, and show a strong impact of host blood meal identity on tick microbiome ... | 2017 | 27858931 |
| absence of measurable malaria-induced mortality in western fence lizards (sceloporus occidentalis) in nature: a 4-year study of annual and over-winter mortality. | theoretical models of parasite virulence often quantify virulence by mortality. however, there is a lack of empirical studies of parasite-induced host mortality because it is often difficult to quantify in natural populations. i have estimated annual and over-winter mortality in a population of fence lizards (sceloporus occidentalis) infected with a malaria parasite, plasmodium mexicanum, in northern california. the duration of time a lizard was observed (an estimate of life-span) throughout the ... | 2001 | 28547496 |
| cyclic nucleotides of cone-dominant retinas. reduction of cyclic amp levels by light and by cone degeneration. | dark-adapted retinas or whole eyes of 13-line ground squirrels (citellus tridecemlineatus) and western fence lizards (sceloporus occidentalis) contain higher levels of cyclic amp than of cyclic gmp. in these cone-dominant retinas, light reduces cyclic amp content selectively. freezing of dark- or light-adapted retinas or eyes also reduces cyclic amp content, with only minimal changes in cyclic gmp levels. in addition, exposure of frozen retinas of dark-adapted ground squirrel to light results in ... | 1981 | 6256308 |
| sylvatic infestation of oklahoma reptiles with immature ixodes scapularis (acari: ixodidae). | reptiles were collected in nine counties in oklahoma from september 2002 to may 2004 and examined for ixodes scapularis (say) larvae and nymphs to determine seasonal incidence and prevalence of these ticks. in total, 209 reptile specimens consisting of nine species of lizards and seven species of snakes were collected. plestiodon fasciatus (l.) was the most numerous species collected (55%) followed by sceloporus undulatus (latreille) (17%) and scincella lateralis (say) (11%). less than 10 indivi ... | 2015 | 26336240 |
| effect of host lizard anemia on host choice and feeding rate of larval western black-legged ticks (ixodes pacificus). | although ticks are known to exhibit preferences among host species, there is little evidence that ticks select hosts within a species based on physiological condition. it may be beneficial for ticks to choose hosts that are easier to feed upon if the ticks can perceive indicative chemical or other signals from the host. for example, if ticks can detect host hematocrit they may choose hosts with high hematocrit, facilitating a faster blood meal. it may similarly be adaptive for ticks to avoid ane ... | 2013 | 23760685 |
| how do host sex and reproductive state affect host preference and feeding duration of ticks? | parasitism is one of the most notable forms of symbiosis in the biological world, with nearly all organisms hosting parasites. in many vertebrates, males have higher ectoparasite burdens than females, especially when testosterone concentrations are elevated. furthermore, reproductive females may have higher ectoparasite burdens than non-reproductive females. it is possible that testosterone-stimulated behaviors in males and offspring investment by females incur energetic costs that inhibit immun ... | 2012 | 22526292 |
| effect of temperature on feeding period of larval blacklegged ticks (acari: ixodidae) on eastern fence lizards. | ambient temperature can influence tick development time, and can potentially affect tick interactions with pathogens and with vertebrate hosts. we studied the effect of ambient temperature on duration of attachment of larval blacklegged ticks, ixodes scapularis say, to eastern fence lizards, sceloporus undulatus (bosc & daudin). feeding periods of larvae that attached to lizards under preferred temperature conditions for the lizards (warm treatment: temperatures averaged 36.6°c at the top of the ... | 2014 | 26309322 |
| fear no colors? observer clothing color influences lizard escape behavior. | animals often view humans as predators, leading to alterations in their behavior. even nuanced aspects of human activity like clothing color affect animal behavior, but we lack an understanding of when and where such effects will occur. the species confidence hypothesis posits that birds are attracted to colors found on their bodies and repelled by non-body colors. here, we extend this hypothesis taxonomically and conceptually to test whether this pattern is applicable in a non-avian reptile and ... | 2017 | 28792983 |
| characterization of gastrointestinal chitinase in the lizard sceloporus undulatus garmani (reptilia: phrynosomatidae). | most studies on chitinase activity in lizards have been concerned with palaearctic (european) and laurasian (middle eastern and asian) taxa. several genera of old world lizards, anguis, uromastix, chamaeleo and lacerta, have been shown to possess chitinolytic activity. to date, only one new world lizard, anolis carolinensis, has been reported to exhibit chitinolytic activity. in the present study, chitinase activity was characterized in a second new world taxon, sceloporus undulatus garmani, a n ... | 2001 | 11290449 |
| tissue-carbon incorporation rates in lizards: implications for ecological studies using stable isotopes in terrestrial ectotherms. | carbon stable isotope (delta(13)c) analysis can be used to infer the origin and to estimate the flow of nutrient resources through animals and across ecological compartments. these applications require knowledge of the rates at which carbon is incorporated into animal tissues and diet-to-tissue discrimination factors (delta(13)c). studies of carbon dynamics in terrestrial vertebrates to date have focused almost solely on endothermic animals; ectotherms such as reptiles have received little atten ... | 2010 | 20441446 |
| ecological release in white sands lizards. | ecological opportunity is any change that allows populations to escape selection from competition and predation. after encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. we identified ecological opportunity and tested for ecological release in three lizard colonists of white sands, new mexico (sceloporus undulatus, holbrookia maculata, and aspidoscelis inornata). first, we ... | 2011 | 22393523 |
| comparative life histories of holbrookia maculata and sceloporus undulatus in western nebraska. | the life histories of the iguanid lizards holbrookia maculata and sceloporus undulatus were studied in western nebraska during 1978-1984. the two species differ in their reproductive strategies and age-specific survival. the reproductive strategy of h. maculata is invariant from year to year. yearlings consistently produced a single clutch and older females (≥2 yr) consistently produced two clutches. the reproductive strategy of s. undulatus is opportunistic. clutch frequency of s. undulatus var ... | 1987 | 29357151 |
| physiological control of warming and cooling during simulated shuttling and basking in lizards. | differences in warming and cooling rates in basking lizards have long been thought to be brought about by adjustments in heart rate and blood flow. we examined the physiological control of warming and cooling in iguana iguana, sceloporus undulatus, and three species of cordylus by measuring time constants, heart rate, and superficial capillary blood flow. previously, techniques have not been available to measure time constants in shuttling animals. using a combination of rapid measurements of te ... | 2007 | 11517453 |
| lead bioaccumulation in texas harvester ants (pogonomyrmex barbatus) and toxicological implications for texas horned lizard (phrynosoma cornutum) populations of bexar county, texas. | uptake of lead from soil was examined in order to establish a site-specific ecological protective concentration level for the texas horned lizard (phrynosoma cornutum) at the former humble refinery in san antonio, texas. soils, harvester ants, and rinse water from the ants were analyzed at 11 texas harvester ant (pogonomyrmex barbatus) mounds. soil concentrations at the harvester ant mounds ranged from 13 to 7474 mg/kg of lead dry weight. ant tissue sample concentrations ranged from < 0.82 to 21 ... | 2018 | 29305803 |
| comparative study of the innervation patterns of the hyobranchial musculature in three iguanian lizards: sceloporus undulatus, pseudotrapelus sinaitus, and chamaeleo jacksonii. | the neuroanatomy and musculature of the hyobranchial system was studied in three species of iguanian lizards: sceloporus undulatus, pseudotrapelus sinaitus, and chamaeleo jacksonii. the goal of this study was to describe and compare the innervation and arrangement of the hyobranchial musculature in the context of its function during tongue protrusion. a comparison of the hyobranchial innervation patterns revealed a relatively conserved innervation pattern in s. undulatus and p. sinaitus, and a m ... | 2002 | 11997887 |
| comparative study of tongue protrusion in three iguanian lizards, sceloporus undulatus, pseudotrapelus sinaitus and chamaeleo jacksonii. | the goal of this study was to investigate the function of the hyolingual muscles used during tongue protraction in iguanian lizards. high-speed videography and nerve-transection techniques were used to study prey capture in the iguanid sceloporus undulatus, the agamid pseudoptrapelus sinaitus and the chameleonid chamaeleo jacksonii. denervation of the mandibulohyoideus muscle slips had an effect only on p. sinaitus and c. jacksonii, in which tongue protrusion or projection distance was reduced. ... | 2000 | 10952882 |
| mitochondrial dna sequences of five squamates: phylogenetic affiliation of snakes. | complete or nearly complete mitochondrial dna sequences were determined from four lizards (western fence lizard, warren's spinytail lizard, terrestrial arboreal alligator lizard, and chinese crocodile lizard) and a snake (texas blind snake). these genomes had a typical gene organization found in those of most mammals and fishes, except for a translocation of the glutamine trna gene in the blind snake and a tandem duplication of the threonine and proline trna genes in the spinytail lizard. althou ... | 2004 | 15449546 |
| survival by genotype: patterns at mc1r are not black and white at the white sands ecotone. | measuring links among genotype, phenotype and survival in the wild has long been a focus of studies of adaptation. we conducted a 4-year capture-recapture study to measure survival by genotype and phenotype in the southwestern fence lizard (sceloporus cowlesi) at the white sands ecotone (transition area between white sands and dark soil habitats). we report several unanticipated findings. first, in contrast with previous work showing that cryptic blanched coloration in s. cowlesi from the heart ... | 2017 | 27775197 |
| linking traits to energetics and population dynamics to predict lizard ranges in changing environments. | i present a dynamic bioenergetic model that couples individual energetics and population dynamics to predict current lizard ranges and those following climate warming. the model predictions are uniquely based on first principles of morphology, life history, and thermal physiology. i apply the model to five populations of a widespread north american lizard, sceloporus undulatus, to examine how geographic variation in traits and life histories influences ranges. this geographic variation reflects ... | 2008 | 18171140 |
| nutritional modulation of igf-1 in relation to growth and body condition in sceloporus lizards. | nutrition and energy balance are important regulators of growth and the growth hormone/insulin-like growth factor (gh/igf) axis. however, our understanding of these functions does not extend uniformly to all classes of vertebrates and is mainly limited to controlled laboratory conditions. lizards can be useful models to improve our understanding of the nutritional regulation of the gh/igf-1 axis because many species are relatively easy to observe and manipulate both in the laboratory and in the ... | 2015 | 25709095 |
| gonadal modulation of in vitro steroidogenic properties of dispersed adrenocortical cells from sceloporus lizards. | effects of adrenal corticosteroids on reproductive and endocrine functions of the gonads are well known, but reciprocal effects of gonadal hormones on the hypothalamo-pituitary-adrenal (hpa) axis and on adrenocortical steroidogenesis in particular have received much less attention. we investigated effects of gonadectomy and testosterone (t) replacement on adrenocortical cell function in a year-long field study of male sceloporus undulatus (eastern fence lizard) and in a shorter term laboratory s ... | 2008 | 18708060 |