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1.
Integr Zool ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39030926

RESUMO

Males of the mountain gazelle deposit dung middens (different colors and shapes represent middens of different haplotypes) in preferable forest plots and countermark the same middens (two color circles) at the boundaries of their territories.

2.
J Zoo Wildl Med ; 55(2): 412-423, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38875197

RESUMO

The nutria (Myocastor coypus) is a globally widespread invasive species. Attempts to eradicate nutria by shooting, poisoning, and trapping have been mostly unsuccessful, leading to calls for the development of new control methods. The compound 4-vinylcyclohexene diepoxide (VCD) is known to cause follicular atresia in mammals and may control conception when administered orally. It was hypothesized that VCD administered PO will cause follicular destruction in female nutria. VCD (250 mg/kg PO) was administered or coconut oil, as a control, to five nutria females each for 12 d. Sixty days following VCD exposure, males were introduced to the females. Over the following 7 mon, the effect of VCD on nutria fertility was assessed by conducting ultrasound monitoring to determine pregnancy status and measuring blood serum progesterone and estradiol levels. Finally, after performing ovariectomies, viable follicles were counted on histologic ovarian cortical sections. It was found that the female estrous cycles became synchronized, suggesting a Whitten effect in this species. Also, an increase in the females' serum progesterone levels following the introduction of males occurred, suggesting a male presence effect. Orally administered doses of 250 mg/kg VCD for 12 d had no significant effect on nutria pregnancy rates or on the number of follicles in the ovaries examined. Further studies, using a higher dose or longer administration period, are necessary to conclude whether orally administered VCD can be used as a contraceptive agent for nutria.


Assuntos
Cicloexenos , Compostos de Vinila , Animais , Feminino , Compostos de Vinila/farmacologia , Compostos de Vinila/administração & dosagem , Projetos Piloto , Cicloexenos/farmacologia , Cicloexenos/administração & dosagem , Fertilidade/efeitos dos fármacos , Masculino , Roedores , Animais de Zoológico , Gravidez
3.
Sci Rep ; 13(1): 16737, 2023 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-37794058

RESUMO

Multiple paternity is common in many species. While its benefits for males are obvious, for females they are less clear. Female indirect benefits may include acquiring 'good genes' for offspring or increasing litter genetic diversity. The nutria (Myocastor coypus) is a successful invasive species. In its native habitat, it is polygynous, with larger and more aggressive males monopolizing paternity. Here, using culled nutria we genetically examined multiple paternity in-utero and found a high incidence of multiple paternity and maintenance of the number of fathers throughout gestation. Moreover, male fetuses sired by the prominent male have higher testosterone levels. Despite being retained, male fetuses of 'rare' fathers, siring commonly only one of the fetuses in the litter, have lower testosterone levels. Considering the reproductive skew of nutria males, if females are selected for sons with higher future reproductive success, low testosterone male fetuses are expected to be selected against. A possible ultimate explanation for maintaining multiple paternity could be that nutria females select for litter genetic diversity e.g., a bet-hedging strategy, even at the possible cost of reducing the reproductive success of some of their sons. Reproductive strategies that maintain genetic diversity may be especially beneficial for invasive species, as they often invade through a genetic bottleneck.


Assuntos
Núcleo Familiar , Testosterona , Feminino , Masculino , Animais , Reprodução/genética , Feto , Comportamento Sexual Animal
4.
Conserv Physiol ; 9(1): coab068, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34512990

RESUMO

The predation-stress hypothesis has been proposed as a general mechanism to explain the negative effect of predation risk on reproduction, through a chronic activation of the stress response. However, in some cases, stress appears to augment the reproductive potential of mammals. Wild boar (Sus scrofa) populations are on a rise worldwide, despite the high hunting pressure that they are exposed to. This hunting pressure instigates, among other effects, earlier sexual maturity in juvenile females, leading to the shortening of wild boars' generation time. The mechanism that underlies this earlier sexual maturity under high hunting pressure has not been examined to date. To explore the physiological effects that hunting has on the reproductive system and whether the stress response is involved, we examined steroid hormone levels in the hair of female wild boars in northern Israel, comparing populations exposed to high and low hunting pressure. Furthermore, we compared steroid levels in the hair of female wild boars that were roaming alone or as a part of a group. We found no hormonal signs of stress in the hunted boars. Cortisol levels were low in both the high and low hunting-pressure groups. Yet, progesterone levels were higher in females that were exposed to high hunting pressure. Females roaming in a group also had higher progesterone levels compared to females that were alone, with no distinguishable differences in cortisol levels. These elevations in reproductive hormones that were associated with hunting may lead to a higher reproductive potential in female wild boars. They further show that high hunting pressure does not necessarily lead to chronic stress that impairs the reproductive potential of female wild boars. This data suggests that a reproductive hormonal response may be one of the factors leading to the rapid wild boars population growth worldwide, despite the high hunting pressure.

5.
Horm Behav ; 111: 105-109, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30790563

RESUMO

Neighboring fetuses may impact their siblings in various respects, depending on their in utero location and sex. The effects of the intrauterine position (IUP) are widely studied in model organisms, especially laboratory bred murine strains that are characterized by short gestations and altricial offspring. In some species, the proximity to a male fetus and its higher circulating testosterone masculinizes neighboring female fetuses. In utero testosterone exposure might be manifested as higher testosterone concentrations, which contribute to a variation in morphology, reproductive potential and behavior. In this study, we examined the influence of neighboring an opposite sex fetus on testosterone levels in a feral animal model characterized by a long gestation and precocious offspring. Using necropsies of culled nutria (Myocastor coypus), we accurately determined the IUP and quantified testosterone immunoreactivity in fetal hair. We found that as expected, both male and female fetuses neighboring a male in utero had longer anogenital distance. However, females adjacent to males in utero showed lower testosterone levels than male fetuses, while testosterone levels of females without a male neighbor did not differ from those of males. This surprising result suggests an alternative mode by which local exogenous steroids may modify the local fetal environment. Our study emphasizes the importance of examining known phenomena in species with different life histories, other than the traditional murine models, to enhance our understanding of the evolutionary mechanisms that are driving sexual differentiation.


Assuntos
Feto/fisiologia , Tamanho da Ninhada de Vivíparos/fisiologia , Efeitos Tardios da Exposição Pré-Natal , Roedores , Diferenciação Sexual/fisiologia , Testosterona/metabolismo , Animais , Feminino , Feto/metabolismo , Cabelo/química , Cabelo/metabolismo , Masculino , Camundongos , Modelos Animais , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Roedores/fisiologia , Caracteres Sexuais , Fatores Sexuais , Esteroides/farmacologia , Testosterona/análise
6.
PLoS One ; 11(1): e0145978, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26815653

RESUMO

Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future related projects.


Assuntos
Conservação dos Recursos Naturais , Biodiversidade , Canadá , Mudança Climática , Demografia , Ecossistema , Humanos , Israel , Políticas , Suíça
7.
J Environ Qual ; 42(5): 1395-401, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24216417

RESUMO

Road runoff is recognized as a substantial nonpoint source of contamination to the aquatic environment. Highway seasonal first flushes contain particularly high concentrations of pollutants. To fully account for the toxicity potential of the runoff, the cumulative effects of the pollutants should be assessed, ideally by biological analyses. Acute toxicity tests with were used to measure the toxicity of runoff from three major highway sections in Israel for 2 yr. Highway first flushes resulted in the mortality of all tested individuals within 24 to 48 h. A first flush collected from Highway 4 (traffic volume: 81,200 cars d) remained toxic even after dilution to <5% (48 h EC <5%). Synthetic solutions with metal concentrations corresponding to highways' first flushes revealed a synergistic adverse effect on survival and a potential additive effect of nonmetal pollutants in the runoff. Because daphnids and other invertebrates constitute the base of the aquatic food chain, detrimental effects of highway runoff may propagate to higher levels of biological organization. The observed high potential of environmental contamination warrants the control of highway runoff in proximity to natural watercourses.


Assuntos
Invertebrados , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Poluição Ambiental , Cadeia Alimentar , Chuva , Movimentos da Água
8.
Am J Trop Med Hyg ; 85(5): 919-23, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22049050

RESUMO

We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed.


Assuntos
Animais Selvagens , Rickettsiaceae/isolamento & purificação , Carrapatos/microbiologia , Animais , Animais Selvagens/parasitologia , Antílopes , DNA Bacteriano/genética , Cervos , Raposas , Humanos , Israel/epidemiologia , Chacais , Filogenia , Rickettsiaceae/genética , Infecções por Rickettsiaceae/epidemiologia , Infecções por Rickettsiaceae/microbiologia , Infecções por Rickettsiaceae/transmissão , Sus scrofa , Carrapatos/classificação
9.
Environ Sci Pollut Res Int ; 18(8): 1264-9, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21384142

RESUMO

PURPOSE: We tested the genetic diversity in wild mice (Mus musculus domesticus) inhabiting the asbestos-polluted area as a model for the long-term mutagenic effect of asbestos. Hazardous effects of deposited asbestos persist in the environment because of low rate of fiber disintegration. The upper layers of the soil in the vicinity of a former asbestos factory are nearly "saturated" with asbestos fibers and dust. Natural populations of mice dwell in this area and are constantly exposed to asbestos fibers. METHODS: We measured the microsatellites genetic diversity of wild mice (Mus musculus domesticus) inhabiting the asbestos-polluted area as a model for the long-term mutagenic effect of this environmental toxin. RESULTS: The six tested microsatellites were highly polymorphic, revealing 111 different alleles for the two sampled populations. Effective number of alleles was slightly higher in the polluted population relative to the control population, while observed heterozygosity was lower. The chromatographic profile of the polluted population exhibited a significantly higher number of bands, probably resulting from somatic mutations, in addition to the ordinary microsatellite band profiles. CONCLUSIONS: Long-term exposure to asbestos fibers significantly elevates the level of somatic mutations. It also leads to a relatively high level of observed homozygosity, a phenomenon that may be associated with loss of heterozygosity. Based on the mice population, our data suggest elevated health risks for humans living in an asbestos-polluted area.


Assuntos
Amianto/toxicidade , Monitoramento Ambiental , Poluentes Ambientais/toxicidade , Animais , Ecotoxicologia , Camundongos , Repetições de Microssatélites , Testes de Mutagenicidade , Polimorfismo Genético
10.
Artigo em Inglês | MEDLINE | ID: mdl-19747559

RESUMO

One mechanism for physiological adjustment of small mammals to different habitats and different seasons is by seasonal acclimatization of their osmoregulatory system. We examined the abilities of broad-toothed field mice (Apodemus mystacinus) from different ecosystems ('sub-alpine' and 'Mediterranean') to cope with salinity stress under short day (SD) and long day (LD) photoperiod regimes. We compared urine volume, osmolarity, urea and electrolyte (sodium, potassium and chloride) concentrations. Significant differences were noted in the abilities of mice from the two ecosystems to deal with salinity load; in particular sub-alpine mice produced less concentrated urine than Mediterranean mice with SD- sub-alpine mice seeming to produce particularly dilute urine. Urea concentration generally decreased with increasing salinity, whereas sodium and potassium levels increased, however SD- sub-alpine mice behaved differently and appeared not to be able to excrete electrolytes as effectively as the other groups of mice. Differences observed provide an insight into the kinds of variability that are present within populations inhabiting different ecosystems, thus how populations may be able to respond to potential changes in their environment. Physiological data pertaining to adaptation to increased xeric conditions, as modelled by A. mystacinus, provides valuable information as to how other species may cope with potential climatic challenges.


Assuntos
Ecossistema , Murinae/fisiologia , Equilíbrio Hidroeletrolítico , Animais , Cloretos/urina , Potássio/urina , Sódio/urina , Cloreto de Sódio , Ureia/urina
11.
Bioessays ; 31(1): 84-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19154006

RESUMO

Carrion and dung odours of various flowers have traditionally been considered an adaptation for attracting the flies and beetles that pollinate them. While we accept the role of such odours in pollinator attraction, we propose that they may also have another, overlooked, anti-herbivore defensive function. We suggest that such odours may deter mammalian herbivores, especially during the critical period of flowering. Carrion odour is a good predictor for two potential dangers to mammalian herbivores: (1) pathogenic microbes, (2) proximity of carnivores. Similarly, dung odour predicts faeces-contaminated habitats that present high risks of parasitism. These are two new types of repulsive olfactory aposematic mimicry by plants: (1) olfactory feigning of carcass (thanatosis), a well-known behavioural defensive strategy in animals, (2) olfactory mimicry of faeces, which also has a defensive visual parallel in animals.


Assuntos
Odorantes , Olfato , Animais , Comportamento Animal , Fezes , Comportamento Alimentar , Flores , Modelos Biológicos , Modelos Genéticos , Modelos Teóricos , Plantas/metabolismo , Polinização
12.
J Wildl Dis ; 44(3): 693-6, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18689655

RESUMO

The ectoparasite fauna of reintroduced roe deer (Capreolus capreolus) was surveyed in a Mediterranean forest in Israel. Ectoparasites were collected from four female hand-reared deer during 2004 and 2005. Seasonality, predilection sites of infestation, and the apparent effect of the parasites are presented. This is the first study of roe deer parasites in the East Mediterranean. The ectoparasite fauna included three hippoboscid fly (Lipoptena capreoli, Hippobosca equina, and Hippobosca longipennis), four tick (Rhipicephalus sanguineus, Rhipicephalus turanicus, Rhipicephalus kohlsi, and Hyalomma marginatum), and one unidentified trombiculid mite species. For most of these ectoparasites, this is the first record on roe deer. All ectoparasite species were documented in Israel prior to the reintroduction program; exotic ectoparasites were not detected.


Assuntos
Cervos/parasitologia , Ectoparasitoses/veterinária , Animais , Reservatórios de Doenças/veterinária , Ectoparasitoses/epidemiologia , Ectoparasitoses/parasitologia , Feminino , Israel/epidemiologia , Infestações por Ácaros/epidemiologia , Infestações por Ácaros/parasitologia , Infestações por Ácaros/veterinária , Miíase/epidemiologia , Miíase/parasitologia , Miíase/veterinária , Estações do Ano , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária
13.
Emerg Infect Dis ; 13(9): 1411-2, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18252125

RESUMO

Sequences from the Anaplasma phagocytophilum 16S rRNA gene were detected in 5 ticks representing 3 species (Hyalomma marginatum, Rhipicephalus turanicus, and Boophilus kohlsi) collected from roe deer (Capreolus capreolus) in Mount Carmel, Israel. The sequences were all identical to those of Ap-variant 1 strain.


Assuntos
Anaplasma phagocytophilum/isolamento & purificação , Carrapatos/microbiologia , Animais , Cervos/parasitologia , Feminino , Israel , Masculino , Infestações por Carrapato/veterinária
14.
Integr Zool ; 2(3): 184-190, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21396034

RESUMO

Human-made agro-ecosystems lack negative feedback controls, which may result in rodent population explosions, causing considerable economic loss and thus increasing human-wildlife conflicts. The traditional solution is the extensive use of rodenticides, which have a negative impact on the environment. In Beit-Sheaan Valley, Israel, which is located on a major route for migrating birds, poisoning of voles may result in the death of birds that prey on the dead voles (e.g. storks and herons). In the present essay we discuss some integrated methods, based on the implementation of ecological principles in agro-ecosystems, that could be used to decrease the use of rodenticides. The first method is light interference during winter (long scotophase), which can result in the death of the social vole Microtus socialis kept in enclosures under natural conditions. Under laboratory conditions such interference causes a decrease in thermoregulatory ability in the cold. As light interference is a source of pollution, only active vole burrows should be illuminated. The second method involves using the mobile irrigation pipelines to flood the vole burrows and force them to escape into the open, where diurnal birds such as storks and herons will prey on them. The third method involves the use of nesting boxes for barn owls and stands for diurnal raptors, both of which prey on voles. The great advantage of using an integrated approach is that voles cannot become adapted to any one of the methods. Such integrated methods, together with appropriate treatment of alfalfa fields by farmers, can provide an efficient and sustainable pest control approach.

15.
Chronobiol Int ; 22(1): 59-66, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15865321

RESUMO

The change in photoperiod is the main environmental cue for seasonal function of the reproductive, thermoregulatory, and immune systems in rodents existing outside of the tropics. In Israel, the social vole Microtus socialis breeds mainly under short photoperiod (SP) conditions. Previous studies showed that exposing voles to light interference (LI) in the field during the winter resulted in death. The aim of the current study was to determine the thermoregulatory response of SP-acclimated voles to LI. Therefore, heat production (VO2) at different ambient temperatures (Ta) and nonshivering thermogenesis (NST) were measured. Results show that LI of 15 min every 4h during the dark period significantly (p < 0.02) decreased VO2 at Ta = 15 degrees C and significantly (p < 0.05) decreased NST-capacity. These results can at least partly explain why LI-voles died during the winter under field conditions, through eliminating winter acclimatization of the thermoregulatory system, or what is considered as "seasons out of time."


Assuntos
Estações do Ano , Aclimatação , Animais , Arvicolinae , Relógios Biológicos , Temperatura Corporal , Regulação da Temperatura Corporal , Ritmo Circadiano , Escuridão , Temperatura Alta , Luz , Masculino , Consumo de Oxigênio , Fotoperíodo , Temperatura , Tempo
16.
Physiol Behav ; 81(4): 645-50, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15178158

RESUMO

The time for reproduction in mammals largely depends on the availability of water and food in their habitat. Therefore, in regions where rains are limited to definite seasons of the year, mammals presumably will restrict their breeding correspondingly. But while mammals living in predictable ecosystems would benefit by timing their season to an ultimate predictable cue, such as photoperiod, in unpredictable ecosystems (e.g., deserts) they will need to use a more proximate signal. We suggest a mechanism by which water shortage (low water content in plants) could act as a proximate cue for ending the reproductive season. The golden spiny mouse (Acomys russatus), a diurnal rodent living in extreme deserts, may face an increased dietary salt content as the summer progresses and the vegetation becomes dry. Under laboratory conditions, increased diet salinity lead to reproductive hiatus in females, notable in imperforated vagina, and a significant decrease in the ovaries, uteri, and body masses. In females treated with vasopressin (VP), a hormone expressed during water stress, the uteri and body masses have decreased significantly, and the ovaries exhibited an increased number of atretic follicles. VP has also led to a significant decrease in relative medullary thickness (RMT) of the kidney. It is thus suggested that VP could act as a modulator linking the reproductive system with water economy in desert rodents, possibly through its act on the energetic pathways.


Assuntos
Desidratação/fisiopatologia , Muridae/fisiologia , Reprodução/fisiologia , Vasopressinas/fisiologia , Equilíbrio Hidroeletrolítico/fisiologia , Adaptação Fisiológica/fisiologia , Glândulas Suprarrenais/anatomia & histologia , Glândulas Suprarrenais/fisiologia , Ração Animal , Animais , Clima Desértico , Feminino , Rim/anatomia & histologia , Rim/fisiologia , Tamanho do Órgão , Ovário/anatomia & histologia , Ovário/fisiologia , Estações do Ano , Útero/anatomia & histologia , Útero/fisiologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-15123215

RESUMO

The common spiny mouse Acomys cahirinus, of Ethiopian origin, has a widespread distribution across arid, semi-arid and Mediterranean parts of the Arabian sub-region. We compared the daily energy expenditure (DEE), water turnover (WTO) and sustained metabolic scope (SusMS=DEE/resting metabolic rate) of two adjacent populations during the winter. Mice were captured from North- and South- facing slopes (NFS and SFS) of the same valley, comprising mesic and xeric habitats, respectively. Both DEE and SusMS winter values were greater in NFS than SFS mice and were significantly greater than values previously measured in the summer for these two populations in the same environments. However, WTO values were consistent with previously established values and were not significantly different from allometric predictions for desert eutherians. We suggest that physiological plasticity in energy expenditure, which exists both temporally and spatially, combined with stable WTO, perhaps reflecting a xeric ancestry, has enabled A. cahirinus to invade a wide range of habitats.


Assuntos
Aclimatação , Temperatura Baixa , Muridae/fisiologia , Animais , Regulação da Temperatura Corporal/fisiologia , Ingestão de Líquidos/fisiologia , Metabolismo Energético/fisiologia , Muridae/metabolismo , Estações do Ano
18.
Artigo em Inglês | MEDLINE | ID: mdl-12020645

RESUMO

We compared body temperature (T(b)) daily rhythms in two populations of common spiny mice, Acomys cahirinus, during summer and winter months in relation to increasing dietary salt content. Mice were collected from the North and South facing slopes (NFS and SFS) of the same valley, that are exhibiting mesic and xeric habitats, respectively. During the summer, whilst mice were offered a water source containing 0.9% NaCl, SFS individuals had T(b) peak values at 24:00, whereas NFS individuals had peak values at 18:00. When the salinity of the water source was increased, from 0.9 to 2.5% and then 3.5%, the difference between maximal and minimal T(b) of both populations increased. In addition, with increased salinity, the T(b) daily peak of SFS mice shifted to 18:00. During the winter, the mean daily T(b) values of both populations of mice were lower than during the summer. At 0.9% salinity, the NFS mice exhibited a daily T(b) variation with a peak at the beginning of the night. However, we did not detect any significant variation in daily T(b) in the SFS mice. At 2.5% salinity, the difference between the mean daily T(b) of mice from the two slopes increased. In winter we were unable to increase the salinity to 3.5% as the animals began to lose weight rapidly. We suggest that common spiny mice that inhabit these two micro-habitats are forming two discrete populations that respond differently to the environmental pressures prevailing in each habitat, by evolving different physiological capacities.


Assuntos
Temperatura Corporal/efeitos dos fármacos , Meio Ambiente , Periodicidade , Estações do Ano , Cloreto de Sódio na Dieta/farmacologia , Animais , Regulação da Temperatura Corporal/efeitos dos fármacos , Ecossistema , Israel , Camundongos , Fatores de Tempo
19.
J Comp Physiol B ; 172(1): 1-5, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11824399

RESUMO

We compared non-shivering thermogenesis between two adjacent populations of the common spiny mouse Acomys cahirinus from different habitats, in relation to increasing salinity. Individuals were captured from the north- and south-facing slopes of the same valley, that represent "Mediterranean" and "desert" habitats, respectively. We hypothesized that the two populations of mice would differ in their thermoregulatory capacities, reflecting their need to cope with the environmental stress in each habitat. We measured resting metabolic rate by recording oxygen consumption, body temperature and response to an injection of exogenous noradrenaline. Mice were maintained on diets with increasing levels of salt intake to examine their abilities to cope with increasing osmotic stress. Mice from north-facing slopes generally had a higher resting metabolic rate and a higher increase in oxygen consumption in response to noradrenaline than mice from south-facing slopes. Increasing salinity decreased resting metabolic rate values, body temperature, and oxygen consumption in response to noradrenaline in both populations, and diminished slope-dependant differences. We suggest that these differences could be a result of an ongoing adaptive process to different climatic conditions, typical of the Mediterranean region, that are a demonstrable example of evolution in action.


Assuntos
Regulação da Temperatura Corporal/efeitos dos fármacos , Regulação da Temperatura Corporal/fisiologia , Cloreto de Sódio na Dieta/farmacologia , Animais , Metabolismo Basal/efeitos dos fármacos , Metabolismo Basal/fisiologia , Peso Corporal , Clima Desértico , Região do Mediterrâneo , Muridae , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Estremecimento
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