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1.
Zool Res ; 42(5): 671-674, 2021 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-34490760

RESUMO

All extant species in the rodent family Spalacidae are subterranean and have evolved various traits for underground life. However, the phylogenomic relationships among its three subfamilies (Myospalacinae, Spalacinae, and Rhizomyinae) and the molecular basis underlying their adaptations to underground life remain poorly understood. Here, we inferred the phylogenomic relationships among these subfamilies based on de novo sequencing the genome of the hoary bamboo rat ( Rhizomys pruinosus). Analyses showed that ~50% of the identified 11 028 one-to-one orthologous protein-coding genes and the concatenated sequences of these orthologous genes strongly supported a sister relationship between Myospalacinae and Rhizomyinae. The three subfamilies diversified from each other within ~2 million years. Compared with the non-subterranean controls with similar divergence dates, the spalacids shared more convergent genes with the African subterranean mole-rats at the genomic scale due to more rapid protein sequence evolution. Furthermore, these convergent genes were enriched in the functional categories of carboxylic acid transport, vascular morphogenesis, and response to oxidative stress, which are closely associated with adaptations to the hypoxic-hypercapnic underground environment. Our study presents a well-supported phylogenomic relationship among the three subfamilies of Spalacidae and offers new insights into the molecular adaptations of spalacids living underground.


Assuntos
Adaptação Fisiológica/genética , Comportamento Animal/fisiologia , Evolução Molecular , Genômica , Roedores/genética , Animais , Genoma , Filogenia , Roedores/fisiologia , Especificidade da Espécie
2.
PLoS One ; 16(8): e0255372, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34383810

RESUMO

This study was conducted in Farta district, south Gondar from 2019 to 2020 cropping years to identify rodent pest species and estimate damage caused on barley crops. Four independent barley crop fields (40 x 40 m each) were sampled randomly to estimate the loss. Two were located near Alemsaga Priority State Forest and the other two were away from the forest. Four (2 x 2 m) rodent exclusion plots were established at 10 m interval as control units in each selected experimental barley fields using fine wire mesh. Rodent pest species were collected using both Sherman and snap traps throughout the different crop growing stages. The damaged and undamaged barley tillers by pest rodents were counted on five 1 x 1 m randomly sampled quadrats for each selected experimental fields. Variations on pest rodent population between cropping years and sites were analyzed using Chi square test. The mean crop damages between cropping years and experimental field sites were analyzed using two way ANOVA. Arvicanthis abyssinicus, Mastomys natalensis, Arvicanthis dembeensis, Mus musculus, Lophuromys simensis, Tachyoryctes splendens and Hystrix cristata were identified as pest rodents in the study area. A total of 968 individual rodents (427 in 2019 and 541 in 2020) were trapped during the study period. There was a statistical variation (χ2 = 13.42, df = 1 and P<0.05) between trapped individuals of the two successive years. The crop fields near the forest were more vulnerable than away from the forest during both cropping years. Statistical variations was observed on mean crop losses between cropping years and experimental barley crop sites. The highest crop damage was seen at maturity stage and the lowest during sowing in all experimental plots and cropping years. The percentage of barley yield loss due to rodent pests was 21.7 kg ha-1. The monetary value of this yield loss was equivalent to 4875 Birr (121.9 US$ h-1). Alemsaga Forest as shelter and conservation strategies like free of farmland from livestock and terracing for soil conservation have great role for the high rodent pest populations in the study area. Field sanitation, trapping and using restricted rodenticides like zinc phosphide are the possible recommendation to local farmers against rodent pests.


Assuntos
Produção Agrícola/métodos , Hordeum/crescimento & desenvolvimento , Roedores/fisiologia , Animais , Produção Agrícola/economia , Produtos Agrícolas/economia , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/parasitologia , Demografia , Etiópia , Fazendas , Florestas , Herbivoria , Hordeum/parasitologia , Controle de Pragas , Roedores/classificação
3.
Meat Sci ; 182: 108625, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34273761

RESUMO

The objective of the study was to evaluate the effect of quantitative feed restriction on the carcass composition and physical, chemical, histochemical and sensory properties of meat from male and female nutria at the end of the feed restriction and fattening period. In the experiment, from two to eight months of age, males and females were divided into two groups: one group was fed ad libitum throughout the experiment, and the second group was restricted to two weeks (from 11 to 12 weeks of age). The restricted nutrias received 75% ad libitum feeding. The significant interaction among feed restriction, sex and age was revealed only in the cross-sectional area of all muscle fiber types. Age was the main factor affecting carcass composition and meat quality characteristics. Sex-related differences in carcass composition and some sensory attributes and feed restriction-related differences in carcass composition were observed.


Assuntos
Composição Corporal , Privação de Alimentos , Carne/análise , Roedores/fisiologia , Fatores Etários , Fenômenos Fisiológicos da Nutrição Animal , Animais , Feminino , Humanos , Masculino , Fibras Musculares Esqueléticas , Odorantes , Fatores Sexuais , Paladar
4.
Int J Mol Sci ; 22(11)2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34070932

RESUMO

The neuronal networks that generate locomotion are well understood in swimming animals such as the lamprey, zebrafish and tadpole. The networks controlling locomotion in tetrapods remain, however, still enigmatic with an intricate motor pattern required for the control of the entire limb during the support, lift off, and flexion phase, and most demandingly when the limb makes contact with ground again. It is clear that the inhibition that occurs between bursts in each step cycle is produced by V2b and V1 interneurons, and that a deletion of these interneurons leads to synchronous flexor-extensor bursting. The ability to generate rhythmic bursting is distributed over all segments comprising part of the central pattern generator network (CPG). It is unclear how the rhythmic bursting is generated; however, Shox2, V2a and HB9 interneurons do contribute. To deduce a possible organization of the locomotor CPG, simulations have been elaborated. The motor pattern has been simulated in considerable detail with a network composed of unit burst generators; one for each group of close synergistic muscle groups at each joint. This unit burst generator model can reproduce the complex burst pattern with a constant flexion phase and a shortened extensor phase as the speed increases. Moreover, the unit burst generator model is versatile and can generate both forward and backward locomotion.


Assuntos
Geradores de Padrão Central/fisiologia , Interneurônios/fisiologia , Locomoção/fisiologia , Atividade Motora/fisiologia , Redes Neurais de Computação , Medula Espinal/fisiologia , Animais , Gatos , Geradores de Padrão Central/citologia , Simulação por Computador , Extremidades/inervação , Extremidades/fisiologia , Humanos , Interneurônios/citologia , Lampreias/fisiologia , Larva/fisiologia , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Roedores/fisiologia , Medula Espinal/citologia , Peixe-Zebra/fisiologia
5.
Science ; 372(6548)2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34140356

RESUMO

Echolocation is the use of reflected sound to sense features of the environment. Here, we show that soft-furred tree mice (Typhlomys) echolocate based on multiple independent lines of evidence. Behavioral experiments show that these mice can locate and avoid obstacles in darkness using hearing and ultrasonic pulses. The proximal portion of their stylohyal bone fuses with the tympanic bone, a form previously only seen in laryngeally echolocating bats. Further, we found convergence of hearing-related genes across the genome and of the echolocation-related gene prestin between soft-furred tree mice and echolocating mammals. Together, our findings suggest that soft-furred tree mice are capable of echolocation, and thus are a new lineage of echolocating mammals.


Assuntos
Ecolocação , Roedores/fisiologia , Animais , Evolução Biológica , Osso e Ossos/anatomia & histologia , Quirópteros/anatomia & histologia , Quirópteros/fisiologia , Genoma , Audição/genética , Laringe/anatomia & histologia , Laringe/fisiologia , Mamíferos/anatomia & histologia , Mamíferos/genética , Mamíferos/fisiologia , Roedores/anatomia & histologia , Roedores/genética , Transportadores de Sulfato/genética , Osso Temporal/anatomia & histologia
6.
J Tissue Viability ; 30(3): 291-300, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34103213

RESUMO

SIGNIFICANCE: Chronic wounds fail to heal in a timely manner and exhibit sustained inflammation with slow tissue repair and remodelling. They decrease mobility and quality of life, and remain a major clinical challenge in the long-term care of many patients, affecting 6.5 million individuals annually in the U.S., decreasing mobility and quality of life. Treatment costs are a major burden on the U.S. healthcare system, totalling between $25 and $100 billion annually. Chronic wound severity depends upon several factors such as comorbidities, severity of tissue damage, infection and presence of necrosis and vary greatly in their healing mechanisms. In vivo animal models are critical for studying healing pathways of chronic wounds and seek to replicate clinical factors for trials of topical, systemic, and device-based therapeutics. This comprehensive review discusses murine, rat, lapine, canine, feline and porcine models of chronic wounds. RECENT ADVANCES: Foundational chronic wound models for several species are discussed together with refinements and advances in the time period between 2015 and 2020 which have the potential for broad utility in investigating biological and device-based wound treatment therapies for human health. CRITICAL ISSUES: Chronic wounds fail to heal in a timely manner and have differing aetiologies, rendering no single in vivo animal model universally applicable. FUTURE DIRECTIONS: Further studies are required to develop clinically relevant chronic wound animal model which reflect the clinical reality of the various influences of age, disease, comorbidities and gender on delayed healing and enhance understanding of the biological processes of human wound healing.


Assuntos
Modelos Animais de Doenças , Cicatrização/fisiologia , Ferimentos e Lesões/fisiopatologia , Ferimentos e Lesões/terapia , Animais , Roedores/anatomia & histologia , Roedores/fisiologia , Pele/efeitos dos fármacos , Pele/lesões , Cicatrização/efeitos dos fármacos
7.
Sci Rep ; 11(1): 12031, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34103594

RESUMO

Compared to Northern Carpathians, the small mammal fauna of Southern Carpathian forests is poorly known, with no data on habitat use; our study seeks to fill this gap. To this end, we conducted a survey in the Southern Carpathians for five years, assessing habitat use by small mammals in forests along an elevational gradient. Trapping was done using live traps set in transects at elevations between 820 and 2040 m. For each transect we evaluated variables related to vegetation structure, habitat complexity, and geographical location. We considered abundance, species composition and species richness as response variables. The rodents Apodemus flavicollis and Myodes glareolus and the shrew Sorex araneus were common and dominant. Their abundance were positively correlated with tree cover, the best explanatory variable. Responses to other variables were mixed. The strong divergence in the relative habitat use by the three most abundant species may act as a mechanism that enables their coexistence as dominant species, exploiting the same wide range of habitat resources. Overall, habitat use in our study area was similar to that reported from Northern Carpathians, but we found also important differences probably caused by the differences in latitude and forest management practices.


Assuntos
Arvicolinae/fisiologia , Biodiversidade , Florestas , Roedores/fisiologia , Musaranhos/fisiologia , Animais , Romênia
8.
J Zoo Wildl Med ; 52(1): 276-286, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33827186

RESUMO

Orotracheal intubation carries greater difficulty in rodents than in most domestic species. The human laryngeal mask airway (LMA) was compared with an endotracheal tube (ETtube) for maintaining airway patency in anesthetized capybaras (Hydrochoerus hydrochaeris). Six capybaras (24-52 kg) were remotely darted with intramuscular ketamine, midazolam, and acepromazine on two occasions (≥7-day intervals). After isoflurane mask induction for random placement of an ETtube or a LMA during each episode, anesthesia was maintained with isoflurane in oxygen under spontaneous ventilation for 90-120 min. Computed tomography of the pharynx and larynx was performed in two of six animals and three of six animals with the ETtube and LMA, respectively. End-tidal isoflurane [median (range)] was not significantly different between ETtube [0.6% (0.5-1.5%)] and LMA [0.6% (0.4-0.9%)]. Heart rate [67 ± 11 beats/min (ETtube) and 67 ± 18 beats/min (LMA)], mean arterial pressure [74 ± 13 mm Hg (ETtube) and 74 ± 14 mm Hg (LMA)], arterial CO2 tension [41 ± 2 mm Hg (ETtube) and 43 ± 4 mm Hg (LMA)], and arterial O2 tension [360 ± 59 mm Hg (ETtube) and 360 ± 63 mm Hg (LMA)] were not significantly different between treatment groups. Computed tomography showed gas in the esophagus with the LMA (three of three animals); the fit of the LMA to the larynx was adequate in two of three animals and fair in one of three animals. Recovery from anesthesia was uneventful. The LMA is a feasible alternative to the ETtube for maintaining airway patency during inhalant anesthesia in spontaneously breathing capybaras. However, the LMA may be dislodged during movement of the animal.


Assuntos
Anestesia por Inalação/veterinária , Intubação Intratraqueal/veterinária , Máscaras Laríngeas/veterinária , Roedores/fisiologia , Anestésicos Inalatórios/administração & dosagem , Anestésicos Inalatórios/farmacologia , Animais , Isoflurano/administração & dosagem , Isoflurano/farmacologia
9.
Int J Mol Sci ; 22(6)2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33803957

RESUMO

Using rotors to expose animals to different levels of hypergravity is an efficient means of understanding how altered gravity affects physiological functions, interactions between physiological systems and animal development. Furthermore, rotors can be used to prepare space experiments, e.g., conducting hypergravity experiments to demonstrate the feasibility of a study before its implementation and to complement inflight experiments by comparing the effects of micro- and hypergravity. In this paper, we present a new platform called the Gravitational Experimental Platform for Animal Models (GEPAM), which has been part of European Space Agency (ESA)'s portfolio of ground-based facilities since 2020, to study the effects of altered gravity on aquatic animal models (amphibian embryos/tadpoles) and mice. This platform comprises rotors for hypergravity exposure (three aquatic rotors and one rodent rotor) and models to simulate microgravity (cages for mouse hindlimb unloading and a random positioning machine (RPM)). Four species of amphibians can be used at present. All murine strains can be used and are maintained in a specific pathogen-free area. This platform is surrounded by numerous facilities for sample preparation and analysis using state-of-the-art techniques. Finally, we illustrate how GEPAM can contribute to the understanding of molecular and cellular mechanisms and the identification of countermeasures.


Assuntos
Hipergravidade/efeitos adversos , Roedores/fisiologia , Voo Espacial , Ausência de Peso/efeitos adversos , Animais , Humanos , Larva/patogenicidade , Larva/efeitos da radiação , Camundongos , Modelos Animais , Xenopus laevis/fisiologia
10.
Elife ; 102021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33779547

RESUMO

Feeding is critical for survival, and disruption in the mechanisms that govern food intake underlies disorders such as obesity and anorexia nervosa. It is important to understand both food intake and food motivation to reveal mechanisms underlying feeding disorders. Operant behavioral testing can be used to measure the motivational component to feeding, but most food intake monitoring systems do not measure operant behavior. Here, we present a new solution for monitoring both food intake and motivation in rodent home-cages: the Feeding Experimentation Device version 3 (FED3). FED3 measures food intake and operant behavior in rodent home-cages, enabling longitudinal studies of feeding behavior with minimal experimenter intervention. It has a programmable output for synchronizing behavior with optogenetic stimulation or neural recordings. Finally, FED3 design files are open-source and freely available, allowing researchers to modify FED3 to suit their needs.


Assuntos
Criação de Animais Domésticos , Condicionamento Operante , Desenho de Equipamento/instrumentação , Comportamento Alimentar , Abrigo para Animais , Roedores/fisiologia , Animais , Ingestão de Alimentos , Feminino , Masculino , Camundongos
11.
Parasit Vectors ; 14(1): 112, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33596984

RESUMO

BACKGROUND: Small mammals are important maintenance hosts of ectoparasites as well as reservoir hosts for many arthropod-borne pathogens. In Germany, only a few studies have investigated ectoparasite communities on small mammals in their natural habitats. The aim of this study was to assess the species diversity and parameters influencing the mean intensity and prevalence of macroscopically visible ectoparasites, such as fleas, predatory mites and ticks. METHODS: A total of 779 small mammals and 3383 ticks were available from earlier investigations for the data analysis of the current study from three differently structured study sites. In addition, fleas and predatory mites were collected from the captured rodents and taxonomically identified. Regression analyses were conducted on the group (ticks/mites/fleas) and species levels using hurdle models for the abundance of ectoparasite groups and a negative binomial model for the abundance of species. RESULTS: Nearly 90% of the small mammals analyzed were infested with ectoparasites, with an average of 7.3 specimens per host. Hosts were infested with up to six species of ectoparasites simultaneously. In total, 12 flea, 11 mite and three tick species were detected. Ticks were more prevalent than fleas or mites, with > 80% of the hosts in urban and forest areas hosting ticks and around 60% of hosts presenting fleas, and only 20-40% of hosts presenting mites. Polyparasitism had a statistically significant influence on the prevalence of the investigated tick, mite and flea species, with odds ratios of > 1.0. Trapping location, season and host characteristics had significant influences on some-but not all-of the investigated species. CONCLUSIONS: The diversity of flea species was unexpectedly high and higher than that reported in comparable studies, which can be explained by the differently structured habitats and regions examined in this study. Polyparasitism was a key influencing factor and had a positive effect on the prevalence and/or abundance of the predominant tick, flea and mite species occurring on small mammals. Season, trapping location, host species and sex of the host species also had an influence on the prevalence and mean intensity of certain, but not all, ectoparasite species.


Assuntos
Ácaros/fisiologia , Roedores/parasitologia , Sifonápteros/fisiologia , Carrapatos/fisiologia , Animais , Ecossistema , Feminino , Alemanha , Interações Hospedeiro-Parasita , Masculino , Ácaros/classificação , Roedores/fisiologia , Estações do Ano , Sifonápteros/classificação , Carrapatos/classificação
12.
Respir Physiol Neurobiol ; 288: 103640, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33588089

RESUMO

Burrowing rodents have a blunted hypercapnic ventilatory response compared to non-burrowing rodents, but semi-fossorial ground squirrels and hamsters are not born with this blunted response when raised in room conditions. This study examined the hypercapnic ventilatory response of rats, hamsters, and ground squirrels raised in burrow-like hypercapnia (∼3 % CO2) through development (embryonic day 16-18 to postnatal day 30) to determine if chronic hypercapnia exerts any effect on the developing and adult semi-fossorial response. Chronic hypercapnia attenuated the ventilatory response to 5 % CO2 by 60 % (rats), 150 % (hamsters), and 70 % (squirrels) in newborns when compared to newborns raised in normal conditions. When raised in burrow conditions, squirrels and hamsters reached the blunted adult response ∼8-12 days sooner in development than their room air counterparts, while burrow-reared rats maintained a consistently blunted response until removal from chronic hypercapnia. Our study revealed no lasting effect of chronic hypercarbia on the ventilatory responses to CO2 in burrowing rodents, but rather a change in the developmental profile such that the blunted adult response was reached earlier in development.


Assuntos
Dióxido de Carbono/metabolismo , Hipercapnia/fisiopatologia , Ventilação Pulmonar/fisiologia , Roedores/fisiologia , Animais , Animais Recém-Nascidos , Animais Selvagens , Cricetinae , Feminino , Gravidez , Ratos , Ratos Sprague-Dawley , Roedores/crescimento & desenvolvimento , Sciuridae
13.
Dev Biol ; 472: 75-84, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33484707

RESUMO

Understanding how sex differences in innate animal behaviors arise has long fascinated biologists. As a general rule, the potential for sex differences in behavior is built by the developmental actions of sex-specific hormones or regulatory proteins that direct the sexual differentiation of the nervous system. In the last decade, studies in several animal systems have uncovered neural circuit mechanisms underlying discrete sexually dimorphic behaviors. Moreover, how certain hormones and regulatory proteins implement the sexual differentiation of these neural circuits has been illuminated in tremendous detail. Here, we discuss some of these mechanisms with three case-studies-mate recognition in flies, maturation of mating behavior in worms, and play-fighting behavior in young rodents. These studies illustrate general and unique developmental mechanisms to establish sex differences in neuroanatomy and behavior and highlight future challenges for the field.


Assuntos
Dípteros/fisiologia , Helmintos/fisiologia , Sistema Nervoso/crescimento & desenvolvimento , Roedores/fisiologia , Caracteres Sexuais , Animais , Encéfalo/metabolismo , Feminino , Hormônios Esteroides Gonadais/metabolismo , Masculino , Sistema Nervoso/metabolismo , Neurônios/metabolismo , Diferenciação Sexual/fisiologia , Comportamento Sexual Animal/fisiologia
14.
Sci Rep ; 11(1): 468, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33432100

RESUMO

Animal behavior is highly structured. Yet, structured behavioral patterns-or "statistical ethograms"-are not immediately apparent from the full spatiotemporal data that behavioral scientists usually collect. Here, we introduce a framework to quantitatively characterize rodent behavior during spatial (e.g., maze) navigation, in terms of movement building blocks or motor primitives. The hypothesis that we pursue is that rodent behavior is characterized by a small number of motor primitives, which are combined over time to produce open-ended movements. We assume motor primitives to be organized in terms of two sparsity principles: each movement is controlled using a limited subset of motor primitives (sparse superposition) and each primitive is active only for time-limited, time-contiguous portions of movements (sparse activity). We formalize this hypothesis using a sparse dictionary learning method, which we use to extract motor primitives from rodent position and velocity data collected during spatial navigation, and successively to reconstruct past trajectories and predict novel ones. Three main results validate our approach. First, rodent behavioral trajectories are robustly reconstructed from incomplete data, performing better than approaches based on standard dimensionality reduction methods, such as principal component analysis, or single sparsity. Second, the motor primitives extracted during one experimental session generalize and afford the accurate reconstruction of rodent behavior across successive experimental sessions in the same or in modified mazes. Third, in our approach the number of motor primitives associated with each maze correlates with independent measures of maze complexity, hence showing that our formalism is sensitive to essential aspects of task structure. The framework introduced here can be used by behavioral scientists and neuroscientists as an aid for behavioral and neural data analysis. Indeed, the extracted motor primitives enable the quantitative characterization of the complexity and similarity between different mazes and behavioral patterns across multiple trials (i.e., habit formation). We provide example uses of this computational framework, showing how it can be used to identify behavioural effects of maze complexity, analyze stereotyped behavior, classify behavioral choices and predict place and grid cell displacement in novel environments.


Assuntos
Comportamento Animal/fisiologia , Roedores/fisiologia , Roedores/psicologia , Navegação Espacial/fisiologia , Animais , Aprendizagem em Labirinto , Atividade Motora/fisiologia , Movimento/fisiologia , Comportamento Estereotipado/fisiologia
15.
Integr Zool ; 16(1): 109-119, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33443820

RESUMO

Density-dependent non-monotonic species interactions are important in maintaining ecosystem stability and function, but empirical evidences are still rare. Rodents, as both seed dispersers and seed predators, have dual effects on plant regeneration and may result in non-monotonic rodent-plant interactions. According to the non-monotonic models, the relative positive or negative effects of rodents on seedling establishment can be measured based on the positive or negative association of seedling recruitment rate and rodent abundance. In this study, we investigated the fates of acorns of Quercus serrata by tracking tagged seeds on 21 fragmented subtropical islands in the Thousand Island Lake, China. We found that the proportion of germinated seeds of all released seeds showed a dome-shaped association with rodent abundance per seed. The proportion of removed seeds and cached seeds showed a saturated- and a weak dome-shaped association with rodent abundance per seed, respectively. Our results demonstrated a clear empirical evidence that rodent abundance per seed triggered a switch between the relative mutualism and predation in a rodent-seed system. Our study implied that the observed non-monotonic interactions between plants and animals may play a significant role in maintaining biodiversity and ecosystem function. We appeal for more investigations of the complex non-monotonic interactions in various ecosystems.


Assuntos
Comportamento Alimentar , Quercus , Roedores/fisiologia , Dispersão de Sementes , Animais , China , Ecossistema , Germinação , Ilhas , Sementes
16.
J Therm Biol ; 95: 102810, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33454040

RESUMO

Abandoning of a stable body temperature (Tb), a phenomenon known as heterothermy, is an adaptation to cope mainly with a lack of food and water, especially in species inhabiting daily or seasonally variable environments. There is increasing evidence that African mammals avoid adverse conditions by heterothermy and eventually by entering torpor. Members of subterranean rodent family, the African mole-rats (Bathyergidae), are suitable candidates to study both phenomena, because of the diversity of their strategies in respect of maintaining stable Tb ranging from homeothermic species to a mammal with the most labile Tb, the naked mole-rat. Currently, there are field data on daily and seasonal Tb in one social species only and such information are lacking for any solitary mole-rat. In our study, we recorded yearly Tb in two solitary bathyergids, the Cape mole-rat Georychus capensis and the Cape dune mole-rat Bathyergus suillus from South Africa using intraperitoneally implanted dataloggers. Since this region is characterised by changing ecological characteristics, we expected either decreases of Tb within 24 h indicating daily torpor and/or longer-term decreases of Tb, which would indicate multiday torpor. Although we found seasonally phase shifted low amplitude daily Tb cycles, we did not find any remarkable and regular daily and/or seasonal Tb deviations, likely showing an absence of torpor in both species. Due to absence of this energy saving mechanism, we may speculate that both species could be vulnerable to ongoing global climatic change.


Assuntos
Aclimatação , Roedores/fisiologia , Torpor , Ciclos de Atividade , Animais
17.
Sci Rep ; 11(1): 2029, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479351

RESUMO

The relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.


Assuntos
Comportamento Animal/fisiologia , Regulação da Temperatura Corporal/fisiologia , Ratos-Toupeira/fisiologia , Roedores/fisiologia , Animais , Temperatura Alta , Especificidade da Espécie
18.
Parasit Vectors ; 14(1): 77, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33494777

RESUMO

Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a variety of intermediate hosts through a combination of carnivory and vertical transmission. However, T. gondii produces gametes only in felids after the predation of infected intermediate hosts. The parasite changes the behavior of its intermediate hosts by reducing their innate fear to cat odors and thereby plausibly increasing the probability that the definitive host will devour the infected host. Here, we provide a short description of such parasitic behavioral manipulation in laboratory rodents infected with T. gondii, along with a bird's eye view of underpinning biological changes in the host. We also summarize critical gaps and opportunities for future research in this exciting research area with broad implications in the transdisciplinary study of host-parasite relationships.


Assuntos
Comportamento Animal , Interações Hospedeiro-Parasita , Roedores/parasitologia , Toxoplasma , Animais , Gatos , Medo , Humanos , Estágios do Ciclo de Vida , Odorantes , Roedores/fisiologia , Toxoplasma/parasitologia , Toxoplasma/patogenicidade , Toxoplasmose Animal/parasitologia , Toxoplasmose Animal/fisiopatologia
19.
Naturwissenschaften ; 108(1): 5, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33411125

RESUMO

Understanding wild animal responses to stressors underpins effective wildlife management. In order for responses to stressors to be correctly interpreted, it is critical that measurements are taken on wild animals using minimally invasive techniques. Studies investigating wild animal responses to stressors often measure either a single physiological or behavioural variable, but whether such responses are comparable and concordant remains uncertain. We investigated this question in a pilot study that measured responses of wild-caught urban brown and black rats (Rattus norvegicus, Rattus rattus) to fur-based olfactory cues from a predator, the domestic cat (Felis catus); a novel herbivore, the koala (Phascolarctos cinereus); and a familiar herbivore and competitor, the common brushtail possum (Trichosurus vulpecula). Physiological responses, measured by assaying faecal glucocorticoid metabolites, were compared to behavioural responses observed via video recordings. We found that physiological and behavioural responses to stressors were expressed concordantly. There was no sizeable physiological response observed, and the behavioural response when considered across the night was negligible. However, the behavioural response to the predator and competitor cues changed across the observation period, with activity increasing with increasing hours of exposure. Our results indicate that responses of wild rodents to cues are nuanced, with stress responses modulated by behaviour changes that vary over time according to the severity of the perceived threat as animals gather further information. If the physiological response alone had been assessed, this moderated response may not have been evident, and in terms of wildlife management, vital information would have been lost.


Assuntos
Animais Selvagens/fisiologia , Comportamento Animal/fisiologia , Odorantes , Roedores/fisiologia , Estresse Fisiológico/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Gatos/fisiologia , Sinais (Psicologia) , Fezes/química , Glucocorticoides/análise , Phascolarctidae/fisiologia , Comportamento Predatório , Olfato , Estresse Fisiológico/efeitos dos fármacos , Trichosurus/fisiologia , População Urbana , Gravação em Vídeo
20.
J Med Entomol ; 58(3): 1171-1187, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33459790

RESUMO

Timber harvest may impact tick-borne disease by affecting small mammal and tick community structures. We assessed tick and small mammal populations in older second-growth redwood (Sequoia sempervirens (D. Don) Endl) habitat at two harvested sites in Santa Cruz County, California, where local risk of tick-borne disease is high and determined the prevalence of tick-borne pathogens in ticks. After single-tree removal harvest in 2014, there was a modest reduction in canopy, primarily toward the end of the study. Harvested sites showed strong reductions in California mouse (Peromyscus californicus, (Gambel)) captures 2-yr after harvest, resolving such that treatments and controls were comparable by the end of the study. Following harvest, treated sites experienced a transient decreased tick infestation while control plots experienced an increase. Ixodes angustus (Neumann) infestation probability on harvested plots decreased immediately after harvest, increasing with time but remaining lower than control plots, whereas I. pacificus (Cooley and Kohls) prevalence was higher shortly after the harvest on harvested plots, and continued to increase. Mean abundance of ticks on vegetation increased on control plots. We detected Borrelia burgdorferi ((Johnson et al.) Baranton) and Anaplasma phagocytophilum ((Foggie 1949) Dumler) in 3.8 and 3.1% of ticks on rodents, but no differences were associated with harvest. Impacts of forest harvest on tick-borne disease depend on removal practice and intensity, whether or not hosts are habitat specialists, and whether or not ticks are host specialists.


Assuntos
Biodiversidade , Agricultura Florestal , Ixodidae , Roedores , Infestações por Carrapato/veterinária , Doenças Transmitidas por Carrapatos/veterinária , Anaplasma phagocytophilum/isolamento & purificação , Animais , Borrelia burgdorferi/isolamento & purificação , California/epidemiologia , Florestas , Ixodidae/microbiologia , Ixodidae/parasitologia , Ixodidae/fisiologia , Dinâmica Populacional , Prevalência , Medição de Risco , Roedores/fisiologia , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/parasitologia , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/microbiologia , Doenças Transmitidas por Carrapatos/parasitologia
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