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Jan A Randall - One of the best experts on this subject based on the ideXlab platform.
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alarm signals of the great Gerbil acoustic variation by predator context sex age individual and family group
Journal of the Acoustical Society of America, 2005Co-Authors: Jan A Randall, Brenda Mccowan, Kellie C Collins, Stacie L Hooper, K A RogovinAbstract:The great Gerbil, Rhombomys opinus, is a highly social rodent that usually lives in family groups consisting of related females, their offspring, and an adult male. The Gerbils emit alarm vocalizations in the presence of diverse predators with different hunting tactics. Alarm calls were recorded in response to three predators, a monitor lizard, hunting dog, and human, to determine whether the most common call type, the rhythmic call, is functionally referential with regard to type of predator. Results show variation in the alarm calls of both adults and subadults with the type of predator. Discriminant function analysis classified an average of 70% of calls to predator type. Call variation, however, was not limited to the predator context, because signal structure also differed by sex, age, individual callers, and family groups. These variations illustrate the flexibility of the rhythmic alarm call of the great Gerbil and how it might have multiple functions and communicate in multiple contexts. Three alarm calls, variation in the rhythmic call, and vibrational signals generated from foot-drumming provide the Gerbils with a varied and multi-channel acoustic repertoire.
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Flexible social structure of a desert rodent, Rhombomys opimus: philopatry, kinship, and ecological constraints
Behavioral Ecology, 2005Co-Authors: Jan A Randall, K A Rogovin, Patricia G. Parker, John A. EimesAbstract:We tested hypotheses based on philopatry, kinship, and ecological constraints to explain sociality in a semifossorial desert rodent, the great Gerbil, Rhombomys opimus. Data were collected in the field in Uzbekistan in the spring and fall of 1996 and 1998–2004. Population densities fluctuated dramatically with high turnover in both males and females to reveal that dispersal and social structure were density dependent. Fewer Gerbils dispersed at higher densities and members of family groups dispersed together. A majority of females lived in groups at high densities, but as population densities declined, proportionally more females were solitary. DNA analysis revealed that group-living females were genetically similar, whereas solitary females visited by the same male, as well as adult males and females in the same family group, were usually not genetically similar. Reproductive success as measured by the number of emergent pups and survival of juveniles during the summer drought was not related to group size or whether females were philopatric. A majority of females in family groups reproduced, and all females engaged in cooperative behaviors. We accepted three hypotheses to explain fluctuations in group formation in the great Gerbil: variation in food abundance and distribution, habitat saturation, and kinship. We conclude that great Gerbils are facultatively social. Flexible social behavior may be adaptive in unpredictable desert conditions. Females live solitarily under conditions of limited food and high mortality that disrupt social behavior and group formation and share territories with female kin under favorable conditions for survival and reproduction when kin groups can be maintained. Males adjust to the distribution of females. Key words: desert, Gerbil, philopatry, Rhombomys opimus, social. [Behav Ecol]
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PREDATION ON A SOCIAL DESERT RODENT, RHOMBOMYS OPIMUS: EFFECT OF GROUP SIZE, COMPOSITION, AND LOCATION
Journal of Mammalogy, 2004Co-Authors: K A Rogovin, Jan A Randall, Irina Kolosova, M P MoshkinAbstract:Predation can provide both positive and negative effects on formation of social groups in rodents. On the basis of observational data of predation by the desert monitor lizard (Varanus griseus caspius) on the great Gerbil (Rhombomys opimus), a social rodent of desert Central Asia, we predicted that in a year after a peak in prey density, when the abundance of terrestrial predators is still high, the group mode of life of a prey species might become disadvantageous. Social groups could advertise themselves and attract predators. We therefore hypothesized that the probability of predation would be higher for Gerbils in outlying social groups than in groups closely associated with each other, in larger compared with smaller groups, and in groups with an active adult male compared with solitary females with no resident male. We also analyzed whether the survival of Gerbils and the stress levels in adult and juvenile males were related to frequency of visits by monitor lizards at Gerbil colonies (isolated systems of burrows used by Gerbil groups of any size), distance between colonies, and size of social groups. We found that frequency of visits by the monitor lizard depended on distance to the nearest neighboring colony. The more distant the Gerbil colony, the more visits by the lizard and the lower the survival of juveniles. We also found a positive correlation between concentration of fecal corticosterone in young males and frequency of monitor lizard visits at colonies. This pattern was not as pronounced in adult males. Results did not support the hypothesis that larger groups would have higher predation because frequency of predator visits, distances to the nearest occupied colonies, and survival of juveniles did not correlate significantly with the size of family groups. There was no difference in survival of juveniles in colonies occupied by single females compared with colonies in which an adult male was present. These results suggest that there is a possible trade-off between competing strategies of antipredator behavior and that factors other than predation are influencing Gerbil survival.
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Variation in and Meaning of Alarm Calls in a Social Desert Rodent Rhombomys opimus
Ethology, 2002Co-Authors: Jan A Randall, K A RogovinAbstract:The great Gerbil (Rhombomys opimus), a social rodent that lives in family groups, emits three different alarm vocalizations in the presence of predators: a rhythmic call; a faster more intense call; and a single whistle. We tested the hypothesis that the alarm calls communicate risk of predation. We quantified the relationship between predator distance and type of alarm call via human approaches to Gerbils. We also tested responses of focal adults in family groups to playback broadcasts of the different calls and controls of bird song and tape noise. Results showed that alarm calls were related to distance from a predator. Gerbils gave the rhythmic call when the predator was farthest away, the more intense call as the predator moved closer; and a short whistle when startled by a close approach of the predator. Gerbils stopped feeding and stood vigilant in a frozen alert posture in response to playbacks of all three alarm calls. They decreased non-vigilant behavior to the alarm vocalizations more than to the controls and decreased non-vigilant behavior significantly more in response to the intense alarm and whistle compared with the rhythmic alarm. We conclude that one function of Gerbil alarm calls is to communicate response urgency to family members. The rhythmic alarm communicates danger at a distance, whereas the intense alarm and whistle signal the close approach of a predator.
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antipredator behavior of a social desert rodent footdrumming and alarm calling in the great Gerbil rhombomys opiums
Behavioral Ecology and Sociobiology, 2000Co-Authors: Jan A Randall, K A Rogovin, Debra M ShierAbstract:We sought to understand why a social, desert rodent, the great Gerbil, Rhombomys opimus, expends energy and possible risk of predation by footdrumming and vocalizing in the presence of a diversity of terrestrial predators: snakes, monitor lizards, polecats, foxes, and humans. Behavioral observations, human approaches, and experiments with tethered predators revealed that both male and female Gerbils called and footdrummed in the presence of offspring, close relatives, and potential mates. Because adults called more often when pups were present, and solitary Gerbils seldom gave an alarm, the alarm behavior probably warns conspecifics, especially vulnerable offspring, of potential danger. We also found that Gerbils altered alarm behavior with the type of predator. They drummed more in the burrow when a dog that could not enter the burrow was present, and they drummed more out of the burrow in response to a snake that could enter the burrow. Gerbils vocalized and stood in an alert posture in response to all stimuli. The different footdrumming responses of Gerbils to terrestrial predators seems related to the hunting style and type of risk posed by the predator, especially its ability to enter the burrow system.
K A Rogovin - One of the best experts on this subject based on the ideXlab platform.
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alarm signals of the great Gerbil acoustic variation by predator context sex age individual and family group
Journal of the Acoustical Society of America, 2005Co-Authors: Jan A Randall, Brenda Mccowan, Kellie C Collins, Stacie L Hooper, K A RogovinAbstract:The great Gerbil, Rhombomys opinus, is a highly social rodent that usually lives in family groups consisting of related females, their offspring, and an adult male. The Gerbils emit alarm vocalizations in the presence of diverse predators with different hunting tactics. Alarm calls were recorded in response to three predators, a monitor lizard, hunting dog, and human, to determine whether the most common call type, the rhythmic call, is functionally referential with regard to type of predator. Results show variation in the alarm calls of both adults and subadults with the type of predator. Discriminant function analysis classified an average of 70% of calls to predator type. Call variation, however, was not limited to the predator context, because signal structure also differed by sex, age, individual callers, and family groups. These variations illustrate the flexibility of the rhythmic alarm call of the great Gerbil and how it might have multiple functions and communicate in multiple contexts. Three alarm calls, variation in the rhythmic call, and vibrational signals generated from foot-drumming provide the Gerbils with a varied and multi-channel acoustic repertoire.
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Flexible social structure of a desert rodent, Rhombomys opimus: philopatry, kinship, and ecological constraints
Behavioral Ecology, 2005Co-Authors: Jan A Randall, K A Rogovin, Patricia G. Parker, John A. EimesAbstract:We tested hypotheses based on philopatry, kinship, and ecological constraints to explain sociality in a semifossorial desert rodent, the great Gerbil, Rhombomys opimus. Data were collected in the field in Uzbekistan in the spring and fall of 1996 and 1998–2004. Population densities fluctuated dramatically with high turnover in both males and females to reveal that dispersal and social structure were density dependent. Fewer Gerbils dispersed at higher densities and members of family groups dispersed together. A majority of females lived in groups at high densities, but as population densities declined, proportionally more females were solitary. DNA analysis revealed that group-living females were genetically similar, whereas solitary females visited by the same male, as well as adult males and females in the same family group, were usually not genetically similar. Reproductive success as measured by the number of emergent pups and survival of juveniles during the summer drought was not related to group size or whether females were philopatric. A majority of females in family groups reproduced, and all females engaged in cooperative behaviors. We accepted three hypotheses to explain fluctuations in group formation in the great Gerbil: variation in food abundance and distribution, habitat saturation, and kinship. We conclude that great Gerbils are facultatively social. Flexible social behavior may be adaptive in unpredictable desert conditions. Females live solitarily under conditions of limited food and high mortality that disrupt social behavior and group formation and share territories with female kin under favorable conditions for survival and reproduction when kin groups can be maintained. Males adjust to the distribution of females. Key words: desert, Gerbil, philopatry, Rhombomys opimus, social. [Behav Ecol]
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PREDATION ON A SOCIAL DESERT RODENT, RHOMBOMYS OPIMUS: EFFECT OF GROUP SIZE, COMPOSITION, AND LOCATION
Journal of Mammalogy, 2004Co-Authors: K A Rogovin, Jan A Randall, Irina Kolosova, M P MoshkinAbstract:Predation can provide both positive and negative effects on formation of social groups in rodents. On the basis of observational data of predation by the desert monitor lizard (Varanus griseus caspius) on the great Gerbil (Rhombomys opimus), a social rodent of desert Central Asia, we predicted that in a year after a peak in prey density, when the abundance of terrestrial predators is still high, the group mode of life of a prey species might become disadvantageous. Social groups could advertise themselves and attract predators. We therefore hypothesized that the probability of predation would be higher for Gerbils in outlying social groups than in groups closely associated with each other, in larger compared with smaller groups, and in groups with an active adult male compared with solitary females with no resident male. We also analyzed whether the survival of Gerbils and the stress levels in adult and juvenile males were related to frequency of visits by monitor lizards at Gerbil colonies (isolated systems of burrows used by Gerbil groups of any size), distance between colonies, and size of social groups. We found that frequency of visits by the monitor lizard depended on distance to the nearest neighboring colony. The more distant the Gerbil colony, the more visits by the lizard and the lower the survival of juveniles. We also found a positive correlation between concentration of fecal corticosterone in young males and frequency of monitor lizard visits at colonies. This pattern was not as pronounced in adult males. Results did not support the hypothesis that larger groups would have higher predation because frequency of predator visits, distances to the nearest occupied colonies, and survival of juveniles did not correlate significantly with the size of family groups. There was no difference in survival of juveniles in colonies occupied by single females compared with colonies in which an adult male was present. These results suggest that there is a possible trade-off between competing strategies of antipredator behavior and that factors other than predation are influencing Gerbil survival.
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Variation in and Meaning of Alarm Calls in a Social Desert Rodent Rhombomys opimus
Ethology, 2002Co-Authors: Jan A Randall, K A RogovinAbstract:The great Gerbil (Rhombomys opimus), a social rodent that lives in family groups, emits three different alarm vocalizations in the presence of predators: a rhythmic call; a faster more intense call; and a single whistle. We tested the hypothesis that the alarm calls communicate risk of predation. We quantified the relationship between predator distance and type of alarm call via human approaches to Gerbils. We also tested responses of focal adults in family groups to playback broadcasts of the different calls and controls of bird song and tape noise. Results showed that alarm calls were related to distance from a predator. Gerbils gave the rhythmic call when the predator was farthest away, the more intense call as the predator moved closer; and a short whistle when startled by a close approach of the predator. Gerbils stopped feeding and stood vigilant in a frozen alert posture in response to playbacks of all three alarm calls. They decreased non-vigilant behavior to the alarm vocalizations more than to the controls and decreased non-vigilant behavior significantly more in response to the intense alarm and whistle compared with the rhythmic alarm. We conclude that one function of Gerbil alarm calls is to communicate response urgency to family members. The rhythmic alarm communicates danger at a distance, whereas the intense alarm and whistle signal the close approach of a predator.
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antipredator behavior of a social desert rodent footdrumming and alarm calling in the great Gerbil rhombomys opiums
Behavioral Ecology and Sociobiology, 2000Co-Authors: Jan A Randall, K A Rogovin, Debra M ShierAbstract:We sought to understand why a social, desert rodent, the great Gerbil, Rhombomys opimus, expends energy and possible risk of predation by footdrumming and vocalizing in the presence of a diversity of terrestrial predators: snakes, monitor lizards, polecats, foxes, and humans. Behavioral observations, human approaches, and experiments with tethered predators revealed that both male and female Gerbils called and footdrummed in the presence of offspring, close relatives, and potential mates. Because adults called more often when pups were present, and solitary Gerbils seldom gave an alarm, the alarm behavior probably warns conspecifics, especially vulnerable offspring, of potential danger. We also found that Gerbils altered alarm behavior with the type of predator. They drummed more in the burrow when a dog that could not enter the burrow was present, and they drummed more out of the burrow in response to a snake that could enter the burrow. Gerbils vocalized and stood in an alert posture in response to all stimuli. The different footdrumming responses of Gerbils to terrestrial predators seems related to the hunting style and type of risk posed by the predator, especially its ability to enter the burrow system.
Rong Guo - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of Yersinia pestis and Its Antibody Response in Great Gerbils (Rhombomys opimus) by Subcutaneous Infection
2016Co-Authors: Yujiang Zhang, Qiguo Wang, Azhati Rehemu, Xinhui Wang, Weiwei Meng, Xiang Dai, Tao Luo, Abulimiti Maituohuti, Yujun Cui, Rong GuoAbstract:Background: Rhombomys opimus (great Gerbil) is a reservoir of Yersinia pestis in the natural plague foci of Central Asia. Great Gerbils are highly resistant to Y. pestis infection. The coevolution of great Gerbils and Y. pestis is believed to play an important role in the plague epidemics in Central Asia plague foci. However, the dynamics of Y. pestis infection and the corresponding antibody response in great Gerbils have not been evaluated. In this report, animal experiments were employed to investigate the bacterial load in both the liver and spleen of infected great Gerbils. The dynamics of the antibody response to the F1 capsule antigen of Y. pestis was also determined. Methodology: Captured great Gerbils that tested negative for both anti-F1 antibodies and bacterial isolation were infected subcutaneously with different doses (105 to 1011 CFU) of a Y. pestis strain isolated from a live great Gerbil during routine plague surveillance in the Junggar Basin, Xinjiang, China. The clinical manifestations, changes in body weight, anal temperature, and gross anatomy of the infected animals were observed. The blood cell count, bacterial load, and anti-F1 antibody titers were determined at different time points after infection using a blood analyzer, plate counts, and an indirect hemagglutination assay, respectively. Conclusions/Significance: The dynamics of bacterial load and the anti-F1 antibody concentration in great Gerbils are highly variable among individuals. The Y. pestis infection in great Gerbils could persist as long as 15 days. They act as a
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Dynamics of Yersinia pestis and its antibody response in great Gerbils (Rhombomys opimus) by subcutaneous infection.
PloS one, 2012Co-Authors: Yujiang Zhang, Qiguo Wang, Azhati Rehemu, Xinhui Wang, Weiwei Meng, Xiang Dai, Tao Luo, Abulimiti Maituohuti, Yujun Cui, Rong GuoAbstract:Background Rhombomys opimus (great Gerbil) is a reservoir of Yersinia pestis in the natural plague foci of Central Asia. Great Gerbils are highly resistant to Y. pestis infection. The coevolution of great Gerbils and Y. pestis is believed to play an important role in the plague epidemics in Central Asia plague foci. However, the dynamics of Y. pestis infection and the corresponding antibody response in great Gerbils have not been evaluated. In this report, animal experiments were employed to investigate the bacterial load in both the liver and spleen of infected great Gerbils. The dynamics of the antibody response to the F1 capsule antigen of Y. pestis was also determined. Methodology Captured great Gerbils that tested negative for both anti-F1 antibodies and bacterial isolation were infected subcutaneously with different doses (105 to 1011 CFU) of a Y. pestis strain isolated from a live great Gerbil during routine plague surveillance in the Junggar Basin, Xinjiang, China. The clinical manifestations, changes in body weight, anal temperature, and gross anatomy of the infected animals were observed. The blood cell count, bacterial load, and anti-F1 antibody titers were determined at different time points after infection using a blood analyzer, plate counts, and an indirect hemagglutination assay, respectively. Conclusions/Significance The dynamics of bacterial load and the anti-F1 antibody concentration in great Gerbils are highly variable among individuals. The Y. pestis infection in great Gerbils could persist as long as 15 days. They act as an appropriate reservoir for plague in the Junggar Basin, which is part of the natural plague foci in Central Asia. The dynamics of the Y. pestis susceptibility of great Gerbil will improve the understanding of its variable resistance, which would facilitate the development of more effective countermeasures for controlling plague epidemics in this focus.
Rohela Mahmud - One of the best experts on this subject based on the ideXlab platform.
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Effect of Brugia pahangi co-infection with Plasmodium berghei ANKA in Gerbils (Meriones unguiculatus)
Parasitology Research, 2020Co-Authors: Olawale Quazim Junaid, Sinnadurai Sivanandam, Indra Vythilingam, Loke Tim Khaw, Rohela MahmudAbstract:Malaria and lymphatic filariasis (LF) are two leading and common mosquito-borne parasitic diseases worldwide. These two diseases are co-endemic in many tropical and sub-tropical regions and are known to share vectors. The interactions between malaria and filarial parasites are poorly understood. Thus, this study aimed at establishing the interactions that occur between Brugia pahangi and Plasmodium berghei ANKA ( Pb A) co-infection in Gerbils. Briefly, the Gerbils were matched according to age, sex, and weight and grouped into filarial-only infection, Pb A-only infection, co-infection, and control group. The parasitemia, survival and clinical assessment of the Gerbils were monitored for a period of 30 days post Plasmodium infection. The immune responses of Gerbils to both mono and co-infection were monitored. Findings show that co-infected Gerbils have higher survival rate than Pb A-infected Gerbils. Food and water consumption were significantly reduced in both Pb A-infected and co-infected Gerbils, although loss of body weight, hypothermia, and anemia were less severe in co-infected Gerbils. Plasmodium -infected Gerbils also suffered hypoglycemia, which was not observed in co-infected Gerbils. Furthermore, Gerbil cytokine responses to co-infection were significantly higher than Pb A-only-infected Gerbils, which is being suggested as a factor for their increased longevity. Co-infected Gerbils had significantly elicited interleukin-4, interferon-gamma, and tumor necrotic factor at early stage of infection than Pb A-infected Gerbils. Findings from this study suggest that B. pahangi infection protect against severe anemia and hypoglycemia, which are manifestations of Pb A infection.
Hiroyoshi Ota - One of the best experts on this subject based on the ideXlab platform.
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immune response to a 26 kda protein alkyl hydroperoxide reductase in helicobacter pylori infected mongolian Gerbil model
Helicobacter, 2001Co-Authors: Jing Yan, Toshiko Kumagai, Makoto Ohnishi, Ichiro Ueno, Hiroyoshi OtaAbstract:Background. The host immune response is thought to play an important role in the outcome of Helico-bacter pylori infection. The successful development of the H. pylori-infected Mongolian Gerbil model that mimics human disease has enabled study of the antibody response against H. pylori antigens. Materials and Methods. Serum samples from ulcer and carcinogenesis models of H. pylori-infected Gerbils were used to screen for H. pylori antigens that cause a humoral immune response in the infected hosts. H. pylori alkyl hydroperoxide reductase (AhpC) is one such antigen on which we report here. The tsaA gene encoding AhpC was amplified by PCR from H. pylori ATCC 43504 strain, cloned into pMALTM-c2 expression vector and expressed in Escherichia coli. Maltose-binding protein fusion protein (MBP-AhpC) was purified by a MBP affinity column. Using purified recombinant AhpC protein as an antigen, the antibody response and changes of antibody levels against AhpC in the Gerbil models were studied by Western blotting and ELISA. Results. Antibody against AhpC was negative in the early stages of infection, and became positive in the Gerbils with the emergence of gastric diseases such as chronic active gastritis, gastric ulcer and gastric cancer. The antibody levels (ELISA) increased gradually over time and were higher in Gerbils with gastric ulcer than that in Gerbils without ulcers. Conclusions. Use of the Gerbil model that mimics human H. pylori infection is likely to provide insights into the role of H. pylori-specific antigens possibly related to the subsequent development of gastric diseases.
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helicobacter pylori induced chronic active gastritis intestinal metaplasia and gastric ulcer in mongolian Gerbils
American Journal of Pathology, 1999Co-Authors: Tatsuo Ikeno, Hiroyoshi Ota, Atsushi Sugiyama, Kimitaka Ishida, T Katsuyama, Robert M Genta, Seiji KawasakiAbstract:The establishment of persisting Helicobacter pylori infection in laboratory animals has been difficult, but in 1996 Hirayama reported the development of a successful Mongolian Gerbil model. The present study was undertaken with two aims: to better characterize the normal histological structure and histochemical properties of the gastric mucosa of the Mongolian Gerbil; and to evaluate the progression of the histopathological features of H. pylori-induced gastritis in this animal model for one year after the experimental infection. Seventy-five Mongolian Gerbils were used. Mongolian Gerbils were sacrificed at 2, 4, 8, 12, 26, 38, and 52 weeks after H. pylori inoculation. Sections prepared from stomachs immediately fixed in Carnoy's solution were stained with hematoxylin and eosin and Alcian blue at pH 2.5/periodic acid-Schiff, a dual staining consisting of the galactose oxidase-cold thionin Schiff reaction and paradoxical Concanavalin A staining, and with immunostaining for H. pylori and BrdU. H. pylori infection induced in the Mongolian Gerbil a chronic active gastritis, in which a marked mucosal infiltration of neutrophils on a background of chronic inflammation became detectable 4 weeks after inoculation and continued up to 52 weeks. Intestinal metaplasia and gastric ulcers appeared after 26 weeks in some of the animals, whereas others developed multiple hyperplastic polyps. The Mongolian Gerbil represents a novel and useful model for the study of H. pylori-induced chronic active gastritis and may lend itself to the investigation of the epithelial alterations that lead to intestinal metaplasia and gastric neoplasia.
