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Jaime Polop - One of the best experts on this subject based on the ideXlab platform.
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Effective Population Size Differences in Calomys musculinus, the Host of Junín Virus: Their Relationship with the Epidemiological History of Argentine Hemorrhagic Fever.
The American journal of tropical medicine and hygiene, 2018Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, Gladys E. Calderón, M. F. Piacenza, María C. Provensal, Jaime PolopAbstract:Argentine hemorrhagic fever (AHF) is a serious endemic disease in Argentina, produced by Junin virus, whose host is the Sigmodontinae rodent Calomys musculinus. Within the endemic area, human incidence and proportion of infected rodents remains high for 5-10 years after the first appearance of the disease (epidemic [E] zone) and then gradually declines to sporadic cases (historic [H] zone). We tested the hypothesis that host populations within the E zone are large and well connected by gene flow, facilitating the transmission and maintenance of the virus, whereas those in the H and nonendemic (NE) zones are small and isolated, with the opposite effect. We estimated parameters affected by levels of gene flow and population size in 14 populations of C. musculinus: population effective size (Ne), genetic variability, and mean relatedness. Our hypothesis was not supported: the lowest levels of variability and of Ne and the highest genetic relatedness among individuals were found in the H zone. Populations from the NE zone displayed opposite results, whereas those in the E zone showed intermediate values. If we consider that populations are first NE, then E, and finally H, a correlative decrease in Ne was observed. Chronically infected females have a low reproductive success. We propose that this would lower Ne because each cohort would originate from a fraction of females of the previous generation, and affect other factors such as proportion of individuals that develop acute infection, probability of viral transmission, and evolution of virulence, which would explain, at least partly, the changing incidence of AHF.
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Habitat use by corn mice (Calomys musculinus) in cropfield borders of agricultural ecosystems in Argentina
Wildlife Research, 2012Co-Authors: Ivana Simone, Cecilia Provensal, Jaime PolopAbstract:Context Calomys musculinus (Cricetidae, Sigmodontinae) is a small rodent species widely distributed in Argentina and particularly abundant in agroecosystems of the Pampean region, where it is known to select border habitats over cropfields. Aims The aim of the present research was to assess habitat use by C. musculinus in cropfield borders. Assuming that the number of rodent captures in each border reflects the intensity of use, we intended to identify the habitat characteristics that would account for abundance differences among borders. Methods Seasonal trapping sessions were carried out in borders of the rural zone of Chucul, Cordoba. Environmental variables were registered from both field surveys and remote-sensing imagery. Generalised linear models were used to identify the habitat variables associated with C. musculinus habitat use. Key results General fit of the models was fairly good; spring, summer and autumn models explained more than 55% of the variation in C. musculinus abundance among borders. Individual plant species were significant predictors of C. musculinus abundance, but they varied with seasons, whereas tree cover and border width were significant predictors in most seasons studied. In general, rodent abundance was positively associated with peanut and maize crops or maize stubbles and negatively related to soybean or its stubbles. In the coldest seasons, rodent abundance increased with increasing land-surface temperature of the border. Conclusions Border use by C. musculinus appeared to respond to differences in border quality, which seems to be more affected by those environmental characteristics that entail a reduction of the predatory risk rather than by those that involve food supply. Crop-fields may partially afford C. musculinus food requirements. Implications Because C. musculinus is the natural reservoir of a zoonotic agent, the identification of the habitat characteristics affecting rodent population numbers in borders may be of crucial importance for the implementation of ecologically based rodent-management strategies aimed at reducing human–rodent contacts. We suggest that wide borders, particularly those contiguous to maize and peanut cropfields, should be understood as priority sites for the implementation of specific control actions.
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Differences in genetic structuring of populations of the Argentine hemorrhagic fever reservoir, the rodent Calomys musculinus , from endemic and non endemic zones
Julius-Kühn-Archiv, 2011Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, C. Provensal, M. F. Piacenza, G. E. Calderón, Jaime PolopAbstract:We estimated the effective population size and genetic structuring within populations of the rodent reservoir of Argentine Hemorrhagic Fever, Calomys musculinus, from zones with different epidemiologic condition (non endemic, historic and epidemic). We found that populations from epidemic zones presented higher effective sizes, higher differentiation among subpopulations and higher levels of internal relatedness than in non-endemic zones. These results would explain the maintenance of the virus in populations from epidemic zones and the patchy distribution of infected rodents.
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Environmental determinants of the small mammal assemblage in an agroecosystem of central Argentina: The role of Calomys musculinus
Mammalian Biology, 2010Co-Authors: Ivana Simone, Francesca Cagnacci, Cecilia Provensal, Jaime PolopAbstract:Agricultural intensification in the central region of Argentina has been accompanied by rodent assemblage changes, involving an increase in Calomys species densities. In particular, Calomys musculinus , the main reservoir of Junín virus (etiological agent of the Argentine Haemorrhagic Fever, AHF) selects field borders over crop-fields. Borders represent relatively-stable habitats within agroecosystems, otherwise highly human modified landscapes. In this article, we assessed the effect of environmental variables on rodent species occurrence and assemblage in the field borders of a pampean agroecosystem. Small rodent occurrence was examined for variation according to vegetation species composition, structure and productivity, using canonical ordination techniques. In a total of 72 crop-field borders of Córdoba province, in spring, summer and autumn (2005-2006), we captured 1041 rodents of 8 different species. Akodon azarae, Calomys venustus and C. musculinus were the dominant species of the assemblage, with the first two associated one another, while C. musculinus tended to be related to different environmental variables. We showed that rodent species associations were mediated by resources that changed seasonally, such as vegetation cover. Also, the strength and “sign” of the association between species seemed to be a consequence of different habitat preferences and activity patterns. Finally, the intra-annual population cycle seemed to influence the relation between species and habitat structure and, possibly, inter-specific competition for resources. Therefore, we suggest that less generalist species of the rodent assemblage, well adapted to linear habitats, may limit C. musculinus occurrence throughout the agroecosystem by habitat and spatial competition. Any action aimed to control AHF, and therefore C. musculinus population density, should exclude negative effects on coexisting species.
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growth and determination of age in Calomys musculinus rodentia cricetidae
Mammalia, 2009Co-Authors: María C. Provensal, Jaime PolopAbstract:Des mesures caracteristiques de l'âge, chez Calomys musculinus, ont ete choisies chez 6 groupes de specimens de laboratoire d'âge connu. Dix-huit mesures du crâne, la longueur du corps, de la queue, le poids du corps et le poids des cristallins ont ete releves pour chaque individu et etudies statistiquement. Un choix de caracteres a ete effectue avant de realiser une ANOVA en fonction de l'âge et du sexe. La distance D2 de Mahalanobis a ete calculee entre chaque paire de classes d'âge. Des fonctions discriminantes ont ete elaborees selon le sexe pour chaque groupe d'âge d'apres les caracteres choisis. Une correlation significative a ete etablie entre, d'une part, l'âge et, d'autre part, la longueur condylo-basale, la longueur de la rangee dentaire, la longueur de la mandibule, la largeur zygomatique, la distance entre les processus jugulaires et la largeur nasale
Cristina N. Gardenal - One of the best experts on this subject based on the ideXlab platform.
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Effective Population Size Differences in Calomys musculinus, the Host of Junín Virus: Their Relationship with the Epidemiological History of Argentine Hemorrhagic Fever.
The American journal of tropical medicine and hygiene, 2018Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, Gladys E. Calderón, M. F. Piacenza, María C. Provensal, Jaime PolopAbstract:Argentine hemorrhagic fever (AHF) is a serious endemic disease in Argentina, produced by Junin virus, whose host is the Sigmodontinae rodent Calomys musculinus. Within the endemic area, human incidence and proportion of infected rodents remains high for 5-10 years after the first appearance of the disease (epidemic [E] zone) and then gradually declines to sporadic cases (historic [H] zone). We tested the hypothesis that host populations within the E zone are large and well connected by gene flow, facilitating the transmission and maintenance of the virus, whereas those in the H and nonendemic (NE) zones are small and isolated, with the opposite effect. We estimated parameters affected by levels of gene flow and population size in 14 populations of C. musculinus: population effective size (Ne), genetic variability, and mean relatedness. Our hypothesis was not supported: the lowest levels of variability and of Ne and the highest genetic relatedness among individuals were found in the H zone. Populations from the NE zone displayed opposite results, whereas those in the E zone showed intermediate values. If we consider that populations are first NE, then E, and finally H, a correlative decrease in Ne was observed. Chronically infected females have a low reproductive success. We propose that this would lower Ne because each cohort would originate from a fraction of females of the previous generation, and affect other factors such as proportion of individuals that develop acute infection, probability of viral transmission, and evolution of virulence, which would explain, at least partly, the changing incidence of AHF.
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Genetic variability in the promoter region of TNF-α gene in the reservoir of Junin virus, Calomys musculinus (Rodentia, Cricetidae): Short communication
2017Co-Authors: Marina B. Chiappero, Imanol Cabaña, Gladys E. Calderón, Cristina N. GardenalAbstract:Abstract In this study, we assessed the genetic variability of the promoter region of TNF-α gene in three natural populations of the cricetid rodent Calomys musculinus . This species is the natural reservoir of Junin virus, the etiological agent of Argentine Hemorrhagic fever. We found different levels of variability and varying signatures of natural selection in populations with different epidemiological histories.
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Restricted gene flow in Calomys musculinus (rodentia, muridae), the natural reservoir of junin virus
2015Co-Authors: Marina B. Chiappero, Cristina N. GardenalAbstract:Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) markers were used to evaluate the relative contribution of gene flow as a determinant of the population genetic structure of the wild rodent Calomys musculinus (the reservoir of Argentine hemorrhagic fever [AHF]) in central Argentina. One hundred eighty-seven individuals from 13 populations (9 of them from the endemic zone of AHF and 5 from areas outside it) were analyzed using 78 polymorphic RAPD loci. Genetic variation within each population was high; each individual was characterized by a unique RAPD phenotype. C. musculinus populations showed a moderate to high genetic subdivision and a random pattern of differentiation. Populations separated by the same geographic distance showed very different degrees of genetic divergence. The results indicate that populations of C. musculinus have colonized their present ranges relatively recently and differentiation by genetic drift has proceeded faster than homogenization by gene flow at the macrogeographic scale analyzed (10–700 km). Calomys musculinus is a wild murid rodent widely distributed throughout most of Argentina. It is an opportunistic species, characterized by a high reproductive rate and the ability to colonize a wide variety of habitats, particularly disturbed ones like crop fields (Crespo et al. 1970; de Villafañe et al
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Differences in genetic structuring of populations of the Argentine hemorrhagic fever reservoir, the rodent Calomys musculinus , from endemic and non endemic zones
Julius-Kühn-Archiv, 2011Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, C. Provensal, M. F. Piacenza, G. E. Calderón, Jaime PolopAbstract:We estimated the effective population size and genetic structuring within populations of the rodent reservoir of Argentine Hemorrhagic Fever, Calomys musculinus, from zones with different epidemiologic condition (non endemic, historic and epidemic). We found that populations from epidemic zones presented higher effective sizes, higher differentiation among subpopulations and higher levels of internal relatedness than in non-endemic zones. These results would explain the maintenance of the virus in populations from epidemic zones and the patchy distribution of infected rodents.
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Contrasting genetic structure of urban and rural populations of the wild rodent Calomys musculinus (Cricetidae, Sigmodontinae)
Mammalian Biology, 2011Co-Authors: Marina B. Chiappero, Graciela M. Panzetta-dutari, Daniela Gomez, Ernesto Castillo, Jaime J. Polop, Cristina N. GardenalAbstract:The alteration of landscapes by human activities worldwide has forced many animal species to persist in remnants of natural habitats. One of the best examples of this process occurs in central-east Argentina, where the original prairies were almost completely replaced by agricultural land, cattle production areas and increasing urbanization. We used nine microsatellite loci to analyze the population genetic structure of the Sigmodontine rodent Calomys musculinus in two anthropically altered habitats: an agroecosystem and a city. Rodents inhabiting urban vacant lots showed higher levels of relatedness and genetic differentiation than rodents inhabiting the agroecosystem. Urban rodents presented a pattern of isolation by distance; in the rural habitat this pattern was present only along the border of a secondary road, but not over the entire area surveyed. In the city, a spatially limited but buffered environment, populations would be small, demographically stable, and dispersal would be restricted. On the contrary, in agroecosystems populations would experience a high rate of turn over: local demes would originate each year by a mixture of overwintering individuals, and dispersal would occur preferentially along the weedy borders of fields.
Marina B. Chiappero - One of the best experts on this subject based on the ideXlab platform.
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Effective Population Size Differences in Calomys musculinus, the Host of Junín Virus: Their Relationship with the Epidemiological History of Argentine Hemorrhagic Fever.
The American journal of tropical medicine and hygiene, 2018Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, Gladys E. Calderón, M. F. Piacenza, María C. Provensal, Jaime PolopAbstract:Argentine hemorrhagic fever (AHF) is a serious endemic disease in Argentina, produced by Junin virus, whose host is the Sigmodontinae rodent Calomys musculinus. Within the endemic area, human incidence and proportion of infected rodents remains high for 5-10 years after the first appearance of the disease (epidemic [E] zone) and then gradually declines to sporadic cases (historic [H] zone). We tested the hypothesis that host populations within the E zone are large and well connected by gene flow, facilitating the transmission and maintenance of the virus, whereas those in the H and nonendemic (NE) zones are small and isolated, with the opposite effect. We estimated parameters affected by levels of gene flow and population size in 14 populations of C. musculinus: population effective size (Ne), genetic variability, and mean relatedness. Our hypothesis was not supported: the lowest levels of variability and of Ne and the highest genetic relatedness among individuals were found in the H zone. Populations from the NE zone displayed opposite results, whereas those in the E zone showed intermediate values. If we consider that populations are first NE, then E, and finally H, a correlative decrease in Ne was observed. Chronically infected females have a low reproductive success. We propose that this would lower Ne because each cohort would originate from a fraction of females of the previous generation, and affect other factors such as proportion of individuals that develop acute infection, probability of viral transmission, and evolution of virulence, which would explain, at least partly, the changing incidence of AHF.
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Genetic variability in the promoter region of TNF-α gene in the reservoir of Junin virus, Calomys musculinus (Rodentia, Cricetidae): Short communication
2017Co-Authors: Marina B. Chiappero, Imanol Cabaña, Gladys E. Calderón, Cristina N. GardenalAbstract:Abstract In this study, we assessed the genetic variability of the promoter region of TNF-α gene in three natural populations of the cricetid rodent Calomys musculinus . This species is the natural reservoir of Junin virus, the etiological agent of Argentine Hemorrhagic fever. We found different levels of variability and varying signatures of natural selection in populations with different epidemiological histories.
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Multiple paternity in a wild population of the corn mouse: its potential adaptive significance for females
Journal of Mammalogy, 2015Co-Authors: Lucia Sommaro, Marina B. Chiappero, José Priotto, José Coda, Noelia Soledad Vera, Andrea R SteinmannAbstract:Mating with multiple males within a single reproductive event is a common female mating strategy in mice and voles, but its adaptive function is often unclear. In this study, we used 7 microsatellite loci to investigate if multiple paternity occurs in wild populations of the socially promiscuous Calomys musculinus. We also analyzed if multiple paternity increases litter size and/or genetic variability among offspring. In addition, we examined if multiple paternity occurs more frequently in litters conceived at high population density than those conceived at low population density. By genotyping 23 females and their 135 embryos (5.9 ± 1.6 SE pups per female), we found that 56.5% of the litters were sired by 2 or 3 males. We found no association between multiple paternity, litter size, and genetic variability. In addition, multiple paternity did not vary in relation to population density. Our results provide clear evidence of multiple paternity and offer the first genetic documentation of mating systems in ...
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Restricted gene flow in Calomys musculinus (rodentia, muridae), the natural reservoir of junin virus
2015Co-Authors: Marina B. Chiappero, Cristina N. GardenalAbstract:Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) markers were used to evaluate the relative contribution of gene flow as a determinant of the population genetic structure of the wild rodent Calomys musculinus (the reservoir of Argentine hemorrhagic fever [AHF]) in central Argentina. One hundred eighty-seven individuals from 13 populations (9 of them from the endemic zone of AHF and 5 from areas outside it) were analyzed using 78 polymorphic RAPD loci. Genetic variation within each population was high; each individual was characterized by a unique RAPD phenotype. C. musculinus populations showed a moderate to high genetic subdivision and a random pattern of differentiation. Populations separated by the same geographic distance showed very different degrees of genetic divergence. The results indicate that populations of C. musculinus have colonized their present ranges relatively recently and differentiation by genetic drift has proceeded faster than homogenization by gene flow at the macrogeographic scale analyzed (10–700 km). Calomys musculinus is a wild murid rodent widely distributed throughout most of Argentina. It is an opportunistic species, characterized by a high reproductive rate and the ability to colonize a wide variety of habitats, particularly disturbed ones like crop fields (Crespo et al. 1970; de Villafañe et al
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Differences in genetic structuring of populations of the Argentine hemorrhagic fever reservoir, the rodent Calomys musculinus , from endemic and non endemic zones
Julius-Kühn-Archiv, 2011Co-Authors: Marina B. Chiappero, Cristina N. Gardenal, C. Provensal, M. F. Piacenza, G. E. Calderón, Jaime PolopAbstract:We estimated the effective population size and genetic structuring within populations of the rodent reservoir of Argentine Hemorrhagic Fever, Calomys musculinus, from zones with different epidemiologic condition (non endemic, historic and epidemic). We found that populations from epidemic zones presented higher effective sizes, higher differentiation among subpopulations and higher levels of internal relatedness than in non-endemic zones. These results would explain the maintenance of the virus in populations from epidemic zones and the patchy distribution of infected rodents.
A. Castro-vazquez - One of the best experts on this subject based on the ideXlab platform.
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Embryo implantation during the short luteal phase of the corn mouse, Calomys musculinus, and the apparent lack of a lactational diapause in South American murid rodents
Reproduction (Cambridge England), 2001Co-Authors: O L Buzzio, N. B. Carreno, A Koninckx, A. Castro-vazquezAbstract:As the corn mouse, Calomys musculinus, has a short luteal phase (2-3 days) that is not prolonged after copulation, it was hypothesized that (i) implantation would occur at the end of this phase, that is, earlier than it occurs in most murid species that have been studied, and (ii) a lactational embryonic diapause would not occur during the luteal phase. These hypotheses were tested in females that had copulated during postpartum oestrus and were either lactating or not lactating. Data were recorded from day 3 to day 5 of pregnancy (day 1 = day after coitus), at both 03:00-05:00 h and 17:00-19:00 h. Evidence of implantation in both non-lactating and lactating animals was apparent at 03:00-05:00 h on day 4 (endometrial 'blue reaction' in all cases and failure to recover free uterine embryos in some cases) and implantation swellings appeared within 24 h in both groups. In another experiment, the increase in duration of interbirth intervals in continuously mated females and their correlation with the number of suckling young were compared among C. musculinus, C. laucha, Akodon molinae (South American murid species) and Peromyscus maniculatus (a North American murid in which a lactational embryonic diapause has been shown). The results were indicative of a lactational embryonic diapause in the North American species, but not in the South American species. It was concluded that in C. musculinus (i) implantation occurs at the end of the spontaneous luteal phase, and (ii) that a lactational embryonic diapause does not occur: the absence of a lactational embryonic diapause may be common to other South American murid rodents.
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Influence of different social partners on the survival and growth of pups in two species of Calomys (Muridae Sigmodontinae)
Ethology Ecology & Evolution, 2000Co-Authors: M.r. Laconi, G.a. Jahn, A. Castro-vazquezAbstract:In this paper we investigated if the contact of a mother-pups unit with different partners may affect pup survival and growth in Calomys musculinus and C. laucha. Mother-pups units were housed with either a virgin female, a familiar male or a strange male, and the effect of these partners on the litter was measured from birth through weaning. In C. laucha both the presence of a strange male or a virgin female was deleterious for pup survival and growth. In C. musculinus, however, the presence of any partner, even the siring male, decreased pup survival and growth (the strange male was the most deleterious for pup growth). In both species the virgin female partner was killed in approximately half of the cases, while there was a differential response to the strange male, C. laucha females appeared less tolerant to strange males than their C. musculinus counterpart, which is consistent with the idea that C. musculinus females interact in nature with more than one male in their home range. All of the familiar...
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Correlative genital tract morphology and plasma progesterone levels during the ovarian cycle in corn mice (Calomys musculinus)
1992Co-Authors: R. A. Cutrera, N. B. Carreno, A. Castro-vazquezAbstract:Described the correlation between genital tract morphology and plasma progesterone in laboratory-reared corn mice (Calomys musculinus). Morphological traits of the ovary, uterus and vagina were used to define stages of the estrous cycle and of some anovulatory states.
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Correlative genital tract morphology and plasma progesterone levels during the ovarian cycle in Corn mice
1992Co-Authors: R. A. Cutrera, N. B. Carreno, A. Castro-vazquez, Tecnologicas MendozaAbstract:Described the correlation between genital tract morphology and plasma progesterone in laboratoryreared corn mice (Calomys musculinus). Morphological traits of the ovary, Uterus and vagina were used to define stages of the estrous cycle and of some anovulatory states. These findings were correlated with changes in the vaginal smear and in plasma progesterone (as measured by radioimmunoassay). Estrous cyclicity and Ovulation occurred in females caged without males. Plasma progesterone during the estrous cycle showed both a periovulatory and a postovulatory peak. Changes in the vaginal smear correlated poorly with ovarian changes, except the formation of new corpora lutea, that correlated with a sudden disappearance of cornified cells from the smear. The most frequent cycle length was 5 days. Finally, two histologically distinct anovulatory conditions were found associated with basal progesterone levels. The ovarian cycle of this species is provisionally classified as type III of Conaway (1971), (spontaneous Ovulation, induced luteal phase).
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Nesting and digging behavior in three species of Calomys (Rodentia; Cricetidae).
Physiology & behavior, 1991Co-Authors: R. M. F. Yunes, R. A. Cutrera, A. Castro-vazquezAbstract:Two sets of behaviors relevant for the construction of shelters, nest building and digging, were studied in three con-generic species of South American cricetid rodents. Significant differences were observed among the three species in both sets of behaviors, but not between sexes within the same species. Calomys musculinus built the largest nests, C. laucha showed the highest number of digging bouts and the shortest digging latency, and C. venustus scored low in both nesting and digging behaviors. In general, these observations are consistent with the few, anecdotal records of the shelters used by these species in the field. The low nesting and digging scores of C. venustus are correlated with that species' low thermal conductance, but the marked differences in the nesting and digging scores of C. musculinus and C. laucha cannot be accounted for by differences in their basal metabolic rates or thermal conductances.
José Priotto - One of the best experts on this subject based on the ideXlab platform.
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Multiple paternity in a wild population of the corn mouse: its potential adaptive significance for females
Journal of Mammalogy, 2015Co-Authors: Lucia Sommaro, Marina B. Chiappero, José Priotto, José Coda, Noelia Soledad Vera, Andrea R SteinmannAbstract:Mating with multiple males within a single reproductive event is a common female mating strategy in mice and voles, but its adaptive function is often unclear. In this study, we used 7 microsatellite loci to investigate if multiple paternity occurs in wild populations of the socially promiscuous Calomys musculinus. We also analyzed if multiple paternity increases litter size and/or genetic variability among offspring. In addition, we examined if multiple paternity occurs more frequently in litters conceived at high population density than those conceived at low population density. By genotyping 23 females and their 135 embryos (5.9 ± 1.6 SE pups per female), we found that 56.5% of the litters were sired by 2 or 3 males. We found no association between multiple paternity, litter size, and genetic variability. In addition, multiple paternity did not vary in relation to population density. Our results provide clear evidence of multiple paternity and offer the first genetic documentation of mating systems in ...
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Ecological preference between generalist and specialist rodents: spatial and environmental correlates of phenotypic variation
Biological Journal of the Linnean Society, 2014Co-Authors: Juan José Martínez, Ivana Simone, Virginie Millien, José PriottoAbstract:Different ecological preferences among species may result in differences in response to similar environmental variation. To test this hypothesis, we assessed the patterns of skull and mandible size and shape variation in three Sigmodontinae mice from agroecosystems of central Argentina with increasing degree of specialization: Calomys musculinus, Akodon azarae and Oxymycterus rufus. Spatial patterns in size and shape were analysed after controlling for allometry and sexual dimorphism using a total of 697 specimens. We then evaluated the covariation between shape, climatic and environmental variables and assessed the contribution of distinct climatic and environmental variables to phenotypic variability. Oxymycterus rufus displayed a marked spatial structure, and there was a high correlation between shape, climatic and environmental variables in this species. Climatic and environmental variables had a moderate effect on the phenotype of A. azarae, and were not correlated with morphological variation in C. musculinus. Our study highlights the difference in phenotypic responses to spatial and environmental gradients across coexisting species, specialist species displaying a more marked spatial structure in morphology than generalist species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 180–203.
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Behavioral counter-strategies against infanticide in corn mouse females, Calomys musculinus
Mastozoología neotropical, 2011Co-Authors: José Coda, José Priotto, Andrea R SteinmannAbstract:Based on the hypothesis that in C. musculinus both female territorial behavior and promiscuity are counter-strategies against infanticide by females and males respectively, our objective was to test the following predictions: (1) mother aggression deters infanticide by females; (2) previous matings prevent infanticide by males. We conducted 116 behavioral encounters between mothers and intruders to study the nest related behaviors. Mother-pups units (Mu) were grouped in three treatments in relation to the intruder feature: 55 Mu were placed with siring males, 27 Mu and 34 Mu were housed with non-siring males and repro- ductively active females, respectively. We also calculated offspring survival rate for each treatment. The nest related behaviors varied among the three groups tested. Mothers showed high rates of aggressive behavior towards females. In presence of siring males mothers remained calm inside the nest. When the intruders were non-siring males mothers exhibited high rates of nest defense behavior. The lowest survival rate was registered in presence of the non-siring males, while the highest rates were registered in presence of females or siring males. The absence of aggressiveness and the high rate of nest defense by mothers against siring and non-siring males respectively, would support that promiscuity acts as a counter-strategy against infanticide by males. Mother aggressive behavior against intruder females would show that female territoriality may be an effective way of pup protection. RESUMEN: Contraestrategias comportamentales contra el infanticidio en hembras de C. musculinus. Bajo la hipotesis de que la territorialidad intra-sexual y el apareamiento multiple por parte de las hembras de C. musculinus actuan como contra-estrategias para evitar el infanticidio cometido por hembras y machos respectivamente, nuestro objetivo fue probar las siguientes predicciones: 1) la agresion de la madre impide el infanticidio por hembras, 2) los apareamientos previos previenen el infanticidio por parte de machos. Estudiamos comportamientos relacionados al nido en 116 unidades madre-cria (Mc) agrupadas en tres tratamientos en relacion a las caracteristicas del intruso: 55 Mc alojadas con los padres de las crias; 27 Mc y 34 Mc alojadas con machos sin experiencia sexual con la madre y con hembras reproductivas, respectivamente. En cada tratamiento se calcularon las tasas de sobrevida Las madres fueron agresivas hacia las hembras. En presencia de los padres las madres permanecieron tranquilas en sus nidos. La menor tasa de sobrevida se registro en presencia del macho no padre; las mayores en presencia del padre y hembras repro- ductivas. La ausencia de agresividad y las altas tasas de defensa del nido exhibidas por las madres hacia los padres y los machos extranos respectivamente, apoyan la hipotesis que propone la promiscuidad como contraestrategia al infanticidio por machos. La respuesta altamente agresiva de las madres hacia las hembras intrusas seria una estrategia efectiva para la proteccion de sus crias.
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Corn mice (Calomys musculinus) movement in linear habitats of agricultural ecosystems
Journal of Mammalogy, 2010Co-Authors: Lucia Sommaro, Marina B. Chiappero, Andrea R Steinmann, Florencia Bonatto, Daniela Gomez, José PriottoAbstract:Movement patterns of Calomys musculinus in linear habitats were studied in relation to sex, season, year, abundance, and width of border. Movement distances (MDs) were measured by seasonal capture, mark, and recapture samples during 2 years in wide and narrow borders in agroecosystems. The smallest MDs were registered in autumn and the highest in spring. In the breeding period MDs of males were larger than those of females. In the nonbreeding period MDs were similar between sexes. Effects of sex on MD were consistent with the promiscuous mating system of C. musculinus. MDs were greater in narrow than in wide borders. The narrowness of suitable habitats would force the mice to extend foraging trips in narrow borders. Opportunistic behavior of C. musculinus allows it to use linear habitats in a similar way to the 2-dimensional natural habitats. DOI: 10.1644/09-MAMM-A-232.1.
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Effect of high density on the short term Calomys musculinus spacing behaviour: A fencing experiment
Acta Oecologica, 2010Co-Authors: Lucia Sommaro, Marina B. Chiappero, Andrea R Steinmann, José PriottoAbstract:We studied the short term spacing behavioural responses of corn mice (Calomys musculinus) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2007 breeding season. The goal of this research was to test the hypothesis that spacing behaviour only operates among C. musculinus adult females. We estimated 207 home ranges to study: 1) the home range size and the overlap degree of adult males and females in relation to population density; 2) the settlement distances of juveniles to the centre of activity of their mothers and the home range overlap proportion between them and their mothers in relation to population density. We found that home range size and overlap degree in C. musculinus adults were determined by sex and density. At high population density males had significant smaller and more exclusive home ranges, and this might reflect induced territoriality derived from social restrictions. Female home range sizes remained similar irrespective of population density, and they kept exclusive home ranges in both control and experimental enclosures. Thus, females maintained their territories independent of the population density values. The settlement distances of juveniles from their mothers and the overlap proportion between them and their mothers were independent of population density. We conclude that spacing behaviour only operates among C. musculinus adult females and it could have a role in regulating population abundances limiting the number of females that acquire breeding spaces.
