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Nancy G Solomon - One of the best experts on this subject based on the ideXlab platform.
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does time after pair bond disruption affect subsequent reproduction in the socially monogamous woodland vole Microtus pinetorum
Behavioural Processes, 2009Co-Authors: Caroline A Renfro, Daniel W Pesek, Kelly Bobeck, Nancy G SolomonAbstract:Abstract Disruption of the pair bond between socially monogamous animals leads to changes in behavior, which may have reproductive consequences. There are two alternative hypotheses to explain the effect of the length of time since pair bond disruption on subsequent reproduction. One hypothesis predicts that voles housed immediately with a new opposite-sex conspecific will be as likely to produce litters and will produce them as quickly as voles separated from their initial mate for longer. Alternatively, if attachment between mates is enduring, we expect that more voles separated longer from their previous mates will produce litters and produce them sooner than voles re-paired immediately after separation from their initial mates. Woodland voles, paired with opposite-sex conspecifics, remained together until parturition. Mates were then separated for 0, 7, or 14 days until re-pairing with an opposite-sex conspecific. Pair bond disruption did not prevent males and females from mating subsequently, which was consistent with data from our breeding colony. In addition, the length of time an individual remained alone after pair bond disruption did not affect the latency to produce a litter. Our results show that having been paired previously does not affect subsequent reproduction in this socially monogamous vole.
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asymmetry in age suppresses reproduction in female woodland voles Microtus pinetorum
Animal Behaviour, 2006Co-Authors: Nancy G Solomon, Lynsey R Steward, Kelly L UlrichAbstract:The partitioning of reproduction in animal societies is a topic of interest to those studying animal behaviour. Under some conditions, two or more females may breed, but lack of reproduction by the younger females occurs frequently. Lack of reproduction by young females may be due to kin asymmetry, dominance asymmetry, or incest avoidance. We conducted breeding experiments to distinguish among these three hypotheses. We show that female reproduction within woodland vole family groups becomes skewed as the asymmetry in age, which is correlated with dominance, between females increases. When daughters were housed with their mothers and a potential mate and the age difference between females was large, we found a high level of skew as compared to females housed with same-age sisters and a potential mate or females housed only with a potential mate. We argue that dominance asymmetry is the best explanation for reproductive skew seen in female woodland voles that have access to unfamiliar, unrelated mates based on reproductive and previous behavioural observations.
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reproductive activation of pine voles Microtus pinetorum examination of physiological markers
Brain Research, 2004Co-Authors: Tammy M Schwab, Nancy G Solomon, Lori G Isaacson, Phyllis CallahanAbstract:Abstract We tested the hypothesis that the presence of an opposite-sex conspecific will result in time-related changes in measures of reproductive activation. We housed male–female pairs of pine voles together for 0, 2, 6, 12, or 24 h before collecting blood, reproductive organs and brains for immunocytochemical analysis of LHRH and c-fos. Control animals were never exposed to an opposite-sex conspecific. Following exposure to a male, there was a significant increase in uterine weight but not in LH levels. In males, there were no changes in peripheral indices of activation, i.e. LH levels, testes and seminal vesicle weights were not altered. Consistent with no change in circulating levels of LH, there was no change in LHRH immunoreactivity at any time. However, c-fos immunoreactivity was significantly greater in both males and females in the cingulate cortex and rostral bed nucleus of the stria terminalis (BNST) at 2 h, and in the caudal BNST at 2, 6 and 12 h. Similarly, c-fos immunoreactivity was increased in the rostral MPOA in both males and females at 2 and 6 h. However, in the caudal MPOA, there was a significant interaction between sex and time due to increased c-fos immunoreactivity in females only at 6 h. These results indicate that, in both male and female pine voles, exposure to an opposite-sex conspecific is sufficient to produce rapid, neural activation in brain areas known to be involved in reproductive activation and sexual behavior. This early activation did not occur in LHRH neurons. It is not known if this activation, particularly at early times, is due to reproductive activation or to the formation of pair bonds.
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testing functional hypotheses for the behavior of resident pine voles Microtus pinetorum toward non residents
Ethology, 2002Co-Authors: Shasta R Back, Lisa A Beeler, Robert L Schaefer, Nancy G SolomonAbstract:Members of a social group should attempt to maximize their fitness by maintaining an optimal group composition. Allowing an immigrant into the group may be beneficial or costly depending on the characteristics of the immigrant as well as the composition of the group. Therefore, we examined behavioral interactions between pine voles to test three functional hypotheses proposed to explain behavior of residents toward non-residents: the resource defense, mate defense, and benefit of extra-pair copulation hypotheses. To test these, we examined the effects of age, sexual experience and sex of non-residents as well as the effects of sex of residents on the behavior of residents. Neither male nor female residents showed affiliative behavior toward non-residents. Residents were more aggressive toward non-residents than vice versa. The frequency of same-sex aggression was greater than opposite-sex aggression for male residents and this aggression was directed at adult male non-residents to a greater degree than at subadult males. Resident males were least aggressive toward adult females. We found no differences in the behavior of females toward subadults, sexually naive adult non-residents or sexually experienced adult non-residents. Females also displayed similar amounts of aggression toward male and female non-residents. Therefore, for males, aggression may function in defense of a mate while for females, aggression functions in resource defense. For both sexes, aggression is likely to play a role in the regulation of group composition.
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Testing Functional Hypotheses for the Behavior of Resident Pine Voles, Microtus pinetorum, Toward Non‐Residents
Ethology, 2002Co-Authors: Shasta R Back, Lisa A Beeler, Robert L Schaefer, Nancy G SolomonAbstract:Members of a social group should attempt to maximize their fitness by maintaining an optimal group composition. Allowing an immigrant into the group may be beneficial or costly depending on the characteristics of the immigrant as well as the composition of the group. Therefore, we examined behavioral interactions between pine voles to test three functional hypotheses proposed to explain behavior of residents toward non-residents: the resource defense, mate defense, and benefit of extra-pair copulation hypotheses. To test these, we examined the effects of age, sexual experience and sex of non-residents as well as the effects of sex of residents on the behavior of residents. Neither male nor female residents showed affiliative behavior toward non-residents. Residents were more aggressive toward non-residents than vice versa. The frequency of same-sex aggression was greater than opposite-sex aggression for male residents and this aggression was directed at adult male non-residents to a greater degree than at subadult males. Resident males were least aggressive toward adult females. We found no differences in the behavior of females toward subadults, sexually naive adult non-residents or sexually experienced adult non-residents. Females also displayed similar amounts of aggression toward male and female non-residents. Therefore, for males, aggression may function in defense of a mate while for females, aggression functions in resource defense. For both sexes, aggression is likely to play a role in the regulation of group composition.
John G Vandenbergh - One of the best experts on this subject based on the ideXlab platform.
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THE USE OF ODOR TO INDUCE AVOIDANCE BEHAVIOR IN PINE VOLES
2005Co-Authors: Christopher J. Salatti, Anthony D. Woolhouse, John G VandenberghAbstract:Commercial orchards, ornamental nurseries, and residential horticulture in North Carolina experience economic losses due to pine vole (Microtus pinetorum) depredation. Predator odors and the herbicide Casoron were tested as potential repellents for pine voles. To test for avoidance behavior, animals were allowed to build a nest in one of two chambers attached to each arm of a Y-maze. The cage containing the nest was treated with either a test repellent compound, methylene chloride (solvent control), or left unmanipulated (control). Animals were categorized as either maintaining or changing nest cage preference between pre-test and test periods. The number of animals that changed cage preference in the control group was compared to the treatment groups. Only the Casoron treatments were significantly different, with approximately 50% of the animals changing preference. The difference in time spent in the nest cage during the pre-test and test periods for the treatment groups were compared to control groups. The Casoron and DTT treatments resulted in significant time differences. These results indicate that Casoron has repellent potential and warrants further investigation into its effectiveness in the field. The predator odors tested showed little promise as repellents.
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rickettsia rickettsii infection in the pine vole Microtus pinetorum
Annals of the New York Academy of Sciences, 2003Co-Authors: John G Vandenbergh, Marina E Eremeeva, Zhongxing Liang, Christopher D Paddock, Sherif R Zaki, Gregory A Dasch, David J SilvermanAbstract:: The pine vole, Microtus pinetorum, was evaluated as a laboratory animal model for infection with Rickettsia rickettsii. Voles demonstrated signs of acute disease, and 45% of infected animals died following intraperitoneal infection with 3 x 10(6) plaque forming units of R. rickettsii. Spleen, liver, kidney, lung, brain, testes and blood were analyzed for rickettsial burden by a quantitative PCR assay. The distribution of rickettsiae in tissues during the course of infection was determined by immunohistochemical staining and pathological changes in tissues were correlated with the clinical severity of infection. Quantitative RT-PCR assays were designed to measure the mRNA levels of the antioxidant enzyme genes for catalase, glutathione peroxidase, glutathione reductase, heme oxygenase, Cu-Zn superoxide dismutase (SOD) and Mn-SOD, and 2 housekeeping genes, actin and glyceraldehyde phosphate dehydrogenase. Tissues from acutely ill animals on days 2 to 6 of infection, convalescent animals, and uninfected control animals were studied. The number of transcripts of each enzyme gene was determined and compared to the degree of rickettsial infection present. These studies demonstrate that the pine vole is a valuable experimental model for studying infection with R. rickettsii. Our results provide the first experimental evidence that R. rickettsii causes alteration(s) of the anti-oxidant system in vivo.
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social influences on intergroup transfer by pine voles Microtus pinetorum
Canadian Journal of Zoology, 1998Co-Authors: Nancy G Solomon, John G Vandenbergh, William T SullivanAbstract:Selection to obtain mating opportunities is hypothesized to be a major factor in dispersal. Thus, if individuals move to another group or switch nests to maximize their reproductive opportunities, they should move to groups or sites where they minimize competition for resources or mates and where they can find potential mates. We examined movement of pine voles (Microtus pinetorum) in an orchard habitat. Males dispersed later than females, but the two sexes showed similar patterns of movement with respect to conspecifics. Males and females immigrated to territories that contained some opposite-sex conspecifics; they also immigrated to territories without same-sex conspecifics. The latter suggests that they may avoid competitors and move to territories where an opening exists. When female breeders were removed from a social group, a replacement female arrived and began to breed relatively rapidly. In control groups where breeding females were not removed, no replacement females appeared. These results sugg...
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Behavioural suppression of female pine voles after replacement of the breeding male
Animal Behaviour, 1998Co-Authors: Christine L Brant, Tammy M Schwab, John G Vandenbergh, Robert L Schaefer, Nancy G SolomonAbstract:Abstract Examination of the mechanism of reproductive suppression includes determining which cues are involved and the context in which they occur. We studied groups of pine voles, Microtus pinetorum , that were disrupted by the replacement of the breeding male and compared them with intact family groups. If reproductive suppression is mediated by chemical cues, then soiled bedding should be sufficient to prevent production of litters by daughters. If reproductive suppression involves a behavioural component, we should observe aggressive behaviours or those indicative of dominance interactions directed from the mother towards the daughter or the replacement male. If replacement of the breeding male leads to conflict between the breeding female and her daughter, then more aggression or dominance interactions would be expected in disrupted than in intact families. The presence of the mother decreased reproduction by daughters, but chemical cues alone were not sufficient to prevent the daughter from mating with the replacement male. Rather, this decrease in reproduction seemed to be mediated by behavioural interactions. We propose that the mother's tugging on the daughter may lead to subordination of the daughter. The mother's presence may also alter the behaviour patterns of the male and daughter, which could delay reproductive activation of the daughter, prevent the formation of pair bonds or inhibit sexual behaviour. These behavioural interactions appear to depend on the presence of an unfamiliar male, because tugging, for example, was less frequent in intact family groups.
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Androgen exposure and reproductive behavior of an induced ovulator, the pine vole (Microtus pinetorum).
Hormones and Behavior, 1996Co-Authors: Kennedy S. Wekesa, John G VandenberghAbstract:Abstract The actions of steroid hormones on brain and behavior are classically divided into organizational effects that are permanent and occur early in development and activational effects that are temporary and occur throughout life. Here, we test the hypothesis that in an induced ovulator, testosterone defeminizes only those neural tissues that rely on synergistic interactions of estrogen and progesterone for normal function in adulthood. Female voles,Microtus pinetorum,injected with testosterone (T) or oil neonatally were paired with males for an 8-week period. During the pairing, androgenized and oil-treated females spent a similar amount of time investigating the caudal and rostral regions of the males. Males spent significantly less time investigating the caudal and rostral regions of androgenized females. Androgenized females mounted males, did not exhibit lordosis, and were less likely to be mounted by males. Moreover, none of the 10 androgenized females gave birth, whereas 8 of 9 control females gave birth. Androgenized females were also not capable of being stimulated into reproductive condition by males. Injection of 0.5 μg of estradiol benzoate for 4 consecutive days resulted in reduced uterine hypertrophy in androgenized females. These results support the original organizational–activational hypothesis by showing that neonatal androgenization defeminizes and masculinizes female pine voles.
L C Drickamer - One of the best experts on this subject based on the ideXlab platform.
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Impact of forest patch characteristics on small mammal communities: a multivariate approach
Biological Conservation, 2001Co-Authors: S Schmid-holmes, L C DrickamerAbstract:We used multivariate analysis to investigate the principal factors affecting forest-floor small mammal occurrence in 80 previously cut and uncut forest patches in temperate woodlands across southern Illinois, USA. Peromyscus leucopus comprised 82.3 % of 836 individuals caught during 24,000 trapnights, followed by Blarina carolinensis, Ochrotomys nuttalli, Tamias striatus and Microtus pinetorum. Small mammal abundances differed between years, possibly due to high winter mortality . Principal component analysis identified three significant environmental gradients, forest structure, forest composition and temperature conditions. Vegetation, rather than spatial characteristics, dominated these gradients. P. leucopus and O. nuttalli abundances were inversely related to forest age and canopy height. B. carolinensis related to temperature conditions. Combined small mammal captures related to forest structure and forest composition. Because heterogeneous forested landscapes differ greatly in spatial and temporal characteristics, extrapolating general small mammal conservation strategies may prove difficult. Integrating habitat restoration with conservation may be more efficient
Lisa A Beeler - One of the best experts on this subject based on the ideXlab platform.
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Testing Functional Hypotheses for the Behavior of Resident Pine Voles, Microtus pinetorum, Toward Non‐Residents
Ethology, 2002Co-Authors: Shasta R Back, Lisa A Beeler, Robert L Schaefer, Nancy G SolomonAbstract:Members of a social group should attempt to maximize their fitness by maintaining an optimal group composition. Allowing an immigrant into the group may be beneficial or costly depending on the characteristics of the immigrant as well as the composition of the group. Therefore, we examined behavioral interactions between pine voles to test three functional hypotheses proposed to explain behavior of residents toward non-residents: the resource defense, mate defense, and benefit of extra-pair copulation hypotheses. To test these, we examined the effects of age, sexual experience and sex of non-residents as well as the effects of sex of residents on the behavior of residents. Neither male nor female residents showed affiliative behavior toward non-residents. Residents were more aggressive toward non-residents than vice versa. The frequency of same-sex aggression was greater than opposite-sex aggression for male residents and this aggression was directed at adult male non-residents to a greater degree than at subadult males. Resident males were least aggressive toward adult females. We found no differences in the behavior of females toward subadults, sexually naive adult non-residents or sexually experienced adult non-residents. Females also displayed similar amounts of aggression toward male and female non-residents. Therefore, for males, aggression may function in defense of a mate while for females, aggression functions in resource defense. For both sexes, aggression is likely to play a role in the regulation of group composition.
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testing functional hypotheses for the behavior of resident pine voles Microtus pinetorum toward non residents
Ethology, 2002Co-Authors: Shasta R Back, Lisa A Beeler, Robert L Schaefer, Nancy G SolomonAbstract:Members of a social group should attempt to maximize their fitness by maintaining an optimal group composition. Allowing an immigrant into the group may be beneficial or costly depending on the characteristics of the immigrant as well as the composition of the group. Therefore, we examined behavioral interactions between pine voles to test three functional hypotheses proposed to explain behavior of residents toward non-residents: the resource defense, mate defense, and benefit of extra-pair copulation hypotheses. To test these, we examined the effects of age, sexual experience and sex of non-residents as well as the effects of sex of residents on the behavior of residents. Neither male nor female residents showed affiliative behavior toward non-residents. Residents were more aggressive toward non-residents than vice versa. The frequency of same-sex aggression was greater than opposite-sex aggression for male residents and this aggression was directed at adult male non-residents to a greater degree than at subadult males. Resident males were least aggressive toward adult females. We found no differences in the behavior of females toward subadults, sexually naive adult non-residents or sexually experienced adult non-residents. Females also displayed similar amounts of aggression toward male and female non-residents. Therefore, for males, aggression may function in defense of a mate while for females, aggression functions in resource defense. For both sexes, aggression is likely to play a role in the regulation of group composition.
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social transmission and memory of food preferences in pine voles Microtus pinetorum
Journal of Comparative Psychology, 2002Co-Authors: Nancy G Solomon, Christopher S Yeager, Lisa A BeelerAbstract:: The social transmission of food preferences is affected by factors including the length of time a preference is maintained. The authors investigated the social transmission of food preferences in pine voles (Microtus pinetorum) and whether food items had to be present for memory to persist. A demonstrator vole was fed cocoa-flavored food, a nonpreferred food. After interacting with a demonstrator vole, observer voles preferred cocoa-flavored food as compared with either naive voles that had not interacted with demonstrators or voles that had been exposed to odors. Observers retained this preference for 72 hr after interacting with an observer whether or not flavored foods were present. The ability to learn which food items are palatable and safe may benefit a generalist herbivore that has faced selection to avoid toxic baits.
Lawrence E. Shapiro - One of the best experts on this subject based on the ideXlab platform.
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Affiliative behavior in different species of voles (Microtus).
Psychological Reports, 1993Co-Authors: Allen L. Salo, Lawrence E. Shapiro, Donald A DewsburyAbstract:: Data were collected on the huddling behavior of pine voles, Microtus pinetorum, and meadow voles, M. pennsylvanicus, to supplement earlier data on prairie voles and montane voles. Species that are social/monogamous in the field tended to huddle more in the laboratory. Contact proneness may be one factor driving different mating systems in the field.
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oxytocin receptor distribution reflects social organization in monogamous and polygamous voles
Proceedings of the National Academy of Sciences of the United States of America, 1992Co-Authors: Thomas R Insel, Lawrence E. ShapiroAbstract:The neuropeptide oxytocin has been implicated in the mediation of several forms of affiliative behavior including parental care, grooming, and sex behavior. Here we demonstrate that species from the genus Microtus (voles) selected for differences in social affiliation show contrasting patterns of oxytocin receptor expression in brain. By in vitro receptor autoradiography with an iodinated oxytocin analogue, specific binding to brain oxytocin receptors was observed in both the monogamous prairie vole (Microtus ochrogaster) and the polygamous montane vole (Microtus montanus). In the prairie vole, oxytocin receptor density was highest in the prelimbic cortex, bed nucleus of the stria terminalis, nucleus accumbens, midline nuclei of the thalamus, and the lateral aspects of the amygdala. These brain areas showed little binding in the montane vole, in which oxytocin receptors were localized to the lateral septum, ventromedial nucleus of the hypothalamus, and cortical nucleus of the amygdala. Similar differences in brain oxytocin receptor distribution were observed in two additional species, the monogamous pine vole (Microtus pinetorum) and the polygamous meadow vole (Microtus pennsylvanicus). Receptor distributions for two other neurotransmitter systems implicated in the mediation of social behavior, benzodiazepines, and mu opioids did not show comparable species differences. Furthermore, in the montane vole, which shows little affiliative behavior except during the postpartum period, brain oxytocin receptor distribution changed within 24 hr of parturition, concurrent with the onset of maternal behavior. We suggest that variable expression of the oxytocin receptor in brain may be an important mechanism in evolution of species-typical differences in social bonding and affiliative behavior.