Potential for social interaction in a natural population of prairie voles (Microtus ochrogaster)

1990 ◽  
Vol 68 (2) ◽  
pp. 391-398 ◽  
Author(s):  
Betty McGuire ◽  
Theresa Pizzuto ◽  
Lowell L. Getz

Many hypotheses on the role of social behavior in population regulation of microtine rodents assume that social interactions are more frequent at high density than at low density. We evaluated this assumption by measuring potential for social contact in a population of prairie voles (Microtus ochrogaster). Our livetrapping regime monitored presence of resident and nonresident animals at the periphery of home ranges of social groups. Resident adults and young of both sexes were captured at home range boundaries. Potential for social interaction with nonresidents was greater at the periphery of home ranges than at nests. Intruders tended to be male adults from neighboring social groups. Presence of adult males in the resident group played an important role in deterring visits by nonresident males. During the spring, summer, and autumn reproductive period, number of captures of nonresident males, but not females, showed a strong positive relationship with population density. Despite relatively high densities during the winter nonreproductive period, there were few captures of residents and nonresidents at the periphery of home ranges. We conclude that the relationship between potential for social interaction and population density varied as a function of sex and season.

2002 ◽  
Vol 80 (5) ◽  
pp. 951-955 ◽  
Author(s):  
Nancy G Solomon ◽  
Joseph J Jacquot

Many studies have documented intraspecific differences in the behavior of males or females. In some species, many adults are territorial while others have larger home ranges encompassing multiple territories. Although these two types of behavior have been documented, they are not well understood in mammals. Therefore, in the mono gamous prairie vole (Microtus ochrogaster) we characterized individuals that engage in these two behavior patterns as residents and wanderers. We monitored populations enclosed in 0.1-ha. enclosures at Miami University's Ecology Research Center. As many as 26% of animals were wanderers: animals captured frequently, but less than 75% of the time, at one nest. As expected, wanderers had larger home ranges than residents. Wanderers were primarily adult males (70%) but included some adult females. This behavior pattern was not fixed, since some wanderers previously had been residents and at least 31% of males and 57% of adult female wanderers became residents during the same field season. Wanderers were not in worse physical condition, as estimated by body mass, and survived for slightly longer than residents. Thus, it does not appear that wanderers are making the best of a bad situation, but analysis of parentage is critical to validate this conclusion.


1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).


1997 ◽  
Vol 75 (7) ◽  
pp. 1051-1058 ◽  
Author(s):  
Steven J. Harper ◽  
George O. Batzli

We investigated the aggressiveness of adult prairie voles (Microtus ochrogaster) in dyadic encounters staged in different types of arena trials to determine if responses differed (i) between neutral arena trials conducted in the laboratory and resident–intruder trials conducted in the field, (ii) between trials staged before and after 3 months of isolation from social contact, (iii) between voles reared in the laboratory and voles reared in the field, and (iv) among trials staged with the same individual over time. Though rodents are usually expected to be more aggressive on their own home range, female prairie voles tended to be more aggressive in neutral arenas. Males showed no difference in aggression between trials held in neutral arenas and trials held in arenas placed in their home ranges. Aggressiveness was not affected by 3 months of isolation for either males or females, suggesting that recent social cues may not strongly influence aggressive behaviour in this species. Voles reared in the laboratory were significantly more aggressive than those reared in enclosed field populations, which suggests that direct comparisons of field and laboratory studies of aggressive behaviour may be suspect. Individuals showed little change in aggressiveness when tested over several weeks in three trials with different opponents. We conclude that encounters staged in arenas provide standardized estimates of aggressiveness that are robust to differences in testing procedures and are repeatable over time. Therefore, their continued use seems warranted for studying aggressive behaviour of voles and lemmings.


1988 ◽  
Vol 66 (3) ◽  
pp. 670-679 ◽  
Author(s):  
Jørund Rolstad ◽  
Per Wegge ◽  
Bjørn Bjerke Larsen

We radio-tracked 52 capercaillie males and 21 broodless females during June, July, and August, 1979–1986, in a 100-km2 coniferous forest in central Scandinavia. After display activity ceased in early June, 77% of adult males made distinct movements, averaging 1.5 km, from lek territories to summer ranges. A similar movement was made by 48% of the females after loss of nest or brood. Males were now nonterritorial, and lived solitarily in overlapping home ranges averaging 170 ha. In June and July, they used successional stages in proportion to availability, but in August they preferred old, natural forest. Females, having home ranges averaging 103 ha, commonly formed small social groups of two to four individuals. They preferred young plantations throughout summer, and also preferred denser habitats than males. Both sexes returned to the same summer ranges in consecutive years. Home ranges of both sexes were distributed in a clumped spacing pattern. This can be explained by preference for patchily distributed habitat types in males, and habitat preference and sociality in broodless females.


Behaviour ◽  
1992 ◽  
Vol 120 (3-4) ◽  
pp. 177-191 ◽  
Author(s):  
Andrew Balmford

AbstractLek-breeding in Uganda kob was associated with extremely high population density (c. 140 animals/km2). Kob were typically found in unstable aggregations of more than one hundred animals, including several adult males. Females occupied unusually large, overlapping home ranges, but reasons for such widespread movements were unclear. The social dispersion of Uganda kob was therefore similar to that of other lekking ungulates, and confirms predictions of several recent hypotheses of lek evolution. However, resolution of alternative models is nevertheless difficult, since in practice these make very few exclusive predictions.


2008 ◽  
Vol 86 (3) ◽  
pp. 224-230 ◽  
Author(s):  
D. Yamoah ◽  
K. Williams-Baginski ◽  
M. Bamshad

In prairie voles, Microtus ochrogaster (Wagner, 1842), the onset of parental caring differs by sex and reproductive condition. Maternal caring is displayed abruptly at parturition, whereas paternal caring intensifies gradually during the reproductive period. To determine if changes in odor responsiveness contribute to sex differences in onset of parental behavior, voles were given a choice to investigate various odors at different times during the reproductive cycle. Subjects were either sexually naïve or mated. Mated pairs cohabited until mid-gestation, late gestation, or 3 days postpartum. Voles crossed a tunnel to explore a row of three filter papers covered with infant odor, orange extract, or saline. Males and females exhibited different odor preferences. Males preferred infant odor to saline and orange extract, whereas females preferred infant odor and saline to orange extract. Mating changed the odor investigative behaviors in both males and females. Some voles vigorously manipulated odor-covered papers. The number of females manipulating the papers increased abruptly at late gestation. The number of males manipulating the papers was particularly high at mid-gestation and after the birth of young. Results suggest that mating and cohabitation in prairie voles influences odor responses in a sex-specific manner.


2000 ◽  
Vol 78 (2) ◽  
pp. 254-264 ◽  
Author(s):  
J A Sinclair ◽  
R L Lochmiller

Seasonal variations in photoperiod, temperature, and population density have been shown to modulate immune responsiveness of animals in laboratory studies. To examine these associations under natural conditions, we monitored 3 populations of prairie voles (Microtus ochrogaster) for temporal variations in selected immunological parameters, population density, and survival rate from winter 1996 to spring 1997. Spontaneous and cytokine-stimulated T-cell proliferative responsiveness of prairie voles peaked in winter and declined in spring. Relative organ mass, hemolytic-complement activity, and in vivo hypersensitivity responses varied temporally but showed no clear seasonal trend. The population density and survival rate of all 3 prairie vole populations varied temporally and correlated with measures of immunity. Multiple regression analysis indicated that the model containing relative spleen mass, cytokine-stimulated T-cell proliferation, and in vivo hypersensitivity explained a significant amount of variability in population density, while cytokine-stimulated T-cell proliferation and relative thymus mass explained a significant amount of variability in survival rate. The results suggest that seasonal environmental changes can enhance immune responsiveness of a host and may counteract the immunoenhancing effects of photoperiod in wild populations of prairie voles. Our results also suggest that there is an association between immune function and demography in wild populations.


1992 ◽  
Vol 19 (3) ◽  
pp. 263 ◽  
Author(s):  
RJC Page ◽  
J Ross ◽  
DH Bennet

The feral cat population at a 178-ha dockland site was studied for 18 months by direct observation assisted by radio-tracking. Although food appeared to be abundant and widely distributed, the population density was low (10-15 adults km-2). There were few females in the population (7 of 22 cats of known sex) and little breeding success: only one weaned litter was seen during the entire study. Home range sizes were similar for males and females, and were much smaller (15 +/- 17 ha and 10+/-7 ha, respectively) than would be expected from the low density. The cats were mostly solitary rather than group-living, with little contact or social interaction. The implications of the findings for feral cat control are discussed, with particular emphasis on emergency measures for rabies outbreaks.


1997 ◽  
Vol 75 (4) ◽  
pp. 525-534 ◽  
Author(s):  
Lowell L. Getz ◽  
Betty McGuire

We describe factors related to the formation, composition, and persistence of communal groups in the prairie vole (Microtus ochrogaster). Communal groups formed by the addition of philopatric offspring and unrelated adults to male – female pair and single-female breeding units. Although unrelated adults did not join a group until at least two philopatric offspring 30 days of age were present, there was no relationship between the presence of reproductively active philopatric offspring of the opposite sex and joining of unrelated adults. Most adults that joined a group were reproductive when they joined. Reproductive activation of philopatric offspring was not related to the joining of unrelated adults. During the breeding period all communal groups included 1 or more reproductive adults of each sex; in at least 75% of the groups, 2 or more adults of each sex were reproductive. There was no relationship between low temperature, snow cover, or population density and formation of communal groups. Dissolution of communal groups was not related to reproductive activation of residents.


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