Browsing by Author "Ebensperger, L. A."

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    Activity, range areas, and nesting patterns in the viscacha rat, Octomys mimax
    (2008) Ebensperger, L. A.; Sobrero, R.; Campos, V.; Giannoni, S. M.
    Several rodent species engage in group living, meaning that individuals share nests, resting places, and range areas. Establishing how group living varies across species is critical for comparative studies to examine the origin and the adaptive value of this behavior. Comparative approaches are more powerful when a diverse array of taxonomic groups is included. We used telemetry techniques to monitor patterns of activity, resting places, and range areas at night to examine the extent of sociality of the scarcely known viscacha rats, Octomys mimax. Seven individuals were live trapped and fitted with radio-collars. Viscacha rat activity, as measured from distance moved between consecutive telemetry scans, took place mostly during the nighttime. During day, animals used from 2 to 6 putative nest places, but one was used more frequently. The sharing of resting locations by two or more radio-collared animals was never recorded. Viscacha rats showed relatively large range areas and low-to-moderate spatial overlap with neighbors. Mate rats had larger range areas than females, but spatial overlap with neighbors was similar. Results suggest that viscacha rats are solitary living animals. This study supported a solitary-to-social trend from basal to more derivate forms across Octodontidae. (c) 2008 Elsevier Ltd. All rights reserved.
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    Food abundance and group size influence the phenology of reproduction in communally breeding Octodon degus
    (2024) Matchinske, M.; Abades, S.; Ebensperger, L. A.; Correa, L. A.; Hayes, L. D.
    Socioecological conditions are expected to influence the timing, or phenology, of when adult females give birth to offspring. Females may time reproduction such that offspring are born to maximize the length of the period that offspring have to forage during the growing season. In communal breeders, females may alter reproductive phenology to maximize benefits of group-living through synchronizing reproduction and improve offspring survival. We used an 11-year dataset on a population of communally breeding degus (Octodon degus) to test whether the (i) reproductive phenology was influenced by the abundance of food, social conditions, and the degree of masculinization of females and (ii) reproductive synchrony was influenced by similar access to food and degree of masculinization among females and communal litter size, in multi-female groups. The phenology of litter parturition (parturition day) was negatively associated with the abundance of food at burrow systems during winter (but not during spring) and was negatively associated with the number of adult females per social unit in the spring. Synchrony of litter production within communal groups increased in years with less available food. Our study suggests that degu females timed reproduction based the socioecological conditions likely to be experienced by their dependent offspring.
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    Isolation and characterization of polymorphic microsatellite loci from Octodon degus
    (2009) Quan, Y. F.; Macmanes, M. D.; Ebensperger, L. A.; Lacey, E. A.; Hayes, L. D.
    Quantifying genetic kinship and parentage is critical to understanding the adaptive consequences of sociality. To measure fitness in a species with variable group structure, we isolated 14 microsatellite loci from Octodon degus, a semi-fossorial rodent endemic to Chile. The number of alleles per locus ranged from four to 14. Thirteen loci were in Hardy-Weinberg proportions, with values of observed heterozygosity ranging from 0.550 to 0.950. These markers provide the basis for future studies of the direct fitness consequences of sociality in O. degus.
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