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Ebensperger LA, Quirici V, Bunster V, León C, Ramírez‐Estrada J, Hayes LD. Effects of Radio‐Collars are not Contingent on Socioecological Conditions in Degus. J Wildl Manage 2021. [DOI: 10.1002/jwmg.22098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Luis A. Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Verónica Quirici
- Centro de Investigación para la Sustentabilidad Facultad de Ciencias de la Vida, Universidad Andrés Bello, República 440 Santiago Chile
| | - Valentina Bunster
- Departamento de Ecología, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Cecilia León
- Departamento de Ecología, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juan Ramírez‐Estrada
- Departamento de Ecología, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Loren D. Hayes
- Department of Biology, Geology, and Environmental Sciences University of Tennessee at Chattanooga Chattanooga 37403 TN USA
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2
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Correa LA, León C, Ramírez-Estrada J, Ly-Prieto Á, Abades S, Hayes LD, Soto-Gamboa M, Ebensperger LA. One for all and all for one: phenotype assortment and reproductive success in masculinized females. Behav Ecol 2021. [DOI: 10.1093/beheco/arab093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Abstract
Homophily by morphological and behavioral traits has been described in several species of vertebrates, but its functional consequences remain poorly studied. Homophily by plurally breeding females may improve direct fitness by enhancing reproductive success. Female mammals may exhibit phenotypical masculinization due to exposure to androgens during early development, a condition that is associated with maternal performance during subsequent breeding. Our goal was to assess whether female composition (in terms of masculinization) of plurally breeding groups influences female fitness in a natural population of degus (Octodon degus). We assessed if plurally breeding female degus assort themselves by anogenital distance (AGD), an accurate measure of masculinization level. We also quantified if homophily by AGD phenotype affects female reproductive success and the reproductive output of the group. Plurally breeding groups typically included similarly masculinized (i.e., long AGD) females or similarly feminized (short AGD) females, indicating a strong degree of homophily. Females weaned more offspring in plurally breeding groups with more masculinized females. Additionally, standardized variance in the number of offspring weaned decreased in plurally breeding groups with mostly masculinized females, indicating greater reproductive equality in these groups. We conclude that female degus organize into homophilic social groups of similar AGD, and that social groups of masculinized females exhibit a higher reproductive success.
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Affiliation(s)
- Loreto A Correa
- Escuela de Medicina Veterinaria, Facultad de Ciencias, Universidad Mayor, Camino la Pirámide, Huechuraba, Santiago, Chile
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Avenida Bernardo O’Higgins, Santiago, Chile
| | - Cecilia León
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Avenida Bernardo O’Higgins, Santiago, Chile
| | - Juan Ramírez-Estrada
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Avenida Bernardo O’Higgins, Santiago, Chile
| | - Álvaro Ly-Prieto
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Avenida Bernardo O’Higgins, Santiago, Chile
| | - Sebastián Abades
- GEMA Center for Genomics, Ecology & Environment, Faculty of Interdisciplinary Studies, Universidad Mayor, Camino La Pirámide, Huechuraba, Santiago, Chile
| | - Loren D Hayes
- Department of Biology, Geology and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Mauricio Soto-Gamboa
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla, Isla Teja s/n, Valdivia, Chile
| | - Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Avenida Bernardo O’Higgins, Santiago, Chile
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Chang LYL, Ardiles AO, Tapia-Rojas C, Araya J, Inestrosa NC, Palacios AG, Acosta ML. Evidence of Synaptic and Neurochemical Remodeling in the Retina of Aging Degus. Front Neurosci 2020; 14:161. [PMID: 32256305 PMCID: PMC7095275 DOI: 10.3389/fnins.2020.00161] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/11/2020] [Indexed: 02/06/2023] Open
Abstract
Accumulation of amyloid-beta (Aβ) peptides is regarded as the hallmark of neurodegenerative alterations in the brain of Alzheimer’s disease (AD) patients. In the eye, accumulation of Aβ peptides has also been suggested to be a trigger of retinal neurodegenerative mechanisms. Some pathological aspects associated with Aβ levels in the brain are synaptic dysfunction, neurochemical remodeling and glial activation, but these changes have not been established in the retina of animals with Aβ accumulation. We have employed the Octodon degus in which Aβ peptides accumulated in the brain and retina as a function of age. This current study investigated microglial morphology, expression of PSD95, synaptophysin, Iba-1 and choline acetyltransferase (ChAT) in the retina of juvenile, young and adult degus using immunolabeling methods. Neurotransmitters glutamate and gamma-aminobutyric acid (GABA) were detected using immunogold labeling and glutamate receptor subunits were quantified using Western blotting. There was an age-related increase in presynaptic and a decrease in post-synaptic retinal proteins in the retinal plexiform layers. Immunolabeling showed changes in microglial morphology characteristic of intermediate stages of activation around the optic nerve head (ONH) and decreasing activation toward the peripheral retina. Neurotransmitter expression pattern changed at juvenile ages but was similar in adults. Collectively, the results suggest that microglial activation, synaptic remodeling and neurotransmitter changes may be consequent to, or parallel to Aβ peptide and phosphorylated tau accumulation in the retina.
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Affiliation(s)
- Lily Y-L Chang
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Alvaro O Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Cheril Tapia-Rojas
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Center for Aging and Regeneration, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Joaquin Araya
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Nibaldo C Inestrosa
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Center for Aging and Regeneration, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Adrian G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Monica L Acosta
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.,Faculty of Medical and Health Sciences, Centre for Brain Research, The University of Auckland, Auckland, New Zealand.,Brain Research New Zealand - Rangahau Roro Aotearoa, Auckland, New Zealand
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4
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Ebensperger LA, Correa LA, Ly Prieto Á, Pérez de Arce F, Abades S, Hayes LD. Multiple mating is linked to social setting and benefits the males in a communally rearing mammal. Behav Ecol 2019. [DOI: 10.1093/beheco/arz003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Individuals in social species may mate with multiple opposite-sex individuals, including members of the same or different social groups. This variation may be linked to genetic benefits, where multiple mating decreases risk of inbreeding. Multiple mating may also be constrained by the sociospatial setting through its effect on availability of mates. Because multiple mating with individuals from same or different groups may determine sex-specific fitness effects, we also examined how multiple mating modulates social benefits of females and males. We used 7 years of data on demography, social organization, and genetics of a natural population of the group-living and colonial rodent, Octodon degus, to determine how kin and sex composition within social groups, and spatial relations between these groups (i.e., colonial habits) influence multiple mating and its fitness consequences. Males (81.3%) and females (64.9%) produced offspring with multiple opposite-sex individuals within groups and with individuals of neighboring groups. Thus, polygynandry was the dominant mating system in the degu population examined. Multiple mating in degus was high when compared with estimates reported in other social mammals. Variation in female and male multiple mating was better explained by social setting through its effect on availability of potential mates rather than by benefits derived from decreasing risk of inbreeding. Finally, our study revealed how multiple mating enhances male, but not female reproductive success.
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Affiliation(s)
- Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins, CP, Chile
| | - Loreto A Correa
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins, CP, Chile
- Escuela de Medicina Veterinaria, Facultad de Ciencias, Universidad Mayor, Camino La Pirámide, Huechuraba, Santiago, Chile
| | - Álvaro Ly Prieto
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins, CP, Chile
| | - Felipe Pérez de Arce
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins, CP, Chile
| | - Sebastian Abades
- GEMA Center for Genomics, Ecology and Environment, Facultad de Ciencias, Universidad Mayor, Camino La Pirámide, Huechuraba, Santiago, Chile
| | - Loren D Hayes
- Department of Biological and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN, USA
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5
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Correa LA, León C, Ramírez-Estrada J, Ly-Prieto Á, Abades S, Hayes LD, Soto-Gamboa M, Ebensperger LA. Highly masculinized and younger males attain higher reproductive success in a social rodent. Behav Ecol 2018. [DOI: 10.1093/beheco/ary015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Loreto A Correa
- Núcleo Interdisciplinario, Escuela de Medicina Veterinaria, Facultad de Ciencias. Universidad Mayor, Camino la Pirámide, Huechuraba, Santiago, Chile
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Santiago, Chile
| | - Cecilia León
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Santiago, Chile
| | - Juan Ramírez-Estrada
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Santiago, Chile
| | - Álvaro Ly-Prieto
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Santiago, Chile
| | - Sebastián Abades
- GEMA Center for Genomics, Ecology & Environment, Universidad Mayor, Camino La Pirámide, Huechuraba, Santiago, Chile
| | - Loren D Hayes
- Department of Biology, Geology and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Mauricio Soto-Gamboa
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla, Valdivia, Chile
| | - Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla, Santiago, Chile
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6
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Correa LA, León C, Ramírez-Estrada J, Soto-Gamboa M, Sepúlveda RD, Ebensperger LA. Masculinized females produce heavier offspring in a group living rodent. J Anim Ecol 2016; 85:1552-1562. [DOI: 10.1111/1365-2656.12588] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/10/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Loreto A. Correa
- Departamento de Ecología; Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Cecilia León
- Departamento de Ecología; Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Juan Ramírez-Estrada
- Departamento de Ecología; Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Mauricio Soto-Gamboa
- Facultad de Ciencias; Instituto de Ciencias Ambientales y Evolutivas; Universidad Austral de Chile; Casilla 567 Valdivia Chile
| | - Roger D. Sepúlveda
- Facultad de Ciencias; Instituto de Ciencias Ambientales y Evolutivas; Universidad Austral de Chile; Casilla 567 Valdivia Chile
| | - Luis A. Ebensperger
- Departamento de Ecología; Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago Chile
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7
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Ebensperger LA, Correa LA, León C, Ramírez‐Estrada J, Abades S, Villegas Á, Hayes LD. The modulating role of group stability on fitness effects of group size is different in females and males of a communally rearing rodent. J Anim Ecol 2016; 85:1502-1515. [DOI: 10.1111/1365-2656.12566] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/13/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Luis A. Ebensperger
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Loreto A. Correa
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Cecilia León
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juan Ramírez‐Estrada
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Sebastian Abades
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
- Instituto de Ecología y Biodiversidad (IEB) Las Palmeras 3425 Santiago Chile
| | - Álvaro Villegas
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Loren D. Hayes
- Department of Biology, Geology and Environmental Sciences University of Tennessee at Chattanooga Chattanooga TN 37403 USA
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8
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Davis GT, Vásquez RA, Poulin E, Oda E, Bazán-León EA, Ebensperger LA, Hayes LD. Octodon degus
kin and social structure. J Mammal 2015. [DOI: 10.1093/jmammal/gyv182] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
A growing body of evidence showing that individuals of some social species live in non-kin groups suggests kin selection is not required in all species for sociality to evolve. Here, we investigate 2 populations of Octodon degus , a widespread South American rodent that has been shown to form kin and non-kin groups. We quantified genetic relatedness among individuals in 23 social groups across 2 populations as well as social network parameters (association, strength, and clustering coefficient) in order to determine if these aspects of sociality were driven by kinship. Additionally, we analyzed social network parameters relative to ecological conditions at burrow systems used by groups, to determine if ecological characteristics within each population could explain variation in sociality. We found that genetic relatedness among individuals within social groups was not significantly higher than genetic relatedness among randomly selected individuals in both populations, suggesting that non-kin structure of groups is common in degus. In both populations, we found significant relationships between the habitat characteristics of burrow systems and the social network characteristics of individuals inhabiting those burrow systems. Our results suggest that degu sociality is non-kin based and that degu social networks are influenced by local conditions.
Es creciente la evidencia que apoya la ocurrencia de especies sociales donde los individuos no están emparentados genéticamente, lo que sugiere que la selección de parentesco no es indispensable para la evolución de la sociabilidad. En este estudio se examinaron dos poblaciones de Octodon degus , un roedor sudamericano donde los grupos sociales pueden o no incluir individuos cercanamente emparentados. Se cuantificó el parentesco genético entre individuos en 23 grupos sociales y en redes sociales de dos poblaciones para determinar si estos aspectos de la sociabilidad dependen del grado de parentesco. Además, se examinaron asociaciones entre los parámetros cuantificados de las redes sociales (asociación, fuerza, coeficiente de anidamiento) y las condiciones ecológicas a nivel de los sistemas de madriguera usados por cada grupo. El grado de parentesco genético dentro de los grupos no fue distinto del grado de parentesco entre individuos de la población tomados al azar, lo que apoya que una estructura de grupos no emparentada es la regla en Octodon degus . En ambas poblaciones se registró una asociación entre características ecológicas de los sistemas de madriguera y atributos de las redes sociales de los individuos que usan estas estructuras. Nuestros resultados indican que la sociabilidad en Octodon degus no está basada en relaciones de parentesco y que las redes sociales de estos animales dependen de las condiciones ecológicas.
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9
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Wey TW, Burger JR, Ebensperger LA, Hayes LD. Reproductive correlates of social network variation in plurally breeding degus ( Octodon degus). Anim Behav 2013; 85:1407-1414. [PMID: 24511149 PMCID: PMC3914217 DOI: 10.1016/j.anbehav.2013.03.035] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studying the causes and reproductive consequences of social variation can provide insight into the evolutionary basis of sociality. Individuals are expected to behave adaptively to maximize reproductive success, but reproductive outcomes can also depend on group structure. Degus (Octodon degus) are plurally breeding rodents, in which females allonurse indiscriminately. However, communal rearing does not appear to enhance female reproductive success, and larger group sizes are correlated with decreasing per capita pup production. To further investigate mechanisms underlying these patterns, we asked how differences in sex, season and average group reproductive success are related to degu association networks. We hypothesized that if reproductive differences mirror social relationships, then females (core group members) should show stronger and more stable associations than males, and female association strength should be strongest during lactation. We also hypothesized that, at the group level, social cohesion would increase reproductive output, while social conflict would decrease it. Females did have higher association strength and more preferred partners than males, but only during lactation, when overall female associations increased. Females also had more stable preferred social partnerships between seasons. A measure of social cohesion (average association strength) was not related to per capita pup production of female group members, but potential social conflict (heterogeneity of association strengths) was negatively related to per capita pup production of female group members. Our results highlight temporal and multilevel patterns of social structure that may reflect reproductive costs and benefits to females.
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Affiliation(s)
- Tina W. Wey
- Department of Environmental Science and Policy, University of California, Davis, CA, U.S.A
| | - Joseph R. Burger
- Department of Biology, University of New Mexico, Albuquerque, NM, U.S.A
| | - Luis A. Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Loren D. Hayes
- Department of Biological and Environmental Sciences, University of Tennessee, Chattanooga, TN, U.S.A
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10
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Quirici V, Palma M, Sobrero R, Faugeron S, Ebensperger LA. Relatedness does not predict vigilance in a population of the social rodent Octodon degus. Acta Ethol 2012. [DOI: 10.1007/s10211-012-0131-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Burger JR, Chesh AS, Muñoz P, Fredes F, Ebensperger LA, Hayes LD. Sociality, exotic ectoparasites, and fitness in the plural breeding rodent Octodon degus. Behav Ecol Sociobiol 2012; 66:57-66. [PMID: 22328801 PMCID: PMC3277428 DOI: 10.1007/s00265-011-1252-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Social animals are susceptible to high infection levels by contact-transmitted parasites due to increased conspecific interaction. Exotic parasites are known to have adverse consequences on native hosts. We examined the relationship between social group size and exotic ectoparasite loads, and adult infection levels with per capita fitness and offspring survival in the plural breeding rodent Octodon degus in central Chile. Degus at our site were almost entirely infected by two exotic ectoparasites: the fleas Leptopsylla segnis and Xenopsylla cheopis. Neither group size nor number of females per group predicted the abundance of either exotic flea species. The per capita number of pups (per capita fitness) that emerged from burrow systems used by known social groups was negatively correlated with abundance of L. segnis but not X. cheopis. On adults, X. cheopis abundance was three times greater than L. segnis but was not significantly correlated with per capita fitness. In females, L. segnis abundance was negatively correlated with peak body mass during pregnancy. Adult ectoparasite load was not correlated with offspring survival. Based on these results, we hypothesize that high infection levels of L. segnis result in decreased reproductive fitness of adult female degus but are not a cost of sociality because parasite loads are not predicted by social group size. Further work is needed to experimentally test this hypothesis and to determine if L. segnis serves as a vector for a deleterious pathogen. Lastly, the lack of native ectoparasites may explain why a previous study at our site determined that behavioral adaptations needed to cope with high ectoparasite burdens (e.g., grooming) are not extensive in degus; they simply have not had the coevolutionary time needed for selection of these behaviors.
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Affiliation(s)
- Joseph R. Burger
- Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Adrian S. Chesh
- Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA
| | - Pamela Muñoz
- Laboratorio de Parasitología Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral, Valdivia, Chile
| | - Fernando Fredes
- Departamento de Parasitología, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Luis A. Ebensperger
- Centro de Estudios Avanzados en Ecología y Biodiversidad, Departmento de Ecología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Loren D. Hayes
- Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA
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Maher CR, Burger JR. Intraspecific variation in space use, group size, and mating systems of caviomorph rodents. J Mammal 2011; 92:54-64. [PMID: 22328790 DOI: 10.1644/09-mamm-s-317.1] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Intraspecific variation in social systems is widely recognized across many taxa, and specific models, including polygamy potential, resource defense, and resource dispersion, have been developed to explain the relationship between ecological variation and social organization. Although mammals from temperate North America and Eurasia have provided many insights into this relationship, rodents from the Neotropics and temperate South America have largely been ignored. In this review we focus on reports documenting intraspecific variation in spacing systems, group size, and mating systems of caviomorphs. This large group of New World hystricognath rodents occupies a diverse array of habitats; thus, members of the same species potentially exhibit different social systems in response to different ecological conditions. Spatial patterns vary in response to a diverse array of factors, including predation, food availability, population density, and soil characteristics. Changes in group size typically correlate with changes in resource availability, particularly food. Mating systems generally reflect the ability of males to control access to females, which may depend on population density or food distribution. In general, social organization in caviomorphs fits predictions of resource-based models; however, most studies have been purely observational, involving small numbers of animals over short time periods and reporting qualitative rather than quantitative levels of ecological correlates. In future studies the use of molecular techniques and controlled, experimental manipulations can increase our understanding of intraspecific variation in caviomorph social systems. This understudied group of rodents offers excellent opportunities to provide insights into the influence of ecological conditions on behavior such as social systems.
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Affiliation(s)
- Christine R Maher
- Department of Biological Sciences, University of Southern Maine, Portland, ME 04103, USA
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13
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Ebensperger LA, Chesh AS, Castro RA, Tolhuysen LO, Quirici V, Burger JR, Sobrero R, Hayes LD. Burrow limitations and group living in the communally rearing rodent, Octodon degus. J Mammal 2011; 92:21-30. [PMID: 22328789 PMCID: PMC3277429 DOI: 10.1644/09-mamm-s-383.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Group living is thought to evolve whenever individuals attain a net fitness advantage due to reduced predation risk or enhanced foraging efficiency, but also when individuals are forced to remain in groups, which often occurs during high-density conditions due to limitations of critical resources for independent breeding. The influence of ecological limitations on sociality has been studied little in species in which reproduction is more evenly shared among group members. Previous studies in the caviomorph rodent Octodon degus (a New World hystricognath) revealed no evidence that group living confers an advantage and suggest that burrow limitations influence formation of social groups. Our objective was to examine the relevance of ecological limitations on sociality in these rodents. Our 4-year study revealed no association between degu density and use of burrow systems. The frequency with which burrow systems were used by degus was not related to the quality of these structures; only in 1 of the 4 years did the frequency of burrow use decrease with decreasing abundance of food. Neither the number of females per group nor total group size (related measures of degu sociality) changed with yearly density of degus. Although the number of males within social groups was lower in 2008, this variation was not related clearly to varying density. The percentage of females in social groups that bred was close to 99% and did not change across years of varying density. Our results suggest that sociality in degus is not the consequence of burrow limitations during breeding. Whether habitat limitations contribute to variation in vertebrate social systems is discussed.
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Affiliation(s)
- Luis A. Ebensperger
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Adrian S. Chesh
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Rodrigo A. Castro
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Liliana Ortiz Tolhuysen
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Verónica Quirici
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Joseph Robert Burger
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Raúl Sobrero
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
| | - Loren D. Hayes
- Centro de Estudios Avanzados en Ecología y Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, 6513677, Santiago, Chile (LAE, RAC, LOT, VQ, RS). Department of Biology, University of Louisiana at Monroe, Monroe, LA 71209, USA (ASC, JRB, LDH)
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Hayes LD, Burger JR, Soto-Gamboa M, Sobrero R, Ebensperger LA. Towards an integrative model of sociality in caviomorph rodents. J Mammal 2011; 92:65-77. [PMID: 22328791 PMCID: PMC3277430 DOI: 10.1644/10-mamm-s-039.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In the late 1990s and early 2000s it was recognized that behavioral ecologists needed to study the sociality of caviomorph rodents (New World hystricognaths) before generalizations about rodent sociality could be made. Researchers identified specific problems facing individuals interested in caviomorph sociality, including a lack of information on the proximate mechanisms of sociality, role of social environment in development, and geographical or intraspecific variation in social systems. Since then researchers have described the social systems of many previously understudied species, including some with broad geographical ranges. Researchers have done a good job of determining the role of social environments in development and identifying the costs and benefits of social living. However, relatively little is known about the proximate mechanisms of social behavior and fitness consequences, limiting progress toward the development of integrative (evolutionary-mechanistic) models for sociality. To develop integrative models behavioral ecologists studying caviomorph rodents must generate information on the fitness consequences of different types of social organization, brain mechanisms, and endocrine substrates of sociality. We review our current understanding and future directions for research in these conceptual areas. A greater understanding of disease ecology, particularly in species carrying Old World parasites, is needed before we can identify potential links between social phenotypes, mechanism, and fitness.
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Affiliation(s)
- Loren D. Hayes
- Department of Biology, 700 University Avenue, University of Louisiana at Monroe, Monroe, LA 72109, USA
| | - Joseph Robert Burger
- Department of Biology, 700 University Avenue, University of Louisiana at Monroe, Monroe, LA 72109, USA
- Department of Biology, MSC03 2020/1, University of New Mexico, Albuquerque, NM 87131, USA
| | - Mauricio Soto-Gamboa
- Instituto de Ecología y Evolución, Facultad de Ciencias, Universidad Austral de Chile, Isla teja S/N, Casilla 567, Chile
| | - Raúl Sobrero
- Centro de Estudios Avanzados en Ecología y Biodiversidad and Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile
| | - Luis A Ebensperger
- Centro de Estudios Avanzados en Ecología y Biodiversidad and Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile
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Quirici V, Faugeron S, Hayes LD, Ebensperger LA. Absence of kin structure in a population of the group-living rodent Octodon degus. Behav Ecol 2010. [DOI: 10.1093/beheco/arq196] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Quirici V, Castro RA, Ortiz-Tolhuysen L, Chesh AS, Burger JR, Miranda E, Cortés A, Hayes LD, Ebensperger LA. Seasonal variation in the range areas of the diurnal rodent Octodon degus. J Mammal 2010; 91:458-466. [PMID: 22328788 DOI: 10.1644/08-mamm-a-337.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Both breeding activity and abundance and quality of available food are expected to influence daily movements of animals. Animals are predicted to range over large areas to meet high energy demands associated with reproduction (females) or to increase mating success (males). However, animals should expand their range areas whenever food conditions deteriorate. To examine the extent to which breeding activity versus food availability influence space use, we compared the size and location of range areas (home ranges) of the degu (Octodon degus), a diurnal rodent from semiarid environments of north-central Chile, during the austral winter and summer seasons. Degus produce young during the austral spring (September-October) when high-quality food is readily available. In contrast, degus do not breed during the austral summer (January-March) when food is scarce and of low quality. We predicted that degus would range over smaller areas in winter if the availability of food has a greater influence on space than breeding activity. Individuals were radiotracked in winter and the following summer over a 3-year period. Surveys of herbaceous cover were conducted during winter and summer to determine seasonal changes in the abundance and quality of primary food. In summer degus expanded and moved the location of their range areas to locations with available food. Given that preferred food was less abundant in summer than winter, we suggest that degu range areas are strongly influenced by food conditions.
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Affiliation(s)
- Verónica Quirici
- Centro de Estudios Avanzados en Ecología and Biodiversidad, and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile (VQ, RAC, LO-T, LAE) Department of Biology, University of Louisiana at Monroe, Louisiana 71209, USA (ASC, JRB, LDH) Departamento de Biología, Universidad de La Serena, La Serena, Chile (EM, AC)
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Hayes LD, Chesh AS, Castro RA, Tolhuysen LO, Burger JR, Bhattacharjee J, Ebensperger LA. Fitness consequences of group living in the degu Octodon degus, a plural breeder rodent with communal care. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2009.03.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ebensperger LA, Chesh AS, Castro RA, Tolhuysen LO, Quirici V, Burger JR, Hayes LD. Instability Rules Social Groups in the Communal Breeder RodentOctodon degus. Ethology 2009. [DOI: 10.1111/j.1439-0310.2009.01635.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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