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Humphreys BR, Mortelliti A. Pilfering personalities: Effects of small mammal personality on cache pilferage. J Anim Ecol 2024. [PMID: 38500218 DOI: 10.1111/1365-2656.14059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/29/2024] [Indexed: 03/20/2024]
Abstract
Small mammals such as mice and voles play a fundamental role in the ecosystem service of seed dispersal by caching seeds in small hoards that germinate under beneficial conditions. Pilferage is a critical step in this process in which animals steal seeds from other individuals' caches. Pilferers often recache stolen seeds, which are often pilfered by new individuals, who may recache again, and so on, potentially leading to compounded increased dispersal distance. However, little research has investigated intraspecific differences in pilfering frequency, despite its importance in better understanding the role of behavioural diversity in the valuable ecosystem service of seed dispersal. We conducted a field experiment in Maine (USA) investigating how intraspecific variation, including personality, influences pilferage effectiveness. Within the context of a long-term capture-mark-recapture study, we measured the unique personality of 3311 individual small mammals of 10 species over a 7-year period. For this experiment, we created artificial caches using eastern white pine (Pinus strobus) seeds monitored with trail cameras and buried antennas for individual identification. Of the 436 caches created, 83.5% were pilfered by 10 species, including deer mice ((Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi). We show how individuals differ in their ability to pilfer seeds and that these differences are driven by personality, body condition and sex. More exploratory deer mice and those with lower body condition were more likely to locate a cache, and female southern red-backed voles were more likely than males to locate caches. Also, caches were more likely to be pilfered in areas of higher small mammal abundance. Because the risk of pilferage drives decisions concerning where an animal chooses to store seeds, pilferage pressure is thought to drive the evolution of food-hoarding behaviour. Our study shows that pilferage ability varies between individuals, meaning that some individuals have a disproportionately strong influence on others' caching decisions and disproportionately contribute to compounded longer-distance seed dispersal facilitated by pilferage. Our results add to a growing body of knowledge showing that the unique personalities of individual small mammals play a critical role in forest regeneration by impacting seed dispersal.
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Affiliation(s)
- Brigit R Humphreys
- Department of Wildlife, Fisheries and Conservation Biology, University of Maine, Orono, Maine, USA
| | - Alessio Mortelliti
- Department of Wildlife, Fisheries and Conservation Biology, University of Maine, Orono, Maine, USA
- Department of Life Science, University of Trieste, Trieste, Italy
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Brehm AM, Mortelliti A. Environmental heterogeneity modifies the link between personality and survival in fluctuating small mammal populations. J Anim Ecol 2024; 93:196-207. [PMID: 38102795 DOI: 10.1111/1365-2656.14037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 11/14/2023] [Indexed: 12/17/2023]
Abstract
Despite numerous studies examining the fitness consequences of animal personalities, predictions concerning the relationship between personality and survival are not consistent with empirical observations. Theory predicts that individuals who are risky (i.e. bold, active and aggressive) should have higher rates of mortality; however, empirical evidence shows high levels of variation in behaviour-survival relationships in wild populations. We suggest that this mismatch between predictions under theory and empirical observations results from environmental contingencies that drive heterogeneity in selection. This uncertainty may constrain any universal directional relationships between personality traits and survival. Specifically, we hypothesize that spatiotemporal fluctuations in perceived risk that arise from variability in refuge abundance and competitor density alter the relationship between personality traits and survival. In a large-scale manipulative experiment, we trapped four small mammal species in five subsequent years across six forest stands treated with different management practices in Maine, United States. Stands all occur within the same experimental forest but contain varying amounts of refuge and small mammal densities fluctuate over time and space. We quantified the effects of habitat structure and competitor density on the relationship between personality traits and survival to assess whether directional relationships differed depending on environmental contingencies. In the two most abundant species, deer mice and southern red-backed voles, risky behaviours (i.e. higher aggression and boldness) predicted apparent monthly survival probability. Mice that were more aggressive (less docile) had higher survival. Voles that were bolder (less timid) had higher survival, but in the risky forest stands only. Additionally, traits associated with stress coping and de-arousal increased survival probability in both species at high small mammal density but decreased survival at low density. In the two less abundant study species, there was no evidence for an effect of personality traits on survival. Our field experiment provides partial support for our hypothesis: that spatiotemporal fluctuations in refuge abundance and competitor density alter the relationship between personality traits and survival. Our findings also suggest that behaviours associated with stress coping and de-arousal may be subject to density-dependent selection and should be further assessed and incorporated into theory.
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Affiliation(s)
- Allison M Brehm
- Department of Wildlife, Fisheries, and Conservation Biology, University of Maine, Orono, Maine, USA
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Alessio Mortelliti
- Department of Wildlife, Fisheries, and Conservation Biology, University of Maine, Orono, Maine, USA
- Department of Life Sciences, University of Trieste, Trieste, Italy
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Yao B, Hegab IM, Kang Y, Tan Y, Zhang D, Su J. Underground environment increases the differentiation of personality traits between male and female plateau zokors (Eospalax baileyi). Acta Ethol 2023. [DOI: 10.1007/s10211-023-00414-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Rohwäder M, Jeltsch F. Foraging personalities modify effects of habitat fragmentation on biodiversity. OIKOS 2022. [DOI: 10.1111/oik.09056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Florian Jeltsch
- Plant Ecology and Nature Conservation, Univ. of Potsdam Potsdam Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB), Altensteinstr. 34, 14195 Berlin Germany
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The socioeconomics of food hoarding in wild squirrels. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gavriilidi I, De Meester G, Van Damme R, Baeckens S. How to behave when marooned: the behavioural component of the island syndrome remains underexplored. Biol Lett 2022; 18:20220030. [PMID: 35440235 PMCID: PMC9039784 DOI: 10.1098/rsbl.2022.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/25/2022] [Indexed: 12/16/2022] Open
Abstract
Animals on islands typically depart from their mainland relatives in assorted aspects of their biology. Because they seem to occur in concert, and to some extent evolve convergently in disparate taxa, these changes are referred to as the 'island syndrome'. While morphological, physiological and life-history components of the island syndrome have received considerable attention, much less is known about how insularity affects behaviour. In this paper, we argue why changes in personality traits and cognitive abilities can be expected to form part of the island syndrome. We provide an overview of studies that have compared personality traits and cognitive abilities between island and mainland populations, or among islands. Overall, the pickings are remarkably slim. There is evidence that animals on islands tend to be bolder than on the mainland, but effects on other personality traits go either way. The evidence for effects of insularity on cognitive abilities or style is highly circumstantial and very mixed. Finally, we consider the ecological drivers that may induce such changes, and the mechanisms through which they might occur. We conclude that our knowledge of the behavioural and cognitive responses to island environments remains limited, and we encourage behavioural biologists to make more use of these 'natural laboratories for evolution'.
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Affiliation(s)
- Ioanna Gavriilidi
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Greece
| | - Gilles De Meester
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Raoul Van Damme
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Simon Baeckens
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
- Evolution and Optics of Nanostructures Lab, Department of Biology, Ghent University, Ghent, Belgium
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Brehm AM, Mortelliti A. Land-use change alters associations between personality and microhabitat selection. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02443. [PMID: 34455633 DOI: 10.1002/eap.2443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Ecologists commonly assess ecological patterns at the population level, focusing on the average response of all individuals within a population, but to predict how populations will respond to land-use change we must understand how changes to habitat differentially affect individuals within a population. For example, forest management is a widespread type of land-use that impacts wildlife through the loss of key habitat features, but individuals within a population may vary in their responses to this loss due to differences in habitat selection among individuals. Specifically, intraspecific variation in habitat selection has been linked to animal personalities (i.e., consistent behavioral differences among conspecifics), but previous research has not examined whether the relationship between personality and habitat selection is influenced by land-use change. To address this knowledge gap, we tested the hypothesis that land-use change alters the association between personality and microhabitat selection in small mammals. Specifically, we investigated two main questions: (1) To what extent are personality type and microhabitat selection correlated among conspecifics? (2) Does land-use change alter individual patterns of microhabitat selection? To answer these questions, we conducted a large-scale field experiment over 4 years, contrasting unmanaged forest (control) with managed forest (two silvicultural treatments) in Maine, USA. We examined the relationships between habitat selection and personality traits in deer mice (Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi). We found that personality traits were correlated with microhabitat selection at multiple spatial scales. Furthermore, land-use change altered these patterns of selection; resulting in either the loss of personality-associated selection or in novel patterns of selection in managed forests. These findings suggest that promoting structural complexity at multiple spatial scales, such as by interspersing stands of mature forest with managed stands, may maintain a variety of intraspecific habitat selection patterns and the associated ecological outcomes.
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Affiliation(s)
- Allison M Brehm
- Department of Wildlife, Fisheries and Conservation Biology, University of Maine, Orono, Maine, 04469, USA
| | - Alessio Mortelliti
- Department of Wildlife, Fisheries and Conservation Biology, University of Maine, Orono, Maine, 04469, USA
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Benedek AM, Sîrbu I, Lazăr A. Responses of small mammals to habitat characteristics in Southern Carpathian forests. Sci Rep 2021; 11:12031. [PMID: 34103594 PMCID: PMC8187625 DOI: 10.1038/s41598-021-91488-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022] Open
Abstract
Compared to Northern Carpathians, the small mammal fauna of Southern Carpathian forests is poorly known, with no data on habitat use; our study seeks to fill this gap. To this end, we conducted a survey in the Southern Carpathians for five years, assessing habitat use by small mammals in forests along an elevational gradient. Trapping was done using live traps set in transects at elevations between 820 and 2040 m. For each transect we evaluated variables related to vegetation structure, habitat complexity, and geographical location. We considered abundance, species composition and species richness as response variables. The rodents Apodemus flavicollis and Myodes glareolus and the shrew Sorex araneus were common and dominant. Their abundance were positively correlated with tree cover, the best explanatory variable. Responses to other variables were mixed. The strong divergence in the relative habitat use by the three most abundant species may act as a mechanism that enables their coexistence as dominant species, exploiting the same wide range of habitat resources. Overall, habitat use in our study area was similar to that reported from Northern Carpathians, but we found also important differences probably caused by the differences in latitude and forest management practices.
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Affiliation(s)
- Ana Maria Benedek
- Faculty of Sciences, Lucian Blaga University of Sibiu, 5-7 Raţiu Street, 550012, Sibiu, Romania.
| | - Ioan Sîrbu
- Faculty of Sciences, Lucian Blaga University of Sibiu, 5-7 Raţiu Street, 550012, Sibiu, Romania
| | - Anamaria Lazăr
- Department of Engineering and Management in Food and Tourism, Faculty of Food and Tourism, Transilvania University of Brașov, 148 Castelului Street, 500036, Braşov, Romania
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Boone SR, Brehm AM, Mortelliti A. Seed predation and dispersal by small mammals in a landscape of fear: effects of personality, predation risk and land‐use change. OIKOS 2021. [DOI: 10.1111/oik.08232] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Sara R. Boone
- Dept of Wildlife, Fisheries and Conservation Biology, Univ. of Maine Orono ME USA
| | - Allison M. Brehm
- Dept of Wildlife, Fisheries and Conservation Biology, Univ. of Maine Orono ME USA
| | - Alessio Mortelliti
- Dept of Wildlife, Fisheries and Conservation Biology, Univ. of Maine Orono ME USA
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