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Yang SC, Shieh KR. Higher exploratory and vigilant behaviors related to higher central dopaminergic activities of Formosan wood mice (Apodemus semotus) in light-dark exploration tests. Pharmacol Biochem Behav 2024; 241:173792. [PMID: 38806117 DOI: 10.1016/j.pbb.2024.173792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/16/2024] [Accepted: 05/23/2024] [Indexed: 05/30/2024]
Abstract
Formosan wood mice (Apodemus semotus) are endemic rodents in Taiwan. Recently Formosan wood mice exhibit similar locomotor behaviors in the laboratory environment as in the field environment has shown. Contemporaneously, Formosan wood mice have higher moving distances of and central dopaminergic (DAergic) activities than C57BL/6 mice in behavioral test. This study tried to compare the behavioral responses between male Formosan wood mice and male C57BL/6 mice in the light-dark exploration tests. We also measured the levels of DA and 3,4-dihydroxyphenylacetic acid (DOPAC), the primary metabolite of DA, to assess the dopaminergic activity of the medial prefrontal cortex, striatum, and nucleus accumbens. Our data show that Formosan wood mice revealed higher exploration and central DAergic activities than did C57BL/6 mice in the light-dark exploration tests, and diazepam (an anxiolytics) treatment reduced the exploratory activity and central dopaminergic activities in Formosan wood mice, but not in C57BL/6 mice. After repeated exposure to light-dark exploration tests, the latency to dark zone was increased, and the duration in light zone as well as the central DAergic activity were decreased in C57BL/6 mice. This study provides comparative findings; Formosan wood mice showed the higher exploratory activities than C57BL/6 mice did, and their central DAergic activities were related to the behavioral responses in these two mice. This could potentially shed light on the reasons behind the prevalence of higher exploration and central dopaminergic activities. Using Formosan wood mice as a model to study human diseases related to hyperactivity adds significant value to the potential research.
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Affiliation(s)
- Shu-Chuan Yang
- Holistic Education Center, Tzu Chi University of Science and Technology, Hualien 970, Taiwan; Department of Physiology, Tzu Chi University, Hualien 970, Taiwan
| | - Kun-Ruey Shieh
- Department of Physiology, Tzu Chi University, Hualien 970, Taiwan; Institute of Biomedical Sciences, Tzu Chi University, Hualien 970, Taiwan.
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2
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Apfelbeck B, Cousseau L, Kung’u GN, Canoine V, Heiskanen J, Korir DK, Lala F, Pellikka P, Githiru M, Lens L. Cooperative breeding alters physiological and behavioral responses to habitat fragmentation. iScience 2024; 27:108717. [PMID: 38299033 PMCID: PMC10829880 DOI: 10.1016/j.isci.2023.108717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/03/2023] [Accepted: 12/11/2023] [Indexed: 02/02/2024] Open
Abstract
Animals respond to habitat alteration with changes in their behavior and physiology. These changes determine individual performance and thus precede changes in population size. They are therefore hypothesized to provide important insights into how animals cope with environmental change. Here, we investigated physiological and behavioral responses of a cooperatively breeding bird, the placid greenbul (Phyllastrephus placidus), in a severely fragmented tropical biodiversity hotspot and combined these data with remotely sensed (LiDAR) environmental data. We found that individuals had increased glucocorticoid hormone levels when breeding in territories with low native canopy cover or located within small fragments. However, when breeding with the help of subordinates, breeders in low quality territories had similar glucocorticoid levels as those in higher quality territories. Our study shows that sociality may impact how well animals cope with environmental change and contributes to our understanding of the role of glucocorticoid physiology and behavior in response to anthropogenic change.
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Affiliation(s)
- Beate Apfelbeck
- Evolutionary Zoology Group, Department of Environment and Biodiversity, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Laurence Cousseau
- Terrestrial Ecology Unit, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Gladys Nyakeru Kung’u
- Evolutionary Zoology Group, Department of Environment and Biodiversity, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Virginie Canoine
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Janne Heiskanen
- Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
- Finnish Meteorological Institute, P.O. Box 503, 00101 Helsinki, Finland
| | - David K. Korir
- Wildlife Research and Training Institute, P.O. Box 842, Naivasha 20117, Kenya
| | - Fredrick Lala
- Wildlife Research and Training Institute, P.O. Box 842, Naivasha 20117, Kenya
| | - Petri Pellikka
- Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
- University of Nairobi, Wangari Maathai Institute for Environmental and Peace Studies, P.O. Box 29053, Kangemi 00625, Kenya
- State Key Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China
| | - Mwangi Githiru
- Wildlife Works, P.O. Box 310, Voi 80300, Kenya
- Zoology Department, National Museums of Kenya, Museum Hill Road, Nairobi 00100, Kenya
| | - Luc Lens
- Terrestrial Ecology Unit, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
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Carrilho M, Monarca RI, Aparício G, Mathias MDL, Tapisso JT, von Merten S. Physiological and behavioural adjustment of a wild rodent to laboratory conditions. Physiol Behav 2024; 273:114385. [PMID: 37866641 DOI: 10.1016/j.physbeh.2023.114385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/24/2023]
Abstract
Wild animals are brought to captivity for different reasons, for example to be kept in zoos and rehabilitation centres, but also for basic research. Such animals usually undergo a process of adjustment to captive conditions. While this adjustment occurs on the behavioural and the physiological level, those are usually studied separately. The aim of this study was to assess both the physiological and behavioural responses of wild wood mice, Apodemus sylvaticus, while adjusting to laboratory conditions. Over the course of four weeks, we measured in wild-caught mice brought to the laboratory faecal corticosterone metabolites and body mass as physiological parameters, stereotypic behaviour and nest-quality, as welfare-linked behavioural parameters, and four personality measures as additional behavioural parameters. The results of our study indicate that mice exhibited an adjustment in both behaviour and physiology over time in the laboratory. While the hormonal stress response decreased significantly, body mass and the proportion of stereotypic behaviours showed a tendency to increase over time. The slight increase of stereotypic behaviours, although not statistically significant, suggests the development of repetitive and non-functional behaviours as a response to laboratory conditions. However, we suggest that those behaviours might have been used by animals as a coping strategy to decrease the physiological stress response. Other behavioural parameters measured, such as boldness and nestbuilding behaviour were stable over time. The information obtained in the present study hints at a complex interplay between behavioural and physiological adjustments of wild animals to laboratory conditions, which should be considered when intending to use wild animals in experimental research.
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Affiliation(s)
- Maílis Carrilho
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal.
| | - Rita I Monarca
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal
| | - Guilherme Aparício
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal
| | - Maria da Luz Mathias
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal
| | - Joaquim T Tapisso
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal
| | - Sophie von Merten
- CESAM - Centre for Environmental and Marine Studies and Department of Animal Biology, Faculty of Sciences of the University of Lisbon, Lisbon 1749-016, Portugal; Department of Environment and Biodiversity, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
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4
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Savazza S, Bartolommei P, Gasperini S, Bonacchi A, Manzo E, Cozzolino R. Should I Stay or Should I Go? Seasonal Fluctuations of Wood Mouse Populations in Fields Surrounded by Woodlands. Animals (Basel) 2023; 13:2017. [PMID: 37370527 PMCID: PMC10295659 DOI: 10.3390/ani13122017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/08/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
The wood mouse Apodemus sylvaticus is common in woodlands and open areas of the Western Palearctic. Despite extensive research, little is known about its population ecology in fields in the Mediterranean area, where the climate involves great seasonal changes in environmental features. Here, we investigated wood mice seasonal fluctuations in the number of captures and population structure by sampling long-fallow fields and woodlands, i.e., oak forest and conifer plantation, in a heterogeneous landscape of central Italy. Mice were live-trapped every two months for three years (23.814 trap-days). The number of captures, mice body weight, and proportion of adult, residents and breeding individuals were analyzed. Mice dynamics changed across seasons and habitats. In fields, we recorded more captures, more reproductive individuals, and fewer non-adults and resident individuals in the warmer months compared to the colder months; mice were heavier in warmer months. During the cold season, the captures and adult proportion in fields were lower than in resource-rich woodlands. Breeding and non-resident mice were more abundant in fields than in woodlands in warmer months. Overall, the seasonal demographic variations we recorded provide evidence that fields can represent a suboptimal habitat in Mediterranean heterogeneous landscapes, acting nonetheless as a source of food resources, cover, and mates for mice in spring-summer.
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Affiliation(s)
| | - Paola Bartolommei
- Fondazione Ethoikos, Convento dell’Osservanza snc, Radicondoli, 53030 Siena, Italy
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Navarro-Castilla Á, Hernández MC, Barja I. An Experimental Study in Wild Wood Mice Testing Elemental and Isotope Analysis in Faeces to Determine Variations in Food Intake Amount. Animals (Basel) 2023; 13:ani13071176. [PMID: 37048432 PMCID: PMC10093285 DOI: 10.3390/ani13071176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
The analysis of carbon and nitrogen elemental (C, N) and isotopic compositions (δ13C, δ15N) in faeces are considered reliable methodologies for the study of diet in wildlife. Here, we tested the suitability of these techniques to detect variations in the amount of food intake. We captured wild wood mice (Apodemus sylvaticus) with Sherman live traps where bait access was initially free, and later it was experimentally limited inside by four different devices to cause intended variations in the amount ingested. The total C and N (%) and stable δ13C and δ15N isotopic values were determined for the bait and in mice faecal samples. Faecal values were lower than bait ones except for N, likely due to animal matter ingested before capture. No significant differences in total C, N and δ13C were found due to individual traits. However, breeding males showed higher δ15N values than breeding females, probably due to differences in energy and protein demands between both sexes during the breeding season. Only δ13C detected food intake variations (≥2 g). Despite further research being needed, these results initially support the potential of δ13C to provide information on the amount ingested, thus being useful to complement trophic ecology studies.
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Affiliation(s)
- Álvaro Navarro-Castilla
- Eco- and Ethophysiology Lab, Departamento de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, C. Darwin 2, 28049 Madrid, Spain
- Correspondence:
| | - M. Carmen Hernández
- Eco- and Ethophysiology Lab, Departamento de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Isabel Barja
- Eco- and Ethophysiology Lab, Departamento de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, C. Darwin 2, 28049 Madrid, Spain
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Variations in home range and core area of red-backed voles (Myodes regulus) in response to various ecological factors. Sci Rep 2022; 12:22226. [PMID: 36564554 PMCID: PMC9789154 DOI: 10.1038/s41598-022-26779-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
The characteristics of animal distribution are determined by interactions between the resource requirements of animals and ecological factors. This study sought to evaluate the effects of diverse ecological factors on the home range and core area of red-backed voles (Myodes regulus) in a natural deciduous forest located on Mt. Gariwang, Pyeongchang and Jeongseon, South Korea. Our study focused on four types of ecological factors: topography, climate, cover, and demography. A total of 29 voles were radio-tracked from August to September 2021. Home range (95% utilization distribution; UD) and core area (50% UD) were calculated using the kernel density estimator (KDE). The home range (1659.49 m2) and core area (317.08 m2) were negatively affected by altitude. The lunar phase and temperature negatively and positively influenced the home range and core area, respectively. The home range was positively affected by understory vegetation, whereas the core area was not. The core area increased within microhabitats with a high density of conspecific individuals, with males having a larger home range (2006.19 m2) and core area (375.40 m2) than females (1043.13 m2 and 213.39 m2, respectively). These findings provide a deeper understanding of the diverse ecological factors affecting the distributions of animals, especially small rodents.
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7
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Liu D, Li Z, Hou Z, Bao H, Luan X, Zhang P, Liang X, Gong S, Tian Y, Zhang D, She W, Yang F, Chen S, Nathan JR, Jiang G. Ecological relationships among habitat type, food nutrients, parasites and hormones in wild boar
Sus scrofa
during winter. WILDLIFE BIOLOGY 2022. [DOI: 10.1002/wlb3.01020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Dongqi Liu
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Zhaoyue Li
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Zhijun Hou
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Heng Bao
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Xue Luan
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Ping Zhang
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Xin Liang
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Shuang Gong
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Yumiao Tian
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Da Zhang
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Wen She
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Feifei Yang
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Shiyu Chen
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - James Roberts Nathan
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
| | - Guangshun Jiang
- Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry Univ. Harbin China
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8
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Ortiz-Jiménez L, Iglesias-Merchan C, Martínez-Salazar AI, Barja I. Effect of intensity and duration of anthropic noises on European mink locomotor activity and fecal cortisol metabolite levels. Curr Zool 2022; 68:688-699. [PMID: 36743224 PMCID: PMC9892796 DOI: 10.1093/cz/zoab104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 12/27/2021] [Indexed: 02/07/2023] Open
Abstract
Human activities involving noise emission can affect wild animals. European mink was exposed to road noise and human voice playbacks to analyze how sound intensity level and duration of both noises altered the time that individuals were active and if their fecal cortisol metabolite (FCM) levels varied. A Hierarchical Analysis Cluster was performed to establish 2 mink groups with respect to both noise source type: short duration/low intensity (SL) and long duration/high intensity (LH). We performed general linear mixed models to evaluate the variation in locomotor activity duration (s) and FCM (nanogram per gram) levels, respectively. The results showed both road noise and human voices decreased locomotor activity duration in SL more sharply compared with LH, and human voices were the triggers that induced the most pronounced response to both exposure conditions. FCM (ng/g) levels increased in SL compared with LH during road noise while the opposite happened during human voices. Differences based on sex and age of individuals were observed. In conclusion, noise characteristics given by the sound type determined the variations in locomotor activity duration while noise exposure level determined the variations in FCM (ng/g) levels. Attention should be paid to noisy activities (e.g., recreational activities for visitors in protected natural areas) and loud groups of people to conserve wildlife, especially noise sensitive species.
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Affiliation(s)
| | - Carlos Iglesias-Merchan
- Department of Forest and Environmental Engineering and Management, Universidad Politécnica de Madrid, Madrid, Spain
| | - Alba Itzel Martínez-Salazar
- Geographic Information Systems Laboratory, Institute of Biology, Universidad Nacional Autónoma de México, Mexico City, México
| | - Isabel Barja
- Department of Biology, Zoology Unit, Universidad Autónoma de Madrid, Madrid, 28049, Spain,Biodiversity and Global Change Research Centre (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
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9
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OUP accepted manuscript. J Mammal 2022. [DOI: 10.1093/jmammal/gyac054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Long-Tailed Pygmy Rice Rats Modify Their Behavioural Response and Faecal Corticosterone Metabolites in Response to Culpeo Fox but Not to Lesser Grison. Animals (Basel) 2021; 11:ani11113036. [PMID: 34827769 PMCID: PMC8614544 DOI: 10.3390/ani11113036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 11/24/2022] Open
Abstract
Simple Summary Prey species must fine-tune their antipredator responses to survive, but also to achieve a positive net energy balance which will enhance biological fitness. Given this, we investigated if Oligoryzomys longicaudatus would adapt their behavioural and physiological antipredator responses depending on their relative presence in the predator’s diet. By exposing this rodent species to culpeo fox and lesser grison faeces, we found that O. longicaudatus behavioural and physiological strategies were modulated depending on the predator’s diet. Specifically, rodents would trigger their antipredator responses in the presence of the most dangerous predator, the culpeo, which consumes a higher proportion of O. longicaudatus compared to the lesser grison. Our findings could be of importance for the development of more humane and efficient strategies to control rodent populations. Abstract Even though behavioural and physiological reactions to predation risk exhibited by prey species have received considerable attention in scientific journals, there are still many questions still unsolved. Our aim was to broaden the knowledge on one specific question: do long-tailed pygmy rice rats adapt their behavioural and physiological antipredator strategies depending on the predator species? For this question, we live-trapped in a temperate forest in Southern Chile long-tailed pygmy rice rats (Oligoryzomys longicaudatus), which were exposed to three predator odour phases (Phase 0: preliminary, no predator cues; Phase 1: one plot with culpeo fox faeces (Lycalopex culpaeus), one plot with lesser grison (Galictis cuja) faeces and one plot acting as a control with no odour; Phase 2: post treatment, no predator cues). We measured the behavioural response by the capture ratio. To assess the physiological stress response, we collected fresh faecal samples to quantify faecal corticosterone metabolites (FCM). Our results showed that O. longicaudatus increased both the capture ratio and FCM levels in the presence of culpeo cues. Culpeo foxes have higher densities in the study area than G. cuja and exhibit a higher activity pattern overlap with O. longicaudatus. Moreover, it has been also been reported in other regions that L. culpaeus consumption of O. longicaudatus is more frequent compared to G. cuja diet. The increase in capturability could be because traps can be regarded as a shelter in high-risk settings, but it can also be explained by the predator inspection behaviour. The increase in FCM concentrations during culpeo treatment can be linked to the adaptive mobilisation of energy to execute antipredator responses to increase survival chances.
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11
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Jenkins MR, Cummings JM, Cabe AR, Hulthén K, Peterson MN, Langerhans RB. Natural and anthropogenic sources of habitat variation influence exploration behaviour, stress response, and brain morphology in a coastal fish. J Anim Ecol 2021; 90:2446-2461. [PMID: 34143892 DOI: 10.1111/1365-2656.13557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/16/2021] [Indexed: 11/27/2022]
Abstract
Evolutionary ecology aims to better understand how ecologically important traits respond to environmental heterogeneity. Environments vary both naturally and as a result of human activities, and investigations that simultaneously consider how natural and human-induced environmental variation affect diverse trait types grow increasingly important as human activities drive species endangerment. Here, we examined how habitat fragmentation and structural habitat complexity affect disparate trait types in Bahamas mosquitofish Gambusia hubbsi inhabiting tidal creeks. We tested a priori predictions for how these factors might influence exploratory behaviour, stress reactivity and brain anatomy. We examined approximately 350 adult Bahamas mosquitofish from seven tidal-creek populations across Andros Island, The Bahamas that varied in both human-caused fragmentation (three fragmented and four unfragmented) and natural habitat complexity (e.g. fivefold variation in rock habitat). Populations that had experienced severe human-induced fragmentation, and thus restriction of tidal exchange from the ocean, exhibited greater exploration of a novel environment, stronger physiological stress responses to a mildly stressful event and smaller telencephala (relative to body size). These changes matched adaptive predictions based mostly on (a) reduced chronic predation risk and (b) decreased demands for navigating tidally dynamic habitats. Populations from sites with greater structural habitat complexity showed a higher propensity for exploration and a relatively larger optic tectum and cerebellum. These patterns matched adaptive predictions related to increased demands for navigating complex environments. Our findings demonstrate environmental variation, including recent anthropogenic impacts (<50 years), can significantly affect complex, ecologically important traits. Yet trait-specific patterns may not be easily predicted, as we found strong support for only six of 12 predictions. Our results further highlight the utility of simultaneously quantifying multiple environmental factors-for example had we failed to account for habitat complexity, we would not have detected the effects of fragmentation on exploratory behaviours. These responses, and their ecological consequences, may be complex: rapid and adaptive phenotypic responses to anthropogenic impacts can facilitate persistence in human-altered environments, but may come at a cost of population vulnerability if ecological restoration was to occur without consideration of the altered traits.
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Affiliation(s)
- Matthew R Jenkins
- Department of Biological Sciences and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA
| | - John M Cummings
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC, USA
| | - Alex R Cabe
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Kaj Hulthén
- Department of Biological Sciences and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA
| | - M Nils Peterson
- Fisheries, Wildlife, and Conservation Biology Program, North Carolina State University, Raleigh, NC, USA
| | - R Brian Langerhans
- Department of Biological Sciences and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA
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12
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Whipple AL, Ray C, Wasser M, Kitchens JN, Hove AA, Varner J, Wilkening JL. Temporal vs. spatial variation in stress-associated metabolites within a population of climate-sensitive small mammals. CONSERVATION PHYSIOLOGY 2021; 9:coab024. [PMID: 34026212 PMCID: PMC8127223 DOI: 10.1093/conphys/coab024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/04/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Temporal variation in stress might signify changes in an animal's internal or external environment, while spatial variation in stress might signify variation in the quality of the habitats that individual animals experience. Habitat-induced variations in stress might be easiest to detect in highly territorial animals, and especially in species that do not take advantage of common strategies for modulating habitat-induced stress, such as migration (escape in space) or hibernation (escape in time). Spatial and temporal variation in response to potential stressors has received little study in wild animals, especially at scales appropriate for relating stress to specific habitat characteristics. Here, we use the American pika (Ochotona princeps), a territorial small mammal, to investigate stress response within and among territories. For individually territorial animals such as pikas, differences in habitat quality should lead to differences in stress exhibited by territory owners. We indexed stress using stress-associated hormone metabolites in feces collected non-invasively from pika territories every 2 weeks from June to September 2018. We hypothesized that differences in territory quality would lead to spatial differences in mean stress and that seasonal variation in physiology or the physical environment would lead to synchronous variation across territories through time. We used linear mixed-effects models to explore spatiotemporal variation in stress using fixed effects of day-of-year and broad habitat characteristics (elevation, aspect, site), as well as local variation in habitat characteristics hypothesized to affect territory quality for this saxicolous species (talus depth, clast size, available forage types). We found that temporal variation within territories was greater than spatial variation among territories, suggesting that shared seasonal stressors are more influential than differences in individual habitat quality. This approach could be used in other wildlife studies to refine our understanding of habitat quality and its effect on individual stress levels as a driver of population decline.
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Affiliation(s)
- Ashley L Whipple
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
- Institute of Arctic and Alpine Research, University of
Colorado, Boulder, CO 80303, USA
| | - Chris Ray
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
- Institute of Arctic and Alpine Research, University of
Colorado, Boulder, CO 80303, USA
| | - Max Wasser
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
| | - James N Kitchens
- Department of Biology, Warren Wilson College,
Asheville, NC 28778, USA
| | - Alisa A Hove
- Department of Biology, Warren Wilson College,
Asheville, NC 28778, USA
| | - Johanna Varner
- Department of Biological Sciences, Colorado Mesa
University, Grand Junction, CO 81501, USA
| | - Jennifer L Wilkening
- US Fish and Wildlife Service, Southern Nevada Fish and Wildlife
Office, Las Vegas, NV 89130, USA
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13
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Ortiz-Jiménez L, Iglesias-Merchan C, Barja I. Behavioral responses of the European mink in the face of different threats: conspecific competitors, predators, and anthropic disturbances. Sci Rep 2021; 11:8266. [PMID: 33859346 PMCID: PMC8050081 DOI: 10.1038/s41598-021-87905-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 03/31/2021] [Indexed: 11/08/2022] Open
Abstract
Prey species assess the risk of threat using visual, olfactory, and acoustic cues from their habitat. Thus, they modify their behavior in order to avoid encounters with competitors, predators, and human disturbances that endanger their fitness. European mink (Mustela lutreola) is a critically endangered species that can be preyed upon by larger carnivores and displaced by dominant conspecifics to areas of lower quality, e.g., near to more anthropized localities which may be noisier. In this study, the behavioral responses of 24 European mink were evaluated by conducting an experiment in which the presence of a conspecific competitor was simulated with a visual cue (mirror) and the presence of predators (terrestrial and aerial) with odorous cues. Additionally, they were also exposed to potential sources of anthropic disturbance with acoustic cues (road traffic noise and human voices). Our results showed that European mink were hidden for longer periods of time due to the presence of conspecifics and being exposed to the fecal odors of a terrestrial predator such as dog, but especially when they were exposed to anthropic noises. In the presence of a conspecific, the females and the subadults were the ones who remained hidden for the longest time. As well, they were hidden for longer periods of time due to the presence of conspecifics but in combination with dog feces and anthropic sounds did not induce variations in the response, as both by themselves already triggered an increase in the time they spent hiding. The vigilance model showed the effects of the same factors as the hiding model, but with antagonistic effects in the case of vigilance time which decreased during anthropic noises exposition. Finally, we want to highlight that European mink showed an innate response favorable to all three types of threats, but attention should be focused on human disturbances-as they trigger the most extreme responses-which may affect the rate of survival of this threatened species.
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Affiliation(s)
- Lorena Ortiz-Jiménez
- Department of Biology, Zoology Unit, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Carlos Iglesias-Merchan
- Department of Forest and Environmental Engineering and Management, Universidad Politécnica de Madrid, Madrid, Spain
| | - Isabel Barja
- Department of Biology, Zoology Unit, Universidad Autónoma de Madrid, Madrid, Spain
- Biodiversity and Global Change Research Center (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
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14
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Fardell LL, Bedoya-Pérez MA, Dickman CR, Crowther MS, Pavey CR, Narayan EJ. Are physiological and behavioural responses to stressors displayed concordantly by wild urban rodents? Naturwissenschaften 2021; 108:5. [PMID: 33411125 PMCID: PMC7790802 DOI: 10.1007/s00114-020-01716-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/09/2020] [Accepted: 12/21/2020] [Indexed: 10/27/2022]
Abstract
Understanding wild animal responses to stressors underpins effective wildlife management. In order for responses to stressors to be correctly interpreted, it is critical that measurements are taken on wild animals using minimally invasive techniques. Studies investigating wild animal responses to stressors often measure either a single physiological or behavioural variable, but whether such responses are comparable and concordant remains uncertain. We investigated this question in a pilot study that measured responses of wild-caught urban brown and black rats (Rattus norvegicus, Rattus rattus) to fur-based olfactory cues from a predator, the domestic cat (Felis catus); a novel herbivore, the koala (Phascolarctos cinereus); and a familiar herbivore and competitor, the common brushtail possum (Trichosurus vulpecula). Physiological responses, measured by assaying faecal glucocorticoid metabolites, were compared to behavioural responses observed via video recordings. We found that physiological and behavioural responses to stressors were expressed concordantly. There was no sizeable physiological response observed, and the behavioural response when considered across the night was negligible. However, the behavioural response to the predator and competitor cues changed across the observation period, with activity increasing with increasing hours of exposure. Our results indicate that responses of wild rodents to cues are nuanced, with stress responses modulated by behaviour changes that vary over time according to the severity of the perceived threat as animals gather further information. If the physiological response alone had been assessed, this moderated response may not have been evident, and in terms of wildlife management, vital information would have been lost.
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Affiliation(s)
- Loren L Fardell
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia.
| | - Miguel A Bedoya-Pérez
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia.,School of Psychology, The University of Sydney, Sydney, New South Wales, 2006, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Christopher R Dickman
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Mathew S Crowther
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Chris R Pavey
- CSIRO, Land and Water, PMB 44, Winnellie, Northern Territory, 0822, Australia
| | - Edward J Narayan
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland, Australia
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15
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Navarro-Castilla Á, Garrido M, Hawlena H, Barja I. Non-Invasive Monitoring of Adrenocortical Activity in Three Sympatric Desert Gerbil Species. Animals (Basel) 2021; 11:ani11010075. [PMID: 33406630 PMCID: PMC7824156 DOI: 10.3390/ani11010075] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 02/06/2023] Open
Abstract
Simple Summary In this era, characterized by remarkable anthropogenic impacts on wildlife, it is crucial to monitor the health of wild animal populations while minimizing the interference to them. To this end, for a better understanding of the eco-physiology of wild animals, the adrenocortical activity can be non-invasively evaluated by measuring glucocorticoid metabolites excreted in feces. However, to ensure that the endocrine information is reliable, the experimental assays should be first validated and the causes for the major variability among individuals should be considered. Here we validated an enzyme immunoassay for measuring fecal corticosterone metabolites (FCM) in three wild gerbil species and emphasized the differences among them. These are endangered species, which play a key role in psammophilic communities, and provide a model system for various aspects in ecology. Thus, this work constitutes the first step toward using the FCMs of these species as indicators for individual and community stress. Abstract The study of the endocrine status can be useful to understand wildlife responses to the changing environment. Here, we validated an enzyme immunoassay (EIA) to non-invasively monitor adrenocortical activity by measuring fecal corticosterone metabolites (FCM) in three sympatric gerbil species (Gerbillus andersoni, G. gerbillus and G. pyramidum) from the Northwestern Negev Desert’s sands (Israel). Animals included into treatment groups were injected with adrenocorticotropic hormone (ACTH) to stimulate adrenocortical activity, while control groups received a saline solution. Feces were collected at different intervals and FCM were quantified by an EIA. Basal FCM levels were similar in the three species. The ACTH effect was evidenced, but the time of FCM peak concentrations appearance differed between the species (6–24 h post-injection). Furthermore, FCM peak values were observed sooner in G. andersoni females than in males (6 h and 18 h post-injection, respectively). G. andersoni and G. gerbillus males in control groups also increased FCM levels (18 h and 48 h post-injection, respectively). Despite the small sample sizes, our results confirmed the EIA suitability for analyzing FCM in these species as a reliable indicator of the adrenocortical activity. This study also revealed that close species, and individuals within a species, can respond differently to the same stressor.
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Affiliation(s)
- Álvaro Navarro-Castilla
- Etho-Physiology Group, Unit of Zoology, Department of Biology, Faculty of Sciences, Autonomous University of Madrid, 28049 Madrid, Spain;
- Correspondence:
| | - Mario Garrido
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 849900, Israel;
| | - Hadas Hawlena
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 849900, Israel;
| | - Isabel Barja
- Etho-Physiology Group, Unit of Zoology, Department of Biology, Faculty of Sciences, Autonomous University of Madrid, 28049 Madrid, Spain;
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Autonomous University of Madrid, C/Darwin 2, 28049 Madrid, Spain
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16
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Wilson AE, Kearney S, Wismer D, Macbeth B, Stenhouse G, Coops NC, Janz DM. Population‐level monitoring of stress in grizzly bears between 2004 and 2014. Ecosphere 2020. [DOI: 10.1002/ecs2.3181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Abbey E. Wilson
- Department of Veterinary Biomedical Sciences University of Saskatchewan 44 Campus Drive Saskatoon SaskatchewanS7N 5B3Canada
| | - Sean Kearney
- Department of Forest Resource Management University of British Columbia 2424 Main Mall Vancouver British ColumbiaV6T 1Z4Canada
| | - Dan Wismer
- Grizzly Bear Program Foothills Research Institute 1176 Switzer Drive Hinton AlbertaT7V 1V3Canada
| | - Bryan Macbeth
- British Columbia Ministry of Forests, Lands, Natural Resource Operations, and Rural Development 2080 Labieux Road Nanaimo British ColumbiaV9T 6J9Canada
| | - Gordon Stenhouse
- Grizzly Bear Program Foothills Research Institute 1176 Switzer Drive Hinton AlbertaT7V 1V3Canada
| | - Nicholas C. Coops
- Department of Forest Resource Management University of British Columbia 2424 Main Mall Vancouver British ColumbiaV6T 1Z4Canada
| | - David M. Janz
- Department of Veterinary Biomedical Sciences University of Saskatchewan 44 Campus Drive Saskatoon SaskatchewanS7N 5B3Canada
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17
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Grant AR, Baldan D, Kimball MG, Malisch JL, Ouyang JQ. Across time and space: Hormonal variation across temporal and spatial scales in relation to nesting success. Gen Comp Endocrinol 2020; 292:113462. [PMID: 32171744 PMCID: PMC7187986 DOI: 10.1016/j.ygcen.2020.113462] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 02/16/2020] [Accepted: 03/10/2020] [Indexed: 12/30/2022]
Abstract
There is a renewed interest in investigating individual variation in hormone levels in relation to fitness metrics, as hormones act as mediators of life-history trade-offs. Hormone concentrations, however, are labile, responding to both internal and external stimuli, so the relationship between hormones and fitness can be non-consistent. One explanation of this inconsistent relationship is that a single hormone sample may not be representative of individual phenotypes in a free-living species. We addressed this issue by repeatedly sampling a free-living population of mountain white-crowned sparrows, Zonotrichia leucophrys oriantha, for baseline and stress-induced corticosterone (cort) and testosterone (T) across different stages of the breeding season. We measured (co)variation using three different methods, taking into account inter- and intra-individual variances, to determine whether hormone levels and the stress response are repeatable. We documented the temporal (over 3 months) and spatial (home-range) variation of individual hormone phenotypes and investigated how these components related to nesting success. At the population level, we found significant repeatability in male stress-induced cort concentrations but no repeatability in male or female baseline cort or male T concentrations. Using a new metric of intra-individual variance focusing on the stress response (profile repeatability), we found a wide range of variance scores, with most individuals showing high variation in their stress response. Similarly, we found a low level of repeatability of the reaction norm intercept and slope for the stress response across different life-history stages. Males with higher concentrations of stress-induced cort had more central home-ranges. Males with higher body condition had larger home-ranges; however, home-range size did not relate to male hormone concentrations or nesting success. We also did not find any significant relationship between variation in hormone levels and nesting success. We recommend that future studies combine both physiological and environmental components to better understand the relationship between hormones and fitness.
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Affiliation(s)
- Avery R Grant
- Department of Biology, University of Nevada, Reno, Reno, NV, USA.
| | - Davide Baldan
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Melanie G Kimball
- Department of Biology, St. Mary's College of Maryland, St. Marys City, MD, USA
| | - Jessica L Malisch
- Department of Biology, St. Mary's College of Maryland, St. Marys City, MD, USA
| | - Jenny Q Ouyang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
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18
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Hernández MC, Navarro-Castilla Á, Piñeiro A, Silván G, Illera JC, Barja I. Are Baseline Glucocorticoid Levels Linked to Aggressive Behaviour in Wild Wood Mice? POLISH JOURNAL OF ECOLOGY 2020. [DOI: 10.3161/15052249pje2020.68.1.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Maria Carmen Hernández
- Unidad Zoología, Departamento de Biología, Universidad Autónoma de Madrid. C/Darwin 2, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Álvaro Navarro-Castilla
- Unidad Zoología, Departamento de Biología, Universidad Autónoma de Madrid. C/Darwin 2, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Ana Piñeiro
- Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago de Chile, Chile
| | - Gema Silván
- Departamento de Fisiología (Fisiología Animal), Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Juan Carlos Illera
- Departamento de Fisiología (Fisiología Animal), Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Isabel Barja
- Unidad Zoología, Departamento de Biología, Universidad Autónoma de Madrid. C/Darwin 2, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
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19
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Shieh KR, Yang SC. Formosan wood mice ( Apodemus semotus) exhibit more exploratory behaviors and central dopaminergic activities than C57BL/6 mice in the open field test. CHINESE J PHYSIOL 2020; 63:27-34. [PMID: 32056984 DOI: 10.4103/cjp.cjp_47_19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Three-quarters of the lands in Taiwan are over 1000 m above sea level. Formosan wood mice (Apodemus semotus), also called Taiwanese field mice, are largely found at altitudes of 1400 ~ 3700 m and are the dominant rodents in these areas. Notably, Formosan wood mice show high levels of exploratory behaviors, not only in the wild but also in laboratory situations. Therefore, in this study, we examined the behavioral responses and central dopaminergic activities of male C57BL/6J mice and Formosan wood mice in the open field test. Dopamine and its major metabolite 3,4-dihydroxyphenylacetic acid were used as indices of dopaminergic activities. Formosan wood mice showed higher levels of exploration and locomotor activity than C57BL/6J mice in the open field test. Higher central dopaminergic activities in the nucleus accumbens, striatum, and medial prefrontal cortex were found in Formosan wood mice than in C57BL/6J mice in the open field test. Higher levels of locomotion and central dopaminergic activities in Formosan wood mice were consistent after two exposures to the open field test; however, dramatic decreases in levels of locomotion and central dopaminergic activities in C57BL/6J mice were found after two exposures to the open field test. The present study found that Formosan wood mice exhibited higher levels of locomotor activity and exploration and central dopaminergic activities than C57BL/6J mice after one or two exposures to the open field test.
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Affiliation(s)
- Kun-Ruey Shieh
- Department of Physiology, Tzu Chi University, Hualien, Taiwan
| | - Shu-Chuan Yang
- Holistic Education Center, Tzu Chi University of Science and Technology, Hualien, Taiwan
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20
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When food access is challenging: evidence of wood mice ability to balance energy budget under predation risk and physiological stress reactions. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2756-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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The role of steroid hormones and individual traits in food intake in the wood mouse (Apodemus sylvaticus). Naturwissenschaften 2019; 106:36. [PMID: 31203436 DOI: 10.1007/s00114-019-1628-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 10/26/2022]
Abstract
Availability of food resources affects animal survival and reproduction. Thus, coping with changes in food availability is one of the most crucial behavioural and physiological processes in wildlife. Food intake is a key concept in animal ecology that is directly conditioned by food quality and abundance or diet choice, but may also vary according to individual-related factors (e.g. foraging behaviours, social rank or energy-demanding periods) and the influence of the endocrine system on energy metabolism. Here, we studied food intake in relation to individual characteristics (sex, breeding condition and age) and whether steroid hormones (testosterone and corticosterone metabolites) mediate food intake in wild wood mouse (Apodemus sylvaticus). Field work was carried out in February-March 2014 in Monte de Valdelatas (Madrid, Spain). Wood mice were live-trapped for 10 consecutive days in four independent plots. Traps were baited with 4 g of toasted corn and food intake was calculated by subtracting the remaining bait found inside traps. Fresh faecal samples from 130 different wood mice were collected and faecal testosterone and corticosterone metabolites (FTM and FCM, respectively) were analysed by enzyme immunoassays. Food intake was higher in females than males, probably due to greater energy requirements. Non-breeders and young individuals also showed a higher food intake. These individuals usually hold a lower social rank which is associated to limited food resources because of dominants; thus, increased food intake may be a result of freely exploit food bait inside traps while avoiding risky competition. In addition, food intake negatively correlated with FTM levels and positively with FCM levels indicating that both hormones have an active role mediating food intake in the wood mouse. Our data suggest that food intake is a function of both individual traits and the endocrine system that accordingly respond throughout different energy-demanding periods.
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22
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Shieh KR, Yang SC. Exploratory and agile behaviors with central dopaminergic activities in open field tests in Formosan wood mice (Apodemus semotus). J Exp Biol 2019; 222:jeb.199356. [DOI: 10.1242/jeb.199356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/19/2019] [Indexed: 12/22/2022]
Abstract
Taiwan is a mountainous island, and nearly 75% of its lands are 1000 m above sea level. Formosan wood mice, Apodemus semotus, are endemic rodents and are broadly distributed at altitudes between 1400 m and 3700 m in Taiwan. Interestingly, Formosan wood mice show similar locomotor activity in the laboratory as they do in the wild. Hence, we are interested in studying whether exploratory behaviors and central dopaminergic activity are changed in the open field test. We used male C57BL/6J mice as the control, comparing their behavioral responses in the open field, step-down inhibitory avoidance discrimination and novel object recognition tests with those of male Formosan wood mice. We also examined dopamine and its major metabolite 3,4-dihydroxyphenylacetic acid in the medial prefrontal cortex, striatum and nucleus accumbens. In open field tests, Formosan wood mice revealed higher levels of locomotion and exploration than C57BL/6J mice. Learning and memory performance in the novel object recognition test was similar in both Formosan wood mice and C57BL/6J mice, but more agile responses in the inhibitory avoidance discrimination task were found in Formosan wood mice. There was no difference in behavioral responses in the open field test between new second-generation Formosan wood mice and Formosan wood mice that were inbred for more than ten generations. After repeated exposure to the open field test, high levels of locomotion and exploration as well as central dopaminergic activities were markedly persistent in Formosan wood mice, but these activities were significantly reduced in C57BL/6J mice. Diazepam (anxiolytic) treatment reduced the higher exploratory activity and central dopaminergic activities in Formosan wood mice, but this treatment had no effect in C57BL/6J mice. This study provides comparative findings, as two phylogenetically related species showed differences in behavioral responses.
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Affiliation(s)
- Kun-Ruey Shieh
- Department of Physiology, Tzu Chi University, Hualien 970, Taiwan
| | - Shu-Chuan Yang
- Holistic Education Center, Tzu Chi University of Science and Technology, Hualien 970, Taiwan
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23
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Hernández MC, Navarro-Castilla Á, Planillo A, Sánchez-González B, Barja I. The landscape of fear: Why some free-ranging rodents choose repeated live-trapping over predation risk and how it is associated with the physiological stress response. Behav Processes 2018; 157:125-132. [PMID: 30266620 DOI: 10.1016/j.beproc.2018.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 09/17/2018] [Accepted: 09/21/2018] [Indexed: 12/27/2022]
Abstract
Live trapping is an essential element of field ecological studies. However, the act of trapping provides two types of conditional benefits (food from the bait when hungry, and refuge from a predator when threatened) against one type of drawback (confinement). Our understanding of how animals assess the two benefits against the lone risk determines how we interpret classic field studies in chemical ecology and wildlife management. Here, we studied wood mice responses to these risks and rewards of field trapping by examining experience through recapture and faecal corticosterone metabolites (FCM) as a physiological response indicator. Wood mice were live-trapped in two different plots subjected to two distinct phases: phase 1, absence of predator cues, and phase 2, in which traps were treated with red fox faeces. During phase 1, the recapture percentage was lower indicating that mice avoided traps while FCM levels in recaptured mice were higher. On the contrary, during phase 2, despite the total number of captures was lower we found an increase in the recapture percentage and FCM levels did not increase in recaptured mice. Our results suggest that under increased risk perception traps could be likely considered as a suitable shelter and thus, for some individuals the benefits of traps may outweigh their risks. In addition, we discovered that the effects of combining two stressors do not result in the addition of the response originated by each factor separately.
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Affiliation(s)
- M C Hernández
- Department of Biology, Universidad Autónoma de Madrid, C/ Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain.
| | - Á Navarro-Castilla
- Department of Biology, Universidad Autónoma de Madrid, C/ Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
| | - A Planillo
- Terrestrial Ecology Group (TEG), Department of Ecology, Universidad Autónoma de Madrid, C. Darwin 2, 28049, Cantoblanco, Madrid, Spain; Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
| | - B Sánchez-González
- Department of Biology, Universidad Autónoma de Madrid, C/ Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
| | - I Barja
- Department of Biology, Universidad Autónoma de Madrid, C/ Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
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