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Muise KA, Dzal YA, Fletcher QE, Willis CKR. Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity. J Exp Biol 2024; 227:jeb246699. [PMID: 38353043 PMCID: PMC10949064 DOI: 10.1242/jeb.246699] [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: 09/25/2023] [Accepted: 02/07/2024] [Indexed: 03/08/2024]
Abstract
Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.
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Affiliation(s)
- Kristina A. Muise
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Yvonne A. Dzal
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Quinn E. Fletcher
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
| | - Craig K. R. Willis
- Department of Biology, University of Winnipeg, 515 Portage Ave, Winnipeg, MN, CanadaR3B 2E9
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Vanderwolf K, Kyle C, Davy C. A review of sebum in mammals in relation to skin diseases, skin function, and the skin microbiome. PeerJ 2023; 11:e16680. [PMID: 38144187 PMCID: PMC10740688 DOI: 10.7717/peerj.16680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Diseases vary among and within species but the causes of this variation can be unclear. Immune responses are an important driver of disease variation, but mechanisms on how the body resists pathogen establishment before activation of immune responses are understudied. Skin surfaces of mammals are the first line of defense against abiotic stressors and pathogens, and skin attributes such as pH, microbiomes, and lipids influence disease outcomes. Sebaceous glands produce sebum composed of multiple types of lipids with species-specific compositions. Sebum affects skin barrier function by contributing to minimizing water loss, supporting thermoregulation, protecting against pathogens, and preventing UV-induced damage. Sebum also affects skin microbiome composition both via its antimicrobial properties, and by providing potential nutrient sources. Intra- and interspecific variation in sebum composition influences skin disease outcomes in humans and domestic mammal species but is not well-characterized in wildlife. We synthesized knowledge on sebum function in mammals in relation to skin diseases and the skin microbiome. We found that sebum composition was described for only 29 live, wild mammalian species. Sebum is important in dermatophilosis, various forms of dermatitis, demodicosis, and potentially white-nose syndrome. Sebum composition likely affects disease susceptibility, as lipid components can have antimicrobial functions against specific pathogens. It is unclear why sebum composition is species-specific, but both phylogeny and environmental effects may drive differences. Our review illustrates the role of mammal sebum function and influence on skin microbes in the context of skin diseases, providing a baseline for future studies to elucidate mechanisms of disease resistance beyond immune responses.
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Affiliation(s)
- Karen Vanderwolf
- Department of Environmental and Life Sciences, Trent University, Peterborough, Ontario, Canada
| | - Christopher Kyle
- Forensic Science Department, Trent University, Peterborough, Ontario, Canada
- Natural Resources DNA Profiling and Forensics Center, Trent University, Peterborough, Ontario, Canada
| | - Christina Davy
- Department of Environmental and Life Sciences, Trent University, Peterborough, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
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3
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Reher S, Rabarison H, Nowack J, Dausmann KH. Limited Physiological Compensation in Response to an Acute Microclimate Change in a Malagasy Bat. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.779381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rapid environmental changes are challenging for endothermic species because they have direct and immediate impacts on their physiology by affecting microclimate and fundamental resource availability. Physiological flexibility can compensate for certain ecological perturbations, but our basic understanding of how species function in a given habitat and the extent of their adaptive scope is limited. Here we studied the effect of acute, experimental microclimate change on the thermal physiology of two populations of the widespread Malagasy bat, Macronycteris commersoni. Populations of this species are found roosting under contrasting conditions, i.e., in a constant hot and humid cave or below foliage unprotected from fluctuations in ambient conditions. We exposed free-ranging individuals of each population to the respective opposite condition and thus to novel microclimate within an ecologically realistic scope while measuring metabolic rate and skin temperature. Cave bats in forest setting had a limited capacity to maintain euthermia to the point that two individuals became hypothermic when ambient temperature dropped below their commonly experienced cave temperature. Forest bats on the other hand, had difficulties to dissipate heat in the humid cave set-up. The response to heat, however, was surprisingly uniform and all bats entered torpor combined with hyperthermia at temperatures exceeding their thermoneutral zone. Thus, while we observed potential for flexible compensation of heat through “hot” torpor, both populations showed patterns suggestive of limited potential to cope with acute microclimate changes deviating from their typically occupied roosts. Our study emphasizes that intraspecific variation among populations could be misleading when assessing species’ adaptive scopes, as variation may arise from genetic adaptation, developmental plasticity or phenotypic flexibility, all of which allow for compensatory responses at differing time scales. Disentangling these mechanisms and identifying the basis of variation is vital to make accurate predictions of species’ chances for persisting in ever rapidly changing habitats and climates.
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Reher S, Rabarison H, Montero BK, Turner JM, Dausmann KH. Disparate roost sites drive intraspecific physiological variation in a Malagasy bat. Oecologia 2021; 198:35-52. [PMID: 34951669 PMCID: PMC8803705 DOI: 10.1007/s00442-021-05088-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/21/2021] [Indexed: 11/07/2022]
Abstract
Many species are widely distributed and individual populations can experience vastly different environmental conditions over seasonal and geographic scales. With such a broad ecological reality, datasets with limited spatial and temporal resolution may not accurately represent a species and could lead to poorly informed management decisions. Because physiological flexibility can help species tolerate environmental variation, we studied the physiological responses of two separate populations of Macronycteris commersoni, a bat widespread across Madagascar, in contrasting seasons. The populations roost under the following dissimilar conditions: either a hot, well-buffered cave or within open foliage, unprotected from the local weather. We found that flexible torpor patterns, used in response to prevailing ambient temperature and relative humidity, were central to keeping energy budgets balanced in both populations. While bats’ metabolic rate during torpor and rest did not differ between roosts, adjusting torpor frequency, duration and timing helped bats maintain body condition. Interestingly, the exposed forest roost induced extensive use of torpor, which exceeded the torpor frequency of overwintering bats that stayed in the cave for months and consequently minimised daytime resting energy expenditure in the forest. Our current understanding of intraspecific physiological variation is limited and physiological traits are often considered to be fixed. The results of our study therefore highlight the need for examining species at broad environmental scales to avoid underestimating a species’ full capacity for withstanding environmental variation, especially in the face of ongoing, disruptive human interference in natural habitats.
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Affiliation(s)
- Stephanie Reher
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany.
| | - Hajatiana Rabarison
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany.,Mention Zoologie et Biodiversité Animale, Faculté des Sciences, Université d'Antananarivo, Antananarivo, Madagascar
| | - B Karina Montero
- Biodiversity Research Institute, Campus of Mieres, Universidad de Oviedo, Mieres, Spain.,Animal Ecology and Conservation, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - James M Turner
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, South Lanarkshire, Scotland, UK
| | - Kathrin H Dausmann
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
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Paces B, Waringer BM, Domer A, Burns D, Zvik Y, Wojciechowski MS, Shochat E, Sapir N, Maggini I. Evaporative Water Loss and Stopover Behavior in Three Passerine Bird Species During Autumn Migration. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.704676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Migratory birds are often not specifically adapted to arid conditions, yet several species travel across deserts during their journeys, and often have more or less short stopovers there. We investigated whether differences in thermoregulatory mechanisms, specifically evaporative cooling, explain the different behavior of three passerine species while stopping over in the Negev desert, Israel. We measured cutaneous water loss (CWL) under ambient conditions and the temperature of panting onset in an experimental setup. In addition, we performed behavioral observations of birds at a stopover site where we manipulated water availability. Blackcaps had slightly higher CWL at relatively low temperatures than Willow Warblers and Lesser Whitethroats. When considered relative to total body mass, however, Willow Warblers had the highest CWL of the three species. Blackcaps started panting at lower ambient temperature than the other two species. Taken together, these results suggest that Willow Warblers are the most efficient in cooling their body, possibly with the cost of needing to regain water by actively foraging during their staging. Lesser Whitethroats had a similar pattern, which was reflected in their slightly higher levels of activity and drinking behavior when water was available. However, in general the behavior of migratory species was not affected by the availability of water, and they were observed drinking rather rarely. Our results indicate that differences in thermoregulatory mechanisms might be at the basis of the evolution of different stopover strategies of migratory birds while crossing arid areas such as deserts.
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Hlubeň M, Kratochvíl L, Gvoždík L, Starostová Z. Ontogeny, phylogeny and mechanisms of adaptive changes in evaporative water loss in geckos. J Evol Biol 2021; 34:1290-1301. [PMID: 34131979 DOI: 10.1111/jeb.13891] [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: 03/30/2021] [Revised: 05/23/2021] [Accepted: 06/01/2021] [Indexed: 11/28/2022]
Abstract
Body size dependence of metabolic rate, body surface and scale morphology complicate disentangling the contribution of these characteristics to adaptive changes in total evaporative water loss (TEWL) of reptiles. To separate adaptive changes from size-related dependence, we compared intra- and interspecific scaling of several candidate traits in eyelid geckos (Eublepharidae), a group exhibiting large variation in body size and TEWL. The intraspecific allometry of TEWL of a eublepharid species fits the geometric surface-mass relationship. However, evolutionary shifts to both higher and lower evaporation were strongly correlated with habitat aridity and cannot be explained by shifts in body size alone. The intraspecific allometry of standard metabolic rate is nearly the same as the interspecific allometry. Unlike for mammals and birds, this pattern rules out respiratory water loss as a driver of the adaptive changes in TEWL among eublepharids. Scale morphology was independent of TEWL variation as well, but the correlation between cutaneous water loss and TEWL suggests a crucial role of skin permeability in adaptation to habitat aridity. Our analyses demonstrate how powerful a comparison between intra- and interspecific allometries can be for detecting body size-dependent mechanisms of adaptive changes in ecophysiological traits correlated with body size.
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Affiliation(s)
- Martin Hlubeň
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lumír Gvoždík
- Czech Academy of Sciences, Institute of Vertebrate Biology, Brno, Czech Republic
| | - Zuzana Starostová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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Pannkuk EL, Dorville NASY, Dzal YA, Fletcher QE, Norquay KJO, Willis CKR, Fornace AJ, Laiakis EC. Hepatic lipid signatures of little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) at early stages of white-nose syndrome. Sci Rep 2021; 11:11581. [PMID: 34078939 PMCID: PMC8172879 DOI: 10.1038/s41598-021-90828-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 05/12/2021] [Indexed: 11/21/2022] Open
Abstract
White-nose syndrome (WNS) is an emergent wildlife fungal disease of cave-dwelling, hibernating bats that has led to unprecedented mortalities throughout North America. A primary factor in WNS-associated bat mortality includes increased arousals from torpor and premature fat depletion during winter months. Details of species and sex-specific changes in lipid metabolism during WNS are poorly understood and may play an important role in the pathophysiology of the disease. Given the likely role of fat metabolism in WNS and the fact that the liver plays a crucial role in fatty acid distribution and lipid storage, we assessed hepatic lipid signatures of little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) at an early stage of infection with the etiological agent, Pseudogymnoascus destructans (Pd). Differences in lipid profiles were detected at the species and sex level in the sham-inoculated treatment, most strikingly in higher hepatic triacylglyceride (TG) levels in E. fuscus females compared to males. Interestingly, several dominant TGs (storage lipids) decreased dramatically after Pd infection in both female M. lucifugus and E. fuscus. Increases in hepatic glycerophospholipid (structural lipid) levels were only observed in M. lucifugus, including two phosphatidylcholines (PC [32:1], PC [42:6]) and one phosphatidylglycerol (PG [34:1]). These results suggest that even at early stages of WNS, changes in hepatic lipid mobilization may occur and be species and sex specific. As pre-hibernation lipid reserves may aid in bat persistence and survival during WNS, these early perturbations to lipid metabolism could have important implications for management responses that aid in pre-hibernation fat storage.
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Affiliation(s)
- Evan L Pannkuk
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, 20057, USA.
| | - Nicole A S-Y Dorville
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, Winnipeg, MB, Canada
| | - Yvonne A Dzal
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, Winnipeg, MB, Canada
| | - Quinn E Fletcher
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, Winnipeg, MB, Canada
| | - Kaleigh J O Norquay
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, Winnipeg, MB, Canada
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR), University of Winnipeg, Winnipeg, MB, Canada.
| | - Albert J Fornace
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, 20057, USA
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Evagelia C Laiakis
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, 20057, USA
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC, 20057, USA
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8
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Weidler JM, Lutterschmidt WI. Nature or Nurture: Can Prey-Based Diets Influence Species-Specific Physiological Performance Traits of Epidermal Lipid Content and Cutaneous Water Loss? Integr Org Biol 2021; 3:obaa043. [PMID: 33791586 PMCID: PMC7905159 DOI: 10.1093/iob/obaa043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Epidermal lipids serve as the primary barrier to cutaneous water loss (CWL) and play a significant role in water conservation and homeostasis. Previous studies have shown the correlation between increased aridity of habitats and the amount of epidermal lipids among species. Generally, increased amounts of epidermal lipids lower skin permeability. Species-specific differences in CWL and prey preferences between two sympatric snake species, the Northern Cottonmouth (Agkistrodon piscivorus) and the Eastern Copperhead (Agkistrodon contortrix), motivated us to question if prey-base can result in these observed species-specific differences in CWL. We experimentally controlled the diets for a captive colony of Northern Cottonmouths (A. piscivorus) by feeding either fish (Notemigonus crysoleucas) or mice (Mus musculus) to investigate if diet can affect the quantity and quality of epidermal lipids and the rates of CWL. Snakes fed mice gained consistently more mass, but diet treatments did not affect growth rate. We found no significant differences in quantitative lipid content or rates of CWL between diet treatments. An analysis for qualitative lipid content using infrared spectrophotometry also showed no diet effect, thus suggesting that lipid content and CWL are strong species-specific physiological performance traits not influenced by recent dietary history. While there is some evidence that epidermal permeability may be variable under certain environmental conditions (e.g., humidity), our findings show that diet has no effect and that a shift in prey preference may not influence or enhance physiological performance for decreasing CWL.
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Affiliation(s)
- J M Weidler
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341, USA
- South Dakota Bureau of Information and Telecommunications, Pierre, SD 57501, USA
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9
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Cooper CE, Withers PC. Two lines of evidence for physiological control of insensible evaporative water loss by a tiny marsupial. J Exp Biol 2020; 223:jeb234450. [PMID: 33097571 DOI: 10.1242/jeb.234450] [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: 08/01/2020] [Accepted: 10/16/2020] [Indexed: 11/20/2022]
Abstract
We present two independent lines of evidence that a tiny dasyurid marsupial, the ningaui (Ningaui spp.), has acute physiological control of its insensible evaporative water loss below and within thermoneutrality. Perturbation of the driving force for evaporation by varying relative humidity, and therefore the water vapour pressure deficit between the animal and the ambient air, does not have the expected physical effect on evaporative water loss. Exposure to a helox atmosphere also does not have the expected physical effect of increasing evaporative water loss for live ningauis (despite it having the expected effect of increasing heat loss for live ningauis), but increases evaporative water loss for dead ningauis. We discuss the relative advantages and disadvantages of both experimental approaches for demonstrating physiological control of insensible evaporative water loss. An appreciation of physiological control is important because insensible evaporative water loss contributes to both water and heat balance, is clearly under environmental selection pressure, and potentially impacts the distribution of endotherms and their response to environmental change.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6845, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Philip Carew Withers
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6845, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
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10
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Gearhart C, Adams AM, Pinshow B, Korine C. Evaporative water loss in Kuhl's pipistrelles declines along an environmental gradient, from mesic to hyperarid. Comp Biochem Physiol A Mol Integr Physiol 2019; 240:110587. [PMID: 31655113 DOI: 10.1016/j.cbpa.2019.110587] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 12/11/2022]
Abstract
Intraspecific variation in animal energy and water balances may play an important role in local adaptation of populations to specific habitats such as deserts. We examined Kuhl's pipistrelle (Pipistrellus kuhlii), a common bat in Israel that ranges in distribution from mesic Mediterranean to hyperarid desert habitats, for intraspecific differences in metabolic rate (MR) and evaporative water loss (EWL) among populations along a climatic gradient. We tested the prediction that EWL, especially at high ambient temperatures is lower in Kuhl's pipistrelles from desert habitats than from mesic habitats. We measured MR and total evaporative water loss (TEWL) at four ambient temperatures (10 °C, 20 °C, 30 °C and 35 °C) in three groups of bats using open-flow respirometry. We fitted the bats with a mask to separate cutaneous water loss (CWL) from respiratory water loss (RWL) at 35 °C. At 35 °C, mean TEWL in the southernmost group, from the hyperarid location, was significantly lower than in the other two groups, with no apparent difference in mean MR. The source of difference TEWL was that the southern group had significantly lower CWL than the other two groups; RWL did not differ among them. This suggests that there are mechanisms that reduce EWL from the skin of the bats; a likely candidate is modification of the lipids in the outer layer of the dermis that make the skin possibly less permeable to water as has been described in birds and a few other species of bat.
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Affiliation(s)
- Cassandra Gearhart
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Amanda M Adams
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel; Department of Biological Sciences, Fort Hays State University, Hays, Kansas 67601, USA
| | - Berry Pinshow
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel.
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Hernández-Jerez A, Adriaanse P, Aldrich A, Berny P, Coja T, Duquesne S, Gimsing AL, Marina M, Millet M, Pelkonen O, Pieper S, Tiktak A, Tzoulaki I, Widenfalk A, Wolterink G, Russo D, Streissl F, Topping C. Scientific statement on the coverage of bats by the current pesticide risk assessment for birds and mammals. EFSA J 2019; 17:e05758. [PMID: 32626374 PMCID: PMC7009170 DOI: 10.2903/j.efsa.2019.5758] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bats are an important group of mammals, frequently foraging in farmland and potentially exposed to pesticides. This statement considers whether the current risk assessment performed for birds and ground dwelling mammals exposed to pesticides is also protective of bats. Three main issues were addressed. Firstly, whether bats are toxicologically more or less sensitive than the most sensitive birds and mammals. Secondly, whether oral exposure of bats to pesticides is greater or lower than in ground dwelling mammals and birds. Thirdly, whether there are other important exposure routes relevant to bats. A large variation in toxicological sensitivity and no relationship between sensitivity of bats and bird or mammal test-species to pesticides could be found. In addition, bats have unique traits, such as echolocation and torpor which can be adversely affected by exposure to pesticides and which are not covered by the endpoints currently selected for wild mammal risk assessment. The current exposure assessment methodology was used for oral exposure and adapted to bats using bat-specific parameters. For oral exposure, it was concluded that for most standard risk assessment scenarios the current approach did not cover exposure of bats to pesticide residues in food. Calculations of potential dermal exposure for bats foraging during spraying operations suggest that this may be a very important exposure route. Dermal routes of exposure should be combined with inhalation and oral exposure. Based on the evidence compiled, the Panel concludes that bats are not adequately covered by the current risk assessment approach, and that there is a need to develop a bat-specific risk assessment scheme. In general, there was scarcity of data to assess the risks for bat exposed to pesticides. Recommendations for research are made, including identification of alternatives to laboratory testing of bats to assess toxicological effects.
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12
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Oufiero CE, Van Sant MJ. Variation and repeatability of cutaneous water loss and skin resistance in relation to temperature and diel variation in the lizard Sceloporus consobrinus. J Comp Physiol B 2018; 188:671-681. [PMID: 29619510 DOI: 10.1007/s00360-018-1156-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/09/2018] [Accepted: 03/21/2018] [Indexed: 11/24/2022]
Abstract
Variation in rates of water loss has been proposed to be an important mechanism in the survival of terrestrial organisms, as high rates of water loss in desiccating environments may lead to hydric stress and death. Vapor density deficit, the driving force for evaporative water loss, increases exponentially as temperature increases. Acute temperature changes may be the result of daily behavioral thermoregulation of ectotherms, which may influence the among individual variation rates of water loss. The goals of this study were to determine (1) how rates of cutaneous water loss (CWL) and skin resistance (Rs) are affected by acute temperature acclimation, (2) how rates of CWL and Rs vary throughout the day allowing behavioral thermoregulation and (3) the repeatability of CWL and Rs within and among sampling periods. We measured CWL and calculated skin resistance (Rs) of 30 male Sceloporus consobrinus lizards across three summers. We measured CWL on the dorsal and ventral surface of each lizard at 23 °C followed by measurements at 35 °C, and three separate times throughout the day. We found a significant increase in Rs and decrease in CWL at increased acclimation temperatures (35 °C), a significant difference in CWL and Rs throughout the day allowing behavioral thermoregulation, and support for the repeatability of CWL and Rs. Our results demonstrate variability in CWL and Rs in relation to temperature acclimation and thermoregulation, but mixed evidence for repeatability across treatments. Our results suggest other factors, such as peripheral blood flow, may be influencing the inter-individual variation in CWL and Rs.
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Affiliation(s)
| | - Matthew J Van Sant
- Department of Agriculture, Biological and Health Sciences, Cameron University, Lawton, OK, 73505, USA
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13
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Ben-Hamo M, Muñoz-Garcia A, Larrain P, Pinshow B, Korine C, Williams JB. The cutaneous lipid composition of bat wing and tail membranes: a case of convergent evolution with birds. Proc Biol Sci 2017; 283:rspb.2016.0636. [PMID: 27335420 DOI: 10.1098/rspb.2016.0636] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/20/2016] [Indexed: 11/12/2022] Open
Abstract
The water vapour permeability barrier of mammals and birds resides in the stratum corneum (SC), the outermost layer of the epidermis. The molar ratio and molecular arrangement of lipid classes in the SC determine the integrity of this barrier. Increased chain length and polarity of ceramides, the most abundant lipid class in mammalian SC, contribute to tighter packing and thus to reduced cutaneous evaporative water loss (CEWL). However, tighter lipid packing also causes low SC hydration, making it brittle, whereas high hydration softens the skin at the cost of increasing CEWL. Cerebrosides are not present in the mammalian SC; their pathological accumulation occurs in Gaucher's disease, which leads to a dramatic increase in CEWL. However, cerebrosides occur normally in the SC of birds. We tested the hypothesis that cerebrosides are also present in the SC of bats, because they are probably necessary to confer pliability to the skin, a quality needed for flight. We examined the SC lipid composition of four sympatric bat species and found that, as in birds, their SC has substantial cerebroside contents, not associated with a pathological state, indicating convergent evolution between bats and birds.
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Affiliation(s)
- Miriam Ben-Hamo
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Agustí Muñoz-Garcia
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel Department of Evolution, Ecology and Organismal Biology, Ohio State University at Mansfield, Mansfield, OH 44906, USA
| | - Paloma Larrain
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Berry Pinshow
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Joseph B Williams
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210, USA
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McGuire LP, Mayberry HW, Willis CKR. White-nose syndrome increases torpid metabolic rate and evaporative water loss in hibernating bats. Am J Physiol Regul Integr Comp Physiol 2017; 313:R680-R686. [PMID: 28835446 DOI: 10.1152/ajpregu.00058.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/26/2017] [Accepted: 08/21/2017] [Indexed: 01/08/2023]
Abstract
Fungal diseases of wildlife typically manifest as superficial skin infections but can have devastating consequences for host physiology and survival. White-nose syndrome (WNS) is a fungal skin disease that has killed millions of hibernating bats in North America since 2007. Infection with the fungus Pseudogymnoascus destructans causes bats to rewarm too often during hibernation, but the cause of increased arousal rates remains unknown. On the basis of data from studies of captive and free-living bats, two mechanistic models have been proposed to explain disease processes in WNS. Key predictions of both models are that WNS-affected bats will show 1) higher metabolic rates during torpor (TMR) and 2) higher rates of evaporative water loss (EWL). We collected bats from a WNS-negative hibernaculum, inoculated one group with P. destructans, and sham-inoculated a second group as controls. After 4 mo of hibernation, TMR and EWL were measured using respirometry. Both predictions were supported, and our data suggest that infected bats were more affected by variation in ambient humidity than controls. Furthermore, disease severity, as indicated by the area of the wing with UV fluorescence, was positively correlated with EWL, but not TMR. Our results provide the first direct evidence that heightened energy expenditure during torpor and higher EWL independently contribute to WNS pathophysiology, with implications for the design of potential treatments for the disease.
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Affiliation(s)
- Liam P McGuire
- Department of Biology, University of Winnipeg, Winnipeg, Manitoba, Canada; .,Department of Biological Sciences, Texas Tech University, Lubbock, Texas; and
| | - Heather W Mayberry
- Department of Biology, University of Winnipeg, Winnipeg, Manitoba, Canada.,Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Craig K R Willis
- Department of Biology, University of Winnipeg, Winnipeg, Manitoba, Canada
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15
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Klüg-Baerwald BJ, Brigham RM. Hung out to dry? Intraspecific variation in water loss in a hibernating bat. Oecologia 2017; 183:977-985. [PMID: 28213638 DOI: 10.1007/s00442-017-3837-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 02/07/2017] [Indexed: 02/05/2023]
Abstract
Hibernation is a period of water deficit for some small mammals, and humidity strongly influences hibernation patterns. Dry conditions reduce length of torpor bouts, stimulate arousals, and decrease overwinter survival. To mitigate these effects, many small mammals hibernate in near saturated (100% RH) conditions. However, big brown bats (Eptesicus fuscus) hibernate in a wider variety of conditions and tolerate lower humidity than most other bats. To assess arid tolerance in this species, we compared torpid metabolic rates (TMR) and rates of total evaporative water loss (TEWL) between two populations of E. fuscus with differing winter ecologies: one that hibernates in humid karst caves and one that hibernates in relatively dry rock crevices. We used flow-through respirometry to measure TMR and TEWL of bats in humid and dry conditions. Torpid metabolic rates did not differ between populations or with humidity treatments. Rates of TEWL were similar between populations in humid conditions, but higher for cave-hibernating bats than crevice-hibernating bats in dry conditions. Our results suggest that E. fuscus hibernating in arid environments have mechanisms to decrease evaporative water loss that are not evident at more humid sites. Drought tolerance may facilitate the sedentary nature of the species, allowing them to tolerate more variable microclimates during hibernation and thus increasing the availability of overwintering habitat. The ability to survive arid conditions may also lessen the susceptibility of E. fuscus to diseases that affect water balance.
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Affiliation(s)
| | - R Mark Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, Canada
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16
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Muñoz-Garcia A, Larraín P, Ben-Hamo M, Cruz-Neto A, Williams JB, Pinshow B, Korine C. Metabolic rate, evaporative water loss and thermoregulatory state in four species of bats in the Negev desert. Comp Biochem Physiol A Mol Integr Physiol 2015; 191:156-165. [PMID: 26459985 DOI: 10.1016/j.cbpa.2015.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 10/07/2015] [Accepted: 10/07/2015] [Indexed: 10/22/2022]
Abstract
Life in deserts is challenging for bats because of their relatively high energy and water requirements; nevertheless bats thrive in desert environments. We postulated that bats from desert environments have lower metabolic rates (MR) and total evaporative water loss (TEWL) than their mesic counterparts. To test this idea, we measured MR and TEWL of four species of bats, which inhabit the Negev desert in Israel, one species mainly restricted to hyper-arid deserts (Otonycteris hemprichii), two species from semi-desert areas (Eptesicus bottae and Plecotus christii), and one widespread species (Pipistrellus kuhlii). We also measured separately, in the same individuals, the two components of TEWL, respiratory water loss (RWL) and cutaneous evaporative water loss (CEWL), using a mask. In all the species, MR and TEWL were significantly reduced during torpor, the latter being a consequence of reductions in both RWL and CEWL. Then, we evaluated whether MR and TEWL in bats differ according to their geographic distributions, and whether those rates change with Ta and the use of torpor. We did not find significant differences in MR among species, but we found that TEWL was lowest in the species restricted to desert habitats, intermediate in the semi-desert dwelling species, and highest in the widespread species, perhaps a consequence of adaptation to life in deserts. Our results were supported by a subsequent analysis of data collected from the literature on rates of TEWL for 35 bat species from desert and mesic habitats.
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Affiliation(s)
- Agustí Muñoz-Garcia
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel; Department of Evolution, Ecology and Organismal Biology, Ohio State University at Mansfield, Aronoff Lab, 318 W 12th Ave., Columbus, OH 43210, United States.
| | - Paloma Larraín
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Miriam Ben-Hamo
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Ariovaldo Cruz-Neto
- Departamento de Zoologia, IB, Universidade Estadual Paulista, Caixa Postal 199, 13506-900 Rio Claro, São Paulo, Brazil
| | - Joseph B Williams
- Department of Evolution, Ecology and Organismal Biology, Ohio State University at Mansfield, Aronoff Lab, 318 W 12th Ave., Columbus, OH 43210, United States
| | - Berry Pinshow
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
| | - Carmi Korine
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000 Midreshet Ben-Gurion, Israel
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17
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Řezanka T, Viden I, Nováková A, Bandouchová H, Sigler K. Wax Ester Analysis of Bats Suffering from White Nose Syndrome in Europe. Lipids 2015; 50:633-45. [PMID: 25975369 DOI: 10.1007/s11745-015-4027-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/28/2015] [Indexed: 12/22/2022]
Abstract
The composition of wax esters (WE) in the fur of adult greater mouse-eared bats (Myotis myotis), either healthy or suffering from white nose syndrome (WNS) caused by the psychrophilic fungus Pseudogymnoascus destructans, was investigated by high-resolution mass spectrometry analysis in the positive ion mode. Profiling of lipid classes showed that WE are the most abundant lipid class, followed by cholesterol esters, and other lipid classes, e.g., triacylglycerols and phospholipids. WE abundance in non-polar lipids was gender-related, being higher in males than in females; in individuals suffering from WNS, both male and female, it was higher than in healthy counterparts. WE were dominated by species containing 18:1 fatty acids. Fatty alcohols were fully saturated, dominated by species containing 24, 25, or 26 carbon atoms. Two WE species, 18:1/18:0 and 18:1/20:0, were more abundant in healthy bats than in infected ones.
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Affiliation(s)
- Tomáš Řezanka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic,
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18
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Cutaneous Water Loss and Epidermal Lipids in Two Sympatric and Congeneric Pitvipers. J HERPETOL 2014. [DOI: 10.1670/13-116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fatty acid methyl ester profiles of bat wing surface lipids. Lipids 2014; 49:1143-50. [PMID: 25227993 DOI: 10.1007/s11745-014-3951-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/03/2014] [Indexed: 01/19/2023]
Abstract
Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration.
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Pannkuk EL, Gilmore DF, Fuller NW, Savary BJ, Risch TS. Sebaceous lipid profiling of bat integumentary tissues: quantitative analysis of free Fatty acids, monoacylglycerides, squalene, and sterols. Chem Biodivers 2014; 10:2122-32. [PMID: 24327437 DOI: 10.1002/cbdv.201300319] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Indexed: 12/16/2022]
Abstract
White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans and is devastating North American bat populations. Sebaceous lipids secreted from host integumentary tissues are implicated in the initial attachment and recognition of host tissues by pathogenic fungi. We are interested in determining if ratios of lipid classes in sebum can be used as biomarkers to diagnose severity of fungal infection in bats. To first establish lipid compositions in bats, we isolated secreted and integral lipid fractions from the hair and wing tissues of three species: big brown bats (Eptesicus fuscus), Eastern red bats (Lasiurus borealis), and evening bats (Nycticeius humeralis). Sterols, FFAs, MAGs, and squalene were derivatized as trimethylsilyl esters, separated by gas chromatography, and identified by mass spectrometry. Ratios of sterol to squalene in different tissues were determined, and cholesterol as a disease biomarker was assessed. Free sterol was the dominant lipid class of bat integument. Squalene/sterol ratio is highest in wing sebum. Secreted wing lipid contained higher proportions of saturated FFAs and MAGs than integral wing or secreted hair lipid. These compounds are targets for investigating responses of P. destructans to specific host lipid compounds and as biomarkers to diagnose WNS.
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Affiliation(s)
- Evan L Pannkuk
- Graduate Program of Environmental Science, Arkansas State University, P.O. Box 847, State University, AR 72467, USA (phone: +1(870) 972-2007, fax: +1(870) 972-3827).
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21
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Pannkuk EL, McGuire LP, Gilmore DF, Savary BJ, Risch TS. Glycerophospholipid analysis of Eastern red bat (Lasiurus borealis) hair by electrospray ionization tandem mass spectrometry. J Chem Ecol 2014; 40:227-35. [PMID: 24532214 PMCID: PMC4167415 DOI: 10.1007/s10886-014-0388-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 01/20/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
Pilosebaceous units found in the mammalian integument are composed of a hair follicle, the proximal portion of the hair shaft, a sebaceous gland, and the erector pili muscle. Pilosebaceous units release protective oils, or sebum, by holocrine secretion onto skin and hair through rupturing of sebocytes. Sebum is composed largely of polar and neutral lipids including glycerolipids, free fatty acids, sterols, wax esters, sterol esters, and squalene. In addition to these lipid classes, there is a small proportion of ionic/anionic glycerophospholipids (GPs). Composition of GPs on hair is rarely addressed despite their broad biological activities as signaling molecules and membrane stability. Furthermore, knowledge on GP composition in bats is lacking. Bat GP composition is important to document due to GP roles ranging from decreasing drag during migration to interaction with the integumentary microbiome. In this study, we analyzed GP molecular composition with liquid chromatography electrospray ionization tandem mass spectrometry and compared GP content to previous literature. A total of 152 GPs were detected. Broad GP classes identified include lysophosphatidylcholine, phosphatidylcholine (PC), lysophosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidic acid, and phosphatidylglycerol, with PC being the most abundant class. The acyl components were consistent with fatty acid methyl esters and triacylglyceride moieties found in Eastern red bat sebum. Glycerophospholipid proportions of the hair surface were different from a previous study on bat lung surfactants. This study determined the broad class and molecular species of bat sebum GPs that may be used in future ecological studies in vespertilionid bats.
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Affiliation(s)
- Evan L Pannkuk
- Graduate Program of Environmental Science, Arkansas State University, P.O. Box 847, State University, Jonesboro, AR, 72467, USA,
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Russo D, Cistrone L, Jones G. Sensory ecology of water detection by bats: a field experiment. PLoS One 2012; 7:e48144. [PMID: 23133558 PMCID: PMC3483877 DOI: 10.1371/journal.pone.0048144] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 09/19/2012] [Indexed: 12/02/2022] Open
Abstract
Bats face a great risk of dehydration, so sensory mechanisms for water recognition are crucial for their survival. In the laboratory, bats recognized any smooth horizontal surface as water because these provide analogous reflections of echolocation calls. We tested whether bats also approach smooth horizontal surfaces other than water to drink in nature by partly covering watering troughs used by hundreds of bats with a Perspex layer mimicking water. We aimed 1) to confirm that under natural conditions too bats mistake any horizontal smooth surface for water by testing this on large numbers of individuals from a range of species and 2) to assess the occurrence of learning effects. Eleven bat species mistook Perspex for water relying chiefly on echoacoustic information. Using black instead of transparent Perspex did not deter bats from attempting to drink. In Barbastella barbastellus no echolocation differences occurred between bats approaching the water and the Perspex surfaces respectively, confirming that bats perceive water and Perspex to be acoustically similar. The drinking attempt rates at the fake surface were often lower than those recorded in the laboratory: bats then either left the site or moved to the control water surface. This suggests that bats modified their behaviour as soon as the lack of drinking reward had overridden the influence of echoacoustic information. Regardless of which of two adjoining surfaces was covered, bats preferentially approached and attempted to drink from the first surface encountered, probably because they followed a common route, involving spatial memory and perhaps social coordination. Overall, although acoustic recognition itself is stereotyped and its importance in the drinking process overwhelming, our findings point at the role of experience in increasing behavioural flexibility under natural conditions.
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Affiliation(s)
- Danilo Russo
- Laboratorio di Ecologia Applicata, Dipartimento ArBo Pa Ve, Facoltà di Agraria, Università degli Studi di Napoli Federico II Portici, Napoli, Italy, United Kingdom.
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