1
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Lobo JM. Hotter-is-not-better: A study on the thermal response of a winter active and nocturnal beetle. JOURNAL OF INSECT PHYSIOLOGY 2024; 153:104602. [PMID: 38142956 DOI: 10.1016/j.jinsphys.2023.104602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
While there are numerous examples of thermogenesis processes in poikilothermic insects that maintain a stable temperature for a certain time and in certain parts of the body, there is a lack of information on ectothermic insect species capable of remaining active under "cold" conditions that would be challenging for other species. Such a thermal strategy would imply the existence of a metabolism that can operate at different temperatures without the need to increase body temperature when experiencing cold environmental conditions. This "hotter-is-not-better" thermal strategy is considered ancestral and conjectured to be linked to the origin and evolution of endothermy. In this study, we examined the thermal performance of a large-bodied dung beetle species (Chelotrupes momus) capable of being active during the winter nights in the Iberian Mediterranean region. Field and laboratory results were obtained using thermocamera records, thermocouples, data loggers and spectrometers that measured ultraviolet, visible and near-infrared wavelengths. The thermal data clearly indicated that this species can remain active at a body temperature of approximately 6 °C without the need to warm its body above ambient temperature. Comparing the spectrophotometric data of the species under study with that from other previously examined dung beetle species indicated that the exoskeleton of this particular species likely enhances the absorption of infrared radiation, thereby implying a dual role of the exoskeleton in both heat acquisition and heat dissipation. Taken together, these results suggest that this species has morphological and metabolic adaptations that enable life processes at temperatures that are typically unsuitable for most insect species in the region.
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Affiliation(s)
- Jorge M Lobo
- Departamento de Biogeografía y Cambio Global, Museo Nacional de Ciencias Naturales-CSIC, Spain.
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2
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Park C, No S, Yoo S, Oh D, Hwang Y, Kim Y, Kang C. Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions. Sci Rep 2023; 13:4203. [PMID: 36918652 PMCID: PMC10015036 DOI: 10.1038/s41598-023-31262-y] [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: 12/14/2022] [Accepted: 03/08/2023] [Indexed: 03/15/2023] Open
Abstract
Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures that influence frogs' adaptive colour change responses. However, certain gaps in our knowledge of this phenomenon remain, namely: (i) how do frogs adjust their colour in response to continuously changing external conditions?; (ii) what is the direction of change when two different functions of colour (camouflage and thermoregulation) are in conflict?; (iii) does reflectance in the near-infrared region show thermally adaptive change?; and (iv) is the colour change ability of each frog an individual trait (i.e., consistent within an individual over time)? Using Dryophytes japonicus (Hylidae, Hyla), we performed a series of experiments to answer the above questions. We first showed that frogs' responses to continuously-changing external conditions (i.e., background colour and temperature) were not linear and limited to the range they experience under natural conditions. Second, when a functional conflict existed, camouflage constrained the adaptive response for thermoregulation and vice versa. Third, though both temperature and background colour induced a change in near-infrared reflectance, this change was largely explained by the high correlation between colour (reflectance in the visible spectrum) and near-infrared reflectance. Fourth, within-individual variation in colour change capacity (i.e., the degree of colour change an individual can display) was lower than inter-individual variation, suggesting individuality of colour change capacity; however, we also found that colour change capacity could change gradually with time within individuals. Our results collectively reveal several new aspects of how evolution shapes the colour change process and highlight how variation in external conditions restricts the extent of colour change in treefrogs.
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Affiliation(s)
- Chohee Park
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Seongsoo No
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Sohee Yoo
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Dogeun Oh
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Yerin Hwang
- Department of Biosciences, Mokpo National University, Cheonggye, Muan, Jeollanamdo, 58554, South Korea.,Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Yongsu Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Changku Kang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea. .,Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, South Korea.
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3
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Schirmer SC, Gawryszewski FM, Cardoso MZ, Pessoa DMA. Melanism and color saturation of butterfly assemblages: A comparison between a tropical rainforest and a xeric white forest. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.932755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The study of butterfly coloration has helped to identify the ecological pressures involved in the evolution of animal coloration. However, almost all studies that addressed this issue have focused on species that inhabit more temperate environments, leaving the species and ecological factors of tropical regions mostly understudied. Here, our purpose was to evaluate whether butterfly assemblages from two distinct Neotropical biomes (i.e., tropical rainforest and xeric white forest) differ regarding their melanism and/or color saturation. Our hypotheses were that (1) tropical rainforest butterflies should be more melanic and color saturated, and that (2) butterflies from more open/arid tropical environments should be more melanic on their dorsal wing surfaces than on their ventral wings. Therefore, we quantified melanism and color saturation from dorsal and ventral surfaces of 121 different butterfly species. Comparisons show that rainforest butterflies, when contrasted to white forest butterflies, have more melanic dorsal wing surfaces, which might be seen as a form of protection against parasites. Our data also show that rainforest butterflies, but not white forest species, have darker dorsal wing surfaces, when compared to their own ventral surfaces, a trend that was also found for species inhabiting both biomes, which might be associated to thermoregulatory advantages. At last, our results also point that butterflies' dorsal wing sides present a higher variance between species (regardless of Biome), when compared to their own ventral wing side, an indication that some ecological factor (e.g., predation avoidance) might be exerting a strong homogenizing force on ventral wing coloration.
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4
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Barrett M, O’Donnell S. Individual reflectance of solar radiation confers a thermoregulatory benefit to dimorphic males bees (Centris pallida) using distinct microclimates. PLoS One 2023; 18:e0271250. [PMID: 36917573 PMCID: PMC10013911 DOI: 10.1371/journal.pone.0271250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 02/28/2023] [Indexed: 03/15/2023] Open
Abstract
Incoming solar radiation (wavelengths 290-2500 nm) significantly affects an organism's thermal balance via radiative heat gain. Species adapted to different environments can differ in solar reflectance profiles. We hypothesized that conspecific individuals using thermally distinct microhabitats to engage in fitness-relevant behaviors would show intraspecific differences in reflectance: we predicted individuals that use hot microclimates (where radiative heat gain represents a greater thermoregulatory challenge) would be more reflective across the entire solar spectrum than those using cooler microclimates. Differences in near-infrared (NIR) reflectance (700-2500 nm) are strongly indicative of thermoregulatory adaptation as, unlike differences in visible reflectance (400-700 nm), they are not perceived by ecological or social partners. We tested these predictions in male Centris pallida (Hymenoptera: Apidae) bees from the Sonoran Desert. Male C. pallida use alternative reproductive tactics that are associated with distinct microclimates: Large-morph males, with paler visible coloration, behave in an extremely hot microclimate close to the ground, while small-morph males, with a dark brown dorsal coloration, frequently use cooler microclimates above the ground near vegetation. We found that large-morph males had higher reflectance of solar radiation (UV through NIR) resulting in lower solar absorption coefficients. This thermoregulatory adaptation was specific to the dorsal surface, and produced by differences in hair, not cuticle, characteristics. Our results showed that intraspecific variation in behavior, particular in relation to microclimate use, can generate unique thermal adaptations that changes the reflectance of shortwave radiation among individuals within the same population.
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Affiliation(s)
- Meghan Barrett
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
- Department of Biology, California State University Dominguez Hills, Carson, CA, United States of America
- * E-mail:
| | - Sean O’Donnell
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
- Department of Biodiversity, Earth, and Environmental Sciences, Drexel University, Philadelphia, PA, United States of America
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5
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Tang CF, Li FF, Cao Y, Liao HJ. Universal cooling patterns of the butterfly wing scales hierarchy deduced from the heterogeneous thermal and structural properties of Tirumala limniace (Lepidoptera: Nymphalidae, Danainae). INSECT SCIENCE 2022; 29:1761-1772. [PMID: 35452162 DOI: 10.1111/1744-7917.13046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/03/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
The radiative cooling of butterfly wing scales hierarchy has great value in understanding how poikilotherms adapt to the environment and developing bionic materials. However, it remains unclear what the cooling system is like and how the variation of hierarchy affects the cooling efficiency. Therefore, the correlation between the variations of the structure and emissivity of scale hierarchy is thoroughly investigated in Tirumala limniace (Cramer, 1775), whose thermal properties are highly heterogeneous among different wings and regions but similar between males and females. Patterns were deduced from the biological and model simulation experiments. The scale hierarchy varies at the micro- to nanolevel on both surface and section, corresponding to the variating emissivity. Scales on wing veins and margins have large nanostructured units with small lumens and are distinctly thickened, which bring extraordinarily high emissivity. The variations of light and dark scales, respectively, lead to the high emissivity of the middle region of wings and the front wings. Generally, the elevation of the inner surface area and the thickness of the chitin is the key to enhancing the cooling efficiency. For the first time, the effects of the variation of hierarchy toward emissivity of the mid-infrared spectrum are systematically clarified. It is demonstrated that wing scales integrally differentiate in coping with the heterogeneous cooling needs, which may benefit in balancing multifunctions and the development toward the adaptation to the abiotic environment. The study provides insights into the comprehensive thermoregulation system of butterflies and the further development of radiative cooling materials.
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Affiliation(s)
- Chu-Fei Tang
- Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Fan-Fan Li
- Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ye Cao
- Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Huai-Jian Liao
- Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China
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6
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Ospina-Rozo L, Subbiah J, Seago A, Stuart-Fox D. Pretty Cool Beetles: Can Manipulation of Visible and Near-Infrared Sunlight Prevent Overheating? Integr Org Biol 2022; 4:obac036. [PMID: 36110288 PMCID: PMC9470487 DOI: 10.1093/iob/obac036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/09/2022] [Accepted: 08/04/2022] [Indexed: 11/21/2022] Open
Abstract
Passive thermoregulation is an important strategy to prevent overheating in thermally challenging environments. Can the diversity of optical properties found in Christmas beetles (Rutelinae) be an advantage to keep cool? We measured changes in temperature of the elytra of 26 species of Christmas beetles, exclusively due to direct radiation from a solar simulator in visible (VIS: 400–700 nm) and near infrared (NIR: 700–1700 nm) wavebands. Then, we evaluated if the optical properties of elytra could predict their steady state temperature and heating rates, while controlling for size. We found that higher absorptivity increases the heating rate and final steady state of the beetle elytra in a biologically significant range (3 to 5°C). There was substantial variation in the absorptivity of Christmas beetle elytra; and this variation was achieved by different combinations of reflectivity and transmissivity in both VIS and NIR. Size was an important factor predicting the change in temperature of the elytra after 5 min (steady state) but not maximum heating rate. Lastly, we show that the presence of the elytra covering the body of the beetle can reduce heating of the body itself. We propose that beetle elytra can act as a semi-insulating layer to enable passive thermoregulation through high reflectivity of elytra, resulting in low absorptivity of solar radiation. Alternatively, if beetle elytra absorb a high proportion of solar radiation, they may reduce heat transfer from the elytra to the body through behavioral or physiological mechanisms.
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Affiliation(s)
- Laura Ospina-Rozo
- School of Biosciences, University of Melbourne , Building 147, Parkville Victoria 3010, Australia
| | - Jegadesan Subbiah
- School of Chemistry, Bio21 Institute - University of Melbourne , 30 Flemington Road, Victoria 3010, Australia
| | - Ainsley Seago
- Carnegie Museum of Natural History , 4400 Forbes Ave, Pittsburgh PA 15213, USA
| | - Devi Stuart-Fox
- School of Biosciences, University of Melbourne , Building 147, Parkville Victoria 3010, Australia
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7
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Krishna A, Nie X, Briscoe AD, Lee J. Air temperature drives the evolution of mid-infrared optical properties of butterfly wings. Sci Rep 2021; 11:24143. [PMID: 34921152 PMCID: PMC8683501 DOI: 10.1038/s41598-021-02810-1] [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: 08/19/2021] [Accepted: 11/09/2021] [Indexed: 11/24/2022] Open
Abstract
This study uncovers a correlation between the mid-infrared emissivity of butterfly wings and the average air temperature of their habitats across the world. Butterflies from cooler climates have a lower mid-infrared emissivity, which limits heat losses to surroundings, and butterflies from warmer climates have a higher mid-infrared emissivity, which enhances radiative cooling. The mid-infrared emissivity showed no correlation with other investigated climatic factors. Phylogenetic independent contrasts analysis indicates the microstructures of butterfly wings may have evolved in part to regulate mid-infrared emissivity as an adaptation to climate, rather than as phylogenetic inertia. Our findings offer new insights into the role of microstructures in thermoregulation and suggest both evolutionary and physical constraints to butterflies' abilities to adapt to climate change.
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Affiliation(s)
- Anirudh Krishna
- Intel Corporation, Hillsboro, OR, 97124, USA. .,Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA, 92697, USA.
| | - Xiao Nie
- grid.266093.80000 0001 0668 7243Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92697 USA
| | - Adriana D. Briscoe
- grid.266093.80000 0001 0668 7243Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697 USA
| | - Jaeho Lee
- Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA, 92697, USA.
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8
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Cuesta E, Lobo JM. Can the spectrophotometric response of the elytra explain environmental preferences? A study in seven Onthophagus species (Coleoptera, Scarabaeidae). JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 225:112348. [PMID: 34742032 DOI: 10.1016/j.jphotobiol.2021.112348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/13/2021] [Accepted: 10/29/2021] [Indexed: 11/16/2022]
Abstract
Beetles are the most successful and diversified animal taxa characterized by the possession of an external pair of sclerotized wings (elytra). Managing electromagnetic radiations could be one of the functions of the exoskeleton. We studied the spectrophotometric response to ultraviolet, visible, and near-infrared radiations of the elytra of seven closely related and sympatric Onthophagus species to examine if the environmental preferences of these species could be associated with the spectrophotometric behaviour of their elytra. Our results indicated that sibling species can drastically differ in their environmental preferences but not in their spectrophotometric responses. However, our results corroborated that there are interspecific differences in the spectrophotometric characteristics of the elytra, which are mainly explained by morphological features. Among the examined morphological variables, darkness seems to be especially relevant as it facilitates the absorbance and obstructs the transmittance of visible and near-infrared radiations.
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Affiliation(s)
- Eva Cuesta
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (C.S.I.C.), Madrid, Spain; Escuela Internacional de Doctorado, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain
| | - Jorge M Lobo
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (C.S.I.C.), Madrid, Spain.
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9
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Wang LY, Franklin AM, Black JR, Stuart-Fox D. Heating rates are more strongly influenced by near-infrared than visible reflectance in beetles. J Exp Biol 2021; 224:272113. [PMID: 34494652 DOI: 10.1242/jeb.242898] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/31/2021] [Indexed: 11/20/2022]
Abstract
Adaptations to control heat transfer through the integument are a key component of temperature regulation in animals. However, there remain significant gaps in our understanding of how different optical and morphological properties of the integument affect heating rates. To address these gaps, we examined the effect of reflectivity in both ultraviolet-visible and near-infrared wavelengths, surface rugosity (roughness), effective area (area subjected to illumination) and cuticle thickness on radiative heat gain in jewel beetles (Buprestidae). We measured heating rate using a solar simulator to mimic natural sunlight, a thermal chamber to control the effects of conduction and convection, and optical filters to isolate different wavelengths. We found that effective area and reflectivity predicted heating rate. The thermal effect of reflectivity was driven by variation in near-infrared rather than ultraviolet-visible reflectivity. By contrast, cuticle thickness and surface rugosity had no detectable effect. Our results provide empirical evidence that near-infrared reflectivity has an important effect on radiative heat gain. Modulating reflectance of near-infrared wavelengths of light may be a more widespread adaptation to control heat gain than previously appreciated.
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Affiliation(s)
- Lu-Yi Wang
- School of Biosciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Amanda M Franklin
- School of Biosciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jay R Black
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Devi Stuart-Fox
- School of Biosciences, The University of Melbourne, Melbourne, VIC 3010, Australia
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10
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Hill GM, Kawahara AY, Daniels JC, Bateman CC, Scheffers BR. Climate change effects on animal ecology: butterflies and moths as a case study. Biol Rev Camb Philos Soc 2021; 96:2113-2126. [PMID: 34056827 PMCID: PMC8518917 DOI: 10.1111/brv.12746] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 01/10/2023]
Abstract
Butterflies and moths (Lepidoptera) are one of the most studied, diverse, and widespread animal groups, making them an ideal model for climate change research. They are a particularly informative model for studying the effects of climate change on species ecology because they are ectotherms that thermoregulate with a suite of physiological, behavioural, and phenotypic traits. While some species have been negatively impacted by climatic disturbances, others have prospered, largely in accordance with their diversity in life-history traits. Here we take advantage of a large repertoire of studies on butterflies and moths to provide a review of the many ways in which climate change is impacting insects, animals, and ecosystems. By studying these climate-based impacts on ecological processes of Lepidoptera, we propose appropriate strategies for species conservation and habitat management broadly across animals.
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Affiliation(s)
- Geena M. Hill
- Florida Natural Areas InventoryFlorida State University1018 Thomasville Rd., #200‐CTallahasseeFL323303U.S.A.
| | - Akito Y. Kawahara
- Florida Museum of Natural HistoryUniversity of Florida3215 Hull RdGainesvilleFL32611U.S.A.
- Department of BiologyUniversity of Florida876 Newell Dr.GainesvilleFL32611U.S.A.
| | - Jaret C. Daniels
- Florida Museum of Natural HistoryUniversity of Florida3215 Hull RdGainesvilleFL32611U.S.A.
- Department of Entomology and NematologyUniversity of Florida1881 Natural Area Dr.GainesvilleFL32608U.S.A.
| | - Craig C. Bateman
- Florida Museum of Natural HistoryUniversity of Florida3215 Hull RdGainesvilleFL32611U.S.A.
| | - Brett R. Scheffers
- Department of Wildlife Ecology and ConservationUniversity of Florida110 Newins‐Ziegler Hall, P.O. Box 110430GainesvilleFL32611U.S.A.
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11
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Gomez D, Pinna C, Pairraire J, Arias M, Barbut J, Pomerantz A, Daney de Marcillac W, Berthier S, Patel N, Andraud C, Elias M. Wing transparency in butterflies and moths: structural diversity, optical properties, and ecological relevance. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Doris Gomez
- CEFE University of Montpellier CNRS, EPHE, IRD Montpellier France
| | - Charline Pinna
- ISYEB UMR 7205 CNRS, MNHN EPHE Sorbonne University Paris France
| | | | - Mónica Arias
- CEFE University of Montpellier CNRS, EPHE, IRD Montpellier France
- ISYEB UMR 7205 CNRS, MNHN EPHE Sorbonne University Paris France
| | - Jérôme Barbut
- ISYEB UMR 7205 CNRS, MNHN EPHE Sorbonne University Paris France
| | - Aaron Pomerantz
- Marine Biological Laboratory Woods Hole Massachusetts 02543 USA
- Department Integrative Biology University of California Berkeley Berkeley California 94720 USA
| | | | | | - Nipam Patel
- Marine Biological Laboratory Woods Hole Massachusetts 02543 USA
- University of Chicago Chicago Illinois 60607 USA
| | | | - Marianne Elias
- ISYEB UMR 7205 CNRS, MNHN EPHE Sorbonne University Paris France
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12
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Kang C, Im S, Lee WY, Choi Y, Stuart-Fox D, Huertas B. Climate predicts both visible and near-infrared reflectance in butterflies. Ecol Lett 2021; 24:1869-1879. [PMID: 34174001 DOI: 10.1111/ele.13821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/22/2021] [Accepted: 05/13/2021] [Indexed: 01/09/2023]
Abstract
Climatic gradients frequently predict large-scale ecogeographical patterns in animal coloration, but the underlying causes are often difficult to disentangle. We examined ecogeographical patterns of reflectance among 343 European butterfly species and isolated the role of selection for thermal benefits by comparing animal-visible and near-infrared (NIR) wavebands. NIR light accounts for ~50% of solar energy but cannot be seen by animals so functions primarily in thermal control. We found that reflectance of both dorsal and ventral surfaces shows thermally adaptive correlations with climatic factors including temperature and precipitation. This adaptive variation was more prominent in NIR than animal-visible wavebands and for body regions (thorax-abdomen and basal wings) that are most important for thermoregulation. Thermal environments also predicted the reflectance difference between dorsal and ventral surfaces, which may be due to modulation between requirements for heating and cooling. These results highlight the importance of climatic gradients in shaping the reflectance properties of butterflies at a continent-wide scale.
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Affiliation(s)
- Changku Kang
- Department of Biosciences, Mopko National University, Muan, South Korea
| | - Sehyeok Im
- Division of Life Sciences, Korea Polar Research Institute, Incheon, South Korea.,University of Science and Technology, Daejeon, South Korea
| | - Won Young Lee
- Division of Life Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Yunji Choi
- Department of Life Sciences, Imperial College London, London, UK
| | - Devi Stuart-Fox
- School of BioSciences, The University of Melbourne, Parkville, Vic, Australia
| | - Blanca Huertas
- Department of Life Sciences, Natural History Museum London, London, UK
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13
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Pincebourde S, Dillon ME, Woods HA. Body size determines the thermal coupling between insects and plant surfaces. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13801] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Sylvain Pincebourde
- Institut de Recherche sur la Biologie de l'Insecte UMR 7261 CNRS ‐ Université de Tours Tours France
| | - Michael E. Dillon
- Department of Zoology & Physiology and Program in Ecology University of Wyoming Laramie WY USA
| | - H. Arthur Woods
- Division of Biological Sciences University of Montana Missoula MT USA
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14
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Infrared optical and thermal properties of microstructures in butterfly wings. Proc Natl Acad Sci U S A 2020; 117:1566-1572. [PMID: 31919285 DOI: 10.1073/pnas.1906356117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
While surface microstructures of butterfly wings have been extensively studied for their structural coloration or optical properties within the visible spectrum, their properties in infrared wavelengths with potential ties to thermoregulation are relatively unknown. The midinfrared wavelengths of 7.5 to 14 µm are particularly important for radiative heat transfer in the ambient environment, because of the overlap with the atmospheric transmission window. For instance, a high midinfrared emissivity can facilitate surface cooling, whereas a low midinfrared emissivity can minimize heat loss to surroundings. Here we find that the midinfrared emissivity of butterfly wings from warmer climates such as Archaeoprepona demophoon (Oaxaca, Mexico) and Heliconius sara (Pichincha, Ecuador) is up to 2 times higher than that of butterfly wings from cooler climates such as Celastrina echo (Colorado) and Limenitis arthemis (Florida), using Fourier-transform infrared (FTIR) spectroscopy and infrared thermography. Our optical computations using a unit cell approach reproduce the spectroscopy data and explain how periodic microstructures play a critical role in the midinfrared. The emissivity spectrum governs the temperature of butterfly wings, and we demonstrate that C. echo wings heat up to 8 °C more than A. demophoon wings under the same sunlight in the clear sky of Irvine, CA. Furthermore, our thermal computations show that butterfly wings in their respective habitats can maintain a moderate temperature range through a balance of solar absorption and infrared emission. These findings suggest that the surface microstructures of butterfly wings potentially contribute to thermoregulation and provide an insight into butterflies' survival.
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Medina I, Vega-Trejo R, Wallenius T, Symonds MRE, Stuart-Fox D. From cryptic to colorful: Evolutionary decoupling of larval and adult color in butterflies. Evol Lett 2019; 4:34-43. [PMID: 32055409 PMCID: PMC7006464 DOI: 10.1002/evl3.149] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/15/2019] [Accepted: 11/05/2019] [Indexed: 12/25/2022] Open
Abstract
Many animals undergo complete metamorphosis, where larval forms change abruptly in adulthood. Color change during ontogeny is common, but there is little understanding of evolutionary patterns in these changes. Here, we use data on larval and adult color for 246 butterfly species (61% of all species in Australia) to test whether the evolution of color is coupled between life stages. We show that adults are more variable in color across species than caterpillars and that male adult color has lower phylogenetic signal. These results suggest that sexual selection is driving color diversity in male adult butterflies at a broad scale. Moreover, color similarities between species at the larval stage do not predict color similarities at the adult stage, indicating that color evolution is decoupled between young and adult forms. Most species transition from cryptic coloration as caterpillars to conspicuous coloration as adults, but even species with conspicuous caterpillars change to different conspicuous colors as adults. The use of high‐contrast coloration is correlated with body size in caterpillars but not adults. Taken together, our results suggest a change in the relative importance of different selective pressures at different life stages, resulting in the evolutionary decoupling of coloration through ontogeny.
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Affiliation(s)
- Iliana Medina
- School of BioSciences University of Melbourne Melbourne Victoria 3010 Australia
| | - Regina Vega-Trejo
- Division of Ecology and Evolution Australian National University Acton Australian Capital Territory 0200 Australia.,Department of Zoology Stockholm University Stockholm Sweden
| | - Thomas Wallenius
- Division of Ecology and Evolution Australian National University Acton Australian Capital Territory 0200 Australia
| | - Matthew R E Symonds
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Burwood Victoria 3125 Australia
| | - Devi Stuart-Fox
- School of BioSciences University of Melbourne Melbourne Victoria 3010 Australia
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Munro JT, Medina I, Walker K, Moussalli A, Kearney MR, Dyer AG, Garcia J, Rankin KJ, Stuart-Fox D. Climate is a strong predictor of near-infrared reflectance but a poor predictor of colour in butterflies. Proc Biol Sci 2019; 286:20190234. [PMID: 30862288 PMCID: PMC6458314 DOI: 10.1098/rspb.2019.0234] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/19/2019] [Indexed: 02/06/2023] Open
Abstract
Colour variation across climatic gradients is a common ecogeographical pattern; yet there is long-standing contention over underlying causes, particularly selection for thermal benefits. We tested the evolutionary association between climate gradients and reflectance of near-infrared (NIR) wavelengths, which influence heat gain but are not visible to animals. We measured ultraviolet (UVA), visible (Vis) and NIR reflectance from calibrated images of 372 butterfly specimens from 60 populations (49 species, five families) spanning the Australian continent. Consistent with selection for thermal benefits, the association between climate and reflectance was stronger for NIR than UVA-Vis wavelengths. Furthermore, climate predicted reflectance of the thorax and basal wing, which are critical to thermoregulation; but it did not predict reflectance of the entire wing, which has a variable role in thermoregulation depending on basking behaviour. These results provide evidence that selection for thermal benefits has shaped the reflectance properties of butterflies.
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Affiliation(s)
- Joshua T. Munro
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Iliana Medina
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ken Walker
- Sciences Department, Museums Victoria, Carlton Gardens, Victoria 3053, Australia
| | - Adnan Moussalli
- Sciences Department, Museums Victoria, Carlton Gardens, Victoria 3053, Australia
| | - Michael R. Kearney
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Adrian G. Dyer
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | - Jair Garcia
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | - Katrina J. Rankin
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Devi Stuart-Fox
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
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