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Carbonell JA, Pallarés S, Velasco J, Millán A, Abellán P. Thermal tolerance does not explain the altitudinal segregation of lowland and alpine aquatic insects. J Therm Biol 2024; 121:103862. [PMID: 38703597 DOI: 10.1016/j.jtherbio.2024.103862] [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: 01/30/2024] [Revised: 04/18/2024] [Accepted: 04/23/2024] [Indexed: 05/06/2024]
Abstract
Elevation gradients provide powerful study systems for examining the influence of environmental filters in shaping species assemblages. High-mountain habitats host specific high-elevation assemblages, often comprising specialist species adapted to endure pronounced abiotic stress, while such harsh conditions prevent lowland species from colonizing or establishing. While thermal tolerance may drive the altitudinal segregation of ectotherms, its role in structuring aquatic insect communities remains poorly explored. This study investigates the role of thermal physiology in shaping the current distribution of high-mountain diving beetles from the Sierra Nevada Iberian mountain range and closely related lowland species. Cold tolerance of five species from each altitudinal zone was measured estimating the supercooling point (SCP), lower lethal temperature (LLT) and tolerance to ice enclosure, while heat tolerance was assessed from the heat coma temperature (HCT). Alpine species exhibited wider fundamental thermal niches than lowland species, likely associated with the broader range of climatic conditions in high-mountain areas. Cold tolerance did not seem to prevent lowland species from colonizing higher elevations, as most studied species were moderately freeze-tolerant. Therefore, fundamental thermal niches seem not to fully explain species segregation along elevation gradients, suggesting that other thermal tolerance traits, environmental factors, and biotic interactions may also play important roles.
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Affiliation(s)
- J A Carbonell
- Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain; Laboratory of Evolutionary Stress Ecology and Ecotoxicology, University of Leuven (KU Leuven), Leuven, Belgium.
| | - S Pallarés
- Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain
| | - J Velasco
- Department of Ecology and Hydrology, Faculty of Biology, University of Murcia, Murcia, Spain
| | - A Millán
- Department of Ecology and Hydrology, Faculty of Biology, University of Murcia, Murcia, Spain
| | - P Abellán
- Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain
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2
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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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3
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Nolasco-Soto J, González-Astorga J, Espinosa de los Monteros A, Favila ME. Evolutionary history and diversity in the ball roller beetle Canthon cyanellus. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1066439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
To understand the evolutionary history of species, it is necessary to know the mechanisms for reproductive isolation, divergence-time between populations, and the relative action of the evolutionary forces (e.g., mutation, genetic drift, gene flow) within and between populations of the same, or closely related species. Although Canthon is one of the more diverse genera of neotropical beetles, insufficient research has been done to comprehend the divergent patterns that explain its speciation process. The absence of diagnostic morphological characters and the wide geographic variation of qualitative traits in Scarabaeinae obscures species delimitation, genealogical limits between populations, and its taxonomy. Canthon cyanellus is one of the best-known species in ecological and evolutionary aspects. It is a widely distributed species in the tropical forests of America. Also, the current deforestation has facilitated its incursion into open areas. Individuals from different populations have similar morphological characters but show wide variation in body color throughout their distribution, which makes it difficult to delimit the subspecies that comprise it. Recently, studies have been carried out to elucidate the pre-and postzygotic isolation mechanisms between populations and the historical biogeographical processes favoring cladogenesis events during the Pleistocene. Morphological variation of the male genitalia does not correspond to the phylogeographic structure. However, the morphological differences in one of the pieces of the endophallic sclerites have allowed a preliminary delimitation of some genetically differentiated clades. Finally, we consider that the joint analysis of traditional morphological taxonomy and phylogeography is important to understand the speciation process in the C. cyanellus complex.
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deCastro-Arrazola I, Andrew NR, Berg MP, Curtsdotter A, Lumaret JP, Menéndez R, Moretti M, Nervo B, Nichols ES, Sánchez-Piñero F, Santos AMC, Sheldon KS, Slade EM, Hortal J. A trait-based framework for dung beetle functional ecology. J Anim Ecol 2023; 92:44-65. [PMID: 36443916 PMCID: PMC10099951 DOI: 10.1111/1365-2656.13829] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/27/2022] [Indexed: 11/30/2022]
Abstract
Traits are key for understanding the environmental responses and ecological roles of organisms. Trait approaches to functional ecology are well established for plants, whereas consistent frameworks for animal groups are less developed. Here we suggest a framework for the study of the functional ecology of animals from a trait-based response-effect approach, using dung beetles as model system. Dung beetles are a key group of decomposers that are important for many ecosystem processes. The lack of a trait-based framework tailored to this group has limited the use of traits in dung beetle functional ecology. We review which dung beetle traits respond to the environment and affect ecosystem processes, covering the wide range of spatial, temporal and biological scales at which they are involved. Dung beetles show trait-based responses to variation in temperature, water, soil properties, trophic resources, light, vegetation structure, competition, predation and parasitism. Dung beetles' influence on ecosystem processes includes trait-mediated effects on nutrient cycling, bioturbation, plant growth, seed dispersal, other dung-based organisms and parasite transmission, as well as some cases of pollination and predation. We identify 66 dung beetle traits that are either response or effect traits, or both, pertaining to six main categories: morphology, feeding, reproduction, physiology, activity and movement. Several traits pertain to more than one category, in particular dung relocation behaviour during nesting or feeding. We also identify 136 trait-response and 77 trait-effect relationships in dung beetles. No response to environmental stressors nor effect over ecological processes were related with traits of a single category. This highlights the interrelationship between the traits shaping body-plans, the multi-functionality of traits, and their role linking responses to the environment and effects on the ecosystem. Despite current developments in dung beetle functional ecology, many knowledge gaps remain, and there are biases towards certain traits, functions, taxonomic groups and regions. Our framework provides the foundations for the thorough development of trait-based dung beetle ecology. It also serves as an example framework for other taxa.
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Affiliation(s)
- Indradatta deCastro-Arrazola
- Germans Cabot Franciscans 48, Bunyola, Spain.,Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Nigel R Andrew
- Insect Ecology Lab, Natural History Museum, University of New England, Armidale, New South Wales, Australia
| | - Matty P Berg
- Department of Ecological Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Alva Curtsdotter
- Insect Ecology Lab, Natural History Museum, University of New England, Armidale, New South Wales, Australia
| | | | - Rosa Menéndez
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Marco Moretti
- Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Beatrice Nervo
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | | | | | - Ana M C Santos
- Terrestrial Ecology Group (TEG-UAM), Departamento de Ecología, Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Kimberly S Sheldon
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States
| | - Eleanor M Slade
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Joaquín Hortal
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain.,Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.,cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
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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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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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Lobo JM, Cuesta E. Seasonal variation in the diel activity of a dung beetle assemblage. PeerJ 2021; 9:e11786. [PMID: 34306833 PMCID: PMC8280883 DOI: 10.7717/peerj.11786] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/24/2021] [Indexed: 11/20/2022] Open
Abstract
The seasonal and diel variations of dung beetle species were studied in an Iberian mid-mountain locality to examine the interaction between these two temporal rhythms. We assume that a seasonal variation in the diel activity would support the notion that both rhythms may assist in achieving a quick and flexible response when the climatic conditions change. Data coming from 4,104 pitfall traps placed during 15 sampling periods and totalling 30 daily sampling cycles were analysed using circular statistics and General Linear Models. A wide variety of seasonal patterns are observed, highlighting those species with a clear unimodal or spring-autumn bimodal seasonal pattern. However, a midday diel pattern is the norm in most of the species, except in the case of those exhibiting a high body weight that prefer dusk or night periods. We hypothesize that most of the dung beetle species fly at noon to promote the passive heating of their muscle activity and minimize the metabolic energy expenditure. Results only partially support the seasonal variation in diel activity. Diel preferences are mainly manifested at the time of the year in which the abundance is greater. Approximately two-thirds of the considered species exhibit a similar diel activity along their seasonal active period. As consequence, a significant portion of the dung beetle species currently inhabiting Mediterranean mid-mountains are not able to use the daily variation in climatic conditions to limit the inconveniences of climate change.
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Affiliation(s)
- Jorge M. Lobo
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (C.S.I.C.), Madrid, Spain
| | - 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
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Cuesta E, Lobo JM. Visible and near-infrared radiation may be transmitted or absorbed differently by beetle elytra according to habitat preference. PeerJ 2019; 7:e8104. [PMID: 31788360 PMCID: PMC6882417 DOI: 10.7717/peerj.8104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/25/2019] [Indexed: 11/20/2022] Open
Abstract
Background The exoskeleton of an insect could be an important factor in the success of its evolutionary process. This reaches its maximum expression in beetles, which constitute the most diversified animal taxon. The involvement in the management of environmental radiation could be one of the most important functions of the exoskeleton due to the passive contributions to the thermoregulation of body temperature. We study whether the elytra of two sympatric and closely related beetle species respond differentially to the radiation of distinct wavelengths in agreement with their ecological preferences. Methods Onthophagus coenobita (Herbst) and O. medius (Kugelaan) occupy different habitats and environmental conditions (shaded vs. unshaded from solar radiation). The potential adaptive variations to thermoregulation under these different ecological conditions were studied using the responses of their exoskeletons to radiation of different wavelengths (ultraviolet, visible and near-infrared). For these two species, the amounts of the three wavelengths that were reflected, transmitted or absorbed by the exoskeleton were measured using of a spectrophotometer. In addition, the darkness and thickness of the elytra were examined to determine whether these two features influence the management of radiation by the exoskeleton. Results Both species differ in the management of visible and near-infrared radiation. In agreement with habitat preferences, the species inhabiting shaded conditions would allow infrared and visible radiation to penetrate the elytra more easily to heat internal body parts, while the elytra of the heliophilous species would have increased absorbance of these same types of radiation. An increase in body size (and therefore in elytron thickness) and the quantity of dark spots may serve as barriers against exogenous heat gain. However, the maintenance of between-species differences independent of the effects of these two morphological features led us to suspect that an unconsidered elytron characteristic may also be affecting these differences. Discussion The results of the involvement of the exoskeleton thickness and spots in the thermoregulation of insects opens new research lines to obtain a better understanding of the function of the exoskeleton as a passive thermoregulation mechanism in Coleoptera.
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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, España
| | - Jorge M Lobo
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (C.S.I.C.), Madrid, Spain
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Distribution of Canthon rutilans rutilans and Canthon rutilans cyanescens Along Spatio-Temporal and Temperature Gradients. INSECTS 2018; 9:insects9040124. [PMID: 30248894 PMCID: PMC6316853 DOI: 10.3390/insects9040124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/05/2018] [Accepted: 09/18/2018] [Indexed: 11/17/2022]
Abstract
Subspecies is a debated taxonomic rank that, in some cases, could indicate that a speciation process is taking place. Studying the degree of co-occurrence among subspecies along environmental gradients may help to determine its taxonomic status. In this study, we explore the distribution of two subspecies of Canthon rutilans along spatio-temporal and temperature gradients in the Atlantic Forest of southern Brazil in order to reinforce their current subspecies status or to support their consideration as two different species. A yearly survey conducted along an elevational transect (from 250 m to 1630 m) shows that there is no spatio-temporal overlap between the two taxa. We collected 899 individuals of Canthon rutilans cyanescens and 29 individuals of Canthon rutilans rutilans. C. rutilans cyanescens can be found at 250 m (all year except in June), 430 m (August to April), and 840 m (September to April) in elevation, and when the air temperature oscillates from 15.3 °C to 24.0 °C. C. rutilans rutilans can be found at 1360 m (October to February), 1630 m (January) in elevation, and when the air temperature oscillates from 14.4 °C to 18.6 °C. Furthermore, local temperature data taken during the survey indicates that both subspecies also have a limited overlap in their thermal response curves. All these results suggest that these two taxa could be considered as two different species with dissimilar physiological and ecological requirements probably as a consequence of temperature-mediated divergent adaptation. Further molecular data can confirm or reject this supposition in the near future.
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