1
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Kaspari M, Welti EAR. Nutrient dilution and the future of herbivore populations. Trends Ecol Evol 2024; 39:809-820. [PMID: 38876933 DOI: 10.1016/j.tree.2024.05.001] [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: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 06/16/2024]
Abstract
Nutrient dilution (ND) - the decrease in the concentration of nutritional elements in plant tissue - arises from an increase in the mass of carbohydrates and/or a decrease in the 20+ essential elements. Increasing CO2 levels and its promotion of biomass are linked to nutrient dilution. We build a case for nutrient dilution as a key driver in global declines in herbivore abundance. Herbivores must build element-rich animal tissue from nutrient-poor plant tissue, and their abundance commonly increases with fertilization of both macro- and micronutrients. We predict the global impacts of nutrient dilution will be magnified in some of Earth's most biodiverse, highly productive, and/or nutrient-poor ecosystems and should favor specific traits of herbivores, including sap-feeding and ruminant microbiomes.
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Affiliation(s)
- Michael Kaspari
- School of Biological Sciences, University of Oklahoma, Norman, OK 73019, USA; Conservation Ecology Center, Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, VA 22630, USA.
| | - Ellen A R Welti
- Conservation Ecology Center, Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, VA 22630, USA
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2
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Piñanez-Espejo YMG, Munévar A, Schilman PE, Zurita GA. It is hot and cold here: the role of thermotolerance in the ability of spiders to colonize tree plantations in the southern Atlantic Forest. Oecologia 2024; 204:789-804. [PMID: 38561554 DOI: 10.1007/s00442-024-05529-8] [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: 09/19/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g., due to forest replacement by tree plantations, is still understudied. To examine the role of thermal tolerance on the responses of specialist and generalist species to habitat disturbances, we measured and compared local temperature throughout the year and thermotolerance traits [upper (CTmax) and lower (CTmin) thermal limits] of the most abundant species of spiders from different guilds inhabiting pine tree plantations and native Atlantic Forests in South America. Following the thermal adaptation hypothesis, we predicted that generalist species would show a wider thermal tolerance range (i.e., lower CTmin and higher CTmax) than forest specialist species. As expected, generalist species showed significantly higher CTmax and lower CTmin values than specialist species with wider thermal tolerance ranges than forest specialist species. These differences are more marked in orb weavers than in aerial hunter spiders. Our study supports the specialisation disturbance and thermal hypotheses. It highlights that habitat-specialist species are more vulnerable to environmental changes associated with vegetation structure and microclimatic conditions. Moreover, thermal tolerance is a key response trait to explain the Atlantic Forest spider's ability (or inability) to colonise and persist in human-productive land uses.
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Affiliation(s)
- Yolanda M G Piñanez-Espejo
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina.
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina.
| | - Ana Munévar
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina
| | - Pablo E Schilman
- Laboratorio de Ecofisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- CONICET-Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Buenos Aires, Argentina.
| | - Gustavo Andrés Zurita
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina.
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina.
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3
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Mayer VE, Voglmayr H, Blatrix R, Orivel J, Leroy C. Fungi as mutualistic partners in ant-plant interactions. FRONTIERS IN FUNGAL BIOLOGY 2023; 4:1213997. [PMID: 37850069 PMCID: PMC10577302 DOI: 10.3389/ffunb.2023.1213997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/11/2023] [Indexed: 10/19/2023]
Abstract
Associations between fungi and ants living in mutualistic relationship with plants ("plant-ants") have been known for a long time. However, only in recent years has the mutualistic nature, frequency, and geographical extent of associations between tropical arboreal ants with fungi of the ascomycete order Chaetothyriales and Capnodiales (belonging to the so-called "Black Fungi") become clear. Two groups of arboreal ants displaying different nesting strategies are associated with ascomycete fungi: carton-building ants that construct nest walls and galleries on stems, branches or below leaves which are overgrown by fungal hyphae, and plant-ants that make their nests inside living plants (myrmecophytes) in plant provided cavities (domatia) where ants cultivate fungi in small delimited "patches". In this review we summarize the current knowledge about these unsuspected plant-ant-fungus interactions. The data suggest, that at least some of these ant-associated fungi seem to have coevolved with ants over a long period of time and have developed specific adaptations to this lifestyle.
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Affiliation(s)
- Veronika E. Mayer
- Department of Botany and Biodiversity Research – Division of Structural and Functional Botany, University of Vienna, Wien, Austria
| | - Hermann Voglmayr
- Department of Botany and Biodiversity Research – Mycology Research Group, University of Vienna, Wien, Austria
| | - Rumsais Blatrix
- CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Jérôme Orivel
- EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, France
| | - Céline Leroy
- EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, France
- AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
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4
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Chen N, Zhang QG. Linking temperature dependence of fitness effects of mutations to thermal niche adaptation. J Evol Biol 2023; 36:1517-1524. [PMID: 37750539 DOI: 10.1111/jeb.14225] [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: 12/05/2022] [Revised: 07/28/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023]
Abstract
Fitness effects of mutations may generally depend on temperature that influences all rate-limiting biophysical and biochemical processes. Earlier studies suggested that high temperatures may increase the availability of beneficial mutations ('more beneficial mutations'), or allow beneficial mutations to show stronger fitness effects ('stronger beneficial mutation effects'). The 'more beneficial mutations' scenario would inevitably be associated with increased proportion of conditionally beneficial mutations at higher temperatures. This in turn predicts that populations in warm environments show faster evolutionary adaptation but suffer fitness loss when faced with cold conditions, and those evolving in cold environments become thermal-niche generalists ('hotter is narrower'). Under the 'stronger beneficial mutation effects' scenario, populations evolving in warm environments would show faster adaptation without fitness costs in cold environments, leading to a 'hotter is (universally) better' pattern in thermal niche adaptation. We tested predictions of the two competing hypotheses using an experimental evolution study in which populations of two model bacterial species, Escherichia coli and Pseudomonas fluorescens, evolved for 2400 generations at three experimental temperatures. Results of reciprocal transplant experiments with our P. fluorescens populations were largely consistent with the 'hotter is narrower' prediction. Results from the E. coli populations clearly suggested stronger beneficial mutation effects at higher assay temperatures, but failed to detect faster adaptation in populations evolving in warmer experimental environments (presumably because of limitation in the supply of genetic variation). Our results suggest that the influence of temperature on mutational effects may provide insight into the patterns of thermal niche adaptation and population diversification across thermal conditions.
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Affiliation(s)
- Nan Chen
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Quan-Guo Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
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5
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Corley RB, Dawson W, Bishop TR. A simple method to account for thermal boundary layers during the estimation of CTmax in small ectotherms. J Therm Biol 2023; 116:103673. [PMID: 37527565 DOI: 10.1016/j.jtherbio.2023.103673] [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: 03/16/2023] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 08/03/2023]
Abstract
As temperatures rise, understanding how ectotherms will become impacted by thermal stress is of critical importance. In this context, many researchers quantify critical temperatures - these are the upper (CTmax) and lower (CTmin) thermal limits at which organisms can no longer function. Most studies estimate CTs using bath-based methods where organisms are submerged within a set thermal environment. Plate-based methods (i.e. hot plates), however, offer huge opportunity for automation and are readily available in many lab settings. Plates, however, generate a unidirectional thermal boundary layer above their surface which means that the temperatures experienced by organisms of different sizes is different. This boundary layer effect can bias estimates of critical temperatures. Here, we test the hypothesis that biases in critical temperature estimation on hot plates are driven by organism height. We also quantify the composition of the boundary layer in order to correct for these biases. We assayed four differently sized species of UK ants for their CTmax in dry baths (with no boundary layer) and on hot plates (with a boundary layer). We found that hot plates overestimated the CTmax values of the different ants, and that this overestimate was larger for taller species. By statistically modelling the thickness of the thermal boundary layer, and combining with estimates of species height, we were able to correct this overestimation and eliminate methodological differences. Our study provides two main findings. First, we provide evidence that organism height is positively related to the bias present in plate-based estimates of CTmax. Second, we show that a relatively simple statistical model can correct for this bias. By using simple corrections for boundary layer effects, as we have done here, researchers could open up a new possibility space in the design and implementation of thermal tolerance assays using plates rather than restrictive dry or water baths.
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Affiliation(s)
| | - Will Dawson
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Tom R Bishop
- School of Biosciences, Cardiff University, Cardiff, UK; Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
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6
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Anderson PSL, Kawano SM. Different traits at different rates: The effects of dynamic strain rate on structural traits in biology. Integr Comp Biol 2022; 62:icac066. [PMID: 35640914 DOI: 10.1093/icb/icac066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Phenotypic diversity is influenced by physical laws that govern how an organism's morphology relates to functional performance. To study comparative organismal biology, we need to quantify this diversity using biological traits (definable aspects of the morphology, behavior, and/or life history of an organism). Traits are often assumed to be immutable properties that need only be measured a single time in each adult. However, organisms often experience changes in their biotic and abiotic environments that can alter trait function. In particular, structural traits represent the physical capabilities of an organism and may be heavily influenced by the rate at which they are exposed to physical demands ('loads'). For instance, materials tend to become more brittle when loaded at faster rates which could negatively affect structures trying to resist those loads (e.g., brittle materials are more likely to fracture). In the following perspective piece, we address the dynamic properties of structural traits and present case studies that demonstrate how dynamic strain rates affect the function of these traits in diverse groups of organisms. First, we review how strain rate affects deformation and fracture in biomaterials and demonstrate how these effects alter puncture mechanics in systems such as snake strikes. Second, we discuss how different rates of bone loading affect the locomotor biomechanics of vertebrates and their ecology. Through these examinations of diverse taxa and ecological functions, we aim to highlight how rate-dependent properties of structural traits can generate dynamic form-function relationships in response to changing environmental conditions. Findings from these studies serve as a foundation to develop more nuanced ecomechanical models that can predict how complex traits emerge and, thereby, advance progress on outlining the Rules of Life.
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Affiliation(s)
- Philip S L Anderson
- Department of Evolution, Ecology, and Behavior; University of Illinois Urbana-Champaign, Champaign, IL 61820, U.S.A
| | - Sandy M Kawano
- Department of Biological Sciences, The George Washington University, Washington, D.C. 20052, U.S.A
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7
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Nascimento G, Câmara T, Arnan X. Critical thermal limits in ants and their implications under climate change. Biol Rev Camb Philos Soc 2022; 97:1287-1305. [PMID: 35174946 DOI: 10.1111/brv.12843] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 11/28/2022]
Abstract
Critical thermal limits (CTLs) constrain the performance of organisms, shaping their abundance, current distributions, and future distributions. Consequently, CTLs may also determine the quality of ecosystem services as well as organismal and ecosystem vulnerability to climate change. As some of the most ubiquitous animals in terrestrial ecosystems, ants are important members of ecological communities. In recent years, an increasing body of research has explored ant physiological thermal limits. However, these CTL data tend to centre on a few species and biogeographical regions. To encourage an expansion of perspectives, we herein review the factors that determine ant CTLs and examine their effects on present and future species distributions and ecosystem processes. Special emphasis is placed on the implications of CTLs for safeguarding ant diversity and ant-mediated ecosystem services in the future. First, we compile, quantify, and categorise studies on ant CTLs based on study taxon, biogeographical region, methodology, and study question. Second, we use this comprehensive database to analyse the abiotic and biotic factors shaping ant CTLs. Our results highlight how CTLs may affect future distribution patterns and ecological performance in ants. Additionally, we identify the greatest remaining gaps in knowledge and create a research roadmap to promote rapid advances in this field of study.
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Affiliation(s)
- Geraldo Nascimento
- Universidade de Pernambuco - Campus Garanhuns, Rua Capitão Pedro Rodrigues, 105 - São José, Garanhuns, 55294-902, Brazil.,Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Universidade de Pernambuco - Campus Petrolina, BR 203, KM 2 - Vila Eduardo, Petrolina, 56328-900, Brazil
| | - Talita Câmara
- Universidade de Pernambuco - Campus Garanhuns, Rua Capitão Pedro Rodrigues, 105 - São José, Garanhuns, 55294-902, Brazil.,Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Universidade de Pernambuco - Campus Petrolina, BR 203, KM 2 - Vila Eduardo, Petrolina, 56328-900, Brazil
| | - Xavier Arnan
- Universidade de Pernambuco - Campus Garanhuns, Rua Capitão Pedro Rodrigues, 105 - São José, Garanhuns, 55294-902, Brazil.,Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Universidade de Pernambuco - Campus Petrolina, BR 203, KM 2 - Vila Eduardo, Petrolina, 56328-900, Brazil.,CREAF, Campus de Bellaterra (UAB) Edifici C, Cerdanyola del Vallès, 08193, Spain
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8
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Kaspari M, Joern A, Welti EAR. How and why grasshopper community maturation rates are slowing on a North American tall grass prairie. Biol Lett 2022; 18:20210510. [PMID: 35078328 PMCID: PMC8790374 DOI: 10.1098/rsbl.2021.0510] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/13/2021] [Indexed: 01/28/2023] Open
Abstract
Invertebrate growth rates have been changing in the Anthropocene. We examine rates of seasonal maturation in a grasshopper community that has been declining annually greater than 2% a year over 34 years. As this grassland has experienced a 1°C increase in temperature, higher plant biomass and lower nutrient densities, the community is maturing more slowly. Community maturation had a nutritional component: declining in years/watersheds with lower plant nitrogen. The effects of fire frequency were consistent with effects of plant nitrogen. Principal components analysis also suggests associated changes in species composition-declines in the densities of grass feeders were associated with declines in community maturation rates. We conclude that slowed maturation rates-a trend counteracted by frequent burning-likely contribute to long-term decline of this dominant herbivore.
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Affiliation(s)
- Michael Kaspari
- Geographical Ecology Group, University of Oklahoma, Norman, OK, USA
| | - Anthony Joern
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Ellen A. R. Welti
- Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany
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9
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Kaspari M, Weiser MD, Marshall KE, Miller M, Siler C, de Beurs K. Activity density at a continental scale: What drives invertebrate biomass moving across the soil surface? Ecology 2021; 103:e03542. [PMID: 34614206 DOI: 10.1002/ecy.3542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/08/2021] [Accepted: 09/22/2021] [Indexed: 11/08/2022]
Abstract
Activity density (AD), the rate that an individual taxon or its biomass moves through the environment, is used both to monitor communities and quantify the potential for ecosystem work. The Abundance Velocity Hypothesis posited that AD increases with aboveground net primary productivity (ANPP) and is a unimodal function of temperature. Here we show that, at continental extents, increasing ANPP may have nonlinear effects on AD: increasing abundance, but decreasing velocity as accumulating vegetation interferes with movement. We use 5 yr of data from the NEON invertebrate pitfall trap arrays including 43 locations and four habitat types for a total of 77 habitat-site combinations to evaluate continental drivers of invertebrate AD. ANPP and temperature accounted for one-third to 92% of variation in AD. As predicted, AD was a unimodal function of temperature in forests and grasslands but increased linearly in open scrublands. ANPP yielded further nonlinear effects, generating unimodal AD curves in wetlands, and bimodal curves in forests. While all four habitats showed no AD trends over 5 yr of sampling, these nonlinearities suggest that trends in AD, often used to infer changes in insect abundance, will vary qualitatively across ecoregions.
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Affiliation(s)
- Michael Kaspari
- Department of Biology, Geographical Ecology Group, University of Oklahoma, Norman, Oklahoma, 73019, USA
| | - Michael D Weiser
- Department of Biology, Geographical Ecology Group, University of Oklahoma, Norman, Oklahoma, 73019, USA
| | - Katie E Marshall
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Matthew Miller
- Department of Biology, Geographical Ecology Group, University of Oklahoma, Norman, Oklahoma, 73019, USA
| | - Cameron Siler
- Department of Biology, Geographical Ecology Group, University of Oklahoma, Norman, Oklahoma, 73019, USA.,Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, Norman, Oklahoma, 73072-7029, USA
| | - Kirsten de Beurs
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, Oklahoma, 73019, USA
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10
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Leahy L, Scheffers BR, Andersen AN, Hirsch BT, Williams SE. Vertical niche and elevation range size in tropical ants: Implications for climate resilience. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Lily Leahy
- Centre for Tropical Environmental and Sustainability Science College of Science & Engineering James Cook University Townsville Qld Australia
| | - Brett R. Scheffers
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| | - Alan N. Andersen
- Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT Australia
| | - Ben T. Hirsch
- Centre for Tropical Environmental and Sustainability Science College of Science & Engineering James Cook University Townsville Qld Australia
| | - Stephen E. Williams
- Centre for Tropical Environmental and Sustainability Science College of Science & Engineering James Cook University Townsville Qld Australia
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11
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12
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Warne RW, Baer SG, Boyles JG. Community Physiological Ecology. Trends Ecol Evol 2019; 34:510-518. [DOI: 10.1016/j.tree.2019.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 02/06/2023]
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13
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Lau MK, Ellison AM, Nguyen A, Penick C, DeMarco B, Gotelli NJ, Sanders NJ, Dunn RR, Helms Cahan S. Draft Aphaenogaster genomes expand our view of ant genome size variation across climate gradients. PeerJ 2019; 7:e6447. [PMID: 30881761 PMCID: PMC6417409 DOI: 10.7717/peerj.6447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 01/10/2019] [Indexed: 11/30/2022] Open
Abstract
Given the abundance, broad distribution, and diversity of roles that ants play in many ecosystems, they are an ideal group to serve as ecosystem indicators of climatic change. At present, only a few whole-genome sequences of ants are available (19 of >16,000 species), mostly from tropical and sub-tropical species. To address this limited sampling, we sequenced genomes of temperate-latitude species from the genus Aphaenogaster, a genus with important seed dispersers. In total, we sampled seven colonies of six species: Aphaenogaster ashmeadi, Aphaenogaster floridana, Aphaenogaster fulva, Aphaenogaster miamiana, Aphaenogaster picea, and Aphaenogaster rudis. The geographic ranges of these species collectively span eastern North America from southern Florida to southern Canada, which encompasses a latitudinal gradient in which many climatic variables are changing rapidly. For the six genomes, we assembled an average of 271,039 contigs into 47,337 scaffolds. The Aphaenogaster genomes displayed high levels of completeness with 96.1% to 97.6% of Hymenoptera BUSCOs completely represented, relative to currently sequenced ant genomes which ranged from 88.2% to 98.5%. Additionally, the mean genome size was 370.5 Mb, ranging from 310.3 to 429.7, which is comparable to that of other sequenced ant genomes (212.8-396.0 Mb) and flow cytometry estimates (210.7-690.4 Mb). In an analysis of currently sequenced ant genomes and the new Aphaenogaster sequences, we found that after controlling for both spatial autocorrelation and phylogenetics ant genome size was marginally correlated with sample site climate similarity. Of all examined climate variables, minimum temperature, and annual precipitation had the strongest correlations with genome size, with ants from locations with colder minimum temperatures and higher levels of precipitation having larger genomes. These results suggest that climate extremes could be a selective force acting on ant genomes and point to the need for more extensive sequencing of ant genomes.
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Affiliation(s)
| | | | - Andrew Nguyen
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
- Department of Biology, University of Vermont, Burlington, VT, USA
| | - Clint Penick
- The Biomimicry Center, Arizona State University, Tempe, AZ, USA
| | | | | | - Nathan J. Sanders
- Environmental Program, Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
| | - Robert R. Dunn
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
| | - Sara Helms Cahan
- Department of Biology, University of Vermont, Burlington, VT, USA
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14
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Kaspari M, Beurs K. On the geography of activity: productivity but not temperature constrains discovery rates by ectotherm consumers. Ecosphere 2019. [DOI: 10.1002/ecs2.2536] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Michael Kaspari
- Geographical Ecology Group Department of Biology University of Oklahoma Norman Oklahoma 73019 USA
| | - Kirsten Beurs
- Department of Geography and Environmental Sustainability University of Oklahoma Norman Oklahoma 73019 USA
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15
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Prather RM, Roeder KA, Sanders NJ, Kaspari M. Using metabolic and thermal ecology to predict temperature dependent ecosystem activity: a test with prairie ants. Ecology 2018; 99:2113-2121. [DOI: 10.1002/ecy.2445] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 05/22/2018] [Accepted: 06/18/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Rebecca M. Prather
- Department of Biology Graduate Program in Ecology and Evolutionary Biology University of Oklahoma Norman Oklahoma 73019 USA
| | - Karl A. Roeder
- Department of Biology Graduate Program in Ecology and Evolutionary Biology University of Oklahoma Norman Oklahoma 73019 USA
| | - Nathan J. Sanders
- Rubenstein School of Environment and Natural Resources University of Vermont Burlington Vermont 05405 USA
| | - Michael Kaspari
- Department of Biology Graduate Program in Ecology and Evolutionary Biology University of Oklahoma Norman Oklahoma 73019 USA
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16
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Is thermal limitation the primary driver of elevational distributions? Not for montane rainforest ants in the Australian Wet Tropics. Oecologia 2018; 188:333-342. [DOI: 10.1007/s00442-018-4154-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 03/05/2018] [Indexed: 12/23/2022]
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17
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Sheldon KS, Huey RB, Kaspari M, Sanders NJ. Fifty Years of Mountain Passes: A Perspective on Dan Janzen’s Classic Article. Am Nat 2018; 191:553-565. [DOI: 10.1086/697046] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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18
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Stark AY, Arstingstall K, Yanoviak SP. Adhesive performance of tropical arboreal ants varies with substrate temperature. ACTA ACUST UNITED AC 2018; 221:jeb.171843. [PMID: 29146768 DOI: 10.1242/jeb.171843] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 11/09/2017] [Indexed: 11/20/2022]
Abstract
The surface temperature of tree branches in the tropical rainforest canopy can reach up to 55°C. Ants and other small cursorial organisms must maintain adequate attachment in this extreme microenvironment to forage effectively and avoid falling. Ant adhesion depends on liquid secretions that should become less viscous at high temperatures, causing ants to slip. However, tropical arboreal ants have high thermal tolerance and actively forage on hot canopy surfaces, suggesting that these ants can maintain adhesion on hot substrates. We measured tarsal pad shear adhesion of 580 workers (representing 11 species and four subfamilies) of tropical arboreal ants at temperatures spanning the range observed in the field (23-55°C). Adhesive performance among species showed three general trends: (1) a linear decrease with increasing temperature, (2) a non-linear relationship with peak adhesive performance at ca. 30-40°C, and (3) no relationship with temperature. The mechanism responsible for these large interspecific differences remains to be determined, but likely reflects variation in the composition of the secreted adhesive fluid. Understanding such differences will reveal the diverse ways that ants cope with highly variable, and often unpredictable, thermal conditions in the forest canopy.
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Affiliation(s)
- Alyssa Y Stark
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, KY 40292, USA
| | - Katherine Arstingstall
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, KY 40292, USA
| | - Stephen P Yanoviak
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, KY 40292, USA.,Smithsonian Tropical Research Institute, Balboa, Republic of Panama
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19
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Warren II RJ, Bayba S, Krupp KT. Interacting effects of urbanization and coastal gradients on ant thermal responses. JOURNAL OF URBAN ECOLOGY 2018. [DOI: 10.1093/jue/juy026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- R J Warren II
- Department of Biology, SUNY Buffalo State, 1300 Elmwood Avenue, Buffalo, NY, USA
| | - S Bayba
- Department of Biology, SUNY Buffalo State, 1300 Elmwood Avenue, Buffalo, NY, USA
| | - K T Krupp
- Department of Biology, SUNY Buffalo State, 1300 Elmwood Avenue, Buffalo, NY, USA
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20
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Rubin AM, Blob RW, Mayerl CJ. Biomechanical factors influencing successful self-righting in the pleurodire turtle, Emydura subglobosa. J Exp Biol 2018; 221:jeb.182642. [DOI: 10.1242/jeb.182642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/21/2018] [Indexed: 11/20/2022]
Abstract
Self-righting performance is a key ability for most terrestrial animals, and has been used as a metric of fitness, exhaustion, and thermal limits in a variety of taxa. However, there is little understanding of the underlying mechanisms that drive variation in self-righting performance. To evaluate the mechanical factors that contribute to success versus failure when animals attempt to self-right, we compared force production and kinematic behavior in the rigid-bodied, pleurodire turtle Emydura subglobosa between successful and unsuccessful self-righting efforts. We found that the moment exerted during efforts to roll the body and the velocity of that roll are the primary drivers behind self-righting success. Specifically, turtles that self-righted successfully produced both larger moments and faster rolls than turtles that failed. In contrast, the angle at which the head was directed to lever the body and the extent of yaw that was incorporated in addition to roll had little impact on the likelihood of success. These results show that specific performance metrics can predict the ability of animals to self-right, providing a framework for biomimetic applications as well future comparisons to test for differences in self-righting performance across animals from different environments, sexes, populations, and species.
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Affiliation(s)
- Alex M. Rubin
- Department of Biological Sciences, Auburn University, Auburn AL, 36830, USA
| | - Richard W. Blob
- Department of Biological Sciences, Clemson University, Clemson SC, 29631 USA
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21
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Bujan J, Kaspari M. Nutrition modifies critical thermal maximum of a dominant canopy ant. JOURNAL OF INSECT PHYSIOLOGY 2017; 102:1-6. [PMID: 28830761 DOI: 10.1016/j.jinsphys.2017.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 08/13/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
While adaptive responses to climate gradients are increasingly documented, little is known about how individuals alter their upper thermal tolerances. Long-term increases in dietary carbohydrates can elevate upper thermal tolerances in insects. We explored how the nutritional state of a Neotropical canopy ant governs its CTmax - the temperature at which individuals lose muscle control. We predicted that Azteca chartifex workers recently fed a carbohydrate-rich diet, such as honeydew and extrafloral nectar, would use that energy to increase their CTmax. Moreover, if a carbohydrate-rich diet increases CTmax, then we predicted that ants from colonies with high CTmaxs feed at a lower trophic level, and thus have a higher carbon:nitrogen ratio. We used A. chartifex colonies from a long-term fertilization experiment where phosphorus addition increased A. chartifex foraging activity with respect to controls. As foraging activity can be governed by resource availability, we first measured CTmax of field collected colonies. In freshly collected field colonies, CTmax was 2°C higher in control plots. This difference disappeared when ants were provided with only water for 10h. Ants were then provided with a 10% sucrose solution ad lib which increased CTmax by 5°C. We thus support the hypothesis that enhanced carbohydrate nutrition enables higher thermal tolerance, but this does not appear to be linked to colony trophic status, higher carbon:nitrogen ratios, or higher total body phosphorus. This short-term thermal plasticity linked to carbohydrate nutrition demonstrates the importance of ant diet in shaping their physiological traits. It is especially relevant to ant species that maintain high abundance by feeding on plant exudates. In a rapidly warming world, carbohydrate availability and use may represent a new element for predicting population and community responses of herbivorous insects.
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Affiliation(s)
- Jelena Bujan
- Department of Biology, Graduate Program in Ecology and Evolutionary Biology, University of Oklahoma, Norman, OK, USA.
| | - Michael Kaspari
- Department of Biology, Graduate Program in Ecology and Evolutionary Biology, University of Oklahoma, Norman, OK, USA; Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
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22
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Stark AY, Adams BJ, Fredley JL, Yanoviak SP. Out on a limb: Thermal microenvironments in the tropical forest canopy and their relevance to ants. J Therm Biol 2017; 69:32-38. [PMID: 29037401 DOI: 10.1016/j.jtherbio.2017.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/22/2017] [Accepted: 06/03/2017] [Indexed: 11/17/2022]
Abstract
Small, cursorial ectotherms like ants often are immersed in the superheated air layers that develop millimeters above exposed, insolated surfaces (i.e., the thermal boundary layer). We quantified the thermal microenvironments around tree branches in the tropical rainforest canopy, and explored the effects of substrate color on the internal body temperature and species composition of arboreal ants. Branch temperatures during the day (09:00-16:00) were hottest (often > 50°C) and most variable on the upper surface, while the lowest and least variable temperatures occurred on the underside. Temperatures on black substrates declined with increasing distance above the surface in both the field and the laboratory. By contrast, a micro-scale temperature inversion occurred above white substrates. Wind events (ca. 2ms-1) eliminated these patterns. Internal temperatures of bodies of Cephalotes atratus workers experimentally heated in the laboratory were 6°C warmer on white vs. black substrates, and 6°C cooler than ambient in windy conditions. The composition of ant species foraging at baits differed between black-painted and unpainted tree branches, with a tendency for smaller ants to avoid the significantly hotter black surfaces. Collectively, these outcomes show that ants traversing canopy branches experience very heterogeneous thermal microenvironments that are partly influenced in predictable ways by branch surface coloration and breezy conditions.
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Affiliation(s)
- Alyssa Y Stark
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, Kentucky 40292, USA
| | - Benjamin J Adams
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, Kentucky 40292, USA
| | - Jennifer L Fredley
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, Kentucky 40292, USA
| | - Stephen P Yanoviak
- Department of Biology, University of Louisville, 139 Life Sciences Building, Louisville, Kentucky 40292, USA; Smithsonian Tropical Research Institute, Balboa, Panama.
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23
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DeLong JP, Gibert JP, Luhring TM, Bachman G, Reed B, Neyer A, Montooth KL. The combined effects of reactant kinetics and enzyme stability explain the temperature dependence of metabolic rates. Ecol Evol 2017; 7:3940-3950. [PMID: 28616189 PMCID: PMC5468145 DOI: 10.1002/ece3.2955] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/28/2017] [Accepted: 03/07/2017] [Indexed: 01/19/2023] Open
Abstract
A mechanistic understanding of the response of metabolic rate to temperature is essential for understanding thermal ecology and metabolic adaptation. Although the Arrhenius equation has been used to describe the effects of temperature on reaction rates and metabolic traits, it does not adequately describe two aspects of the thermal performance curve (TPC) for metabolic rate—that metabolic rate is a unimodal function of temperature often with maximal values in the biologically relevant temperature range and that activation energies are temperature dependent. We show that the temperature dependence of metabolic rate in ectotherms is well described by an enzyme‐assisted Arrhenius (EAAR) model that accounts for the temperature‐dependent contribution of enzymes to decreasing the activation energy required for reactions to occur. The model is mechanistically derived using the thermodynamic rules that govern protein stability. We contrast our model with other unimodal functions that also can be used to describe the temperature dependence of metabolic rate to show how the EAAR model provides an important advance over previous work. We fit the EAAR model to metabolic rate data for a variety of taxa to demonstrate the model's utility in describing metabolic rate TPCs while revealing significant differences in thermodynamic properties across species and acclimation temperatures. Our model advances our ability to understand the metabolic and ecological consequences of increases in the mean and variance of temperature associated with global climate change. In addition, the model suggests avenues by which organisms can acclimate and adapt to changing thermal environments. Furthermore, the parameters in the EAAR model generate links between organismal level performance and underlying molecular processes that can be tested for in future work.
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Affiliation(s)
- J P DeLong
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
| | - J P Gibert
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA.,Present address: The University of California, Merced Merced CA USA
| | - T M Luhring
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
| | - G Bachman
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
| | - B Reed
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
| | - A Neyer
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
| | - K L Montooth
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
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24
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Spicer ME, Stark AY, Adams BJ, Kneale R, Kaspari M, Yanoviak SP. Thermal constraints on foraging of tropical canopy ants. Oecologia 2017; 183:1007-1017. [PMID: 28132105 DOI: 10.1007/s00442-017-3825-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
Abstract
Small cursorial ectotherms risk overheating when foraging in the tropical forest canopy, where the surfaces of unshaded tree branches commonly exceed 50 °C. We quantified the heating and subsequent cooling rates of 11 common canopy ant species from Panama and tested the hypothesis that ant workers stop foraging at temperatures consistent with the prevention of overheating. We created hot experimental "sunflecks" on existing foraging trails of four ant species from different clades and spanning a broad range of body size, heating rate, and critical thermal maxima (CTmax). Different ant species exhibited very different heating rates in the lab, and these differences did not follow trends predicted by body size alone. Experiments with ant models showed that heating rates are strongly affected by color in addition to body size. Foraging workers of all species showed strong responses to heating and consistently abandoned focal sites between 36 and 44 °C. Atta colombica and Azteca trigona workers resumed foraging shortly after heat was removed, but Cephalotes atratus and Dolichoderus bispinosus workers continued to avoid the heated patch even after >5 min of cooling. Large foraging ants (C. atratus) responded slowly to developing thermal extremes, whereas small ants (A. trigona) evacuated sunflecks relatively quickly, and at lower estimated body temperatures than when revisiting previously heated patches. The results of this study provide the first field-based insight into how foraging ants respond behaviorally to the heterogeneous thermal landscape of the tropical forest canopy.
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Affiliation(s)
- Michelle Elise Spicer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Alyssa Y Stark
- Department of Biology, University of Louisville, Louisville, KY, 40292, USA
| | - Benjamin J Adams
- Department of Biology, University of Louisville, Louisville, KY, 40292, USA
| | - Riley Kneale
- Department of Biology, University of Louisville, Louisville, KY, 40292, USA
| | - Michael Kaspari
- Department of Biology, University of Oklahoma, Norman, OK, 73019, USA.,Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Stephen P Yanoviak
- Department of Biology, University of Louisville, Louisville, KY, 40292, USA. .,Smithsonian Tropical Research Institute, Balboa, Republic of Panama.
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25
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Báez S, Jaramillo L, Cuesta F, Donoso DA. Effects of climate change on Andean biodiversity: a synthesis of studies published until 2015. NEOTROPICAL BIODIVERSITY 2016. [DOI: 10.1080/23766808.2016.1248710] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Selene Báez
- Consorcio para el Desarrollo Sostenible de la Ecoregion Andina, Lima, Peru
- Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Quito, Ecuador
| | - Liliana Jaramillo
- Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador
| | - Francisco Cuesta
- Consorcio para el Desarrollo Sostenible de la Ecoregion Andina, Lima, Peru
- Institute for Biodiversity & Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands
| | - David A. Donoso
- Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador
- Facultad de Ciencias Agropecuarias, Universidad de Cuenca, Cuenca, Ecuador
- Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Quito, Ecuador
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