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MacLean HJ, Hjort Hansen J, Sørensen JG. Validating the automation of different measures of high temperature tolerance of small terrestrial insects. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104362. [PMID: 35108549 DOI: 10.1016/j.jinsphys.2022.104362] [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: 05/20/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Accurately phenotyping numerous test subjects is essential for most experimental research. Collecting such data can be tedious or time-consuming, and it can be biased or limited using manual observations. The thermal tolerance of small ectotherms is a good example of this type of phenotypic data, and it is widely used to investigate thermal adaptation, acclimation capacity and climate change resilience of small ectotherms. Here, we present the results of automatically generated thermal tolerance data using motion-tracking software on video recordings. The automatization was applied to two different heat tolerance assays, in two Drosophila species and used temperature acclimation to create variation in thermal tolerances. We find similar effect sizes of acclimation and hardening responses between manual and automated approaches, but different absolute tolerance estimates. This discrepancy likely reflects both technical differences in the assay conditions as well as the measured end-points of the assays. We conclude that both methods generate biological meaningful results, which reflect different aspects of the thermal biology, find no evidence of inflated variance in the manually scored assays, but find that automation can increase throughput several times without compromising quality. Further we show that the method can be applied to a wide range of arthropod taxa. We suggest that this automated method is a useful example of high throughput phenotyping. Further, we suggest this approach might be applied to other tedious laboratory traits, such as desiccation or starvation tolerance, with similar benefits to throughput but caution that the interpretation and potential comparison to results using different methodology rely on thorough validation of the assay and the involved biological mechanism.
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Affiliation(s)
- Heidi J MacLean
- Department of Biology, Aarhus University, Ny Munkegade 114, Bldg. 1540, 8000 Aarhus C, Denmark.
| | - Jonas Hjort Hansen
- Department of Biology, Aarhus University, Ny Munkegade 114, Bldg. 1540, 8000 Aarhus C, Denmark
| | - Jesper G Sørensen
- Department of Biology, Aarhus University, Ny Munkegade 114, Bldg. 1540, 8000 Aarhus C, Denmark
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Laursen SF, Hansen LS, Bahrndorff S, Nielsen HM, Noer NK, Renault D, Sahana G, Sørensen JG, Kristensen TN. Contrasting Manual and Automated Assessment of Thermal Stress Responses and Larval Body Size in Black Soldier Flies and Houseflies. INSECTS 2021; 12:380. [PMID: 33922364 PMCID: PMC8146041 DOI: 10.3390/insects12050380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 11/16/2022]
Abstract
Within ecophysiological and genetic studies on insects, morphological and physiological traits are commonly assessed and phenotypes are typically obtained from manual measurements on numerous individuals. Manual observations are, however, time consuming, can introduce observer bias and are prone to human error. Here, we contrast results obtained from manual assessment of larval size and thermal tolerance traits in black soldier flies (Hermetia illucens) and houseflies (Musca domestica) that have been acclimated under three different temperature regimes with those obtained automatically using an image analysis software (Noldus EthoVision XT). We found that (i) larval size estimates of both species, obtained by manual weighing or by using the software, were highly correlated, (ii) measures of heat and cold tolerance using manual and automated approaches provided qualitatively similar results, and (iii) by using the software we obtained quantifiable information on stress responses and acclimation effects of potentially higher ecological relevance than the endpoint traits that are typically assessed when manual assessments are used. Based on these findings, we argue that automated assessment of insect stress responses and largescale phenotyping of morphological traits such as size will provide new opportunities within many disciplines where accurate and largescale phenotyping of insects is required.
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Affiliation(s)
- Stine Frey Laursen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark; (S.B.); (N.K.N.); (T.N.K.)
| | - Laura Skrubbeltrang Hansen
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark; (L.S.H.); (H.M.N.); (G.S.)
| | - Simon Bahrndorff
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark; (S.B.); (N.K.N.); (T.N.K.)
| | - Hanne Marie Nielsen
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark; (L.S.H.); (H.M.N.); (G.S.)
| | - Natasja Krog Noer
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark; (S.B.); (N.K.N.); (T.N.K.)
| | - David Renault
- University of Rennes, CNRS, ECOBIO (Ecosystémes, Biodiversité, Evolution)-UMR, 6553 Rennes, France;
- Institut Universitaire de France, 1 Rue Descartes, CEDEX 05, 75231 Paris, France
| | - Goutam Sahana
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark; (L.S.H.); (H.M.N.); (G.S.)
| | - Jesper Givskov Sørensen
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Ny Munkegade 116, 8000 Aarhus C, Denmark;
| | - Torsten Nygaard Kristensen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark; (S.B.); (N.K.N.); (T.N.K.)
- Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark
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Saito D, Maruyama N, Hashimoto Y, Ikegami T. Visualization of dynamic structure in flocking behavior. ARTIFICIAL LIFE AND ROBOTICS 2020. [DOI: 10.1007/s10015-020-00660-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Burton T, Einum S. The old and the large may suffer disproportionately during episodes of high temperature: evidence from a keystone zooplankton species. CONSERVATION PHYSIOLOGY 2020; 8:coaa038. [PMID: 32411372 PMCID: PMC7210711 DOI: 10.1093/conphys/coaa038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/05/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Widespread declines in the body size of aquatic ectotherms have been attributed to the poorer ability of older, larger individuals to tolerate high temperature. Here, using the thermal death time curve framework, we investigate the relationship between temperature tolerance and size/age by measuring the change in heat tolerance of the keystone zooplankton species Daphnia magna across a range of temperature intensities (and hence exposures of varying duration) among individuals that differed up to 3-fold in size and thus varied in age also. Across the gradient of exposure temperatures, younger, smaller individuals were more tolerant than older, larger individuals. This suggests that the young and the small may be better equipped to withstand temperature challenges that are both intense/brief and more moderate/prolonged. Our study generalizes results obtained from more acute tolerance assays, providing physiological evidence consistent with the observed reductions in ectotherm body size as a response to warming in aquatic systems.
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Affiliation(s)
- Tim Burton
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
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Burton T, Lakka HK, Einum S. Acclimation capacity and rate change through life in the zooplankton Daphnia. Proc Biol Sci 2020; 287:20200189. [PMID: 32228409 PMCID: PMC7209067 DOI: 10.1098/rspb.2020.0189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/10/2020] [Indexed: 12/26/2022] Open
Abstract
When a change in the environment occurs, organisms can maintain an optimal phenotypic state via plastic, reversible changes to their phenotypes. These adjustments, when occurring within a generation, are described as the process of acclimation. While acclimation has been studied for more than half a century, global environmental change has stimulated renewed interest in quantifying variation in the rate and capacity with which this process occurs, particularly among ectothermic organisms. Yet, despite the likely ecological importance of acclimation capacity and rate, how these traits change throughout life among members of the same species is largely unstudied. Here we investigate these relationships by measuring the acute heat tolerance of the clonally reproducing zooplankter Daphnia magna of different size/age and acclimation status. The heat tolerance of individuals completely acclimated to relatively warm (28°C) or cool (17°C) temperatures diverged during development, indicating that older, larger individuals had a greater capacity to increase heat tolerance. However, when cool acclimated individuals were briefly exposed to the warm temperature (i.e. were 'heat-hardened'), it was younger, smaller animals with less capacity to acclimate that were able to do so more rapidly because they obtained or came closer to obtaining complete acclimation of heat tolerance. Our results illustrate that within a species, individuals can differ substantially in how rapidly and by how much they can respond to environmental change. We urge greater investigation of the intraspecific relationship between acclimation and development along with further consideration of the factors that might contribute to these enigmatic patterns of phenotypic variation.
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Affiliation(s)
- Tim Burton
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| | - Hanna-Kaisa Lakka
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
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Affiliation(s)
- Tim Burton
- Department of Biology Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway
| | - Hanna‐Kaisa Lakka
- Department of Biology Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Sigurd Einum
- Department of Biology Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway
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Kielland ØN, Bech C, Einum S. Warm and out of breath: Thermal phenotypic plasticity in oxygen supply. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13449] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Øystein Nordeide Kielland
- Department of Natural History Centre for Biodiversity Dynamics Norwegian Univ. of Science and Technology NTNU University Museum Trondheim Norway
- Department of Biology Centre for Biodiversity Dynamics Norwegian Univ. of Science and Technology NTNU Trondheim Norway
| | - Claus Bech
- Department of Biology Norwegian Univ. of Science and Technology NTNU Trondheim Norway
| | - Sigurd Einum
- Department of Biology Centre for Biodiversity Dynamics Norwegian Univ. of Science and Technology NTNU Trondheim Norway
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