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Hoffmann AA, Sgrò CM. Comparative studies of critical physiological limits and vulnerability to environmental extremes in small ectotherms: How much environmental control is needed? Integr Zool 2019; 13:355-371. [PMID: 29168624 PMCID: PMC6099205 DOI: 10.1111/1749-4877.12297] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Researchers and practitioners are increasingly using comparative assessments of critical thermal and physiological limits to assess the relative vulnerability of ectothermic species to extreme thermal and aridity conditions occurring under climate change. In most assessments of vulnerability, critical limits are compared across taxa exposed to different environmental and developmental conditions. However, many aspects of vulnerability should ideally be compared when species are exposed to the same environmental conditions, allowing a partitioning of sources of variation such as used in quantitative genetics. This is particularly important when assessing the importance of different types of plasticity to critical limits, using phylogenetic analyses to test for evolutionary constraints, isolating genetic variants that contribute to limits, characterizing evolutionary interactions among traits limiting adaptive responses, and when assessing the role of cross generation effects. However, vulnerability assessments based on critical thermal/physiological limits also need to take place within a context that is relevant to field conditions, which is not easily provided under controlled environmental conditions where behavior, microhabitat, stress exposure rates and other factors will differ from field conditions. There are ways of reconciling these requirements, such as by taking organisms from controlled environments and then testing their performance under field conditions (or vice versa). While comparisons under controlled environments are challenging for many taxa, assessments of critical thermal limits and vulnerability will always be incomplete unless environmental effects within and across generations are considered, and where the ecological relevance of assays measuring critical limits can be established.
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Affiliation(s)
- Ary A Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Carla M Sgrò
- School of Biological Sciences, Monash University, Melbourne, Australia
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2
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Colinet H, Rinehart JP, Yocum GD, Greenlee KJ. Mechanisms underpinning the beneficial effects of fluctuating thermal regimes in insect cold tolerance. J Exp Biol 2018; 221:221/14/jeb164806. [DOI: 10.1242/jeb.164806] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
ABSTRACT
Insects exposed to low temperature often have high mortality or exhibit sublethal effects. A growing number of recent studies have shown beneficial effects of exposing insects to recurrent brief warm pulses during low-temperature stress (fluctuating thermal regime, FTR). The physiological underpinnings of the beneficial effects of FTR on cold survival have been extensively studied over the past few years. Profiling with various ‘-omics’ techniques has provided supporting evidence for different physiological responses between insects exposed to FTR and constant low temperature. Evidence from transcriptomic, metabolomic and lipidomic studies points to a system-wide loss of homeostasis at low temperature that can be counterbalanced by repair mechanisms under FTR. Although there has been considerable progress in understanding the physiological mechanisms underlying the beneficial effects of FTR, here we discuss how many areas still lack clarity, such as the precise role(s) of heat shock proteins, compatible solutes or the identification of regulators and key players involved in the observed homeostatic responses. FTR can be particularly beneficial in applied settings, such as for model insects used in research, integrated pest management and pollination services. We also explain how the application of FTR techniques in large-scale facilities may require overcoming some logistical and technical constraints. FTR definitively enhances survival at low temperature in insects, but before it can be widely used, we suggest that the possible fitness and energy costs of FTR must be explored more thoroughly. Although FTR is not ecologically relevant, similar processes may operate in settings where temperatures fluctuate naturally.
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Affiliation(s)
- Hervé Colinet
- Univ Rennes, CNRS, ECOBIO-UMR 6553, 263 Ave du Général Leclerc, 35042 Rennes, France
| | - Joseph P. Rinehart
- USDA-ARS Red River Valley Agricultural Research Center, Biosciences Research Laboratory, 1605 Albrecht Boulevard, Fargo, ND 58102-2765, USA
| | - George D. Yocum
- USDA-ARS Red River Valley Agricultural Research Center, Biosciences Research Laboratory, 1605 Albrecht Boulevard, Fargo, ND 58102-2765, USA
| | - Kendra J. Greenlee
- Department of Biological Sciences, PO Box 6050, Dept 2715, North Dakota State University, Fargo, ND 58108-6050, USA
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Enriquez T, Colinet H. Basal tolerance to heat and cold exposure of the spotted wing drosophila, Drosophila suzukii. PeerJ 2017; 5:e3112. [PMID: 28348931 PMCID: PMC5366067 DOI: 10.7717/peerj.3112] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/21/2017] [Indexed: 11/20/2022] Open
Abstract
The spotted wing Drosophila, Drosophila suzukii, is a new pest in Europe and America which causes severe damages, mostly to stone fruit crops. Temperature and humidity are among the most important abiotic factors governing insect development and fitness. In many situations, temperature can become stressful thus compromising survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality of D. suzukii is essential to facilitate management of this pest. The objective of the present study was to investigate D. suzukii basal cold and heat tolerance. Adults and pupae were subjected to six low temperatures (-5-7.5 °C) and seven high temperatures (30-37 °C) for various durations, and survival-time-temperature relationships were investigated. Data showed that males were globally more cold tolerant than females. At temperature above 5 °C, adult cold mortality became minor even after prolonged exposures (e.g., only 20% mortality after one month at 7.5 °C). Heat tolerance of males was lower than that of females at the highest tested temperatures (34, 35 and 37 °C). Pupae appeared much less cold tolerant than adults at all temperatures (e.g., Lt50 at 5° C: 4-5 d for adults vs. 21 h for pupae). Pupae were more heat tolerant than adults at the most extreme high temperatures (e.g., Lt50 at 37 °C: 30 min for adults vs. 4 h for pupae). The pupal thermal tolerance was further investigated under low vs. high humidity. Low relative humidity did not affect pupal cold survival, but it reduced survival under heat stress. Overall, this study shows that survival of D. suzukii under heat and cold conditions can vary with stress intensity, duration, humidity, sex and stage, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description of D. suzukiithermal tolerance and limits.
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Affiliation(s)
- Thomas Enriquez
- Université de Rennes I, UMR CNRS 6553 ECOBIO, Rennes, France
| | - Hervé Colinet
- Université de Rennes I, UMR CNRS 6553 ECOBIO, Rennes, France
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Affiliation(s)
- Johannes Overgaard
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark;
| | - Heath A. MacMillan
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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Plantamp C, Salort K, Gibert P, Dumet A, Mialdea G, Mondy N, Voituron Y. All or nothing: Survival, reproduction and oxidative balance in Spotted Wing Drosophila (Drosophila suzukii) in response to cold. JOURNAL OF INSECT PHYSIOLOGY 2016; 89:28-36. [PMID: 27040270 DOI: 10.1016/j.jinsphys.2016.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/23/2016] [Accepted: 03/31/2016] [Indexed: 06/05/2023]
Abstract
Winter severity and overwintering capacity are key ecological factors in successful invasions, especially in ectotherms. The integration of physiological approaches into the study of invasion processes is emerging and promising. Physiological information describes the mechanisms underlying observed survival and reproductive capacities, and it can be used to predict an organism's response to environmental perturbations such as cold temperatures. We investigated the effects of various cold treatments on life history and physiological traits of an invasive pest species, Drosophila suzukii, such as survival, fertility and oxidative balance. This species, a native of temperate Asian areas, is known to survive where cold temperatures are particularly harsh and has been recently introduced into Europe and North America. We found that cold treatments had a strong impact on adult survival but no effect on female's fertility. Although only minor changes were observed after cold treatment on studied physiological traits, a strong sex-based difference was observed in both survival and physiological markers (antioxidant defences and oxidative markers). Females exhibited higher survival, reduced oxidative defences, less damage to nucleic acids, and more damage to lipids. These results suggest that D. suzukii relies on a pathway other than oxidative balance to resist cold injury. Altogether, our results provide information concerning the mechanisms of successful invasion by D. suzukii. These findings may assist in the development of population models that predict the current and future geographic ranges of this species.
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Affiliation(s)
- Christophe Plantamp
- Université de Lyon, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, CNRS, Université Lyon 1, Université Claude Bernard, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France.
| | - Katleen Salort
- Université de Lyon, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, CNRS, Université Lyon 1, Université Claude Bernard, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France; Université de Lyon, UMR 5023, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, Université Claude Bernard, ENTPE, CNRS, 6 rue Raphaël Dubois, F-69622 Villeurbanne, France
| | - Patricia Gibert
- Université de Lyon, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, CNRS, Université Lyon 1, Université Claude Bernard, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France
| | - Adeline Dumet
- Université de Lyon, UMR 5023, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, Université Claude Bernard, ENTPE, CNRS, 6 rue Raphaël Dubois, F-69622 Villeurbanne, France
| | - Gladys Mialdea
- Université de Lyon, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, CNRS, Université Lyon 1, Université Claude Bernard, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France
| | - Nathalie Mondy
- Université de Lyon, UMR 5023, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, Université Claude Bernard, ENTPE, CNRS, 6 rue Raphaël Dubois, F-69622 Villeurbanne, France
| | - Yann Voituron
- Université de Lyon, UMR 5023, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, Université Claude Bernard, ENTPE, CNRS, 6 rue Raphaël Dubois, F-69622 Villeurbanne, France
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Javal M, Renault D, Colinet H. Impact of fluctuating thermal regimes on Drosophila melanogaster survival to cold stress. ANIM BIOL 2016. [DOI: 10.1163/15707563-00002510] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Temperature directly affects survival, development and reproduction in insects and thereby it is a key environmental driver for geographic distribution and population dynamics. This study aims at testing the survival of Drosophila melanogaster under constant low temperatures (CLTs) (2, 3, 4, and 5°C) vs. fluctuating thermal regimes (FTRs). In the latter, the cold stress period was interrupted daily by 2 h pulses at 20°C. Since acclimation enhances cold tolerance, we tested whether benefits of acclimation can combine with those of FTRs. Since D. melanogaster overwinters as non-reproductive adults, we tested if actively reproducing adults are more susceptible to cold stress than virgin females that have a much reduced reproductive activity. The results show that short interruptions of cold stress enhanced survival of adult flies. Survival was time- and temperature-dependent. Prior acclimation to low temperature allowed flies to better cope with cold stress under CLTs. On the other hand, acclimated flies did not profit from the benefits of FTRs and even showed lower survival under FTRs, probably because flies deacclimated during the periodic warm intervals. Gravid females were overall less cold tolerant than virgin females, and both survived better under FTRs. Cold survival at pupal stage was much lower than at adult stage, and no clear benefit of FTR was observed in this life stage. Our study highlights critical variables to take into account when designing experiments of prolonged exposure to low temperature in insects.
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Affiliation(s)
| | - David Renault
- 2Université de Rennes 1, UMR CNRS 6553 ECOBIO, 263 Avenue du Général-Leclerc, 35042 Rennes, France
| | - Hervé Colinet
- 2Université de Rennes 1, UMR CNRS 6553 ECOBIO, 263 Avenue du Général-Leclerc, 35042 Rennes, France
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Olsson T, MacMillan HA, Nyberg N, Stærk D, Malmendal A, Overgaard J. Hemolymph metabolites and osmolality are tightly linked to cold tolerance of Drosophila species: a comparative study. J Exp Biol 2016; 219:2504-13. [DOI: 10.1242/jeb.140152] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/04/2016] [Indexed: 01/20/2023]
Abstract
Drosophila, like most insects, are susceptible to low temperatures, and will succumb to temperatures above the freezing point of their hemolymph. For these insects, cold exposure causes a loss of extracellular ion and water homeostasis, leading to chill injury and eventually death. Chill tolerant species are characterized by lower hemolymph [Na+] than chill susceptible species and this lowered hemolymph [Na+] is suggested to improve ion and water homeostasis during cold exposure. It has therefore also been hypothesized that hemolymph Na+ is replaced by other “cryoprotective” osmolytes in cold tolerant species. Here, we compare the hemolymph metabolite profiles of five drosophilid species with marked difference in chill tolerance. All species were examined under “normal” thermal conditions (i.e. 20°C) and following cold exposure (4 hours at 0°C). Under benign conditions total hemolymph osmolality was similar among all species despite chill tolerant species having lower hemolymph [Na+]. Using NMR spectroscopy we found that chill tolerant species instead have higher levels of sugars and free amino acids in their hemolymph, including classical “cryoprotectants” such as trehalose and proline. In addition, we found that chill tolerant species maintain a relatively stable hemolymph osmolality and metabolite profile when exposed to cold stress while sensitive species suffer from large increases in osmolality and massive changes in their metabolic profiles during a cold stress. We suggest that the larger contribution of classical “cryoprotectants” in chill tolerant Drosophila play a non-colligative role for cold tolerance that contributes to osmotic and ion homeostasis during cold exposures and in addition we discuss how these comparative differences may represent an evolutionary pathway toward more extreme cold tolerance of insects.
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Affiliation(s)
- Trine Olsson
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Møllers Allé 3, Building 1131, DK-8000 Aarhus, Denmark
| | - Heath A. MacMillan
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Møllers Allé 3, Building 1131, DK-8000 Aarhus, Denmark
| | - Nils Nyberg
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen O, Denmark
| | - Dan Stærk
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen O, Denmark
| | - Anders Malmendal
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Johannes Overgaard
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Møllers Allé 3, Building 1131, DK-8000 Aarhus, Denmark
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