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Adaptive changes in energy reserves and effects of body melanization on thermal tolerance in Drosophila simulans. Comp Biochem Physiol A Mol Integr Physiol 2022; 271:111258. [PMID: 35705113 DOI: 10.1016/j.cbpa.2022.111258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/11/2022] [Accepted: 06/08/2022] [Indexed: 11/22/2022]
Abstract
Seasonally polyphenic types have been documented in many Drosophilids, which differ significantly during thermal stress. Although Drosophila simulans is a sibling species to Drosophila melanogaster, both thrive in the temperate and tropical climates, but various climatic factors are expected to impact their distribution and abundance. As a result, D. simulans may use phenotypic plasticity to adapt to colder and drier circumstances in temperate zones, although such studies are less known. In the present study, our main aim was to find a link between adaptive plasticity and thermal tolerance in D. simulans. We characterized two morphs in D. simulans flies based on the abdominal melanization collected from the same locality and season, as this trait is highly associated with the larval developmental conditions. Our results suggested that flies reared from dark and light morph showed significant differences in the basal level of proline, carbohydrates (trehalose, glycogen), and lipids (cuticular lipids and total body lipids) within simulated seasons and morph lineages in D. simulans flies. We further showed that D. simulans reared from dark morph are better adapted to cold conditions, whereas light flies are more adapted to warm conditions. The flies, both from light and dark morph lineages, when reared at 15 °C, showed an increase in the level of total body lipids after acclimation at 0 °C but a decrease in the level of proline and carbohydrates (trehalose, glycogen). Heat acclimation increases glycogen levels in the flies from light morph lineage while decreases trehalose and proline.
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2
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Rajpurohit S, Zhao X, Schmidt PS. A resource on latitudinal and altitudinal clines of ecologically relevant phenotypes of the Indian Drosophila. Sci Data 2017; 4:170066. [PMID: 28509912 PMCID: PMC5433391 DOI: 10.1038/sdata.2017.66] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 04/07/2017] [Indexed: 01/26/2023] Open
Abstract
The unique geography of the Indian subcontinent has provided diverse natural environments for a variety of organisms. In this region, many ecological indices such as temperature and humidity vary predictably as a function of both latitude and altitude; these environmental parameters significantly affect fundamental dynamics of natural populations. Indian drosophilids are diverse in their geographic distribution and climate tolerance, possibly as a result of climatic adaptation. These associations with environmental parameters are further reflected in a large number of clines that have been reported for various fitness traits along these geographical ranges. This unique amalgamation of environmental variability and genetic diversity make the subcontinent an ecological laboratory for studying evolution in action. We assembled data collected over the last 20 years on the geographical clines for various phenotypic traits in several species of drosophilids and present a web-resource on Indian-Drosophila ( http://www.indian-drosophila.org/). The clinal data on ecologically relevant phenotypes of Indian drosophilids will be useful in addressing questions related to future challenges in biodiversity and ecosystems in this region.
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Affiliation(s)
- Subhash Rajpurohit
- Department of Biology, University of Pennsylvania, 433 S University Ave, Philadelphia, Pennsylvania 19104, USA
| | - Xiaqing Zhao
- Department of Pathology, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195, USA
| | - Paul S. Schmidt
- Department of Biology, University of Pennsylvania, 433 S University Ave, Philadelphia, Pennsylvania 19104, USA
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3
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Kalra B, Tamang AM, Parkash R. Cross-tolerance effects due to adult heat hardening, desiccation and starvation acclimation of tropical drosophilid-Zaprionus indianus. Comp Biochem Physiol A Mol Integr Physiol 2017; 209:65-73. [PMID: 28454925 DOI: 10.1016/j.cbpa.2017.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/02/2023]
Abstract
Some insect taxa from polar or temperate habitats have shown cross-tolerance for multiple stressors but tropical insect taxa have received less attention. Accordingly, we considered adult flies of a tropical drosophilid-Zaprionus indianus for testing direct as well as cross-tolerance effects of rapid heat hardening (HH), desiccation acclimation (DA) and starvation acclimation (SA) after rearing under warmer and drier season specific simulated conditions. We observed significant direct acclimation effects of HH, DA and SA; and four cases of cross-tolerance effects but no cross-tolerance between desiccation and starvation. Cross-tolerance due to heat hardening on desiccation showed 20% higher effect than its reciprocal effect. There is greater reduction of water loss in heat hardened flies (due to increase in amount of cuticular lipids) as compared with desiccation acclimated flies. However, cross-tolerance effect of SA on heat knockdown was two times higher than its reciprocal. Heat hardened and desiccation acclimated adult flies showed substantial increase in the level of trehalose and proline while body lipids increased due to heat hardening or starvation acclimation. However, maximum increase in energy metabolites was stressor specific i.e. trehalose due to DA; proline due to HH and total body lipids due to SA. Rapid changes in energy metabolites due to heat hardening seem compensatory for possible depletion of trehalose and proline due to desiccation stress; and body lipids due to starvation stress. Thus, observed cross-tolerance effects in Z. indianus represent physiological changes to cope with multiple stressors related to warmer and drier subtropical habitats.
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Affiliation(s)
- Bhawna Kalra
- Department of Genetics, M. D. University, Rohtak 124001, India
| | | | - Ravi Parkash
- Department of Genetics, M. D. University, Rohtak 124001, India.
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4
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Rajpurohit S, Schmidt PS. Measuring thermal behavior in smaller insects: A case study in Drosophila melanogaster demonstrates effects of sex, geographic origin, and rearing temperature on adult behavior. Fly (Austin) 2016; 10:149-61. [PMID: 27230726 PMCID: PMC5036927 DOI: 10.1080/19336934.2016.1194145] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 10/21/2022] Open
Abstract
Measuring thermal behavior in smaller insects is particularly challenging. In this study, we describe a new horizontal thermal gradient apparatus designed to study adult thermal behavior in small insects and apply it using D. melanogaster as a model and case study. Specifically, we used this apparatus and associated methodology to examine the effects of sex, geographic origin, and developmental rearing temperature on temperature preferences exhibited by adults in a controlled laboratory environment. The thermal gradient established by the apparatus was stable over diurnal and calendar time. Furthermore, the distribution of adult flies across thermal habitats within the apparatus remained stable following the period of acclimation, as evidenced by the high degree of repeatability across both biological and technical replicates. Our data demonstrate significant and predictable variation in temperature preference for all 3 assayed variables. Behaviorally, females were more sensitive than males to higher temperatures. Flies originating from high latitude, temperate populations exhibited a greater preference for cooler temperatures; conversely, flies originating from low latitude, tropical habitats demonstrated a relative preference for higher temperatures. Similarly, larval rearing temperature was positively associated with adult thermal behavior: low culture temperatures increased the relative adult preference for cooler temperatures, and this response was distinct between the sexes and for flies from the temperate and subtropical geographic regions. Together, these results demonstrate that the temperature chamber apparatus elicits robust, predictable, and quantifiable thermal preference behavior that could readily be applied to other taxa to examine the role of temperature-mediated behavior in a variety of contexts.
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Affiliation(s)
- Subhash Rajpurohit
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul S. Schmidt
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
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5
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Yin H, Shi Q, Shakeel M, Kuang J, Li J. The Environmental Plasticity of Diverse Body Color Caused by Extremely Long Photoperiods and High Temperature in Saccharosydne procerus (Homoptera: Delphacidae). Front Physiol 2016; 7:401. [PMID: 27672370 PMCID: PMC5018601 DOI: 10.3389/fphys.2016.00401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/29/2016] [Indexed: 11/13/2022] Open
Abstract
Melanization reflects not only body color variation but also environmental plasticity. It is a strategy that helps insects adapt to environmental change. Different color morphs may have distinct life history traits, e.g., development time, growth rate, and body weight. The green slender planthopper Saccharosydne procerus (Matsumura) is the main pest of water bamboo (Zizania latifolia). This insect has two color morphs. The present study explored the influence of photoperiod and its interaction with temperature in nymph stage on adult melanism. Additionally, the longevity, fecundity, mating rate, and hatching rate of S. procerus were examined to determine whether the fitness of the insect was influenced by melanism under different temperature and photoperiod. The results showed that a greater number of melanic morphs occurred if the photoperiod was extremely long. A two-factor ANOVA showed that temperature and photoperiod both have a significant influence on melanism. The percentages of variation explained by these factors were 45.53 and 48.71%, respectively. Moreover, melanic morphs had greater advantages than non-melanic morphs under an environmental regime of high temperatures and a long photoperiod, whereas non-melanic morphs were better adapted to cold temperatures and a short photoperiod. These results cannot be explained by the thermal melanism hypothesis. Thus, it may be unavailable to seek to explain melanism in terms of only one hypothesis.
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Affiliation(s)
- Haichen Yin
- Department of Plant Protection, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Qihao Shi
- Department of Plant Protection, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Muhammad Shakeel
- Department of Plant Protection, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jing Kuang
- Wuhan Vegetable Research Institute Wuhan, China
| | - Jianhong Li
- Department of Plant Protection, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
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Matthews G, Goulet CT, Delhey K, Chapple DG. The effect of skin reflectance on thermal traits in a small heliothermic ectotherm. J Therm Biol 2016; 60:109-24. [PMID: 27503723 DOI: 10.1016/j.jtherbio.2016.06.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/16/2016] [Accepted: 06/20/2016] [Indexed: 11/19/2022]
Abstract
Variation in colour patterning is prevalent among and within species. A number of theories have been proposed in explaining its evolution. Because solar radiation interacts with the pigmentation of the integument causing light to either be reflected or absorbed into the body, thermoregulation has been considered to be a primary selective agent, particularly among ectotherms. Accordingly, the colour-mediated thermoregulatory hypothesis states that darker individuals will heat faster and reach higher thermal equilibria while paler individuals will have the opposite traits. It was further predicted that dark colouration would promote slower cooling rates and higher thermal performance temperatures. To test these hypotheses we quantified the reflectance, selected body temperatures, performance optima, as well as heating and cooling rates of an ectothermic vertebrate, Lampropholis delicata. Our results indicated that colour had no influence on thermal physiology, as all thermal traits were uncorrelated with reflectance. We suggest that crypsis may instead be the stronger selective agent as it may have a more direct impact on fitness. Our study has improved our knowledge of the functional differences among individuals with different colour patterns, and the evolutionary significance of morphological variation within species.
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Affiliation(s)
- Genevieve Matthews
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Celine T Goulet
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - David G Chapple
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
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7
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Sunaga S, Akiyama N, Miyagi R, Takahashi A. Factors underlying natural variation in body pigmentation of Drosophila melanogaster. Genes Genet Syst 2016; 91:127-137. [PMID: 27021917 DOI: 10.1266/ggs.15-00061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Molecular mechanisms underlying standing genetic variation of an ecologically relevant trait such as pigmentation trait variation in a model insect, Drosophila melanogaster, are relevant to our understanding of different kinds of intergenomic interactions. In this study, we focused on the association between body pigmentation and stress resistance, and on genotype-by-environment interaction, both of which are likely to contribute to the persistence of phenotypic variation in a natural population. First, we detected a significant association between pigmentation traits in females and starvation resistance (darker strains were weaker) and a weak association between pigmentation and chill coma recovery time (darker strains showed shorter recovery time) among 20 inbred strains from the Drosophila melanogaster Genetic Reference Panel (DGRP), which originated from a natural population in North America. These associations revealed a complex relationship between body pigmentation and physiological traits that may give rise to balanced selective forces acting on the traits under fluctuating environmental conditions. Second, using four of the DGRP strains, a substantial degree of genotype (strain) × environment (rearing temperature) interaction was detected among expression levels of the genes encoding effector enzymes in the melanin biosynthesis pathway. These interactions can potentially reduce the efficiency of purifying selection on the pigmentation traits over a wide range of temperature conditions. Finally, we discuss possible mechanisms that contribute to the maintenance of the standing pigmentation variation in this species.
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Affiliation(s)
- Saki Sunaga
- Department of Biological Sciences, Tokyo Metropolitan University
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8
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Social huddling and physiological thermoregulation are related to melanism in the nocturnal barn owl. Oecologia 2015; 180:371-81. [PMID: 26552377 DOI: 10.1007/s00442-015-3491-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 10/19/2015] [Indexed: 12/11/2022]
Abstract
Endothermic animals vary in their physiological ability to maintain a constant body temperature. Since melanin-based coloration is related to thermoregulation and energy homeostasis, we predict that dark and pale melanic individuals adopt different behaviours to regulate their body temperature. Young animals are particularly sensitive to a decrease in ambient temperature because their physiological system is not yet mature and growth may be traded-off against thermoregulation. To reduce energy loss, offspring huddle during periods of cold weather. We investigated in nestling barn owls (Tyto alba) whether body temperature, oxygen consumption and huddling were associated with melanin-based coloration. Isolated owlets displaying more black feather spots had a lower body temperature and consumed more oxygen than those with fewer black spots. This suggests that highly melanic individuals display a different thermoregulation strategy. This interpretation is also supported by the finding that, at relatively low ambient temperature, owlets displaying more black spots huddled more rapidly and more often than those displaying fewer spots. Assuming that spot number is associated with the ability to thermoregulate not only in Swiss barn owls but also in other Tytonidae, our results could explain geographic variation in the degree of melanism. Indeed, in the northern hemisphere, barn owls and allies are less spotted polewards than close to the equator, and in the northern American continent, barn owls are also less spotted in colder regions. If melanic spots themselves helped thermoregulation, we would have expected the opposite results. We therefore suggest that some melanogenic genes pleiotropically regulate thermoregulatory processes.
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9
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Castañeda LE, Rezende EL, Santos M. Heat tolerance in Drosophila subobscura along a latitudinal gradient: Contrasting patterns between plastic and genetic responses. Evolution 2015; 69:2721-34. [PMID: 26292981 DOI: 10.1111/evo.12757] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/13/2015] [Accepted: 08/11/2015] [Indexed: 01/17/2023]
Abstract
Susceptibility to global warming relies on how thermal tolerances respond to increasing temperatures through plasticity or evolution. Climatic adaptation can be assessed by examining the geographic variation in thermal-related traits. We studied latitudinal patterns in heat tolerance in Drosophila subobscura reared at two temperatures. We used four static stressful temperatures to estimate the thermal death time (TDT) curves, and two ramping assays with fast and slow heating rates. Thermal death time curves allow estimation of the critical thermal maximum (CT(max)), by extrapolating to the temperature that would knock down the flies almost "instantaneously," and the thermal sensitivity to increasing stressful temperatures. We found a positive latitudinal cline for CT(max), but no clinal pattern for knockdown temperatures estimated from the ramping assays. Although high-latitude populations were more tolerant to an acute heat stress, they were also more sensitive to prolonged exposure to less stressful temperatures, supporting a trade-off between acute and chronic heat tolerances. Conversely, developmental plasticity did not affect CT(max) but increased the tolerance to chronic heat exposition. The patterns observed from the TDT curves help to understand why the relationship between heat tolerance and latitude depends on the methodology used and, therefore, these curves provide a more complete and reliable measurement of heat tolerance.
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Affiliation(s)
- Luis E Castañeda
- Instituto de Ecología y Biodiversidad (IEB-Chile), Casilla 653, Santiago, Chile. .,Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, PO 5090000, Valdivia, Chile.
| | - Enrico L Rezende
- Department of Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, United Kingdom
| | - Mauro Santos
- Departament de Genètica i de Microbiologia, Grup de Genòmica, Bioinformàtica i Biologia Evolutiva (GGBE), Universitat Autonòma de Barcelona, 08193, Bellaterra (Barcelona), Spain
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10
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Keller I, Alexander JM, Holderegger R, Edwards PJ. Widespread phenotypic and genetic divergence along altitudinal gradients in animals. J Evol Biol 2013; 26:2527-43. [PMID: 24128377 DOI: 10.1111/jeb.12255] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 12/13/2022]
Abstract
Altitudinal gradients offer valuable study systems to investigate how adaptive genetic diversity is distributed within and between natural populations and which factors promote or prevent adaptive differentiation. The environmental clines along altitudinal gradients tend to be steep relative to the dispersal distance of many organisms, providing an opportunity to study the joint effects of divergent natural selection and gene flow. Temperature is one variable showing consistent altitudinal changes, and altitudinal gradients can therefore provide spatial surrogates for some of the changes anticipated under climate change. Here, we investigate the extent and patterns of adaptive divergence in animal populations along altitudinal gradients by surveying the literature for (i) studies on phenotypic variation assessed under common garden or reciprocal transplant designs and (ii) studies looking for signatures of divergent selection at the molecular level. Phenotypic data show that significant between-population differences are common and taxonomically widespread, involving traits such as mass, wing size, tolerance to thermal extremes and melanization. Several lines of evidence suggest that some of the observed differences are adaptively relevant, but rigorous tests of local adaptation or the link between specific phenotypes and fitness are sorely lacking. Evidence for a role of altitudinal adaptation also exists for a number of candidate genes, most prominently haemoglobin, and for anonymous molecular markers. Novel genomic approaches may provide valuable tools for studying adaptive diversity, also in species that are not amenable to experimentation.
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Affiliation(s)
- I Keller
- Institute of Integrative Biology, ETH Zentrum CHN, ETH Zürich, Universitätsstrasse 16, Zürich, Switzerland; Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry, Kastanienbaum, Switzerland; Department of Aquatic Ecology and Macroevolution, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
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11
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Chahal J, Dev K, Kataria SK, Parkash R. Opposite Latitudinal Clines for First Mating and Second Mating (Remating) in Males of Drosophila melanogaster. Ethology 2013. [DOI: 10.1111/eth.12136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Kapil Dev
- Department of Genetics; Maharshi Dayanand University; Rohtak; Haryana; India
| | | | - Ravi Parkash
- Department of Genetics; Maharshi Dayanand University; Rohtak; Haryana; India
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12
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Chahal J, Kataria SK, Parkash R. Invasion and adaptation of a warm-adapted species to montane localities: effect of acclimation potential. J Exp Biol 2013; 216:1578-86. [PMID: 23348937 DOI: 10.1242/jeb.080200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Drosophila ananassae has successfully invaded the cold and dry montane localities of the Western Himalayas in recent years. The ability of this desiccation- and cold-sensitive tropical species to evolve in response to seasonal changes in montane localities is largely unknown. Here, we investigated how this sensitive species adapt to seasonally varying environmental conditions that are lethal to its survival. We observed change in the frequency of dark and light morphs of D. ananassae in five mid-altitude localities during the last decade (2000-2010). We document invasion of D. ananassae to montane localities and increase in frequency of the dark morph. The stress tolerance of morphs (dark and light) remained unaffected of developmental acclimation. However, adult acclimation has shown significant effects on tolerance to various environmental stresses in morphs and effect of this acclimation persist for long durations. Desiccation and cold stress tolerance was increased after adult acclimation for respective stress in the dark morph; while tolerance of the light morph was not affected. Further, heat tolerance of the light morph was increased after adult heat acclimation with no influence on heat tolerance of the dark morph. Our results suggest a possible role of adult acclimation in successful invasion and adaptation of D. ananassae to montane localities. Future experiments should be carried out to determine whether the survival in adverse conditions of low versus high temperature and humidity during seasonal changes is assisted by different acclimation abilities of the two morphs of D. ananassae.
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Affiliation(s)
- Jyoti Chahal
- Drosophila Research Lab, Department of Genetics, Maharshi Dayanand University, Rohtak, India.
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13
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Dev K, Chahal J, Parkash R. Seasonal variations in the mating-related traits of Drosophila melanogaster. J ETHOL 2013. [DOI: 10.1007/s10164-013-0364-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Ramniwas S, Kajla B, Dev K, Parkash R. Direct and correlated responses to laboratory selection for body melanisation in Drosophila melanogaster: support for the melanisation-desiccation resistance hypothesis. ACTA ACUST UNITED AC 2012; 216:1244-54. [PMID: 23239892 DOI: 10.1242/jeb.076166] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
For Drosophila melanogaster, cuticular melanisation is a quantitative trait, varying from no melanin to completely dark. Variation in melanisation has been linked with stress resistance, especially desiccation, in D. melanogaster and other species. As melanism has a genetic component, we selected melanic and non-melanic phenotypes of D. melanogaster in order to confirm the association of desiccation resistance and rate of water loss with cuticular melanisation previously reported for this species. A bidirectional selection experiment for dark (D1-D4) and light (L1-L4) body colour in D. melanogaster was conducted for 60 generations. We observed a 1.6-fold increase in abdominal melanisation in selected dark strains and a 14-fold decrease in selected light strains compared with control populations. Desiccation resistance increased significantly in the dark-selected morphs as compared with controls. The observed increase in desiccation resistance appeared as a consequence of a decrease in cuticular permeability. Our results show that traits related to water balance were significantly correlated with abdominal melanisation and were simultaneously selected bidirectionally along with melanisation.
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Affiliation(s)
- Seema Ramniwas
- Lab No. 13, Drosophila Genetics Laboratory, Maharshi Dayanand University, Rohtak-124001, Haryana, India.
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15
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Santos M, Castañeda LE, Rezende EL. Keeping pace with climate change: what is wrong with the evolutionary potential of upper thermal limits? Ecol Evol 2012; 2:2866-80. [PMID: 23170220 PMCID: PMC3501637 DOI: 10.1002/ece3.385] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/20/2012] [Accepted: 08/27/2012] [Indexed: 11/10/2022] Open
Abstract
The potential of populations to evolve in response to ongoing climate change is partly conditioned by the presence of heritable genetic variation in relevant physiological traits. Recent research suggests that Drosophila melanogaster exhibits negligible heritability, hence little evolutionary potential in heat tolerance when measured under slow heating rates that presumably mimic conditions in nature. Here, we study the effects of directional selection for increased heat tolerance using Drosophila as a model system. We combine a physiological model to simulate thermal tolerance assays with multilocus models for quantitative traits. Our simulations show that, whereas the evolutionary response of the genetically determined upper thermal limit (CTmax) is independent of methodological context, the response in knockdown temperatures varies with measurement protocol and is substantially (up to 50%) lower than for CTmax. Realized heritabilities of knockdown temperature may grossly underestimate the true heritability of CTmax. For instance, assuming that the true heritability of CTmax in the base population is h(2) = 0.25, realized heritabilities of knockdown temperature are around 0.08-0.16 depending on heating rate. These effects are higher in slow heating assays, suggesting that flawed methodology might explain the apparently limited evolutionary potential of cosmopolitan D. melanogaster.
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Affiliation(s)
- Mauro Santos
- Departament de Genètica i de Microbiologia, Grup de Biologia Evolutiva (GBE), Universitat Autònoma de Barcelona 08193, Bellaterra, Barcelona, Spain
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16
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Hoffmann AA, Chown SL, Clusella-Trullas S. Upper thermal limits in terrestrial ectotherms: how constrained are they? Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.02036.x] [Citation(s) in RCA: 447] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ary A. Hoffmann
- Departments of Zoology and Genetics; Bio21 Institute; The University of Melbourne; 30 Flemington Road; Parkville; Victoria; 3052; Australia
| | | | - Susana Clusella-Trullas
- Department of Botany and Zoology; Centre for Invasion Biology; Stellenbosch University; Private Bag X1; Matieland; 7602; South Africa
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17
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Santos M, Castañeda LE, Rezende EL. Making sense of heat tolerance estimates in ectotherms: lessons from Drosophila. Funct Ecol 2011. [DOI: 10.1111/j.1365-2435.2011.01908.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Trade-off of energy metabolites as well as body color phenotypes for starvation and desiccation resistance in montane populations of Drosophila melanogaster. Comp Biochem Physiol A Mol Integr Physiol 2011; 161:102-13. [PMID: 21983144 DOI: 10.1016/j.cbpa.2011.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 09/20/2011] [Accepted: 09/23/2011] [Indexed: 11/22/2022]
Abstract
Storage of energy metabolites has been investigated in different sets of laboratory selected desiccation or starvation resistant lines but few studies have examined such changes in wild-caught populations of Drosophila melanogaster. In contrast to parallel selection of desiccation and starvation tolerance under laboratory selection experiments, opposite clines were observed in wild populations of D. melanogaster. If resistance to desiccation and starvation occurs in opposite directions under field conditions, we may expect a trade-off for energy metabolites but such correlated changes are largely unknown. We tested whether there is a trade-off for storage as well as actual utilization of carbohydrates (trehalose and glycogen), lipids and proteins in D. melanogaster populations collected from different altitudes (512-2500 m). For desiccation resistance, darker flies (>50% body melanization) store more body water content and endure greater loss of water (higher dehydration tolerance) as compared to lighter flies (<30% body melanization). Based on within population analysis, we found evidence for coadapted phenotypes i.e. darker flies store and actually utilize more carbohydrates to confer greater desiccation resistance. In contrast, higher starvation resistance in lighter flies is associated with storage and actual utilization of greater lipid amount. However, darker and lighter flies did not vary in the rate of utilization of carbohydrates under desiccation stress; and of lipids under starvation stress. Thus, we did not find support for the hypothesis that a lower rate of utilization of energy metabolites may contribute to greater stress resistance. Further, for increased desiccation resistance of darker flies, about two-third of total energy budget is provided by carbohydrates. By contrast, lighter flies derive about 66% of total energy content from lipids which sustain higher starvation tolerance. Our results support evolutionary trade-off for storage as well as utilization of energy metabolites for desiccation versus starvation resistance in D. melanogaster.
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Coadapted changes in energy metabolites and body color phenotypes for resistance to starvation and desiccation in latitudinal populations of D. melanogaster. Evol Ecol 2011. [DOI: 10.1007/s10682-011-9482-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Divergence of water balance mechanisms in two melanic Drosophila species from the western Himalayas. Comp Biochem Physiol A Mol Integr Physiol 2011; 158:531-41. [DOI: 10.1016/j.cbpa.2010.12.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 11/22/2022]
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