Efecto del incremento de temperatura sobre la tolerancia al calor de Drosophila melanogaster.
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Date
2024
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Universidad de Concepción
Abstract
En la actualidad, el incremento de eventos climáticos extremos y el aumento de la temperatura media del planeta contribuyen a la pérdida de biodiversidad global. La capacidad de los individuos para responder con cambios morfológicos, fisiológicos o conductuales (i.e., plasticidad fenotípica) a tales desafíos podría ser clave para su sobrevivencia. Estudios han demostrado que la capacidad de tolerar altas temperaturas depende de la intensidad y de la temperatura del desafío térmico. En este sentido, las curvas de muerte térmica (TDT) incluyen estos factores mediante la estimación de CTmax (tolerancia al calor) y Z (susceptibilidad térmica) como descriptores de tolerancia térmica. Esta tesis explora como la exposición a ambientes térmicos cada vez más estresantes afecta la tolerancia al calor y la sobrevivencia de Drosophila melanogaster. Para responder a esta pregunta, se elaboraron curvas TDT y estimamos CTmax y Z en organismos adultos aclimatados a diferentes temperaturas durante la ontogenia (21, 24, 27 y 30ºC). Además, se evaluó el efecto de la temperatura sobre la masa corporal (Mc) y se analizó la magnitud de la respuesta plástica de estos atributos (i.e., CTmax, Z y Mc). Los resultados demostraron que la temperatura de aclimatación (Tacl), la temperatura del ensayo térmico (Tens) y Mc tuvieron impactos significativos sobre la sobrevivencia de Drosophila melanogaster. Organismos aclimatados a altas temperaturas mostraron un aumento significativo en su sobrevivencia, así como valores más altos de CTmax y Z en comparación con los individuos provenientes de temperaturas más bajas. La aclimatación a temperaturas estresantes generó cambios en la tolerancia al calor, sobrevivencia y en la morfología de Drosophila melanogaster. Los resultados sugieren que existe un compromiso entre CTmax y Z, lo cual implica una mayor tolerancia a altas temperaturas, pero durante cortos periodos de tiempo.
Currently, the increase in extreme climate events and the increase in average temperature of the planet contribute to the loss of global biodiversity. The ability of individuals to respond to these challenges through morphological, physiological or behavioral changes (i.e., phenotypic plasticity) may be crucial for their survival. Studies have shown that the ability to tolerate high temperatures depends on the intensity and temperature of the thermal challenge. In this sense, thermal death time (TDT) curves incorporates these factors by estimating CTmax (heat tolerance) and Z (thermal susceptibility) as the thermal tolerance descriptors. This thesis investigates how exposure to increasingly stressful thermal environments affects the heat tolerance and survival of Drosophila melanogaster. To address this, TDT curves were generated to estimate CTmax and Z in adult organisms acclimated to different temperatures (21, 24, 27 and 30ºC) during ontogeny. In addition, the effect of temperature on body mass (Mc) was evaluated and the magnitude of the plastic response of these attributes was analyzed (i.e., CTmax, Z and Mc). The findings revealed that acclimatization temperature, thermal assay, and Mc had significant impacts on the survival of Drosophila melanogaster. Flies acclimated to high temperatures exhibited significantly increased survival, along with higher values of CTmax and Z, compared to individuals from lower temperatures. Acclimatization to stressful temperatures induced changes in heat tolerance, survival and morphology in Drosophila melanogaster. The results suggest a tradeoff between CTmax and Z, which implies a greater susceptibility to high temperatures over shorter periods of time.
Currently, the increase in extreme climate events and the increase in average temperature of the planet contribute to the loss of global biodiversity. The ability of individuals to respond to these challenges through morphological, physiological or behavioral changes (i.e., phenotypic plasticity) may be crucial for their survival. Studies have shown that the ability to tolerate high temperatures depends on the intensity and temperature of the thermal challenge. In this sense, thermal death time (TDT) curves incorporates these factors by estimating CTmax (heat tolerance) and Z (thermal susceptibility) as the thermal tolerance descriptors. This thesis investigates how exposure to increasingly stressful thermal environments affects the heat tolerance and survival of Drosophila melanogaster. To address this, TDT curves were generated to estimate CTmax and Z in adult organisms acclimated to different temperatures (21, 24, 27 and 30ºC) during ontogeny. In addition, the effect of temperature on body mass (Mc) was evaluated and the magnitude of the plastic response of these attributes was analyzed (i.e., CTmax, Z and Mc). The findings revealed that acclimatization temperature, thermal assay, and Mc had significant impacts on the survival of Drosophila melanogaster. Flies acclimated to high temperatures exhibited significantly increased survival, along with higher values of CTmax and Z, compared to individuals from lower temperatures. Acclimatization to stressful temperatures induced changes in heat tolerance, survival and morphology in Drosophila melanogaster. The results suggest a tradeoff between CTmax and Z, which implies a greater susceptibility to high temperatures over shorter periods of time.
Description
Tesis presentada para optar al título de Bióloga
Keywords
Drosophila melanogaster, Cambio climático, Plasticidad fenotípica