Evolved patterns and rates of water loss and ion regulation in laboratory-selected populations ofDrosophila melanogaster
| Autor: | Timothy J. Bradley, Donna G. Folk |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Ion regulation
Physiology Potassium Sodium chemistry.chemical_element Zoology Aquatic Science Chlorides Hemolymph Botany Extracellular Animals Selection Genetic Molecular Biology Ecology Evolution Behavior and Systematics Dehydration biology fungi Water-Electrolyte Balance biology.organism_classification Adaptation Physiological Water Loss Insensible Drosophila melanogaster chemistry Excretory system Insect Science Animal Science and Zoology Desiccation |
| Zdroj: | Journal of Experimental Biology. 206:2779-2786 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.00498 |
| Popis: | SUMMARYWe have investigated water loss from, and ion regulation within, the hemolymph and tissues of five replicate populations of Drosophila melanogaster that have undergone laboratory selection for enhanced desiccation resistance (i.e. the D populations). We compared the patterns and rates of water loss and the ion content of the D populations prior to and during desiccation with those of five replicate control (C) populations. The net rate of water loss in the C flies was ∼3-fold greater than that of the D flies during the initial hours of desiccation. After 8 h, both C and D flies had considerable reductions in water loss rate. During 24 h of desiccation,the tissue water content of the D flies was conserved, while the C flies were faced with significant loss of tissue water during the initial 8 h of desiccation. We propose that the increased hemolymph volume of the D flies plays a role in buffering water loss from the tissues. One consequence of this large hemolymph pool is that the hydrated D flies contained approximately seven times more sodium within the hemolymph than did the hydrated C flies. Despite a continual loss of hemolymph volume in the D flies during lengthy periods of desiccation, the sodium content of the hemolymph was significantly reduced only during a single event. We provide evidence that the regulation of extracellular sodium, as well as chloride, occurred via excretory processes during desiccation. In addition, whole-body potassium was not significantly decreased in the D flies during desiccation but was reduced(i.e. excreted) in the C flies; hence, we suggest that the potassium content paralleled tissue water level. |
| Databáze: | OpenAIRE |
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