Adaptation to larval crowding in Drosophila ananassae and Drosophila nasuta nasuta: increased larval competitive ability without increased larval feeding rate

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• 作者：ARCHANA NAGARAJAN ; SHARMILA BHARATHI NATARAJAN ; MOHAN JAYARAM…
• 刊名：Journal of Genetics
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：95
• 期：2
• 页码：411-425
• 全文大小：865 KB
• 刊物主题：Life Sciences, general; Microbial Genetics and Genomics; Plant Genetics & Genomics; Animal Genetics and Genomics; Evolutionary Biology;
• 出版者：Springer India
• ISSN：0973-7731
• 卷排序：95

文摘

The standard view of adaptation to larval crowding in fruitflies, built on results from 25 years of multiple experimental evolution studies on Drosophila melanogaster, was that enhanced competitive ability evolves primarily through increased larval feeding and foraging rate, and increased larval tolerance to nitrogenous wastes, at the cost of efficiency of food conversion to biomass. These results were at odds from the predictions of classical K-selection theory, notably the expectation that selection at high density should result in the increase of efficiency of conversion of food to biomass, and were better interpreted through the lens of α-selection. We show here that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolve greater competitive ability and pre-adult survivorship at high density, primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater time efficiency of food conversion to biomass and increased pupation height, with a relatively small role of increased urea/ammonia tolerance, if at all. This is a very different suite of traits than that seen to evolve under similar selection in D. melanogaster, and seems to be closer to the expectations from the canonical theory of K-selection. We also discuss possible reasons for these differences in results across the three species. Overall, the results reinforce the view that our understanding of the evolution of competitive ability in fruitflies needs to be more nuanced than before, with an appreciation that there may be multiple evolutionary routes through which higher competitive ability can be attained.Keywordslife-history evolutionexperimental evolutiondevelopment timedry weightcompetitionK-selection.