evolution; population genomics; drosophila; behavior; malnutrition; immunity
(2015), Idiosyncratic evolution of maternal effects in response to juvenile malnutrition in Drosophila., in Journal of Evolutionary Biology
, 28(4), 876.
(2015), Prepupal building behavior in Drosophila melanogaster and its evolution under resource and time constraints, in PLOS ONE
, 10(2), e0117280.
(2015), Quantitative genetics of learning ability and resistance to stress in Drosophila melanogaster, in ECOLOGY AND EVOLUTION
, 5(3), 543-556.
(2014), Evolution under monogamy feminizes gene expression in Drosophila melanogaster., in Nature communications
, 5, 3482-3482.
(2013), Epistasis and maternal effects in experimental adaptation to chronic nutritional stress in Drosophila, in JOURNAL OF EVOLUTIONARY BIOLOGY
, 26(12), 2566-2580.
(2013), Predatory cannibalism in Drosophila melanogaster larvae, in NATURE COMMUNICATIONS
, 4, 1789.
, Gut physiology mediates a trade-off between adaptation to malnutrition and susceptibility to food-borne pathogens, in Ecology Letters
The general aim of the proposed research is to understand how evolution shapes animal phenotypes and genomes in response to natural selection imposed by chronic exposure to juvenile malnutrition. The project takes advantage of six replicate experimental Drosophila populations derived from nature and maintained for >120 generations on a nutritionally poor larval food. Compared to six Control populations of the same origin, these Selected populations now survive much better and develop and grow markedly faster the poor food. This indicates that they have evolved mechanisms allowing them to cope better with malnutrition. However, they also show evidence of trade-offs in life history and immunity. The Selected populations thus represent biological replicates of an evolutionary process of adaptation and can be used as a model to study how species may adapt to chronic nutritional stress over evolutionary time. We are aiming to unravel the mechanisms that mediate the malnutrition tolerance of the Selected populations and mediate the trade-offs. Within this broad framework, I propose here three projects which address three aspects of evolutionary adaptation to malnutrition.First, I propose to study how evolution under malnutrition modulates sensory and behavioral responses to food. Fine tuning sensory capacities and behavioral responses may help the animal to make best of the bad food situation; on the other hand, such changes may be costly. Using behavioral experiments, we would address a number of specific questions about evolutionary changes in the ability to detect small variation in food quality, overcome aversion to heat or pain to approach food, or remember odors previously associated with food. Second, I aim to investigate an apparent trade-off between tolerance to malnutrition and immunity to intestinal pathogens: the Selected populations are more susceptible than Controls to oral but not systemic infections with the pathogen Pseudomonas entomophila. I plan to capitalize on recent advances in understanding of the interaction between gut pathogens and the host's defenses to elucidate the mechanisms and extent of this trade-off. In addition to its role in nutrient acquisition, the gut acts as an immune organ protecting the organism from pathogens ingested with food, and these results will throw light on the degree in which these two functions may compromise each other. Third, I propose to use next generation sequencing to resequence the genomes of the Selected and Control populations. Together with an ongoing transcriptome sequencing project (RNAseq), this would help to unravel the genomic basis of evolutionary change driven by malnutrition and generate new hypotheses about the molecular and physiological bases of improved malnutrition tolerance. It would also create synergism with the above two projects, as experimental data can direct the search for signatures of selection to particular genes, while finding genes showing signs of selection can point to hypotheses and experimentsGenetically-based physiological and behavioral adaptations to malnutrition have been suggested to play an important role in the human susceptibility to disease. Our study would throw light on such putative links in a model species.