Offre de stage M2 neurobiologie des comportements chez la Drosophile

 RESEARCH PROJECT PROPOSAL FOR THE YEAR 2021-2022Project title:Investigating the roleof a single pair of neurons in regulating aggressive behaviors in Drosophila melanogaster.HOST RESEARCH GROUPName of the group: Interindividual Varibility and Emergent PlasticityHost institution: Research Center for Animal CognitionWebsite: http://crca.cbi-toulouse.fr/https://www.severinetrannoylab.com/INFORMATION ON THE PROJECTShort project description:A social behavior consists of a set of interactions among conspecifics, ranging animals aggregating, sexual partners engaging in courtship and/or parental behavior, to rivals fighting over territory and mates. These naturally complex social behaviors are composed of innate and learned components that ultimately influence animal reproductive fitness. Aggressive behavior is used throughout the animal kingdom to compete for resources, access mates, defend territory and toprotect oneself and the family. As an innate behavior, the neural basis underlying aggression is genetically hardwired. However, cognitive abilities, external sensory information, past experiences and the internal state of the animals also strongly influence the display of aggressive behavioral patterns, demonstrating the adaptive and malleable features of this complex behavior(1, 2). The ecological and ethological significance of aggressive behavior (species-typical aggression), however, has to be distinguished from the maladaptive one (hyper-aggression). Pathological forms of aggression have long been investigated in the context of psychology influences. Decades of studies have demonstrated that both environmental and genetic factors influence aggression, however, the roots driving hyper-aggressivebehavior remains poorly understood.In this study, we will use Drosophila melanogasteras a model organism to investigate the function of a single pair of neurons in regulating hyper-aggressive behavior and its impact on other social behaviors.Like other animals, in competitionfor food, mates and territory, both males and females exhibit aggressive behaviors in same sex pairings(3).However, only male flies establish dominance relationships between competitors, while female fights end up with flies sharing resources(4). Selection of wild type males for their fighting abilities for generationsyielded to hyper-aggressive flies, called “bullies”, with specific phenotypes: i) they employ extreme fighting behavioral patterns, ii) they do not establish dominance relationship because of retaliation, iii) only males are hyper-aggressive, and iv) they have lower reproduction success rate(5). To date, some candidate genes havebeen associated with hyper-aggressive behavior(6), however, we know very little about the neuronal population that controls the display of hyper-aggressive behavioral patterns.Our preliminary experiments have shown that the artificial activation of a pair of neurons recapitulatesin part,the phenotypes observed with the bully flies. To better understand thefunctionsof these neurons, we have manipulated their neuronal activity during behavioral assays, and have shownthat, when activated,these neurons increase specificallymale’s aggressive behaviorand potentially reducethe reproduction success rateof the animals.

Therefore, theobjectives of the internship are to better understand the function of this single pair of neurons in regulating hyper-aggressive behavior, and study how they can negatively impact males’ fitness. To tackle this question, we will manipulate the synaptic transmission of the neurons with thermosensitive genetic tools during drosophila aggression and courtship assays and measure the behavioral consequencesin various experimental conditions.References 1.Y. Hsu, R. L. Earley, L. L. Wolf, Modulation of aggressive behaviour by fighting experience: mechanisms and contest outcomes. Biol Rev Camb Philos Soc81, 33-74 (2006).2.M. S. Reichert, J. L. Quinn, Cognition in Contests: Mechanisms, Ecology, and Evolution. Trends Ecol Evol32, 773-785 (2017).3.K. Asahina, Neuromodulation and Strategic Action Choice in Drosophila Aggression. Annu Rev Neurosci, (2017).4.S. Chen, A. Y. Lee, N. M. Bowens, R. Huber, E. A. Kravitz, Fighting fruit flies: a model system for the study of aggression. Proc Natl Acad Sci U S A99, 5664-5668 (2002).5.J. K. Penn, M. F. Zito, E. A. Kravitz, A single social defeat reducesaggression in a highly aggressive strain of Drosophila. Proc Natl Acad Sci U S A107, 12682-12686 (2010).6.B. Chowdhury, Y. B. Chan, E. A. Kravitz, Putative transmembrane transporter modulates higher-level aggression in Drosophila. Proc Natl Acad Sci U S A114, 2373-2378 (2017).Techniques that will be used by the student:-Genetic crosses,-Behavioral experiments,-Analyze of behavioral patterns,-Tracking system using MATLAB.Background/skills requested:We seek for a candidate motivated for the study of aggressive behaviors and interested by the neurobiology of behavior using Drosophila melanogasteras a model system. Having knowledge about Drosophila melanogasterand MATLAB would be positive points, but not requested. Requested skills: neurobiology, behavior, basic statistic.RESEARCH SUPERVISOR(S): Names: Séverine TrannoyE-mail: severine.trannoy@univ-tlse3.fr