Projet:
"Investigating the link between hyper-aggressivity and fitness."
Laboratoire:
Centre de Recherches sur la Cognition Animale (CRCA) au CBI, Toulouse
Application:
Par email directement à Séverine Trannoy: severine.trannoy@univ-tlse3.fr
Date limite d'application: 01 octobre 2021
Date du stage: janvier - juin 2022
Project title: Investigating the link between hyper-aggressivity and fitness.
HOST RESEARCH GROUPName of the group: Interindividual Varibility and Emergent PlasticityHost institution: Research Center for Animal Cognition, CBI, ToulouseWebsite: http://crca.cbi-toulouse.fr/RESEARCH SUPERVISOR(S): Names: Séverine TrannoyE-mail: severine.trannoy@univ-tlse3.frPhone/Fax: 0689182827INFORMATION ON THE PROJECTShort project description:A social behavior consists of a set of interactions among conspecifics, ranging from animals aggregating, sexual partners engaging in courtship and/or parental behaviors, 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. As aninnate 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 ofstudies have demonstrated that both environmental and genetic factors influence aggression, however, the roots driving hyper-aggressive behavior remains poorly understood.In this study, we will use Drosophila melanogasteras a model organism to investigate the impact of hyperaggressivity on other social behaviors. Like other animals, in competition for food, mates and territory, both Drosophila males and females exhibit aggressive behaviors in same sexpairings(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 generations yielded 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 have been associated with hyper-aggressive behavior(6), however, we know very little about the link between hyperaggressivity and fitness.Pioneering studies showed that dominant males had a reproductive advantage, however, other studies that selected animals for their hyper-aggressive behavioral trait have shownthat these males were less likely to reproduce when competing with some"control"animals(5). Our preliminary results confirmed these previous observations. Thus, the objectivesof this internship is to better 2understand the link between hyper-aggressive behavior and reproductive success. To tackle this question, we willperformbehavioral tests (aggression and reproduction assays) using hyper-aggressive and control animals in order to confirm the previous observations. Then,we will manipulate a) the expression of specific genes (known to be differentially expressed between hyper-aggressive and normal animals(6)) and b) the synaptic transmission of neuronswithin particular brain areaswith thermosensitive genetic tools during Drosophila aggression and courtship assays and measure the behavioral consequencesin various experimental conditions. The aim is to identifythe brain structures and molecular mechanisms involved in the regulation of reproductive behavior. The fundamental aim is to understand the relationship between hyperaggressivity and the innate reproductive behavior in order to identify the regulatory mechanisms.During this internship, the studentwill learn to 1) work with Drosophila as a modelanimal, 2) performbehavioral tests (male-male aggression and courtship assays withmales and females) under different environmental conditions, 3) observe and quantify the behavioral responses (automatic analysis via MATLAB and manual analysis for specific behaviors) and 4) interpret the results obtained and draw conclusions.References1.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 reduces aggression 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.