How Food Controls Aggression in Drosophila

Abstract

How animals use sensory information to weigh the risks vs. benefits of behavioral decisions remains poorly understood. Inter-male aggression is triggered when animals perceive both the presence of an appetitive resource, such as food or females, and of competing conspecific males. How such signals are detected and integrated to control the decision to fight is not clear. For instance, it is unclear whether food increases aggression directly, or as a secondary consequence of increased social interactions caused by attraction to food. Here we use the vinegar fly, Drosophila melanogaster, to investigate the manner by which food influences aggression. We show that food promotes aggression in flies, and that it does so independently of any effect on frequency of contact between males, increase in locomotor activity or general enhancement of social interactions. Importantly, the level of aggression depends on the absolute amount of food, rather than on its surface area or concentration. When food resources exceed a certain level, aggression is diminished, suggestive of reduced competition. Finally, we show that detection of sugar via Gr5a+ gustatory receptor neurons (GRNs) is necessary for food-promoted aggression. These data demonstrate that food exerts a specific effect to promote aggression in male flies, and that this effect is mediated, at least in part, by sweet-sensing GRNs.

Neurons that Function within an Integrator to Promote A Persistent Behavioral State in Drosophila

“…3g-i). But in the presence of a dead female, which produced increased baseline aggression in male flies 36 , activation of pCd neurons significantly enhanced fly aggressiveness after photostimulation, an effect not observed in photostimulated controls (Fig. 3j-l).…”

Targeted manipulation of neuronal activity in behaving adult flies

“…Chambers containing male-female combinations promote courtship, whereas male-male combinations can promote aggression. Furthermore, flies are more likely to show aggressive behavior when female or a food source is present, and the amount of food within the chamber can influence the probability and nature of aggressive behavior (Hoffmann 1987;Chen et al 2002;Lim et al 2014). Flies can also leave pheromones or other chemicals behind in chambers, which can affect the social behaviors of new inhabitants (Suh et al 2004;Wang and Anderson 2010;Lin et al 2015).…”

“…This has revealed how neurons can elicit persistent behaviors or cause alterations in behavioral states (Inagaki et al 2014;Bath et al 2014;Hoopfer et al 2015;Hampel et al 2015). Different odorant or food conditions have been used to study their contributions to feeding, attraction, avoidance, social behaviors, and learning (Gao et al 2013;Aso et al 2014b;Lim et al 2014;Ramdya et al 2014;Albin et al 2015). Wild type, mutant, and flies with neural manipulations have been used to test different cues of conspecific flies that can affect social behaviors Hoopfer et al 2015).…”

Satiety, Thermosensation and Mechanosensation Regulate a Spontaneous C. elegans Sleep State

“…Understanding how animals select behaviors based on sensory information is a fundamental goal of neuroscience [1][2][3][4]; however, sensorimotor transformations can vary dramatically depending on the state of the animal's nervous system [5][6][7][8]. Wakefulness and arousal [9,10], locomotor activity states [11,12], satiety [13], attention [14], and emotions [5,6,15] represent a spectrum of physiological and neural states that can dramatically affect how animals respond to a given stimuli. Small animals like the nematode C. elegans are tractable model organisms for understanding how physiological and neural states combine with information from multiple sensory pathways and give rise to specific behavior [3,6,8,13,[16][17][18][19][20][21].…”