Biology subjects

Vasconcelos, M. L.

Publications and source records attributed to Vasconcelos, M. L..

4 recordsLinked to original sources

bioRxiv2022

Mate Competition Drives Aggressive Behaviour in Female Drosophila

Aggression is an adaptive set of behaviours that allows animals to compete against one another in an environment of limited resources. In Drosophila such aggressive behaviour has been extensively studied in males. Despite recent work highlighting territorial defence in females, female aggression in Drosophila is still poorly understood. Indeed, whether females compete for mating partners, as males do, has remained unknown so far. In the present work, we report that Drosophila melanogaster females reliably display aggression towards mating pairs. This aggressive behaviour is positively associated with the females mating drive and relies heavily on olfaction. Furthermore, we found that food odour in combination with OR47b-dependent fly odour sensing are required for proper expression of aggressive behaviour. Taken together, we describe a social context linked to reproduction in which Drosophila females aspiring to mate produce consistent and stereotyped displays of aggression. These findings open the door for further inquiries into the neural mechanisms that govern this behaviour.

neuroscience↗

bioRxiv2021

Neuronal control of suppression, initiation and completion of egg deposition in Drosophila melanogaster

Egg-laying in Drosophila is the product of post-mating physiological and behavioural changes that culminate in a stereotyped sequence of actions. While egg-laying behaviour has been mostly used as a system to understand the neuronal basis of decision making in the context of site selection, it harbours a great potential as a paradigm to uncover how, once a site is selected, the appropriate motor circuits are organized and activated to deposit an egg. To study this programme, we first describe the different stages of the egg-laying programme and the specific actions associated with each stage. Using a combination of neuronal activation and silencing experiments we characterize the role of three distinct neuronal populations in the abdominal ganglion with different contributions to the egg deposition motor elements. Specifically, we identify a subset of glutamatergic neurons and a subset of cholinergic neurons that promote the initiation and completion of egg expulsion respectively, while a subset of GABAergic neurons suppresses egg-laying. This study provides insight into the organization of neuronal circuits underlying complex motor behaviour.

neuroscience↗

bioRxiv2018

Avoidance response to CO2 in the lateral horn

In flies, the olfactory information is carried from the first relay in the brain, the antennal lobe, to the mushroom body (MB) and the lateral horn (LH). Olfactory associations are formed in the MB. The LH was ascribed a role in innate responses based on the stereotyped connectivity with the antennal lobe, stereotyped physiological responses to odors and MB silencing experiments. Direct evidence for the functional role of the LH is still missing. Here we investigate the behavioral role of the LH neurons directly, using the CO2 response as a paradigm. Our results show the involvement of the LH in innate responses. Specifically, we demonstrate that activity in two sets of neurons is required for the full behavioral response to CO2. Using calcium imaging we observe that the two sets of neurons respond to CO2 in different manners. Using independent manipulation and recording of the two sets of neurons we find that the one that projects to the SIP also outputs to the local neurons within the LH. The design of simultaneous output at the LH and the SIP, an output of the MB, allows for coordination between innate and learned responses.

neuroscience↗

bioRxiv2017

Speed dependent descending control of innate freezing behavior in Drosophila melanogaster

SummaryThe most fundamental choice an animal has to make when it detects a predator, or other threats, is whether to freeze, reducing its chances of being noticed, or to flee to safety. Here we show that Drosophila melanogaster exposed to looming stimuli in a confined arena either froze or fled. The probability of freezing versus fleeing was modulated by the flys walking speed at the time of threat, demonstrating that freeze/flee decisions were context dependent. We describe a pair of descending neurons crucially implicated in freezing. Genetic silencing of P9 descending neurons disrupted freezing yet did not prevent fleeing. Optogenetic activation of both P9 neurons induced running and freezing in a state-dependent manner. Our findings establish walking speed as a key factor in defensive response choices and reveal a pair of descending neurons as a critical component in the circuitry mediating selection and execution of freezing or fleeing behaviors.

neuroscience↗