Multimodal Behavioral Phenotyping Of Stress-Induced Depression-like States In Drosophila melanogaster

Summary

This protocol provides a framework for assessing stress-induced behavioral changes in Drosophila melanogaster. Combining complementary assays enables the quantification of activity, exploration, and decision-making for individual flies. The approach is flexible and can be adapted to a wide range of studies investigating stress biology, metabolism, and neurobehavioral function.

Abstract

Metabolic, neurodegenerative, and stress-related disorders are frequently accompanied by altered locomotion, impaired decision-making, and reduced behavioral flexibility. However, accessible multimodal behavioral frameworks for quantifying these phenotypes in Drosophila melanogaster remain limited. Here, a protocol integrating forced swim exposure, Y-maze turning behavior and handedness, phototaxis, and activity assessment in the FlyVac system, open-field exploration, and long-term locomotor monitoring using the Drosophila Activity Monitor is presented. These complementary assays capture multiple dimensions of behavior, including motor output, motivation, decision structure, and behavioral variability, as functional readouts of neural and metabolic states. The pipeline is scalable, reproducible, and adaptable to pharmacological, genetic, and environmental manipulations, providing a versatile framework for detecting stress-, metabolic-, and neurodegeneration-related behavioral phenotypes in Drosophila.

Introduction

Behavioral alterations such as changes in locomotion, decision-making, and exploratory activity are widely used as organism-level indicators of neural and physiological state. Across taxa, neural dysfunction often manifests as altered movement structure, reduced exploratory motivation, impaired sensory-guided decision behavior, and changes in behavioral predictability. Because these organism-level outputs integrate neural, metabolic, and physiological state, they provide scalable readouts for detecting disease-relevant phenotypes. However, despite the extensive use of Drosophila melanogaster in molecular genetics and neuroscience, standardized multimodal beha....

Protocol

The forced swim assay was conducted in accordance with the principles of the 3Rs (Replacement, Reduction, and Refinement). Replacement was achieved by using Drosophila melanogaster as an invertebrate model, thereby avoiding vertebrate forced swim paradigms that are increasingly restricted for ethical reasons. Reduction was supported by the assay's high-throughput nature, which enables robust behavioral inference from relatively small cohorts while minimizing animal use. Refinement was addressed by limiting swim exposure to 2 min, a duration that prevents exhaustion or drowning and allows full recovery of normal locomotor behavior immediately after testing....

Results

Application of the vibration stress protocol produced measurable behavioral alterations across multiple assays (Figure 1) designed to capture activity, coping behavior, and decision-making in D. melanogaster.

Depression-like induction

Flies exposed to repeated mechanical vibration (Figure 1A) displayed reduced exploratory activity and altered behavioral responses compared to unstre.......

Discussion

The present protocol demonstrates a multimodal approach for inducing and quantifying depression-like behavioral states in D. melanogaster. Using a vibration-based stress paradigm combined with complementary behavioral assays, this study shows that depression-like induction can be detected across measures of coping behavior, locomotor activity, exploratory dynamics, decision-making, and behavioral variability¹⁶. The stress regime employed in this study serves as a practical tool to elicit .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anesthesia equipment: e.g., Benchtop Flowbuddy, Complete System w/ Ultimate Flypad	Genesis Scientific, El Cajon, CA, USA	59-122BCU
BioSan MSV-3500 multispeed vortex	Biosan SIA, Riga, Latvia	BS-010210-TAH	With all platforms
Cotton closures for narrow vials	Flystuff by Genesee Scientific, El Cajon, CA 92020 USA	Catalog number: 51-101
Drosophila Activity Monitor (DAM2)	TriKinetics Inc, Waltham, MA, USA	DAM2; RRID: not available	32 tubes
Drosophila melanogaster (Oregon-R-modENCODE)	Drosophila melanogaster (Oregon-R-modENCODE)	BDSC:25211; RRID:BDSC_25211
GraphPad Prism	GraphPad Software, Boston, MA, USA;	Catalog name: GraphPad Prism, RRID:SCR_002798	Version 11.0.1
Logitech C920 HD Pro Webcam, HD 1080p lensCatalog name: HD Pro Webcam C920	Logitech Europe S.A., Lausanne, Switzerland	RRID: not available	The overhead recording camera used for FST
Narrow Fly Vial, Polypropylene	Flystuff by Genesee Scientific, El Cajon, CA 92020 USA	Catalog number: 32-120BF
Noldus EthoVision XT	Noldus Information Technology, Wageningen, The Netherlands	RRID: SCR_000441	v. 15.0
Sodium dodecyl sulfate (SDS, ≥99%)	Merck KGaA (Sigma-Aldrich), Darmstadt, Germany	Catalog name: Sodium dodecyl sulfate (ACS reagent, ≥99% purity); RRID: not available
ZEISS Stemi 508 Stereomicroscope	Carl Zeiss AG, Oberkochen, Baden-Württemberg, Germany	15634448