Musculoskeletal simulation of limb movement biomechanics in Drosophila melanogaster

ICLR 2026 Conference SubmissionAnonymous Authors
Musculoskeletal ModelingDrosophila melanogasterImitation Learning
Abstract:

Computational models are critical to advance our understanding of how neural, biomechanical, and physical systems interact to orchestrate animal behaviors. Despite the availability of near-complete reconstructions of the Drosophila melanogaster central nervous system, musculature, and exoskeleton, anatomically and physically grounded models of fly leg muscles are still missing. These models provide an indispensable bridge between motor neuron activity and joint movements. Here, we introduce the first 3D, data-driven musculoskeletal model of Drosophila legs, implemented in both OpenSim and MuJoCo simulation environments. Our model incorporates a Hill-type muscle representation based on high-resolution X-ray scans from multiple fixed specimens. We present a pipeline for constructing muscle models using morphological imaging data and for optimizing unknown muscle parameters specific to the fly. We then combine our musculoskeletal models with detailed 3D pose estimation data from behaving flies to achieve muscle-actuated behavioral replay in OpenSim. Simulations of muscle activity across diverse walking and grooming behaviors predict coordinated muscle synergies that can be tested experimentally. Furthermore, by training imitation learning policies in MuJoCo, we test the effect of different passive joint properties on learning speed and find that damping and stiffness facilitate learning. Overall, our model enables the investigation of motor control in an experimentally tractable model organism, providing insights into how biomechanics contribute to generation of complex limb movements. Moreover, our model can be used to control embodied artificial agents to generate naturalistic and compliant locomotion in simulated environments.

Disclaimer
This report is AI-GENERATED using Large Language Models and WisPaper (A scholar search engine). It analyzes academic papers' tasks and contributions against retrieved prior work. While this system identifies POTENTIAL overlaps and novel directions, ITS COVERAGE IS NOT EXHAUSTIVE AND JUDGMENTS ARE APPROXIMATE. These results are intended to assist human reviewers and SHOULD NOT be relied upon as a definitive verdict on novelty.
NOTE that some papers exist in multiple, slightly different versions (e.g., with different titles or URLs). The system may retrieve several versions of the same underlying work. The current automated pipeline does not reliably align or distinguish these cases, so human reviewers will need to disambiguate them manually.
If you have any questions, please contact: mingzhang23@m.fudan.edu.cn

Overview

Overall Novelty Assessment

The paper presents a 3D, data-driven musculoskeletal model of Drosophila legs incorporating Hill-type muscle representations derived from high-resolution X-ray scans. It resides in the 'Leg Musculoskeletal Models' leaf, which contains only two papers total. This is a notably sparse research direction within the broader taxonomy, suggesting that anatomically detailed leg models remain an underexplored area despite the availability of connectome and morphological data. The sibling paper in this leaf shares the focus on muscle-tendon-skeleton systems for simulating limb biomechanics.

The taxonomy reveals that neighboring work divides into two main streams: whole-body neuromechanical frameworks (five papers) that integrate neural control with musculoskeletal dynamics across walking and flight, and kinematic analysis methods (four papers) that focus on joint angles and motion capture without muscle force modeling. The paper's emphasis on anatomical detail and muscle-actuated replay positions it between these streams—more mechanistic than pure kinematics, yet more limb-focused than whole-body neuromechanical platforms. The exclude_note for this leaf explicitly distinguishes it from neural integration frameworks and kinematic-only approaches.

Among 26 candidates examined, each of the three contributions shows at least one potentially overlapping prior work. The first contribution (3D musculoskeletal model) examined six candidates with one refutable match; the pipeline for constructing muscle models examined ten candidates with one refutable; and the behavioral replay contribution examined ten candidates with one refutable. These statistics indicate that within the limited search scope, each major claim encounters some degree of prior overlap, though the majority of examined candidates (23 of 26 total) do not clearly refute the contributions. The search scale is modest, leaving open the possibility of additional relevant work beyond the top-K semantic matches.

Based on the limited literature search, the work appears to occupy a relatively sparse research niche—detailed leg musculoskeletal modeling—while each contribution shows partial overlap with at least one prior candidate. The taxonomy structure confirms that this specific combination of anatomical detail, muscle modeling, and behavioral replay is less crowded than adjacent areas like whole-body neuromechanical simulation. However, the modest search scope (26 candidates) and the presence of refutable matches for all three contributions suggest that claims of absolute novelty should be tempered by acknowledgment of existing foundational work in this domain.

Taxonomy

Core-task Taxonomy Papers
29
3
Claimed Contributions
26
Contribution Candidate Papers Compared
3
Refutable Paper

Research Landscape Overview

Core task: musculoskeletal modeling of limb movement in fruit flies. This field integrates biomechanics, neuroscience, and computational modeling to understand how Drosophila generate and control leg movements. The taxonomy reveals a multifaceted landscape organized around several complementary themes. Neuromechanical Simulation Frameworks provide computational platforms that couple neural control with physical dynamics, exemplified by tools like NeuroMechFly[1] and its successor NeuroMechFly v2[5]. Leg Musculoskeletal Models focus on detailed anatomical representations of limb structure, muscle arrangements, and joint mechanics, as seen in Drosophila Leg Model[3]. Kinematic Analysis and Modeling emphasizes motion capture and quantitative descriptions of limb trajectories, while Mechanosensory Biomechanics and Proprioception and Motor Control branches explore how sensory feedback from campaniform sensilla and proprioceptors shapes movement. Biomimetic Robotics translates biological insights into engineered systems, and Connectomics and Neural Circuits leverage large-scale neural wiring diagrams such as the Drosophila Connectome[6] to inform control architectures. Methodological Advances capture cross-cutting technical innovations in imaging, simulation, and data analysis. Within this landscape, a particularly active line of work centers on building increasingly realistic leg models that integrate muscle geometry, passive forces, and sensory feedback. Drosophila Limb Simulation[0] sits squarely in the Leg Musculoskeletal Models branch, emphasizing detailed anatomical fidelity and biomechanical accuracy. It shares this focus with Drosophila Leg Model[3], which similarly prioritizes muscle-tendon arrangements and joint kinematics, though the two may differ in their treatment of passive tissue properties or sensory integration. Meanwhile, works like NeuroMechFly[1] and NeuroMechFly v2[5] adopt a broader neuromechanical perspective, embedding leg models within whole-body simulations that couple neural circuits to physical dynamics. A key open question across these branches is how to balance anatomical detail with computational tractability, and how to validate models against behavioral data when proprioceptive feedback and neural control remain incompletely understood.

Claimed Contributions

First 3D data-driven musculoskeletal model of Drosophila legs

The authors develop the first anatomically and physically grounded musculoskeletal model of Drosophila melanogaster legs incorporating Hill-type muscle representations based on high-resolution X-ray scans. The model is implemented in two widely used physics engines (OpenSim and MuJoCo) and includes 15 muscle-tendon units per foreleg actuating seven degrees of freedom across three leg joints.

6 retrieved papers
Can Refute
Pipeline for constructing muscle models from morphological imaging data

The authors introduce an end-to-end automated pipeline that extracts anatomical features from imaging data, estimates physiological parameters, and optimizes unknown parameters using multi-objective optimization to match behavioral kinematics. This framework links anatomical inputs to functional muscle-driven simulations.

10 retrieved papers
Can Refute
Muscle-actuated behavioral replay combining musculoskeletal models with 3D pose estimation

The authors integrate their musculoskeletal model with detailed 3D pose estimation data from behaving flies to reproduce muscle-driven movements in simulation. This enables prediction of coordinated muscle synergies across diverse behaviors like walking and grooming that can be experimentally tested.

10 retrieved papers
Can Refute

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

First 3D data-driven musculoskeletal model of Drosophila legs

The authors develop the first anatomically and physically grounded musculoskeletal model of Drosophila melanogaster legs incorporating Hill-type muscle representations based on high-resolution X-ray scans. The model is implemented in two widely used physics engines (OpenSim and MuJoCo) and includes 15 muscle-tendon units per foreleg actuating seven degrees of freedom across three leg joints.

Contribution

Pipeline for constructing muscle models from morphological imaging data

The authors introduce an end-to-end automated pipeline that extracts anatomical features from imaging data, estimates physiological parameters, and optimizes unknown parameters using multi-objective optimization to match behavioral kinematics. This framework links anatomical inputs to functional muscle-driven simulations.

Contribution

Muscle-actuated behavioral replay combining musculoskeletal models with 3D pose estimation

The authors integrate their musculoskeletal model with detailed 3D pose estimation data from behaving flies to reproduce muscle-driven movements in simulation. This enables prediction of coordinated muscle synergies across diverse behaviors like walking and grooming that can be experimentally tested.