Biology subjects

Faruque, I. A.

Publications and source records attributed to Faruque, I. A..

4 recordsLinked to original sources

bioRxiv2022

Insect visuomotor delay adjustments in group flightsupport swarm cohesion

Flying insects routinely demonstrate coordinated flight in groups. How they achieve this with very limited communication, vision, and neural systems remains an open question. We measured the visual reaction time in flying honeybees while they chased a moving target, and compared in-flight reaction times for solo animals with those flying in groups. Across 425 insects, the solo honeybees show diverse reaction times (an average of 30ms and a standard deviation of 50ms). The reaction times in groups are significantly more uniform (an average of 15ms and a standard deviation of only 7ms), indicating that honeybees in group flight adjust their reaction times to match their neighbors. To investigate the role of this adjustment, we curve fit the reaction time distributions and analyzed them in a mathematical model of swarming, finding that the reaction time increases the stable region of a cohesive swarm. To verify the stabilizing effect was not an artifact of curve fitting, we then inserted the measured delays in a swarm simulation, which breaks apart under the solo reaction times and achieves stable formations for the group reaction times. Together, our findings highlight how flying animals can synchronize their reaction times in group flights to improve group cohesion.

animal behavior and cognition↗

bioRxiv2022

Experimental identification of individual insect visual tracking delays in free flight and their effects on visual swarm patterns

Insects are model systems for swarming robotic agents, yet engineered descriptions do not fully explain the mechanisms by which they provide onboard sensing and feedback to support such motions; in particular, the exact value and population distribution of visuomotor processing delays are not yet quantified, nor the effect of such delays on a visually-interconnected swarm. This study measures untethered insects performing a solo in-flight visual tracking task and applies system identification techniques to build an experimentally-consistent model of the visual tracking behaviors, and then integrates the measured experimental delay and its variation into a visually interconnected swarm model to develop theoretical and simulated solutions and stability limits. The experimental techniques include the development of a moving visual stimulus and real-time multi camera based tracking system called VISIONS1 providing the capability to recognize and simultaneously track both a visual stimulus (input) and an insect at a frame rate of 60-120 Hz. A frequency domain analysis of honeybee tracking trajectories is conducted via fast Fourier and Chirp Z transforms, identifying a coherent linear region and its model structure. The model output is compared in time and frequency domain simulations. The experimentally measured delays are then related to probability density functions, and both the measured delays and their distribution are incorporated as inter-agent interaction delays in a second order swarming dynamics model. Linear stability and bifurcation analysis on the long range asymptotic behavior is used to identify delay distributions leading to a family of solutions with stable and unstable swarm center of mass (barycenter) locations. Numerical simulations are used to verify these results with both continuous and modeled distributions. The results of this experiment quantify a model structure and temporal lag (transport delay) in the closed loop dynamics, and show that this delay varies across 50 individuals from 5-110ms, with an average delay of 22ms and a standard deviation of 40ms. When analyzed within the swarm model, the measured delays support a diversity of solutions and indicate an unstable barycenter.

bioengineering↗

bioRxiv2022

Honey bee flights under ethanol-exposure show changes in body and wing kinematics

Flying social insects can provide model systems for inflight interactions in computationally-constrained aerial robot swarms, whose interactions may be chemically modulated under recent measurement advancements provide a capability to simultaneously make precise measurements of insect wing and body motions. This paper presents the first quantitative measurements of ethanol-exposed honey bee flight body and wing kinematic parameters. Four high speed cameras (9000 fps) were used to track the wing and body motions of insects (Apis mellifera). Digitization, consisting of data association, hull reconstruction, and segmentation, achieved the first high speed measurements of ethanol exposed honey bees wing and body motions. Kinematic changes induced by exposure to ethanol concentrations from 0% to 5% were studied using statistical analysis tools. Analysis considered trial wide mean and maximum values and gross wingstroke parameters, and tested deviations for statistical significance using Welchs t-test and Cohens d test. The results indicate a decrease in maximal heading and pitch rates of the body, and that roll rate is affected at high concentrations (5%). The wingstroke effects include a stroke frequency decrease, stroke amplitude increase, stroke inclination angle increase, and a more planar wingstroke. These effects due to ethanol exposure are valuable tools to separate from interaction effects.

animal behavior and cognition↗

bioRxiv2022

High Speed Visual Insect Swarm Tracker (Hi-VISTA) used to identify the effects of confinement on individual insect flight

Individual insects flying in crowded assemblies perform complex aerial maneuvers by sensing and feeding back neighbor measurements to small changes in their wing motions. To understand the individual feedback rules that permit these fast, adaptive behaviors in group flight, a high-speed tracking system is needed capable of tracking both body motions and more subtle wing motion changes for multiple insects in simultaneous flight. This capability extends tracking beyond the previous focus on individual insects to multiple insects. This paper presents Hi-VISTA, which provides a capability to track wing and body motions of multiple insects using high speed cameras (9000 fps). Processing steps consist of automatic background identification, data association, hull reconstruction, segmentation, and feature measurement. To improve the biological relevance of laboratory experiments and develop a platform for interaction studies, this paper applies the Hi-VISTA measurement system to Apis mellifera foragers habituated to transit flights through a transparent tunnel. Binary statistical analysis (Welchs t-test, Cohens d effect size) of 95 flight trajectories is presented, quantifying the differences between flights in an unobstructed tunnel and in a confined tunnel volume. The results indicate that body pitch angle, heading rate, flapping frequency, and vertical speed (heave) are all affected by confinement, and other flight variables show minor or statistically insignificant changes. These results form a baseline as swarm tracking and analysis begins to isolate the effects of neighbors from environment.

animal behavior and cognition↗