Biology subjects

Srinivasan, M. V.

Publications and source records attributed to Srinivasan, M. V..

5 recordsLinked to original sources

bioRxiv2026

Threading the needle: Spatial constraints sharpen visual sensitivity in honeybees

Navigating dense clutter requires honeybees to execute rapid visuomotor comparisons to identify the best route. How they resolve perceptual inputs to make a passage choice from multiple options is an open question. We studied this in a free flying paradigm where bees were challenged to choose between a taller and shorter aperture with varying height difference. We monitored choice across four height difference ratios at three spatial scales. Bees chose the taller aperture in all tests, but the precision of these choices depended heavily on the absolute size of the gap. For each size scale of aperture pairs, psychometric modelling revealed that when making a choice bees generally evaluate the relative height difference, conforming to Webers law. However, bees choices were non-uniformly sensitive across aperture size scales. Bees had greater sensitivity at the smallest spatial scale, where the likelihood of collision danger is larger. This deviation in behaviour due to absolute aperture size suggests a dynamic risk-cost trade-off. Bees appear to prioritise costly, high-acuity inspections only when imposed by critical physical constraints of the environment, relaxing this vigilance at safer, larger scales to conserve energy.

animal behavior and cognition↗

bioRxiv2022

3D Analysis of the Force Generated by a Honeybee During Flight

To better understand the turning flight characteristics of the bees, we developed a procedure for estimating the instantaneous total force generated by the bee, along with its centrifugal force component, at each instant of time. We calculated the magnitude and direction of the total force vector (TFV) with respect to the three body axes of the bee and examined its variation with time during turning flights. The results of this study revealed that turns in the cloud are executed by (a) holding the magnitude of the TFV vector constant and (b) by redirecting the body (and therefore the turning force) appropriately to execute a coordinated turn. We also calculated and analysed the TFVs of bees flying in a curved tunnel. The characteristics of these TFVs (magnitude and direction) are very similar to those for bees flying in the cloud. This is a novel finding as there are no studies which have estimated the instantaneous flight force magnitude and direction of a turning bee (these are not saccadic or evasive turns) in an outdoor or indoor setup. However, similar results have been reported for pigeons and cockatiels while executing smooth turns in the horizontal plane.

animal behavior and cognition↗

bioRxiv2022

Reconstruction of Three-Dimensional Trajectories of Honeybees Flying in High-Density Aerial Environments

So far, relatively few studies have investigated the flight of insects moving in experimental conditions approximating natural scenes. This is mainly because of the technical difficulties involved in detecting and tracking individual insects in three dimensions in outdoor scenarios, as well as matching views of corresponding insects in stereo images for trajectory reconstruction (the so-called Correspondence Problem). In this study, we describe the methods we have developed to track and unambiguously reconstruct the trajectories and body orientations of a large number of bees flying in close proximity in a bee cloud, using just two high-speed video cameras configured as a stereo pair in a semi-outdoor setting. Using these methods, two separate bee clouds were filmed and the data were analysed to reconstruct the three-dimensional trajectories, including the head and tail positions, of a total of 382 bees. This dataset should enable future analysis of the movement characteristics of bees flying in a dense environment, as well as uncover potential strategies for mid-air collision avoidance.

animal behavior and cognition↗

bioRxiv2018

3D Reconstruction of Bird Flight Using a Single Video Camera

Video cameras are finding increasing use in the study and analysis of bird flight over short ranges. However, reconstruction of flight trajectories in three dimensions typically requires the use of multiple cameras and elaborate calibration procedures. We present an alternative approach that uses a single video camera and a simple calibration procedure for the reconstruction of such trajectories. The technique combines prior knowledge of the wingspan of the bird with a camera calibration procedure that needs to be used only once in the lifetime of the system. The system delivers the exact 3D coordinates of the position of the bird at the time of every full wing extension and uses interpolated height estimates to compute the 3D positions of the bird in the video frames between successive wing extensions. The system is inexpensive, compact and portable, and can be easily deployed in the laboratory as well as the field.

animal behavior and cognition↗

bioRxiv2018

COORDINATED TURNING BEHAVIOUR OF LOITERING HONEYBEES (APIS MELLIFERA)

Turning during flight is a complex behaviour that requires coordination to ensure that the resulting centrifugal force is never large enough to disrupt the intended turning trajectory. The centrifugal force during a turn increases with the curvature (sharpness) of the turn, as well as the speed of flight. Consequently, sharp turns would require lower flight speeds, in order to limit the centrifugal force to a manageable level and prevent unwanted sideslips. We have video-filmed honeybees flying near a hive entrance when the entrance is temporarily blocked. A 3D reconstruction and analysis of the flight trajectories executed during this loitering behaviour reveals that sharper turns are indeed executed at lower speeds. During a turn, the flight speed is matched to the curvature, moment to moment, in such a way as to maintain the centrifugal force at an approximately constant, low level of about 30% of the body weight, irrespective of the speed or the curvature of the turn. This ensures that turns are well coordinated, with few or no sideslips - as is evident from analysis of other properties of the flight trajectories.

animal behavior and cognition↗