Non-contact measurement of a free flying bumblebee's (Bombus terrestris) electrical potential as it approaches and leaves a fixed electrode
With increasing evidence of electroreception in terrestrial arthropods, understanding receptor level processes is vital to appreciating the capabilities and limits of this sense. Here, we examine the spatio-temporal sensitivity of mechanoreceptive filiform hairs in detecting electrical fields. We first present empirical data, highlighting the time-varying characteristics of biological electrical signals. We then explore how electrically sensitive hairs may respond to such stimuli.
The main findings are: 1) oscillatory signals (elicited by wingbeats) influence the spatial sensitivity of hairs, unveiling an inextricable spatio-temporal link; 2) wingbeat direction modulates spatial sensitivity; 3) electrical wingbeats can be approximated by sinusoidally modulated DC signals; and 4) for a moving point charge, maximum sensitivity occurs at a faster timescale than a hair's frequency-based tuning.
Our results show that electro-mechanical sensory hairs may capture different spatio-temporal information, depending on an object's movement and wingbeat and in comparison, to aero-acoustic stimuli. Crucially, we suggest that electrostatic and aero-acoustic signals may provide distinguishable channels of information for arthropods.
Given the pervasiveness of electric fields in nature, our results suggest further study to understand electrostatics in the ecology of arthropods and to reveal unknown ecological relationships and novel interactions between species.