Early metamorphic insertion technology for insect flight behavior monitoring

Behavioral control and changes in brain activity of honeybee during flapping

INTRODUCTION

Insect cyborg is a kind of novel robot based on insect-machine interface and principles of neurobiology. The key idea is to stimulate live insects by specific stimuli; thus, the flight trajectory of insects could be controlled as anticipated. However, the neuroregulatory mechanism of insect flight has not been elucidated completely at present.

METHODS

To explore the neuro-mechanism of insect flight behaviors, a series of electrical stimulation was applied on the optic lobes of semi-constrained honeybees. Times of flight initiation, flapping frequency, and duration were recorded by a high-speed camera. In addition, flapping and steering initiation experiments of the cyborg honeybee were verified. Moreover, series of local field potential signals of optic lobes during flapping were collected, pre-processed to remove baseline wander and DC components, then analyzed by power spectrum estimation.

RESULTS

A quantitative optimization method and optimal stimulation parameters of flight initiation were presented. Stimulation results showed that the flapping duration differed greatly while the flapping frequency varied with little difference among different individuals. Moreover, there was always a fluctuation peak around 20-30 Hz in power spectral density (PSD) curves during flapping, distinguishing from calm state, which indicated some brain activity changes during flapping.

CONCLUSIONS

Our study presented a range of relatively optimal electrical parameters to initiate honeybee flight behavior. Meanwhile, the regularity of flapping duration and flapping frequency under electrical stimulations with different parameters were given. The feasibility of controlling a honeybee's flight behavior by brain electrical stimulation was verified through the flapping and steering initiation experiment of honeybees under semi-constrained state. PSD fluctuations reflected changes in brain activity during flapping and that those fluctuation characteristics at the specific frequency band could be sensitive determinants to distinguish whether the honeybee was flying or not, which benefits our understanding of honeybee's flapping behavior and furthers the study of honeybee cyborgs.

Electrical Stimulation of Coleopteran Muscle for Initiating Flight

Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.