This material is based on the works supported by Nanyang Assistant Professorship (NAP, M4080740), Agency for Science, Technology and Research (A*STAR) Public Sector Research Funding (PSF, M4070190), A*STAR-JST (The Japan Science and Technology Agency) joint grant (M4070198), and Singapore Ministry of Education (MOE2013-T2-2-049). The authors would like to thank Mr. Roger Tan Kay Chia, Prof. Low Kin Huat, Mr. Poon Kee Chun, Mr. Chew Hock See, Mr. Lam Kim Kheong and Dr. Mao Shixin at School of MAE for their support in setting up and maintaining the research facilities. The authors thank Prof. Michel Maharbiz (U.C. Berkeley) his advice and discussion, Prof. Kris Pister and his group (U.C. Berkeley) for their support in providing the GINA used in this study.

1. Study Animal
<ol>
	<li>Rear individual Mecynorrhina torquata beetles (6 cm, 8 g) in separate plastic containers with wood pellet bedding.</li>
	<li>Feed each beetle a cup of sugar jelly (12 ml) every 3 days.</li>
	<li>Keep the temperature and humidity of the rearing room at 25 &#176;C and 60%, respectively.</li>
	<li>Test the flight capability of each beetle before implanting thin wire electrodes.
	<ol>
		<li>Gently throw a beetle into the air. If the beetle can fly for longer than 10 sec for 5 consecutive trials, conclude that the beetle has regular flight capabilities and employ it for subsequent flight experiments. To recapture the beetle, switch off all the lights in the room to make it dark. This causes the beetle to terminate flight. 
		Note: A beetle spontaneously begins to fly away when released into the air. It is better to conduct the flight experiments in a large closed room such as the one shown in Figure 1 (16 x 8 x 4 m3 with a motion capture space of 12.5 x 8 x 4 m3), as a flying beetle moves very fast (approximately 3-5 m/sec) and draws large arcs when turning in the air.</li>
	</ol>
	</li>
</ol>
2. Electrode Implantation
<ol>
	<li>Anesthetize the beetle by placing it in a plastic container filled with CO2 for 1 min13,16,20-24.</li>
	<li>Soften dental wax by dipping it in hot water for 10 sec. Place the anesthetized beetle on a wooden block and immobilize it with the softened dental wax. The dental wax naturally cools and solidifies within a few minutes.</li>
	<li>Cut insulated silver wires (127 &#181;m bare diameter, 178 &#181;m diameter when coated with perfluoroalkoxy) into lengths of 25 mm to use as thin wire electrodes for implantation.</li>
	<li>Expose 3 mm of bare silver by flaming the insulator at both ends of each wire.</li>
	<li>Dissect the top surface of the beetle&#39;s cuticle using a fine-tipped scissor to create a small window of approximately 4 x 4 mm on the metepisternum (Figure 2c). Note: A soft brown-colored cuticle is then exposed, as shown in Figures 2c-e. The 3Ax muscle is located underneath the soft cuticle.</li>
	<li>Pierce two holes on the exposed brown cuticle using an insect pin (size 00) with a distance of 2 mm between the two holes (Figure 2d).</li>
	<li>Insert two wire electrodes (including one active and one return electrodes prepared in step 2.4) carefully through the holes and implant them into each 3Ax muscle at a depth of 3 mm.</li>
	<li>Secure the implanted electrodes and hold them in place to avoid contact and short-circuits by dropping melted beeswax on the holes. If needed, reflow the beeswax over the cuticle by touching the beeswax with the tip of a hot soldering iron. The beeswax quickly solidifies and reinforces the implantation. 
	Note: To check if the implantation is correct, the elytra of the beetle can be lifted to observe the movement of the 3Ax muscle during electrical stimulation.</li>
</ol>
3. Wireless Backpack Assembly
Note: The backpack consisted of a built-in radio microcontroller on a 4 layered FR-4 board (1.6 x 1.6 cm2). The backpack was driven by a lithium polymer microbattery (3.7 V, 350 mg, 10 mAh). The total mass of the backpack including the battery was 1.2 &#177; 0.26 g which is less than the payload capacity of the beetle (30% of 10 g body weight). The backpack was pre-programmed to receive wireless communications and had two output channels.
<ol>
	<li>Clean the pronotum surface (remove the wax layer on the cuticle) using double-sided tape. Then, attach the backpack on the pronotum of the beetle with a piece of double-sided tape.</li>
	<li>Connect the ends of the implanted electrodes to the outputs of the backpack.</li>
	<li>Wrap retro-reflective tape around the microbattery to produce a marker for motion capture cameras to detect.</li>
	<li>Attach the microbattery to the top of the backpack using a piece of double-sided tape so that the retro-reflective tape can be detected by motion capture cameras.</li>
</ol>
4. Wireless Control System
Note: In this case, the term wireless control system includes a receiver for the remote controller, a laptop computer to run the custom flight control software, a base station, the backpack, and the motion capture system.
<ol>
	<li>Connect the base station and receiver of the remote controller to the laptop computer via USB ports.</li>
	<li>Switch on the motion capture system and connect it to the laptop computer via an Ethernet port.</li>
	<li>Perform volume calibration by waving the calibration wand (provided by the vendor company of the motion capture system) to fully cover the motion capture space.
	<ol>
		<li>Open the motion capture software from the desktop of the laptop. Click and drag to select all the cameras on the &#34;System&#34; menu of the &#34;Resources&#34; panel.</li>
		<li>Click on the &#34;3D Perspective&#34; menu and select &#34;Camera&#34; to change to the camera view. Click on the &#34;Camera&#34; tab on the &#34;Tools&#34; panel to show the calibration setup. Click &#34;Start&#34; on the &#34;Create Camera Masks&#34; menu to eliminate noise from the cameras and then &#34;Stop&#34; after the noise is masked in blue.</li>
		<li>Click and select &#34;5 Marker Wand &#38; L-Frame&#34; from the &#34;Wand&#34; menu and the &#34;L-Frame&#34; menu on the &#34;Camera&#34; tab. Set the &#34;Wand Count&#34; to 2,500, click &#34;Start&#34; on the &#34;Calibrate Cameras&#34; menu, and wave the calibration wand through the entire motion capture space. The calibration process stops when the wand count reaches 2,500.</li>
		<li>Repeat the calibration process if image error (at the bottom of the &#34;Camera&#34; tab of the &#34;Tools&#34; panel) is higher than 0.3 for any camera. After calibrating, put the wand on the floor in the middle of the motion capture space and click &#34;Start&#34; on the &#34;Set Volume Origin&#34; menu to set the origin of the motion capture space.</li>
	</ol>
	</li>
	<li>Check the coverage of the motion capture system using a dummy test to record the motion path of a marker waved by a user in the motion capture space and confirm whether the marker is detected and tracked. If the marker is frequently lost during detection, repeat volume calibration until the dummy test succeeds.
	<ol>
		<li>Click on the &#34;Capture&#34; tab on the &#34;Tools&#34; panel and then &#34;Start&#34; on the &#34;Capture&#34; menu before waving the sample marker through the entire motion capture space to record its trajectory.</li>
		<li>After recording, click on &#34;Runs the Reconstruct pipeline&#34; to reconstruct the positions of the marker and check the quality of the recording.</li>
	</ol>
	</li>
	<li>Connect the terminals of the microbattery (attached to the backpack in step 3.4) to the power pins of the backpack.</li>
	<li>Test the wireless communication between the laptop and the backpack using the custom flight control software. Click the &#34;Start&#34; command on the software and check the displayed connection status.</li>
</ol>
5. Free Flight Experiment
<ol>
	<li>Carry out the free flight experiment in a flight arena measuring 16 x 8 x 4 m3.</li>
	<li>Input the appropriate parameters to the flight control software (voltage, pulse width, frequency, and stimulation duration). Note: For demonstration, we fixed the voltage to 3 V, pulse width to 3 msec, and stimulation duration to 1 sec and varied the frequency from 60 to 100 Hz.
	<ol>
		<li>On the software screen, type 3 for 3 V in the &#34;Voltage&#34; box, 1,000 for 1,000 msec in the &#34;Stimulation Duration&#34; box, 3 for 3 ms in the &#34;Pulse Width&#34; box, and a desired frequency in Hz in the &#34;Frequency&#34; box on the command window.</li>
	</ol>
	</li>
	<li>Release the backpack-mounted beetle into the air allowing it to fly freely within the flight arena. Manually trigger the stimulation when the beetle enters the motion capture space. Press the appropriate command button (Left or Right) on the remote to stimulate the target muscle on the left or right side of the beetle. 
	Note: Once the button is pressed, the flight control software running on the laptop generates the command and sends it to the backpack. The backpack then outputs the electrical stimulus to the muscle of interest (on the left or right side).</li>
	<li>Observe the beetle&#39;s reaction in real time during the stimulation and reconstruct the data using 3D graphing software.
	<ol>
		<li>Select one of the trials recorded in the data list of the &#34;Beetle Display&#34; window and click &#34;Export Panda&#34; to copy the data of that trial to the analysis folder and run the 3D graphing module.</li>
		<li>Press &#34;N&#34; on the keyboard to combine the stimulus signal with the recorded trajectory. Press I to show the trajectory of the beetle with the highlighted stimulation periods.</li>
	</ol>
	</li>
</ol>

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The authors declare that there are no conflicts of interest.

The implantation process is important, as it affects the reliability of the experiment. The electrodes should be inserted into the muscle at a depth of 3 mm or less depending on the size of the beetle (avoiding contact with nearby muscles). If the electrodes touch the nearby muscles, undesirable motor actions and behaviors may occur owing to the contraction of nearby muscles. The two electrodes should be well aligned to ensure that no short circuits occur. When melting and reflowing beeswax using a soldering iron, the ex...

An insect-machine hybrid system, often referred to as a cyborg insect or biobot, is the fusion of a living insect platform with a miniature mounted electronic device. The electronic device, which is wirelessly commanded by a remote user, outputs an electrical signal to electrically stimulate neuromuscular sites in the insect via implanted wire electrodes to induce user desired motor actions and behaviors. In the early stages of this research field, researchers were limited to conducting wireless recording of the muscular action of an insect, using simple analog circuits comprised of surface-mounted components1-3. The development of system-on-a-chip technology with radio frequency functionality enabled not only the wireless recording of neuromuscular signals but also the electrical stimulation of the neuromuscular sites in living insects. At present, a built-in radio microcontroller is small enough to be mounted on living insects without causing any obstructions to their locomotion4-13.
The development of the built-in radio microcontroller allows researchers to determine electrical stimulation protocols to induce desired motor actions to control the locomotion of the insect of interest. On the ground, researchers have demonstrated walking control by stimulating the neuromuscular sites of cockroaches4,12,14, spiders15, and beetles16,17. In the air, the initiation and cessation of flight were achieved using different methods such as the stimulation of the optic lobes (the massive neural cluster of a compound eye) in beetles7,9 and brain sub-regions in bees18, whereas turning control has been demonstrated by stimulating the antennae muscles and nervous system of the abdomens in moths11,19 and the flight muscles of beetles7,9,13. In most cases, a built-in radio microcontroller was integrated on a custom-designed printed circuit board to produce a miniature wireless stimulator (backpack), which was mounted on the insect of interest. This allows wireless electrical stimulation to be applied to a freely walking or flying insect. Such a microcontroller-mounted insect is what is referred to as an insect-machine hybrid system. 
This study describes the experimental protocols for building an insect-machine hybrid system, wherein a living beetle is employed as the insect platform, and instructs on how to operate the robot and test its flight control systems. The third axillary sclerite (3Ax) muscle was chosen as the muscle of interest for electrical stimulation and demonstration of left or right turning control13. A pair of thin silver wire electrodes was implanted in both the left and right 3Ax muscles. Moreover, a backpack was mounted on the living beetle. The other ends of the wire electrode were connected to the output pins of the microcontroller. The backpack was small enough for the beetle to carry in flight. Thus, this allows an experimentalist to remotely stimulate the muscle of interest of an insect in free flight and investigate its reactions to the stimulations.

<table><tbody><tr><td>Mecynorrhina torquata beetle</td><td>Kingdom of Beetle Taiwan</td><td></td><td>10 g, 8 cm, pay load capacity is 30% of the body mass&lt;br/&gt; Aproval of importing and using by Agri-Food and Veterinary Authority of Singapore (AVA; HS code: 01069000, product code: ALV002).</td></tr><tr><td>Wireless backpack stimulator</td><td>Custom</td><td></td><td>TI CC2431 micocontroler&lt;br/&gt; The board is custom made based on the GINA board from Prof. Kris Pister&amp;rsquo;s lab. The layout of GINA board can be found at&amp;nbsp;&amp;nbsp;&amp;nbsp; https://openwsn.atlassian.net/wiki/display/OW/GINA</td></tr><tr><td>Wii Remote control</td><td>Nintendo</td><td></td><td>Bluetooth remote control to send the command to the operator laptop</td></tr><tr><td>BeetleCommander v1.8</td><td>Custom. Maharbiz group at UC Berkeley and Sato group at NTU</td><td></td><td>Establish the wireless communication of the backpack and the operator laptop. Configure the stimulus parameters and log the positional data. Visualize the flight data.</td></tr><tr><td>GINA base station</td><td>Kris Pister group at UC Berkeley</td><td></td><td>TI MSP430F2618 and AT86RF231</td></tr><tr><td>Motion capture system</td><td>VICON</td><td>T160</td><td>8 cameras for a flight arena of 12.5 m x 8 m x 4 m</td></tr><tr><td>Motion capture system</td><td>VICON</td><td>T40s</td><td>12 cameras for a flight arena of 12.5 x 8 x 4 m</td></tr><tr><td>Micro battery</td><td>Fullriver</td><td>&amp;nbsp;201013HS10C&amp;nbsp;</td><td>3.7V, 10 mAh</td></tr><tr><td>Retro reflective tape</td><td>Reflexite</td><td>V92-1549-010150</td><td>V92 reflective tape, silver color</td></tr><tr><td>PFA-Insulated Silver Wire&amp;nbsp;</td><td>A-M systems</td><td>786000</td><td>127 &amp;micro;m bare, 177.8 &amp;micro;m coated, 3 mm bare silver flame exposed at tips</td></tr><tr><td>SMT Micro Header&amp;nbsp;</td><td>SAMTEC</td><td>FTSH-110-01-L-DV</td><td>0.3 mm x 6 mm, bend to make a 3 mm long slider to secure the electrode into the PCB header.</td></tr><tr><td>Beeswax</td><td></td><td></td><td>Secure the electrodes</td></tr><tr><td>Dental Wax</td><td>Vertex</td><td></td><td>Immobilize the beetle</td></tr><tr><td>Insect pin</td><td>ROBOZ</td><td>RS-6082-30</td><td>Size&amp;nbsp; 00; 0.3 mm Rod diameter; 0.03 mm tip width; 38 mm Length&amp;nbsp;&lt;br/&gt; Make electrode guiding holes on cuticle</td></tr><tr><td>Tweezers</td><td>DUMONT</td><td>RS-5015</td><td>Pattern #5; .05 mm x .01 mm Tip Size; 110 mm Length&lt;br/&gt; Dissecting and implantation</td></tr><tr><td>Scissors</td><td>ROBOZ</td><td>RS-5620</td><td>Vannas Micro Dissecting Spring Scissors; Straight; 3mm Cutting Edge; 0.1 mm Tip Width; 3&quot; Overall Length&amp;nbsp;&lt;br/&gt; Dissecting and implantation</td></tr><tr><td>Potable soldering iron</td><td>DAIYO</td><td>DS241</td><td>Reflow beeswax</td></tr><tr><td>Hotplate&amp;nbsp;</td><td>CORNING</td><td>PC-400D</td><td>Melting beeswax and dental wax</td></tr><tr><td>Flourescent lamp</td><td>Philips</td><td>TL5 14W</td><td>Light the entire flight arena with 30 panels (60 x 60 cm&lt;sup&gt;2&lt;/sup&gt;). Each panel has 3 lamps.&lt;br/&gt; 14 W, 549 mm x 17 mm&amp;nbsp;</td></tr></tbody></table>

insect-machine hybrid system: remote radio control of a freely flying beetle (mercynorrhina torquata)

The rise of radio-enabled digital electronic devices has prompted the use of small wireless neuromuscular recorders and stimulators for studying in-flight insect behavior. This technology enables the development of an insect-machine hybrid system using a living insect platform described in this protocol. Moreover, this protocol presents the system configuration and free flight experimental procedures for evaluating the function of the flight muscles in an untethered insect. For demonstration, we targeted the third axillary sclerite (3Ax) muscle to control and achieve left or right turning of a flying beetle. A thin silver wire electrode was implanted on the 3Ax muscle on each side of the beetle. These were connected to the outputs of a wireless backpack (i.e., a neuromuscular electrical stimulator) mounted on the pronotum of the beetle. The muscle was stimulated in free flight by alternating the stimulation side (left or right) or varying the stimulation frequency. The beetle turned to the ipsilateral side when the muscle was stimulated and exhibited a graded response to an increasing frequency. The implantation process and volume calibration of the 3 dimensional motion capture camera system need to be carried out with care to avoid damaging the muscle and losing track of the marker, respectively. This method is highly beneficial to study insect flight, as it helps to reveal the functions of the flight muscle of interest in free flight.

The electrode implantation procedure is presented in Figure 2. Thin silver wire electrodes were implanted into the 3Ax muscle of the beetle through small holes pierced on the soft cuticle on the muscle (Figures 2d-e). This soft cuticle is found just above the apodema of the basalar muscle after removing the anterior part of the metepisternum (Figures 2d-c). The electrodes were then secured using beeswax (...

Watch this Scientific Journal Video about Insect-machine Hybrid System: Remote Radio Control of a Freely Flying Beetle Mercynorrhina torquata at JoVE.com

Insect-machine Hybrid System: Remote Radio Control of a Freely Flying Beetle Mercynorrhina torquata

This protocol describes the process of constructing an insect-machine hybrid system and carrying out wireless electrical stimulation of the flight muscles required to control the turning motion of a flying insect.

Insect-machine Hybrid System: Remote Radio Control of a Freely Flying Beetle (Mercynorrhina torquata)

The rise of radio-enabled digital electronic devices has prompted the use of small wireless neuromuscular recorders and stimulators for studying in-flight ...

insect-machine-hybrid-system-remote-radio-control-freely-flying

Research

JoVE Journal

Neuroscience

12.1K Views.  Nanyang Technological University. This protocol describes the process of constructing an insect-machine hybrid system and carrying out wireless electrical stimulation of the flight muscles required to control the turning motion of a flying insect.

Video: Insect-machine Hybrid System: Remote Radio Control of a Freely Flying Beetle Mercynorrhina torquata

An Experimental Platform to Study the Closed-loop Performance of Brain-machine Interfaces

The non-stationary nature and variability of neuronal signals is a fundamental problem in brain-machine interfacing. We developed a brain-machine interface to assess the robustness of different control-laws applied to a closed-loop image stabilization task. Taking advantage of the well-characterized fly visuomotor pathway we record the electrical activity from an identified, motion-sensitive neuron, H1, to control the yaw rotation of a two-wheeled robot. The robot is equipped with 2 high-speed video cameras providing visual motion input to a fly placed in front of 2 CRT computer monitors. The activity of the H1 neuron indicates the direction and relative speed of the robot's rotation. The neural activity is filtered and fed back into the steering system of the robot by means of proportional and proportional/adaptive control. Our goal is to test and optimize the performance of various control laws under closed-loop conditions for a broader application also in other brain machine interfaces.

We use a closed-loop fly-machine interface to investigate general principles in neuronal control.

The non-stationary nature and variability of neuronal signals is a fundamental problem in brain-machine interfacing. We developed a brain-machine ...

Early Metamorphic Insertion Technology for Insect Flight Behavior Monitoring

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on insects during their metamorphic development. Here, the implants are fused within the structure and function of the neuromuscular system as a result of metamorphic tissue remaking. The implants emerge with the insect where the development of tissue around the electronics during pupal development results in a bioelectrically and biomechanically enhanced tissue interface. This relatively more reliable and stable interface would be beneficial for many researchers exploring the neural basis of the insect locomotion with alleviated traumatic effects caused during adult stage insertions. In this article, we implant our electrodes into the indirect flight muscles of Manduca sexta. Located in the dorsal-thorax, these main flight powering dorsoventral and dorsolongitudinal muscles actuate the wings and supply the mechanical power for up and down strokes. Relative contraction of these two muscle groups has been under investigation to explore how the yaw maneuver is neurophysiologically coordinated. To characterize the flight dynamics, insects are often tethered with wires and their flight is recorded with digital cameras. We also developed a novel way to tether Manduca sexta on a magnetically levitating frame where the insect is connected to a commercially available wireless neural amplifier. This set up can be used to limit the degree of freedom to yawing &#8220;only&#8221; while transmitting the related electromyography signals from dorsoventral and dorsolongitudinal muscle groups.

We present a novel surgical procedure to implant electrodes in Manduca sexta during its early metamorphic stages. This technique allows mechanically stable and electrically reliable coupling with the neuromuscular tissue to study flight neurophysiology dynamics. We also present a novel magnetic levitation platform for tethered studies of insect yaw.

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on ...

Behavior

Measuring the Flight Ability of the Ambrosia Beetle, Platypus Quercivorus (Murayama), Using a Low-Cost, Small, and Easily Constructed Flight Mill

The ambrosia beetle, Platypus quercivorus (Murayama), is the vector of a fungal pathogen that causes mass mortality of Fagaceae trees (Japanese oak wilt). Therefore, knowing the dispersal capacity may help inform trapping/tree removal efforts to prevent this disease more effectively. In this study, we measured the flight velocity and duration and estimated the flight distance of the beetle using a newly developed flight mill. The flight mill is low cost, small, and constructed using commonly available items. Both the flight mill arm and its vertical axis comprise a thin needle. A beetle specimen is glued to one tip of the arm using instant glue. The other tip is thick due to being covered with plastic, thus it facilitates the detection of rotations of the arm. The revolution of the arm is detected by a photo sensor mounted on an infrared LED, and is indicated by a change in the output voltage when the arm passed above the LED. The photo sensor is connected to a personal computer and the output voltage data are stored at a sampling rate of 1 kHz. By conducting experiments using this flight mill, we found that P. quercivorus can fly at least 27 km. Because our flight mill comprises cheap and small ordinary items, many flight mills can be prepared and used simultaneously in a small laboratory space. This enables experimenters to obtain a sufficient amount of data within a short period.

Measuring the Flight Ability of the Ambrosia Beetle, Platypus Quercivorus Murayama, Using a Low-Cost, Small, and Easily Constructed Flight Mill

We developed a low cost and small flight mill, constructed with commonly available items and easily used in experimentation. Using this apparatus, we measured the flight ability of an ambrosia beetle, Platypus quercivorus.

The ambrosia beetle, Platypus quercivorus (Murayama), is the vector of a fungal pathogen that causes mass mortality of Fagaceae trees (Japanese oak wilt). ...

Environment

A Precise and Autonomous System for the Detection of Insect Emergence Patterns

Existing systems to measure insect emergence patterns have limitations; they are only partially automated and are limited in the maximum number of emerging insects they can detect. In order to obtain precise measurement of insect emergence, it is necessary for systems to be semi-automated and able to measure large numbers of emerging insects. We addressed these issues by designing and building a system that is automated and can measure emergence of up to 1200 insects. We modified the existing &#34;falling-ball&#34; system using Arduino microcontrollers to automate data collection and expand the sample size through multiple data channels. Multiple data channels enable the user to not only increase their sample size, but also allows for multiple treatments to be run simultaneously in a single experiment. Furthermore, we created an R script to automatically visualize the data as a bubble plot, while also calculating the median day and time of emergence. The current system was designed using 3D printing so the user can modify the system to be adjusted for different species of insects. The goal of this protocol is to investigate important questions in chronobiology and stress physiology, using this precise and automated system to measure insect emergence patterns.

Measurement of insect emergence patterns requires precision. Existing systems are only semi-automated and sample size is limited. We addressed these issues by designing a system using microcontrollers to precisely measure the time of emergence of large numbers of emerging insects.

Existing systems to measure insect emergence patterns have limitations; they are only partially automated and are limited in the maximum number of ...

Flying Insect Detection and Classification with Inexpensive Sensors

An inexpensive, noninvasive system that could accurately classify flying insects would have important implications for entomological research, and allow for the development of many useful applications in vector and pest control for both medical and agricultural entomology. Given this, the last sixty years have seen many research efforts devoted to this task. To date, however, none of this research has had a lasting impact. In this work, we show that pseudo-acoustic optical sensors can produce superior data; that additional features, both intrinsic and extrinsic to the insect&#8217;s flight behavior, can be exploited to improve insect classification; that a Bayesian classification approach allows to efficiently learn classification models that are very robust to over-fitting, and a general classification framework allows to easily incorporate arbitrary number of features. We demonstrate the findings with large-scale experiments that dwarf all previous works combined, as measured by the number of insects and the number of species considered.

We proposed a system that uses inexpensive, noninvasive pseudo-acoustic optical sensors to automatically and accurately detect, count, and classify flying insects based on their flying sound.

An inexpensive, noninvasive system that could accurately classify flying insects would have important implications for entomological research, and allow ...

Bioengineering

Building an Enhanced Flight Mill for the Study of Tethered Insect Flight

Makerspaces have a high potential of enabling researchers to develop new techniques and to work with novel species in ecological research. This protocol demonstrates how to take advantage of the technology found in makerspaces in order to build a more versatile flight mill for a relatively low cost. Given that this study extracted its&#160;prototype from flight mills built in the last decade, this protocol focuses more on outlining divergences made from the simple, modern flight mill. Previous studies have already shown how advantageous flight mills are to measuring flight parameters such as speed, distance, or periodicity. Such mills have allowed researchers to associate these parameters with morphological, physiological, or genetic factors. In addition to these advantages, this study discusses the benefits of using the technology in makerspaces, like 3D printers and laser cutters, in order to build a more flexible, sturdy, and collapsible flight mill design. Most notably, the 3D printed components of this design allow the user to test insects of various sizes by making the heights of the mill arm and infrared (IR) sensors adjustable. The 3D prints also enable the user to easily disassemble the machine for quick storage or transportation to the field. Moreover, this study makes greater use of magnets and magnetic paint to tether insects with minimal stress. Lastly, this protocol details a versatile analysis of flight data through computer scripts that efficiently separate and analyze differentiable flight trials within a single recording. Although more labor-intensive, applying the tools available in makerspaces and on online 3D modeling programs facilitates multidisciplinary and process-orientated practices and helps researchers avoid costly, premade products with narrowly adjustable dimensions. By taking advantage of the flexibility and reproducibility of technology in makerspaces, this protocol promotes creative flight mill design and inspires open science.

This protocol uses three-dimensional (3D) printers and laser cutters found in makerspaces in order to create a more flexible flight mill design. By using this technology, researchers can reduce costs, enhance design flexibility, and generate reproducible work when constructing their flight mills for tethered insect flight studies.

Makerspaces have a high potential of enabling researchers to develop new techniques and to work with novel species in ecological research. This protocol ...

Engineering

Electroantennography-based Bio-hybrid Odor-detecting Drone using Silkmoth Antennae for Odor Source Localization

Small drones with chemical or biosensor devices that can detect airborne odorant molecules have attracted considerable attention owing to their applicability in environmental and security monitoring and search-and-rescue operations. Small drones with commercial metal-oxide-semiconductor (MOX) gas sensors have been developed for odor source localization; however, their real-time-odor-detection performance has proven inadequate. However, biosensing technologies based on insect olfactory systems exhibit relatively high sensitivity, selectivity, and real-time response with respect to odorant molecules compared to commercial MOX gas sensors. In such devices, excised insect antennae function as portable odorant biosensor elements and have been found to deliver excellent sensing performance. This study presents experimental protocols for odorant-molecule detection in the air using a small autonomous bio-hybrid drone based on a mountable electroantennography (EAG) device incorporating silkmoth antennae.
We developed a mountable EAG device including sensing/processing parts with a Wi-Fi module. The device was equipped with a simple sensor enclosure to enhance the sensor directivity. Thus, odor source localization was conducted using the spiral-surge algorithm, which does not assume an upwind direction. The experimental bio-hybrid odor-detecting drone identified real-time odorant-concentration differences in a pseudo-open environment (outside a wind tunnel) and localized the source. The developed drone and associated system can serve as an efficient odorant molecule-detection tool and a suitable flight platform for developing odor source localization algorithms owing to its high programmability.

This study introduces experimental protocols for a bio-hybrid odor-detecting drone based on silkmoth antennae. The operation of an experimental electroantennogram device with silkmoth antennae is presented, in addition to the structure of a bio-hybrid drone designed for odor source localization using the spiral-surge algorithm.

Small drones with chemical or biosensor devices that can detect airborne odorant molecules have attracted considerable attention owing to their ...

Radio Frequency Identification and Motion-sensitive Video Efficiently Automate Recording of Unrewarded Choice Behavior by Bumblebees

We present two methods for observing bumblebee choice behavior in an enclosed testing space. The first method consists of Radio Frequency Identification (RFID) readers built into artificial flowers that display various visual cues, and RFID tags (i.e., passive transponders) glued to the thorax of bumblebee workers. The novelty in our implementation is that RFID readers are built directly into artificial flowers that are capable of displaying several distinct visual properties such as color, pattern type, spatial frequency (i.e., &#8220;busyness&#8221; of the pattern), and symmetry (spatial frequency and symmetry were not manipulated in this experiment). Additionally, these visual displays in conjunction with the automated systems are capable of recording unrewarded and untrained choice behavior. The second method consists of recording choice behavior at artificial flowers using motion-sensitive high-definition camcorders. Bumblebees have number tags glued to their thoraces for unique identification. The advantage in this implementation over RFID is that in addition to observing landing behavior, alternate measures of preference such as hovering and antennation may also be observed. Both automation methods increase experimental control, and internal validity by allowing larger scale studies that take into account individual differences. External validity is also improved because bees can freely enter and exit the testing environment without constraints such as the availability of a research assistant on-site. Compared to human observation in real time, the automated methods are more cost-effective and possibly less error-prone.

This video describes Radio-Frequency Identification (RFID) and motion-sensitive video recording methods to monitor choice behavior by bumblebees.

We present two methods for observing bumblebee choice behavior in an enclosed testing space. The first method consists of Radio Frequency Identification ...

A Simple Flight Mill for the Study of Tethered Flight in Insects

Flight in insects can be long-range migratory flights, intermediate-range dispersal flights, or short-range host-seeking flights. Previous studies have shown that flight mills are valuable tools for the experimental study of insect flight behavior, allowing researchers to examine how factors such as age, host plants, or population source can influence an insects' propensity to disperse. Flight mills allow researchers to measure components of flight such as speed and distance flown. Lack of detailed information about how to build such a device can make their construction appear to be prohibitively complex. We present a simple and relatively inexpensive flight mill for the study of tethered flight in insects. Experimental insects can be tethered with non-toxic adhesives and revolve around an axis by means of a very low friction magnetic bearing. The mill is designed for the study of flight in controlled conditions as it can be used inside an incubator or environmental chamber. The strongest points are the very simple electronic circuitry, the design that allows sixteen insects to fly simultaneously allowing the collection and analysis of a large number of samples in a short time and the potential to use the device in a very limited workspace. This design is extremely flexible, and we have adjusted the mill to accommodate different species of insects of various sizes.

Flight in insects is influenced by a number of factors and the propensity to disperse is an important variable in understanding insect ecology and biological control strategies. We describe the construction and use of a simple, relatively inexpensive, and flexible flight mill for measuring parameters of tethered flight in insects.

Flight in insects can be long-range migratory flights, intermediate-range dispersal flights, or short-range host-seeking flights. Previous studies have ...

Insect-controlled Robot: A Mobile Robot Platform to Evaluate the Odor-tracking Capability of an Insect

Robotic odor source localization has been a challenging area and one to which biological knowledge has been expected to contribute, as finding odor sources is an essential task for organism survival. Insects are well-studied organisms with regard to odor tracking, and their behavioral strategies have been applied to mobile robots for evaluation. This "bottom-up" approach is a fundamental way to develop biomimetic robots; however, the biological analyses and the modeling of behavioral mechanisms are still ongoing. Therefore, it is still unknown how such a biological system actually works as the controller of a robotic platform. To answer this question, we have developed an insect-controlled robot in which a male adult silkmoth (Bombyx mori) drives a robot car in response to odor stimuli; this can be regarded as a prototype of a future insect-mimetic robot. In the cockpit of the robot, a tethered silkmoth walked on an air-supported ball and an optical sensor measured the ball rotations. These rotations were translated into the movement of the two-wheeled robot. The advantage of this "hybrid" approach is that experimenters can manipulate any parameter of the robot, which enables the evaluation of the odor-tracking capability of insects and provides useful suggestions for robotic odor-tracking. Furthermore, these manipulations are non-invasive ways to alter the sensory-motor relationship of a pilot insect and will be a useful technique for understanding adaptive behaviors.

The capability to localize an odor source is necessary for insect survival and is expected to be applicable to artificial odor-tracking. The insect-controlled robot is driven by an actual silkmoth and enables us to evaluate the odor-tracking capability of insects through a robotic platform.

Robotic odor source localization has been a challenging area and one to which biological knowledge has been expected to contribute, as finding odor ...