Movement assay for the undergraduate neuroscience laboratory

Abstract

Described is a design for easy-to-construct apparatus that measures movement of flying insects suitable for the undergraduate teaching laboratory. The system does not require the purchase of specialized scientific equipment or software. The apparatus can be constructed and operated without advanced knowledge in electronics or programming. The goal of this apparatus was to expand upon previous research detecting insect flight in response to radiation. We improved upon the quantification and resolution of flight across differing intensities of white light. All of this was achieved using low-cost and commonly available materials and open-source software to collect and analyze data. The only substantial prerequisites for this design are a PC with a 3.5 mm microphone input and an understanding of basic electrical connections. The apparatus was validated with comparative physiological data from two different species of butterfly.

Keywords: Behavior; Flight; Movement; Piezoelectric.

Graphical abstract

Fig. 1

Example of piezoelectric construction. Male-ended jumper wires soldered to each PCB trace of the piezoelectric. Small wooden dowel attached with hot glue to the other end.

Fig. 2

Schematic of piezoelectric wiring. Two pins coming from the 6.35 mm RCA were connected to separate terminal strips in a breadboard. The male-ended jumper from the piezoelectric were connected to corresponding terminal strips. Schematic made with Fritzing (www.fritzing.org).

Fig. 3

Schematic of the LED lightboard. The power ground pin of the Arduino Uno was connected to the ground bus strip of a breadboard (labeled GND). The cathode (long pin) of each LED was connected to the ground bus strip (GND). The anode (short pin) of each LED was connected to a numbered terminal of the breadboard. A resistor was connected to each LED in accordance to brightness desired for the LED. The resistor was connected to another numbered terminal of the breadboard across the notch. A corresponding coded digital pin of the Arduino Uno was connected to each resistor through a numbered terminal (1–5). Schematic made with Fritzing (www.fritzing.org).

Fig. 4

Schematic of the tactile button switch. The legs of the button were placed across a breadboard notch. The digital ground of the Arduino Uno was connected through a terminal of the breadboard to a pin of the button switch. The digital pin coded to control the button was connected to a bus strip. A resistor was connected to the same bus strip and connected to a second pin of the tactile button switch. Note: the resistance of the resistor used for this connection is arbitrary. Schematic made with Fritzing (www.fritzing.org).

Fig. 5

Example of habituation chamber construction. Note the location of the piezoelectric sensor fitting part-way into the chamber wall. Also note the lightboard inside the chamber, while the Arduino and tactile button are outside the chamber.

Fig. 6

Example piezoelectric recordings in Audacity. (A) Sample recording using a flick test using a 0.04 g (0.39 mN force) Von Frey filament. (B) Sample recording of Painted Lady flight during experiment. The downward red arrow marks LED illumination. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 7

Example piezoelectric recordings in Labscribe3. (A) Deflections in the piezoelectric were recorded and digitized through the iWorx TA module and displayed using Labscribe3 software. (B) Raw recordings were offset to have a zero baseline. (C) The period was calculated from the zero-baseline channel. (D) The reciprocal of the period was plotted to produce a rate of peak deflections per second (i.e. hertz).

Fig. 8

Example deflections from two painted ladies following 57.1 fc illumination. (A) Deflections recorded using the BYB amplifier and Audacity. (B) Deflections recorded using the iWorx TA module and Labscribe3. Each system produced a rhythmic, complex wingbeat.

Fig. 9

Response rate to illumination following dark adaptation. Response rate was calculated per group as any measureable deflection per intensity (fc). Cabbage whites (CW; white bars) consistently flew to all intensities. Painted ladies (PL; pink bars) did not consistently fly until 57.1 fc. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 10

Wingbeat frequency to illumination following dark adaptation. Average movement was calculated as peak deflections of the piezoelectric per 10 s. Cabbage whites (CW; white bars) initiated more wingbeats to illumination than painted ladies (PL; pink bars). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)