Ratiometric Decoding of Pheromones for a Biomimetic Infochemical Communication System

Abstract

Biosynthetic infochemical communication is an emerging scientific field employing molecular compounds for information transmission, labelling, and biochemical interfacing; having potential application in diverse areas ranging from pest management to group coordination of swarming robots. Our communication system comprises a chemoemitter module that encodes information by producing volatile pheromone components and a chemoreceiver module that decodes the transmitted ratiometric information via polymer-coated piezoelectric Surface Acoustic Wave Resonator (SAWR) sensors. The inspiration for such a system is based on the pheromone-based communication between insects. Ten features are extracted from the SAWR sensor response and analysed using multi-variate classification techniques, i.e., Linear Discriminant Analysis (LDA), Probabilistic Neural Network (PNN), and Multilayer Perception Neural Network (MLPNN) methods, and an optimal feature subset is identified. A combination of steady state and transient features of the sensor signals showed superior performances with LDA and MLPNN. Although MLPNN gave excellent results reaching 100% recognition rate at 400 s, over all time stations PNN gave the best performance based on an expanded data-set with adjacent neighbours. In this case, 100% of the pheromone mixtures were successfully identified just 200 s after they were first injected into the wind tunnel. We believe that this approach can be used for future chemical communication employing simple mixtures of airborne molecules.

Sensing of Airborne Infochemicals for Green Pest Management: What Is the Challenge?

“…In presence of the gaseous component of interest, absorption of the volatile analyte on the sensing material changes the overall mass, which results in a resonant frequency shift. Excellent reviews of the gravimetric gas sensing principle, resonators, and sensitizers are available in the literature. − Several sensors were developed for the detection of ICs that can be applied in push–pull pest control. , Wei et al developed a high-frequency SAW sensor for detection of ( E )-11-tetradecenyl acetate and ( Z )-9-tetradecenyl acetate, the main components of the pheromone produced by the cotton leafworm, Spodoptera littoralis . In their biomimetic sensing system, a synthetic pheromone was released from chemo­emitter (a silicon-based microreactor mimicking the moth’s glands that produce pheromone) to the odor chamber, where it was detected by the piezoelectric chemoreceiver (an array of polymer-coated SAW sensors mimicking the moth’s antenna) as a frequency shift due the adsorption of volatiles (Figure ).…”

“…(c) Schematic block diagram of the oscillator circuit. Reprinted with permission from ref . Copyright 2017 MDPI.…”

“…123,124 Wei et al developed a high-frequency SAW sensor for detection of (E)-11-tetradecenyl acetate and (Z)-9tetradecenyl acetate, the main components of the pheromone produced by the cotton leafworm, Spodoptera littoralis. 125 In their biomimetic sensing system, a synthetic pheromone was released from chemoemitter (a silicon-based microreactor mimicking the moth's glands that produce pheromone) to the odor chamber, where it was detected by the piezoelectric chemoreceiver (an array of polymer-coated SAW sensors mimicking the moth's antenna) as a frequency shift due the adsorption of volatiles (Figure 7). The sex pheromone blend released by the female cotton bollworm, Helicoverpa armigera, composed of (Z)-11-hexadecenal and (Z)-9-hexadecenal in 25:1 weight ratio, was detected by a field-portable device based on a SiO 2 microcantilever covalently modified with (3aminopropyl)triethoxysilane (APTES), developed by Moitra et al 126 Introduced amine functional groups formed imine derivatives (Schiff bases) with pheromone aldehydes, and pheromone mass loading was measured from the decrease in resonant frequency with a remarkably low detection limit of 4 fg.…”

A Vision-Based Counting and Recognition System for Flying Insects in Intelligent Agriculture

“…Some studies [ 8 , 9 , 10 , 11 ] chose insect specimens which were well preserved in an ideal laboratory environment to avoid the problem, and images can be captured at high resolution, but since less environmental issues are considered in this method, it is limited in specific applications. A more practical method is to use traps, in this way, insects can be attracted by a variety of ways based on light [ 12 ], color [ 5 , 13 ], pheromones [ 7 , 14 ], etc. Sticky traps [ 15 ] are usually used to stick insects and fix them, and then, the sticky trap is photographed.…”

“…Sticky traps [ 15 ] are usually used to stick insects and fix them, and then, the sticky trap is photographed. In [ 5 , 12 , 13 , 14 , 15 , 16 ] researchers collected insects in the wild with traps and acquired images in an ideal lab environment by hand. This method can this get clear images since the shooting settings, such as illumination and angle, can be adjusted according to the requirements, however, shooting in a manual way was still time consuming and labor intensive.…”