Avoidance of an electric field by insects: Fundamental biological phenomenon for an electrostatic pest-exclusion strategy (original) (raw)
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Insects, 2021
This study analysed the mechanism of avoidance behaviour by adult Turkestan cockroaches (Shelfordella lateralis Walker) in response to a static electric field (S-EF) formed in the space between a negatively charged polyvinyl chloride-insulated iron plate (N-PIP) and a grounded metal net (G-MN). The negative surface charge supplied to the iron plate by a voltage generator caused the G-MN to polarise positively via electrostatic induction. In the S-EF, the negative charge of the N-PIP created a repulsive force that pushed free electrons in the field toward the ground via the G-MN. When insects released in the space surrounded by the S-EF inserted their antennae into the S-EF, they pulled them back reflexively and moved backward. The analysis indicated that an electric current flowed transiently toward the ground when an insect inserted its antennae into the S-EF. The insect became positively charged via this discharge and was attracted to the opposite pole (N-PIP). In response to this...
European Journal of Plant Pathology, 2012
Dual functions (insect repelling and capturing) of a single-charged dipolar electric field screen were evaluated to successfully exclude whiteflies from a window-open greenhouse. The screen consisted of three parts: 1) insulated conductor wires (ICWs) arrayed in parallel at 5 mm intervals, 2) two earthed stainless nets placed within 3 mm of both sides of the ICW layer, and 3) a voltage generator for the negatively charged ICWs. The screen formed two electric fields between the ICW-layer and the ICW-side surface of the earthed net and between the ICWs. At negative charging of 1.5-2.5 kV, all whiteflies reaching the outer surface of the screen net avoided entering the electric field and flew away from the screen. This avoidance was disturbed by 3 m s −1 wind, as the insects were compulsorily blown inside. However, almost all whiteflies (99.4 %) were captured with the ICW. These results indicate that the insect-capturing function is effective to complement a failure to repel. A greenhouse assay was conducted in the screen-attached and non-screened parts in which a greenhouse was divided with a partition. During the 3-month operation, the screen was durable and functional for excluding pests, and better air ventilation changed the climate conditions in the greenhouse. Thus, the present study demonstrated that our electric field screen can provide an airy condition for tomatoes in a window-open greenhouse and successfully exclude whiteflies using dual screen functions.
Insects are electrified in an electric field by deprivation of their negative charge
Annals of Applied Biology, 2012
An electric field screen (EF-screen) is a physical device for excluding pest insects from greenhouses and warehouses to protect crops during their production and storage periods. In this study, a simple version of the EF-screen, an insulated conductor iron wire (ICW) paralleled to an earthed net, was constructed to effectively observe the attraction of test insects in relation to their electricity release. The ICW was negatively charged to dielectrically polarise the insulator sleeve of the ICW: negatively on the outer surface and positively on the inner conductor wire surface of the sleeve. The negative surface charge of the ICW caused an electrostatic induction in the earthed net and a resultant positive charge at the ICW-side surface of the net. An electric field formed between the ICW (negative pole) and earthed net (positive pole). Insects were attracted to the ICW when they were placed onto the earthed net. A vital step for the attraction was the creation of a transient bioelectric discharge from an insect. During this discharge, an electric charge of the insect was transferred to the earthed net. Eventually, the insect became net positive and was then attracted to the ICW. The magnitude of the current increased in direct proportion to the increase in voltage applied to the ICW, and the attraction force was directly proportional to the increase in the electric current. Larger voltages were necessary to attract much larger insects because larger insects were stronger and therefore more able to escape from the ICW attraction. Similar results were obtained for a wide range of pest insects belonging to different taxonomic groups (8 orders and 15 families). This study demonstrated that transient bioelectric discharge is common in insects and can be utilised to create an electrostatic force capable of moving insects in a generated electric field.
Static electric field detection and behavioural avoidance in cockroaches
Journal of Experimental Biology, 2008
Electric fields are pervasively present in the environment and occur both as a result of man-made activities and through natural occurrence. We have analysed the behaviour of cockroaches to static electric fields and determined the physiological mechanisms that underlie their behavioural responses. The behaviour of animals in response to electric fields was tested using a Y-choice chamber with an electric field generated in one arm of the chamber. Locomotory behaviour and avoidance were affected by the magnitude of the electric fields with up to 85% of individuals avoiding the charged arm when the static electric field at the entrance to the arm was above 8-10 kV m -1 . Electric fields were found to cause a deflection of the antennae but when the antennae were surgically ablated, the ability of cockroaches to avoid electric fields was abolished. Fixation of various joints of the antennae indicated that hair plate sensory receptors at the base of the scape were primarily responsible for the detection of electric fields, and when antennal movements about the head-scape joint were prevented cockroaches failed to avoid electric fields. To overcome the technical problem of not being able to carry out electrophysiological analysis in the presence of electric fields, we developed a procedure using magnetic fields combined with the application of iron particles to the antennae to deflect the antennae and analyse the role of thoracic interneurones in signalling this deflection. The avoidance of electric fields in the context of high voltage power lines is discussed.
Journal of Agricultural Science, 2019
Applied electrostatic engineering can be used to construct greenhouses that prevent entry of insect pests. Two types of electric field screen were used to exclude pests from the greenhouse: single- and double-charged dipolar electric field screens (S- and D-screen, respectively). The S-screen consisted of iron insulated conductor wires (ICWs) arrayed in parallel (ICW-layer), a grounded metal net on either side of the ICW-layer, and a direct current voltage generator. S-screens were attached to the side windows of the greenhouse to repel whiteflies (Bemisia tabaci) that approached the nets. The D-screen was installed in a small anteroom at the greenhouse entrance to capture whiteflies entering through it. The ICW-layers of the D-screen were oppositely charged with equal voltages and arrayed alternately, and an insulator board or grounded metal net was placed on one side of the ICW-layer. The ICW-layers captured whiteflies entering the electric field of the double-charged dipolar elec...
Crop Protection, 2011
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy A newly devised electric field screen for avoidance and capture of cigarette beetles and vinegar flies
Analysis of Pole-Ascending–Descending Action by Insects Subjected to High Voltage Electric Fields
Insects
The present study was conducted to establish an electrostatic-based experimental system to enable new investigations of insect behavior. The instrument consists of an insulated conducting copper ring (ICR) linked to a direct current voltage generator to supply a negative charge to an ICR and a grounded aluminum pole (AP) passed vertically through the center of the horizontal ICR. An electric field was formed between the ICR and the AP. Rice weevil (Sitophilus oryzae) was selected as a model insect due to its habit of climbing erect poles. The electric field produced a force that could be imposed on the insect. In fact, the negative electricity (free electrons) was forced out of the insect to polarize its body positively. Eventually, the insect was attracted to the oppositely charged ICR. The force became weaker on the lower regions of the pole; the insects sensed the weaker force with their antennae, quickly stopped climbing, and retraced their steps. These behaviors led to a pole-a...
Insects, 2015
Our greenhouse tomatoes have suffered from attacks by viruliferous whiteflies Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) over the last 10 years. The fundamental countermeasure was the application of an electric field screen to the greenhouse windows to prevent their entry. However, while the protection was effective, it was incomplete, because of the lack of a guard at the greenhouse entrance area; in fact, the pests entered from the entrance door when workers entered and exited. To address this, we developed a portable electrostatic insect sweeper as a supplementary technique to the screen. In this sweeper, eight insulated conductor wires (ICWs) were arranged at constant intervals along a polyvinylchloride (PVC) pipe and covered with a cylindrical stainless net. The ICWs and metal net were linked to a DC voltage generator (operated by 3-V alkaline batteries) inside the grip and oppositely electrified to generate an electric field between them. Whiteflies on the plants were...
2016
Our greenhouse tomatoes have suffered from attacks by viruliferous whiteflies Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) over the last 10 years. The fundamental countermeasure was the application of an electric field screen to the greenhouse windows to prevent their entry. However, while the protection was effective, it was incomplete, because of the lack of a guard at the greenhouse entrance area; in fact, the pests entered from the entrance door when workers entered and exited. To address this, we developed a portable electrostatic insect sweeper as a supplementary technique to the screen. OPEN ACCESS In this sweeper, eight insulated conductor wires (ICWs) were arranged at constant intervals along a polyvinylchloride (PVC) pipe and covered with a cylindrical stainless net. The ICWs and metal net were linked to a DC voltage generator (operated by 3-V alkaline batteries) inside the grip and oppositely electrified to generate an electric field between them. Whiteflies on the plants were attracted to the sweeper that was gently slid along the leaves. This apparatus was easy to operate on-site in a greenhouse and enabled capture of the whiteflies detected during the routine care of the tomato plants. Using this apparatus, we caught all whiteflies that invaded the non-guarded entrance door and minimized the appearance and spread of the viral disease in tomato plants in the greenhouse.