Static electric field detection and behavioural avoidance in cockroaches

Abstract

SUMMARYElectric 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.

Exposure to static electric fields leads to changes in biogenic amine levels in the brains ofDrosophila

“…This modelling provides accurate estimates of the magnitude of the electric fields within the Y-tube that can be correlated with the response of the flies at different field strengths [7]. In MAXWELL SV, the Y-tube was drawn as a simple two-dimensional x-y model with a cross-section taken from each part of the Y-tube (figure 1b).…”

“…Thus, the surface area of the wings appears to be a major determinant of avoidance rather than the antennae or other structure such as the halteres. Previously, we suggested that electric fields could be detected via electrical forces causing deflection of sensory appendages resulting in mechanical stimulation [7]. Any electrically neutral object has a random distribution of negative and positive charges over the surface, and when that object enters an electric field it will experience forces on the electrons that cause an uneven distribution ( polarization) of charges.…”

“…Other studies have suggested that accumulation of charge during flight could assist foraging and pollination through the transfer of pollen grains onto plant stigmata [3][4][5]. Static electric fields can also lead to changes in walking [6,7] and avoidance behaviour [6,8], and influence locomotion and agitation [9][10][11].…”

Galvanotaxis of Caenorhabditis elegans: current understanding and its application in improving research

“…several species of fish), may be evolutionary preserved in aquatic environments as it is an excellent conductor of EF, as well as in few terrestrial organisms (e.g. monotremes, Dictyostelium, cockroaches, bees and nematode worms) [2,[5][6][7][8][9][10]. The predominant use of electrosensation and movement at desired direction is utilized for identification of food such as prey and host, to escape from potential predator and navigation to different locations in an environment.…”

Static electric fields modify the locomotory behaviour of cockroaches

“…Deflection of hairs on the legs of spiders has also been reported when individuals are exposed to electric fields similar to those beneath power lines (Orlov and Romanenko, 1989). It has recently been shown that cockroaches are able to detect electric fields by means of their antennae (Hunt et al, 2005;Newland et al, 2008) and these movements underpin avoidance behaviour. The antennae are highly active and flexible appendages that are present on all insects (Okada and Toh, 2001;Schneider, 1964) and in cockroaches they contribute to escape responses via the activation of mechanoreceptors at the base of the antennae during movement Stierle et al, 1994).…”