128

Bioelectromagnetism

electric feld, they stopped moving. Blow fy needs a stronger feld to elicit a response than fruit fy.

Further, in order to investigate the efects of the static electric feld caused by thunderclouds, Edwards

studied the pupal period of the larvae of the pyralid beetle, the egg-laying sites of its adults, and the

number of egg laid, etc. in the static electric feld of 19 kV/m (Edwards, 1961). It was reported that the

pupal period was longer and the mortality rate was slightly higher, and that 65% of the eggs were laid

in the felds compared to the controls. Negative efects such as a decreased oviposition rate and delayed

hatching in hemlock loopers (18 kV/m) were reported.

Static electric feld infuences on locomotor activity were refected in reduced rates of locomotion pro­

portional to electric feld strength in blow fy (Calliphora vicina) and fruit fy (Drosophila melanogaster)

(Watson, 1984) and in the cockroach (Jackson et al., 2011). As results of perception behavior experiments

with blow fy and fruit fy (Watson, 1984), agitation occurred at about 200 kV/m. Mean values for paraly­

sis of fruit fies at 416 kV/m, for blow fies at 359 kV/m, and insects were killed at feld of 350–400 kV/m.

In this report, it is unclear whether the efect is statistically signifcant or not because there is not enough

data, and the efect size cannot be calculated. Te animal becomes paralyzed in a high static electric feld

that does not produce fashover and recovers when the feld is turned of. Tis occurs when the animal

touches the static electric feld during fight, and it is thought that the central nervous system is afected

by the current from the corona discharge. Te perception experiments in cockroaches (Periplaneta

Americana; third and fourth instar; n = 126 in total) was reported (Jackson et al., 2011). Exposure to

electric felds of 66–166 kV/m was used to examine detection and avoidance behavior. Decrease of activ­

ity an increased feld avoidance behavior at higer feld strengths; less distance covered in treated zone for

feld strength above 99 kV/m. animals spent less time in the treated zone at 132 kV/m.

It was reported that the static electric felds were 20–150 kV/m for 3 minutes for housefy (Musca

domestia L.) and 25–150 kV/m for cabbage loopers (Trichoplusia ni) (Perumpral et al., 1978). Exposure to

electric felds was used to examine detection and avoidance behavior. In cabbage loopers, the wing beat

frequency was also examined. Te fight behavior of the cabbage looper exposed to a static electric feld

of 20 kV/m was disturbed (Perumpral et al., 1978). When house fies were taught to choose between areas

with and without electric feld of 100 kV/m, they avoided areas with electric felds. Tey preferred static

electric feld of 75 kV/m and avoidance behavior by house fy occurred in the range of 100–150 kV/m. Te

efect of static electric felds on wingbeat frequency in male cabbage loopers was, in all cases, afected

inconsistently although between 20 and 150 kV/m. On the other hand, females were not signifcantly

afected.

Newland et al. examined the mechanism underlying the ability to perceive static electric feld and

scrutinized sensory structures for the detection and avoidance behaviors of such feld in cockroaches

(Periplaneta Americana; third and fourth instar and imagines with n = 5–40 per group) to static elec­

tric felds of 4–30 kV/m (2008). As a result, they found insect behavioral changes in response to static

electric felds as tested using a Y-choice chamber an electric feld generated in one arm of the chamber.

Locomotor and avoidance were afected by the magnitude of the electric felds with up to 85% of indi­

viduals avoiding the charged arm when the static electric feld at the entrance to the arm was above

8–10 kV/m. In order to determine mechanisms of perception, they ablated the antennae of cockroaches

and found that the ability of cockroaches to avoid static electric felds was abolished. Te authors con­

cluded that the antennae are very crucial organs for the detection of static electric felds in cockroaches.

Newland reported the experiments on fruit fy (Drosophila melanogaster; male and female) with dif­

ferent wing forms or excised wings n = 8–160 per group (2015). Te animals were exposed to the static

electric feld of 28–183 kV/m for 5 minutes in avoidance experiments and to static electric felds of 70

kV/m between 4 and 72 hours in measurements of biogenic amine levels in the brain. It was shown that

threshold for avoidance behavior at 34–43 kV/m, statistically signifcant in response index compared

to that of controls. Intact wings played an important role in avoidance behavior. Tey suggested that

static electric feld generates an uneven charge distribution on the body surface and causes mechanical

detection of negatively charged body attachments, such as antennae in cockroaches and wings in fruit

fies, toward the positive electrode. Tis mechanical defection was recognized by sensory receptors at