Five strains of the fruit fly Drosophila subobscura (named B16/1, B24/4, B39/1, B57/2 and B69/5) were prepared with each strain derived from a single pair of flies (isofemale strains) and defined via mitochondrial DNA variability. The flies were exposed either in egg-first instar larval stage (group 1, number not mentioned) or as 1-day-old adult animals (group 2, n=30). For each exposure group, a control group without any treatment and a sham exposure group (n=30 each for adult animals, no number stated for larvae) were examined in the same developmental stages.
Exposure duration: continuous for 48 hours
|Exposure duration||continuous for 48 hours|
|Chamber||isolated room at 19°C and 60% humidity|
|Setup||petri dishes with eggs or vials with flies were exposed to a homogeneous horizontal magnetic field without observable temperature variations and heating in the zone where the samples were placed|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||0.5 mT||-||measured||-||± 0.01 mT|
No significant differences were found between the sham exposure and untreated control groups, so they were pooled and used as one control group, respectively.
Exposure of egg-first instar larvae (group 1) to the magnetic field resulted in a significantly shortened developmental time in all strains compared to the control group but did not affect viability or sex ratio.
Exposure of 1-day-old male and female adults (group 2) to the magnetic field significantly decreased the motor activity compared to the control group in the strains B16/1 and B24/4 and this effect lasted longer in females than males.
The authors conclude that exposure to a 50 Hz magnetic field might have different effects on development and motor activity of Drosophila subobscura at various developmental stages depending on their genetic background.