## 3 Discussion  
In this work, we assumed that electromagnetic field (EMF, 50 Hz, 1 mT, and 7 mT) exposure functions as a stressor, exerting an influence on the metabolism and metamorphosis rate of mealworms in a manner contingent upon the dosage administered and insect's stage of development. We found that exposure to the potent EMF (7 mT), as opposed to the weaker one (1 mT), resulted in accelerated weight loss for both adults and larvae, along with elevated mortality rates and increased metabolic activity in adults. Nevertheless, the EMF impact did not affect the rate or success of metamorphosis in pupae and adults, the CO2 production of larvae, or the sugar content in the henamolymph. Notably, no discernible changes were induced in the pupal stage by the EMF exposure. The results obtained in the present work indicate that biological systems may react and behave differently under the influence of different parameters of (electro)magnetic exposure. This is similar to what other researchers discovered in studies on both vertebrates and invertebrates. For example, when locusts were exposed to EMFs of 1 mT, 4 mT, and 7 mT, noticeable effects happened only at an EMF exceeding 4 mT. These effects included changes in behavior, physiology, and stress protein levels [16]. Interesting outcomes also emerged from the studies on oxidative stress. In animals exposed to an EMF of 1 mT, the levels of markers for oxidative stress and antioxidants were quite similar to the control values. The changes were more pronounced at intensities exceeding 6 mT (e.g., the level of malondialdehydedehyde (MDA) and reactive oxygen species (ROS) were significantly higher, while superoxide dismutase (SOD) activity was decreased) [14; 24; 27]. Additionally, numerous studies suggest that values at or below 1 mT exhibit a stimulating impact of an EMF on brain plasticity processes by the production of protective proteins, e.g., Hsp70 or BDNF, or an increase in the activity of antioxidant enzymes, which could have potential applications in neuroprotection [13; 28; 29; 30; 31]. It appears that an EMF of 1 mT could mark the threshold for the appearance of (adverse) biological effects and/or might trigger cellular adaptation aimed at reducing adverse physiological outcomes. However, further, more detailed research is needed concerning a specific EMF-induced effect [14]. As anticipated, exposure to EMFs led to enhanced weight loss in both adults and larvae. We link this to the stress response, similar to the reaction of the _Gryllus texensis_ cricket subjected to chronic stress from simulated predator situations [32]. Studies suggest that exposure to both EMFs and stress reduces feeding behavior [33; 34]. In our experiments, we deliberately restricted the insects' access to food. As a result, any observed effects are likely attributable to alterations in their metabolic processes. Exposure to EMFs and stress have the potential to stimulate animals, leading to increased levels of aggression, anxiety, locomotor activity, and the tendency to produce flight behaviors [25; 26; 32; 35; 36]. The metabolic state of an organism is influenced by its overall level of activity; for instance, a heightened activity corresponds to an increase in the sense of hunger and CO2 production, thereby facilitating the opportunity to rectify energy deficits [37]. Several studies indicate that metabolic changes induced by EMF and static magnetic field (SMF) exposure were evident through an increase in the O2 uptake or CO2 production in the exposed animals [38; 39]. Our findings also indicate that adults exposed to EMFs demonstrated noticeably elevated CO2 levels; however, the impact of EMF exposure on CO2 production in larvae was found to be statistically insignificant. The results suggest that adults exhibited the highest susceptibility to EMF exposure. Among the exposed groups, adults experienced the greatest reduction in body weight, followed by larvae. Additionally, adults displayed elevated metabolism rates and an increased mortality rate.