Borik asitin Galleria mellonella L. (Lepidoptera: Pyralidae) larvalarında hemosit aracılı immün sistem üzerine etkilerinin incelenmesi

Boric acid (BA) is used as an insecticide, fungicide and in various industrial processes and thus different populations are exposed to it. The aim of this study was to analyze the effects of BA on the hemocyte mediated immune mechanism and its insecticidal potential on the model organism Galleria mellonella L. (Pyralidae: Lepidoptera). Different BA concentrations (78.125- 10,000 ppm) were administrated to the larvae using force-feeding method. Concentration-dependent mortality was observed in all experimental groups. According to the data obtained from the probit analysis, the LC30, LC50 and LC70 values of BA were determined as 112.438, 320.133 and 911.484 ppm respectively. These lethal concentrations were used in all biological and immunological assays. In BA treated groups, larval developmental time increased while pupal and adult weight, pupal developmental time and adult longevity reduced. Post BA treatment, significant decreases in the total hemocyte counts, prohemocyte, plasmatocyte and oenocyte ratios and increments in granulocyte and sperulocyte counts were observed. Hemocyte viability assays showed a decrease in the numbers of live cells and an increase in necrotic and apoptotic ratios. However, no significant change was observed in the mitotic indices of larval hemocytes. Using Sephadex DEAX beads as encapsulation and melanisation targets, results showed that encapsulation and melanisation decreased with increasing BA concentrations. Nonetheless, the nodulation ability of the larvae exposed to BA significantly reduced post-laminarin injection. This investigation is the first of its kind to demonstrate the potential immunotoxicity of BA in insects, and our results suggest G. mellonella's immune system is suppressed at high BA concentrations.