Effects of toxic organic compounds on Tenebrio molitor and its parasite Gregarina steini

Environmental pollution by toxic compounds affects various species of living organisms, their life cycles and symbiotic relationships. This study investigated the host-parasite relationship between Tenebrio molitor Linnaeus, 1758 (Coleoptera, Tenebrionidae) and Gregarina steini Berthold, 1827 (Eugregarinorida, Gregarinida) under exposure to o-xylene, formaldehyde and aniline at different concentrations. For laboratory studies, 480 larvae of T. molitor and five concentrations of the studied organic compounds were used. Groups of T. molitor, each consisting of ten individuals, were subjected to the tested compounds for 10 days following the initial weight measurement. We measured the body weight and survival rate of T. molitor and the number of G. steini in them to assess the impact of the tested organic compounds on the host-parasite relationship. For all the compounds studied, a decrease in body weight and high mortality were observed in T. molitor at high concentrations. The lethality of the studied organic compounds was concentration-dependent. o-Xylene showed low toxicity at lower concentrations (10.4 and 26.0 mg/kg of feed), with a survival rate of 93.3% and 86.7%, respectively. At a concentration of 10.4 mg/kg, no lethal cases in T. molitor were observed. At higher concentrations (78 and 104 mg/kg feed), T. molitor mortality significantly increased to 33.3% and 53.3%, respectively.