Occurrence of gregarine parasites of Tenebrio molitor (Coleoptera: Tenebrionidae) in Georgia and Türkiye

Gregarines, which belong to the parasitic protozoa, have a variety of negative effects on their hosts. Therefore, it's important to report this pathogen for the first time from a new insect population in Tbilisi, Georgia. Several life stages of the gregarine were found in the midgut lumen of the yellow mealworm, Tenebrio molitor , a pest species of grain and stored food products, which is also gaining attention as a potential sustainable food source. Forty samples from both larvae and adults were dissected, and their intestines were examined under a microscope, demonstrating that both were infected by the parasite. Several life stages of the gregarine parasite were found in the midgut lumens of these mealworms, with the largest trophozoite observed being 67.9 µm in length. Gregarine infection rates in T. molitor larvae were found to be higher than in the adults. Twenty-nine of the 40 examined larvae were infected (72.5%) compared to seven of the 40 examined adults (17.5%). These results suggest that T. molitor larvae are more susceptible to gregarine parasite infection than adults. Our study contrasts with a similar study in Antalya, Turkey, where no gregarine infection was observed in either larval or adult T. molitor .