Ghrelin effect on nutritional indices, midgut and fat body of Lymantria dispar L. (Lymantriidae)

► Four injections of ghrelin (0.3 pmol) were applied every 24 h to 4th instar larvae of L. dispar. ► The nutritional parameters were higher in the ghrelin treated than in the control group. ► The relative midgut/fat body mass, digestive enzyme activities increase after ghrelin treatment. ► The morphometric changes of columnar and goblet cells of the midgut were correlated with ghrelin treatment. ► In this report, the presence of ghrelin-like hormone in insect's midgut is presented for the first time.