Feeding efficiency and digestive physiology of Trogoderma granarium Everts (Coleoptera: Dermestidae) on different rice cultivars

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is one of the economic pests infesting many stored cereals in the world. The effects of six commercial rice, Oryza sativa L. cultivars including Hashemi, Shiroodi, Gilane, Khazar, Ali Kazemi and Domsiah were evaluated on nutritional indices and digestive enzymatic activity of fifth instar T. granarium at controlled conditions (33±1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14:10 (L:D) h). Fifth instar larvae consumed more food when reared on Gilane, and less food when reared on Khazar and Ali Kazemi. The larvae fed with Khazar had the lowest weight gain, efficiency of conversion of ingested food and growth index. The relative growth rate was the highest when larvae were fed with Gilane and lowest when they were fed with Khazar. The highest midgut proteolytic and amylolytic activities of larvae were on Gilane. However, the lowest proteolytic activity was on Khazar and the lowest amylolytic activity was on Khazar and Ali Khazemi. According to the obtained results, Khazar is an unsuitable cultivar for feeding and growth of T. granarium. [Display omitted] •Nutritional indices and digestive enzymatic activity of fifth instar T. granarium were investigated on six rice cultivars.•The highest enzymatic activity was on cultivar Gilane and the lowest activity was on cultivar Khazar.•Our results will be helpful to introduce unsuitable rice cultivar(s) to develop transgenic grains against T. granarium.