Nutritional responses and digestive enzymatic profile of Trogoderma granarium Everts (Coleoptera: Dermestidae) on 10 commercial rice cultivars

• Published in: Journal of stored products research 2020-05, Vol.87, p.101591, Article 101591
• Main Authors: Naseri, Bahram, Aeinehchi, Pezhman, Ashjerdi, Abbas Rahimi
• Format: Article
• Language: English
• Subjects: Digestive enzyme; Grain resistance; Khapra beetle; Nutritional index; Rice cultivar
• ISSN: 0022-474X; 1879-1212
• DOI: 10.1016/j.jspr.2020.101591

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important polyphagous pest of stored grains in the world. Nutritional performance and digestive amylase and protease activity of fifth instar larvae were studied on different commercial rice cultivars (Sadri, Tarom, Neda, Fajr, Nemat, Shafagh, Kadous, Gohar, Gilane, and Khazar) at 33 ± 1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14:10 (L:D) h. Larvae fed with cultivar Gilane consumed more food and increased body weight higher than those fed with other cultivars. However, the lowest values of nutritional indices were found in larvae fed with cultivar Khazar. The lightest pupal weight was on cultivars Fajr, Nemat and Sadri. The larval growth index differed from 1.99 to 2.67 on cultivars Khazar and Tarom, respectively. Among various tested cultivars, the highest standardized insect-growth index was on cultivar Gilane, whereas the lowest index was on cultivars Fajr, Nemat and Sadri. Furthermore, the fitness index showed the highest value on cultivars Gilane and Neda, and the lowest on cultivar Sadri. The amylolytic activity was the highest in larvae fed with cultivar Gilane, and the lowest in larvae fed with cultivars Fajr and Khazar. The cultivar Gilane-fed larvae exhibited the highest proteolytic activity as compared with other cultivars. The cluster analysis showed that Nemat, Neda, Fajr and Khazar were the least suitable (partially resistant) cultivars to T. granarium, which could be further investigated to identify proteins that contribute to khapra beetle resistance. [Display omitted] •Trogoderma granarium is an important polyphagous pest of stored products globally.•The lowest values of nutritional indices were found in larvae fed with cultivar Khazar.•Among various tested cultivars, the lowest standardized insect-growth index was on cultivars Fajr, Nemat and Sadri.•The amylolytic activity showed the lowest level in larvae fed with cultivars Fajr and Khazar.•Cluster analysis showed that cultivars Nemat, Neda, Fajr and Khazar were partially resistant to T. granarium.