Different diets affecting biology and digestive physiology of the Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) Ehsan Borzoui, Bahram Naseri * , Foroogh Rahimi Namin Department of Plant Protection, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili, Ardabil, Iran article info Article history: Received 8 March 2015 Received in revised form 11 March 2015 Accepted 11 March 2015 Available online Keywords: Khapra beetle Trogoderma granarium Biology Digestive physiology Diet abstract The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is a serious pest of grain and other stored products through the world. In this research, effect of five host diets including barley, rice, rye, wheat and walnut was studied on some of biological traits, nutritional indices and digestive enzy- matic activity of T. granarium at 33 ± 1  C, 65 ± 5% RH and a photoperiod of 14:10 (L:D) h. The Khapra beetle larvae reared on walnut had the highest number of larval instar and longest duration of larval and pupal stages (91.30 ± 0.4 days). The heaviest pupal weight of T. granarium was on rye (4.22 ± 0.01 mg) and the lightest weight was on rice (3.99 ± 0.01 mg) and walnut (4.00 ± 0.01 mg). The highest realized fecundity and fertility were recorded for the females reared on rye (45.88 ± 1.08 eggs/female and 69.39 ± 0.68%, respectively) and wheat (49.02 ± 1.55 eggs/female and 67.54 ± 0.69%, respectively), and the lowest ones were observed for the females came from larvae fed walnut (15.45 ± 0.71 eggs/female and 34.55 ± 0.82%, respectively). Also, the results showed that T. granarium larvae reared on walnut had the lowest values of the efficiency of conversion of ingested food (7.67 ± 0.04%) and relative growth rate (0.044 ± 0.0002 mg/mg/day). The lowest midgut amylolytic (0.044 ± 0.0005 and 0.047 ± 0.0005 mU/ individual, respectively) and proteolytic (0.015 ± 0.0004 and 0.016 ± 0.0001 mU/individual, respectively) activity of the sixth instar was detected on walnut and rice. The highest inhibition of amylase (53.37 ± 0.75%) and protease activity (48.54 ± 0.96%) was estimated by incubating midgut extracts from the last instars with wheat and barley proteinaceous extracts, respectively. The results indicated that walnut was the most unsuitable diet for feeding and development of T. granarium. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is one of the most economic insect pests of grain, cereal and other stored products particularly in tropical and sub- tropical regions of Asia and Africa (Jood et al., 1996; Burges, 2008). The larvae of this pest cause economic damage by loss of carbo- hydrate, crude fat and protein contents of stored products (Jood and Kapoor, 1993; Ahmedani et al., 2009). In a high population density of T. granarium larvae, quality and quantity of grains decrease through feeding, and contamination with skins and barbed hairs of the larvae may prove a serious hazard to human health (Hosseininaveh et al., 2007; Ahmedani et al., 2009). Application of chemical pesticides have been the primary control method of stored product pests such as T. granarium (Finkelman et al., 2006), however, many problems are associated with using the pesticides (Hagstrum and Subramanyam, 1996). Consequently, for develop- ment of alternative control methods of T. granarium, it is essential to understand the nutritional physiology (Kazzazi et al., 2005) and biological aspects of the pest in response to feeding on various host diets. Several studies have been done to evaluate the post-ingestive regulation of nutritional protein and carbohydrate in insects by changing the digestive enzymes secretion (Silva et al., 2001; Lazarevic and Peric-Mataruga, 2003; Naseri and Razmjou, 2013; Piasecka-Kwiatkowska et al., 2013). Since larval feeding of T. granarium is related to protein and starch digestibility (Jood et al., 1996), the selective inhibition of the digestive enzymes (a-amylase and protease) can be one of the most crucial aspects of this insect control (Bigham and Hosseininaveh, 2010). * Corresponding author. E-mail address: bnaseri@uma.ac.ir (B. Naseri). Contents lists available at ScienceDirect Journal of Stored Products Research journal homepage: www.elsevier.com/locate/jspr http://dx.doi.org/10.1016/j.jspr.2015.03.003 0022-474X/© 2015 Elsevier Ltd. All rights reserved. Journal of Stored Products Research 62 (2015) 1e7