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The rose sawfly, Arge rosae Linnaeus, is one of the most destructive pests of rose bushes in the north of Iran. Nowadays, many attempts have been made to reduce pesticide application by looking for new methods of pest control. A non chemical method for controlling insect pests including A. rosae can be achieved by using genetically engineered plants expressing carbohydrase inhibitors. Therefore, in present study we characterized biochemical properties of digestive carbohydrases in the gut of A. rosae for achieving a new method for control of this pest. The specific activity of α-amylase in the digestive system of last larval instars of A. rosae was obtained as 9.46 ± 0.06 μmol min^-1 mg^-1 protein. Also, the optimal pH and temperature for α-amylase were found to be at pH 8 and 50 °C. As calculated from Lineweaver-Burk plots, the K_m and V_maxvalues for α-amylase were 0.82 mg/ml and 7.32 µmol min^-1 mg^-1 protein, respectively, when starch was used as substrate. The effects of ions on amylolytic activity showed that Mg²⁺ and Na⁺ significantly increased amylase activity, whereas SDS and EDTA decreased the enzyme activity. The highest activities of α-/β-glucosidase and β-galactosidase were obtained at pH 5.0. By the native PAGE, three, one, one and two bands were clearly detected for α-amylase, α-/β-glucosidase and β-galactosidase, respectively. No bands were found for α-galactosidase that confirmed the absence or low activity of this carbohydrate in the digestive system of A. rosae. These results could provide the knowledge needed to produce transgenic plants for control of this pest.  

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The family Meloidae Gyllenhaal‎, 1810 (Coleoptera), commonly known as blister beetles, exist in warm, dry, and vast habitats. This family was studied in Kerman province of Iran during 2018–2019. The specimens were collected using sweeping net and via hand-catch. They were identified by the morphological characters, genitalia, and acceptable identification keys. To improve the knowledge of the Meloidae species of southeastern Iran, faunistic investigations on blister beetles of this region were carried out. Totally, 30 species belonging to 10 genera from two subfamilies (Meloinae and Nemognathinae) were identified. Among the identified specimens, 22 species were new for fauna of Kerman province.

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The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is one of the most destructive insect pests, feeding exclusively on wild and cultivated cruciferous species. The attacked plants produce considerable amount of glucosinolates in response to insects’ feeding. Herein, we studied digestive activities of P. xylostella on four different genotypes of family Brassicaceae including two canola cultivars (SLM₀₄₆ and RGS₀₀₃) and two cabbage cultivars (Green-Cornet and Glob-Master). The highest proteolytic and amylolytic activities of P. xylostella were observed on Green-Cornet and the lowest occurred on RGS₀₀₃ and Glob-Master, respectively. The highest activity of α-glucosidase and β-glucosidases were observed on Green-Cornet and SLM₀₄₆ and the lowest was observed on Glob-Master and RGS₀₀₃. The zymogram analysis revealed different isozymes of protease, trypsin-like and α-amylase in the midgut extract of P. xylostella. Activity of the above mentioned isozymes was inhibited in larvae feeding on RGS₀₀₃ and Glob Master as resistant host cultivars. Also, larvae feeding on the resistant genotypes showed more glucosidase activities, indicating possibility of high glycosinolate existence in the resistant genotypes. By these results we can state that host plant property can affect insect digestive physiology through inhibiting digestive enzyme activities. These findings provide insights into the direct effects of host plants on insect physiology which are conducive to change in insect fitness.