نشریه نامه انجمن حشره شناسی ایران
سال چهلم شماره 3 (پیاپی 83، پاییز 1399)

The cotton bollworm, Helicoverpa armigera (Hübner),is a wide host range pest that causes severe economic damages to agricultural crops in Iran and all around the world. During recent years, chemical insecticides have been used as the most effective strategy in control of this pest, but due to their hazardous effects, most of the researches are being conducted to offer an alternative approach for chemical control. In this regard, digestive systems, in particular inhibition of insect digestive enzymes, are considered as a target for pest control. Here, we used the original pro-region of H. armigera chymotrypsin as a potent and specific inhibitor of the pest enzyme. The structural model of the insect chymotrypsin was predicted based on homology modeling and the crystal structure of Bos taurus L. as template. The reliability of the model was assessed using VERIFY_3D, ERRAT, PROCHECK, WHAT-IF and Z-scores, and the results confirmed that the predicted structural model has an appropriate quality. Moreover, molecular docking simulations between the predicted structural model of enzyme and designed peptide showed that the inhibitor peptide has the most appropriate docking score and total binding energy for interactions with the insect chymotrypsin’s active site. However, it showed a weak potential for interaction with Sus scrofa L. chymotrypsin, as a representative of the mammalian enzyme. The results of this report indicate the importance of computational studies in design and selection of the favored inhibitor pro-peptides against the target enzymes. Such inhibitors can be further suggested as a replacement of chemical pesticides for controlling of H. armigera as well as the other pests in future.

In a faunistic study on the edaphic Mesostigmata in Mahan City in center of Kerman Province, soil samples were collected from different habitats, their mites extracted using Berlese-Tullgren funnels, cleared in Nesbitt’s fluid and then identified after mounting in Hoyer's medium on microscope slides. Totally, 34 species belonging to 26 genera and 15 families of Mesostigmata were collected, including female and male specimens of Pergamasus (Thenargamasus) quisquiliarus (G. & R. Canestrini) that was considered as the first record of the subgenus and species from Iran. List of the collected mites and also morphological attributes of the new recorded mite were presented. Additionally, the pergamasine mites of Iran and their classification were revised and a key to the Iranian genera and species was provided. Additionally, Hypoaspis sclerotarsus Costa was transferred to the genus Hypoaspisella Bernhard and diagnostic morphological features of the species were presented.

The material belonging to the genus Asiotmethis (Pamphagidae: Thrinchinae) housed in the Hayk Mirzayans Insect Museum, Iranian Research Institute of Plant Protection as well as the specimens that collected in 2018, were examined based on morphological characters. As a result, three species were identified, i.e., A. artemisianus Shumakov, A. turritus (Fischer von Waldheim) and A. Limbatus (Charpentier). The first species was previously reported from Golestan province (North of Iran) and Khorasan-e-Razavi province (North East of Iran). The second species was previously reported from Golestan province and Azarbaijan-e-Sharghi (North West of Iran). A. limbatus that was collected and identified in Ilam province, South West of Iran is new to the Iranian fauna. Morphological identification key to the Iranian species belonging to the genus ‌Asiotmethis, measurements data and major morphological characteristics of the three species are given along with original photographs and distribution map for the new record.

Semiochemicals play a key role on host selection of parasitoids. Responses of parasitoid wasp, Habrobracon hebetor (Say), to volatiles emitted from Ectomyelois ceratoniae Zeller larva, pomegranate as its host plant and herbivorous induced plant volatiles (HIPVs) were investigated using a Y-shaped olfactometer. The results showed that the last larval instar of E. ceratoniae, its feces, the mechanically damaged pomegranates and the infested pomegranates by larva were attractive for the parasitoid wasp. The volatiles of E. ceratoniae larvae and its feces were extracted by solid phase micro-extractionand then identified by GC-MS. Respectively, 40 and 45 components were identified in headspaces of the last larval instar of E. ceratoniae and its feces. The major identified components were1-Pentadecane, Nonanal, Octanal, Decanal, Hexanal and Limonene. More studies are needed to identify HIPVs and also to evaluate the behavioral activity of identified volatiles.

Nowadays, with the advent of powerful statistical techniques and neural networks, predictive models of distribution have been rapidly developed in ecology. This study was carried out to model distribution of aphid, Rhopalosiphum padi,using MLP neural networks combined with Particle Swarm Optimization in wheat fields of Badjgah area, Fars province. Population data of the pest was obtained by sampling at 100 locations across wheat fields during 2013. For evaluation the capability of neural networks used in dispersal prediction, statistical comparison of parameters such as mean, variance, statistical distribution of spatial predicted values by neural network and their actual values, were conducted. Results showed that there were not significant differences between variance, mean and statistical distribution of actual and predicted values in training and test phases of neural network combined Particle Swarm Optimization algorithm. Our map showed a patchy pest distribution offers large potential for using site-specific pest control on this field.

In a natural ecosystem, there is a close relationship between natural enemies and environmental factors. Use of Geographic Information System (GIS) in analysis of spatial patterns of pest populations has increased during recent years. The purpose of this study was using Analytic Hierarchy Process (AHP) to determine the relationship in predatory ladybird, Exochomus nigripennis (Erichson) for biological control of the sucking pests. In order to determine the suitable areas for activity of E. nigripennis, the variables of temperature, humidity, rainfall, elevation and nutrition were selected as the most important criteria. The basis of AHP is the pair comparison of options and the possibility of examining different scenarios. ArcMap 10.1 and ArcCatalog 10.1 softwares were used to form spatial data and related analytics. The results indicated that nearly 4.34% of the province's regions, including some parts of Taft, Abarkuh and Mehriz were very good for activity and nearly 17.07% of the province's areas, such as the major part of Ardakan, Bahabad and Meybod were determined as very unsuitable for activity. Furthermore, comparison of the studied factors showed temperature with the final weight of 0.0529 is the most important factor influencing the activity of E. nigripennis and nutrition, humidity, elevation and rainfall are important in the next categories, respectively.

In the recent decade, Lema melanopa L. has become one of the most important pests of wheat fields in Golstan province. Both adults and larvae of this pest feed on the leaves of most cereals and of course wheat and cause severe damage. Due to the lack of information about the physiology of this pest, in the present study, the biochemical properties of alpha amylase, glucosidase, galactosidase and gastrointestinal proteases from adult stage of this pest were investigated. The results showed that the highest level of optimal enzyme activity was observed in the range of 4 to 6 and the optimum temperature of 35 ° C. Electrophoresis showed two isoforms of alpha-amylase in the gut of the insect. The maximum activity of alpha and beta glucosidase enzymes and alpha and beta galactosidase of the gut was obtained in acidity 5 and in the temperature range of 35 to 45°C, respectively. The highest general protease activity was shown among gut proteases at pH 6 and at 45°C. Study Results of the effect of enzymatic inhibitors including EDTA, TLCK, TPCK, PMSF, sodium Iodo Acetate and Iodoacetic acid protease activity showed that cysteine proteinase inhibitors had the greatest inhibitory effect on enzyme activity. Therefore, it can be concluded that this group of proteases is dominant in the gut of cereal leaf beetle. By determining the biochemical properties of important gut enzymes of pest, compounds can be synthesized that are more efficient and reduce the consumption of insecticides and reduce the amount of damage to the environment.