The effects of starvation stresses and nutritional diets on the immune system of Indian Meal Moth Plodia interpunctella (Lepidoptera: Pyralidae)
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
Indian meal moth, Plodia interpunctella (Hȕbner) is an ubiquitous insect and one component of pests of stored products. The larvae of this insect spin a silky caul, on the surface of the food and feed in it. This infections can cause damage, such as control costs, reduce the quality and consumer complaints. Cellular defense of insects are accompanied with cooperation of hemocytes. Nutrition, starvation stresses and any attack caused by invading factors lead to changes in the number of hemocytes. In this study, the effects of starvation stresses in 4 treatments in different intervals, 24, 48 and 72 hours, and effect of different nutritional diets in 4 treatments include of pea and raisin, walnut, pistachios and artificial diet on immunity system of Indian meal moth have been investigated. In both experiments, the number of repetitions for each treatment was 30 larvae. For total hemocyte count, the hemolymph of 5 instars larvae collected and were diluted with physiologic buffer. Anticoagulant buffer used in the test was Tyson solution. THC was conducted with a standard Neubauer hemocytometer. The cells were counted using a light microscope at 40x magnification and number of total hemocytes per cubic millimeter (mm3) was calculated using the formula of Jones. Data analysis was performed with SAS program and comparison of means by Tukey,s test (p<0.01) was conducted. The results of starvation periods experiments have suggested that the total hemocyte count has decreased with the increasing of the length of starvation period. The number of plasmotocyte also has reduced considerably with the rising of the length of starvation period. The number of granulocyte after 72 hours starvation has shown a more significant decrease in comparison with the two previous treatments. Following a slight increase after 24 hours, the number of prohemocyte started to decrease gradually. The number of oenocytoids in comparison with control treatment increased dramatically in 24 hours of starvation, followed by a downward trend after 24 and 72 hours. In experiment of the effect of different nutritional diets, the maximum and minimum total hemocyte count were obtained for pea and raisin diet and pistachios diet, respectively. The number of plasmotocytes and Prohemocytes in larvae fed with pea and raisin diet, and the artificial diet were the maximum and minimum number respectively, compared with other treatments. The maximum and minimum number of granulocytes and oenocytoids were attributed to the larvae fed with pea and raisin, and walnut, respectively.
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