نوع مقاله : مقالات پژوهشی
نویسندگان
1 گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه تبریز، تبریز، ایران
2 گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه تبریز، تبریز، ایران.
3 گروه گیاهپزشکی، پژوهشکده کشاورزی هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، کرج، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
The Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae) (Hubner, 1813) is one of the most important and well-known stored-product pests in most parts of the world. The larvae of this insect are omnivorous and have the ability to grow and reproduce on a wide variety of grains, dried fruits, dried vegetables, nuts, oil seeds, chocolate, animal feed and various processed products. Therefore, it causes economic losses to various agricultural and stored products. On the other hand, this insect is used as a host in the rearing of various useful insect species. In general, the Indian moth eats carbohydrate-rich foods, and its growth and development is highly dependent on biochemical compounds and especially the quality and quantity of nutrients in its diet. The enzymes like amylase and pectinase in the digestive system of the lepidoperan larvae, which are secreted by the cells of the midgut, play an effective role in the digestion and absorption of food. Investigating some of the biological and physiological properties of this insect on various types of foods will help to optimize the rearing of this insect for management studies and also as a host for rearing of other pest insect’s predators and parasitoids.
Materials and Methods
In this study, the effect of different diets; raisin, fig, pistachio, peanut, almond and walnut, which are among the main hosts of this insect, on the changes of protein content in the last instar larval gut of the Indian meal moth was measured and their protein patterns and content were compared using SDS-PAGE. Furthermore, the activities of the digestive alpha-amylase and pectinase enzymes were assayed using DNS (Dinitrosalicylic acid). For this purpose, 1% starch and pectin were used as substrates for alpha-amylase and pectinase, respectively. In order to better comparison of the relative enzymatic activities, their activities were calculated as a percentage of the highest enzymatic activity. Some biological parameters such as the incubation period, the larval period, the pupal period, the adult’s longevity, the life span and the adult emergence have been also compared.
Results and Discussion
The results showed that the lowest amounts of gut protein were observed in insects fed on figs and raisins, and the highest on pistachio, peanut, almond and walnut diets, respectively. Determining the amount of protein from the colorimetric study using the Bradford method and the image related to polyacrylamide gels (SDS-PAGE) were consistent and the protein concentration of the samples was clearly visible on the gel. The activity of alpha-amylase enzyme in the gut of larvae fed on pistachio and fig diets showed the highest and lowest amounts, respectively. Also, the highest and lowest activity of pectinase enzyme in the larval gut were observed in pistachio and raisin diets, respectively. The results showed that this pest has the same embryonic period in different diets. In comparing the length of the larval period, the length of the pupal period and the length of the total growth period, the lowest value was observed for pistachio and the highest for raisin. The lower desirability of a food for feeding the insect, the longer growth period of the insect. The shortest lifespan appeared in the diet of almond and pistachio and the longest was measured in raisins. In the examination of the adult emergence, almond and fig diets have the highest and lowest values, respectively. In general, it can be concluded that pistachio, almond and walnut diets are more favorable diets comparing to peanut, fig and raisin diets.
Conclusions
In this research, which was conducted with the aim of finding the best diet for rearing the Indian meal moth, the investigated diets, which are among the main foods of this insect, affect the amount and concentration of intestinal protein of the last instar larvae and alpha-amylase and pectinase activity. The biological components of the Indian meal moth were affected and significant differences were observed between the diets. For all these physiological and biological components, the highest values were recorded in the insects reared on pistachio diet and the lowest values were seen in the insects reared on the fig and raisin diets. With the investigations carried out in this research, it can be concluded that for the purpose of laboratory breeding of this insect, pistachio, walnut and almond diets are favorable and appropriate diets compared to peanut, raisin and fig diets; among them, pistachio is the most suitable diet.
کلیدواژه‌ها [English]
37-1
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