Document Type : Research Article
Department of Plant Protection, Faculty of Agriculture, University of Tabriz
University of Tabriz
Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University
The striped bug, Graphosoma lineatum L. is one of the pests of Apiaceae family such as parsley, carrot, celery and some medicinally important plants. The adults and nymphs of this insect feed on seeds of host plants. The eggs of the striped bug have an important role in mass rearing program of some parasitoids. Nutritional supplements undertake an essential function in mass rearing of insects and increase the efficiency of production. Vitamins such as B group have different functions in physiology of insects. Growth and development of insects depend on essential nutrients which have to receive them via food materials. Essential amino acids and some minerals are other parts of nutritional materials which need to be utilized by insects and must be obtained from food materials. Delayed growth, weight loss, prolonging immature stages, increasing mortality, some deformities in wings, change in mating and behaviors and some physiological problems are symptoms of deficiency in nutritional materials and vitamins reported in different researches. In this study the effects of some vitamins and amino acids on anatomy of salivary glands, total protein of body, developmental time and fecundity of G. lineatum were evaluated in controlled conditions.
Material and methods
Insects reared on parsley seeds adhered on the inner side of big plastic containers in controlled condition. Supplements including vitamins B12, B6, B1 and Serine and Phenylalanine amino acids selected for evaluation. These supplements used for the treatmnet of G. lineatum in four different concentrations dissolved in water. For evaluating the effects of nutritional supplements on anatomy of salivary glands, both glands separate after dissection of adult’s thorax, and dimension of glands including width and length of posterior and anterior lobs, measured by micrometer apparatus located on stereomicroscope. Total body protein measured by Kjeldahl apparatus after well drying the total body of insects in oven followed by fine powder of dry materials. Total protein calculated as multiplying the nitrogen amounts in 6.38 (a constant number) as a standard method. In separate experiments, the effect of nutritional supplements on each nymphal stage duration studied. One day old eggs used for this purpose, after justifying treatments the time required for developing each instar recorded daily. All tests replicated three times and distilled water were used for control treatment. The data were analyzed by One-way ANOVA experimental randomized design and Duncan’s multiple range test using SAS software used for comparing the means.
Results and discussion
The results revealed that all vitamins and amino acids significantly affected all studied parameters. In the case of salivary glands, especially posterior lobe of them more affected in insects fed by B1, B6 and Phenylalanine. Different concentrations of vitamin B6, B1 and Phenylalanine affected total protein content of male and female insect’s body. Vitamin B12 had non-significant effect on male and female total body protein. Nutritional supplements changed the rate of laid and hatched eggs in addition with nymph’s developmental time. Vitamin B12 in the concentration of 0.005 g/l, B6 in the concentration of 0.25 g/l, B1 in the concentration of 0.5 g/l, Serine and Phenylalanine both in the concentration of 0.5 g/l showed the highest rate of laid and hatched eggs. Vitamin B6 and B1 in the concentration of 1 and 1.5 g/l resulted in prolonging the nymph’s life span in comparing with controls. The negative effects of high concentrations of nutritional supplements on fecundity and normal developmental period of nymphs well documented in this study. Metabolism, cell division, hormone synthesis, enzymes activity and many physiological parameters affects by supplements especially vitamins. Any disorder in utilization, absorption and inhibition of their function leads to biological and behavioral problems in insects. In some cases, the function of symbionts for compensation essential supplements documented.
The results of this study indicate important function of vitamins B12, B6 and B1 on G. lineatum nymphal developmental period. In high concentrations, rate of growth decreased in comparison with controls. Salivary glands anatomy showed some changes in dimensions especially in posterior lobs in dose-depending manner. Number of eggs laid and hatched decreased especially in high concentrations of nutritional supplements. The results of this study will help to justify better meridic diet for rearing striped bug. In semi-artificial diets for rearing this insect, corporation of little concentrations (optimum) will improve the fitness of insects.