Fatty Acids Present in Wheat Kernels Influence the Development of the Grain Weevil (Sitophilus granarius L.)

SIMPLE SUMMARY: The grain weevil (Sitophilus granarius L.) is a common storage pest species, whose foraging on stored cereal grain causes major losses worldwide every year. Traditional ways to control this species (non-chemical) are expensive or do not guarantee effective control against this pest insect. The application of chemical methods, on the other hand, is contradictory to consumers’ expectations regarding food safety, and cause a negative impact on the natural environment. An important step in the development of a safe and effective strategy for limiting the losses caused by the grain weevil is to search for mechanisms influencing the natural resistance of cereal grain and then to use this knowledge in the breeding of new cultivars. This experiment entailed assessing the content of fatty acids in grains of selected wheat cultivars. The content of these compounds and their composition in the wheat cultivars varied. In addition, the life cycle of S. granarius on the tested wheat grain was assessed. The results of the experiment suggested that the intensity of the development of S. granarius is significantly correlated with a higher content of saturated fatty acids and unsaturated ones in kernels. The substances that might stimulate the development of the grain weevil or reduce the number of offspring of this beetle were identified. ABSTRACT: Sitophilus granarius (L.) is considered to be one of the major pests causing damage to cereal grain stored in silos and granaries. Using traditional methods (synthetic insecticides, mechanical, or physical methods) to control this pest is either ineffective or dangerous to people and nature. It is, therefore, necessary to develop new cultivars of cereals that will be distinguished by a high natural tolerance of the foraging by S. granarius. The aim of this study is expressed in the set research hypothesis, stating that the number of offspring of the grain weevil on stored wheat kernels can depend on the content of fatty acids in the kernels. Thus, the qualitative and quantitative composition of fatty acids was determined in kernels of 10 winter wheat cultivars, and the abundance of the beetle’s offspring generation of S. granarius that developed on the wheat grain, as well as the mass of produced dust and loss in the mass of wheat grain were determined. By applying statistical analyses (GLM, ANOVA, Pearson’s linear correlation coefficient, and analysis of redundancy), the presence and character of the dependence between the determined content of fatty acids in wheat grain and the factors describing the development of S. granarius were established. The research results indicate that fatty acids from the groups C 18:1 and C 20:1 probably play an important role as substances stimulating the increase in the number of the tested pest progeny. In contrast, fatty acids C 15:0, C 16:1, and C 18:3, which were determined in large amounts in the grain of wheat cultivars Speedway, KWS Livius, and Julius, can reduce the number of offspring of pest insect.