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

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.

Keywords: fatty acids; granary weevil; natural resistance; stored product pest.

Figure 1

The average number of progeny beetles of S. granarius (a), the mass of produced dust (b), and the grain mass loss (c) observed on the grain of the studied wheat cultivars (* means followed by the same letter do not differ—Tukey’s HSD test).

Figure 2

Redundancy analysis diagram (RDA) presenting correlations between analysed parameters pertaining to the development of S. granarius and the content of fatty acids in the analysed wheat cultivars.