Effect of organic farming on insect diversity

Abstract

The paper focuses on the insect community as a "link" between ecosystem producers, secondary consumers and decomposers and the mobile and informative indicator of structure, biological stability and productivity. Consortium and other subsystems of agricultural ecosystems are mainly destroyed annually as a result of technological measures – chemical, mechanical, biological. External ecological factors, including the structure of the agrolandscape, in particular field protective forest shelter belts and ecotones between them, also have a certain influence. The research was conducted in organic agrolandscape (Kyiv region, Ukraine), comparing it with the conventional one. Insects were collected in winter wheat fields, ecotones and adjacent forest shelterbelts. The number of orders, families and individuals is greater under organic farming. The highest number of families and individuals was recorded in the forest shelterbelts adjacent to the organic landscape (26.3 and 111.7, respectively). The number of individuals in organic winter wheat fields was twice as large as in conventional fields and amounted to 85.3 individuals on average; the number of families was by 1.8 times larger. Biodiversity indices (Shannon, Menhinick, Margalef, Berger-Parker, and Pielou) confirm the greater diversity of insects in the organic fields of winter wheat. The Sørensen similarity coefficient was higher in the organic fields and forest shelterbelts near the conventional fields (Cs=0.7), which is explained by the largest number of phytophages in these ecosystems. The share of predators and parasites that control pests in the agricultural system was highest in organic ecotones and forest shelterbelts – 26.21% and 33.12% (against 10.24 and 18.16% in conventional, respectively).