Effects of intercropping crops on arthropod diversity and temporal niche in apple orchard

Orchard intercropping is an artificial ecological community formed by the complementary combination of tall fruit trees and low crops based. In this study, the differences and changes of arthropod diversity, richness and evenness were compared and the niche width, overlap index and competition relationship among populations in time dimension were analyzedin the apple orchards intercropping with annual crops, perennial crops, and clear tillage in Alar, China. The results showed that a large number of arthropods (97% - 99%) belonged to 7 orders, 11 families and 18 species. The relative abundanceof natural enemies in orchard intercropping crops was higher than that without intercropping, especially for Chrysoperla sinica and Adonia variegata , and that of pests was lower (except for Mirids), and especially for Aphis citricola and Lithocolletis ringoniella . Diversity analysis showed that compared to control, Shannon index and Pilu evenness index were higher in intercropping orchard , while the Simpson index was close to the control. In the three orchards, the niche widths of L. ringoniella, C. sinica , and A. variegata were larger, while the niche widths of A. citricola and spiders were smaller. It followed that the time niche overlap index of insects with similar occurrence period was high, showing the coexistence of multiple clusters. In this study, we reported that orchard intercropping had a promoting effect on the occurrence of the insects, which not only reinforced the ecosystem service of pest regulation, but also achieved the purposes of maintaining the stability of ecosystem and protecting ecological environment. Implications for insect conservation This study suggests that orchard intercropping has a promoting effect on the occurrence of the insects.