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Understanding how species richness changes along elevational gradients has attracted increasing attention from many researchers. The relationships between species richness and elevations were characterized by monotonic decreases or mid-elevational peaks. The western Sichuan Plateau is an important species diversity hotspot. However, there is little information available about the ant species diversity and distribution patterns of this region. In this study, we hypothesize that ant diversity will show a monotonic decrease from mid-elevation with increasing elevation. Here, the ant species diversity and distribution patterns of this region were investigated by plot surveys. A total of 22,645 ants were collected from eight elevational transects in the central and northern parts of the western Sichuan Plateau, which were identified as belonging to 40 species, 18 genera, and 4 subfamilies. We found a unimodal relationship between elevation and ant species richness, with the highest ant species richness occurring at mid-elevations. The similarity coefficient of ant communities in each elevational transect was at a moderate level of dissimilarity, indicating that the elevation difference and habitat heterogeneity had a great impact on ant communities in the central and northern areas of the western Sichuan Plateau.

In an attempt to find the neonicotinoid insecticides, twenty novel dihydropyridine derivatives were designed, “green” synthesized via one pot facile three-component reaction and evaluated for their bioactivities against Tetranychus cinnabarinus, Myzus persicae, Brevicoryne brassicae, Fusarium oxysporum f. sp. vasinfectum, Magnaporthe oryzae, Sclerotinia sclerotiorum and Botrytis cinereal. All of the tested compounds showed potent insecticidal activity, and some were much better in comparison with imidacloprid (IMI). Especially, compounds 3d (LC50: 0.011 mM) and 5c (LC50: 0.025 mM) were 12.2- and 5.4-fold more active than IMI (LC50: 0.135 mM) against T. cinnabarinus, respectively. Moreover, out of all the derivatives, compound 3d (LC50: 0.0015 mM) exhibited the strongest insecticidal activity against B. brassicae and compound 3i (LC50: 0.0007 mM) displayed the strongest insecticidal activity against M. persicae. Surprisingly, when the concentration of compound 4 was 50 mg/L, the inhibition rate against F. oxysporum and S. sclerotiorum reached 45.00% and 65.83%, respectively. The present work indicated that novel dihydropyridine derivatives could be used as potential lead compounds for developing neonicotinoid insecticides and agricultural fungicides.