Time variations of species diversity of wheat field aphids in Saman city, Chaharmahal and Bakhtiari Province, Iran

This research investigated the time variation of aphid species diversity in wheat field of Saman, Chaharmahal and Bakhtiari province during 2017. Sampling was conducted from a 3 hectare wheat farm in Saman, twice a month, in each time 100 plants were randomly taken. Alpha species diversity indexes including Shannon-Wiener, Simpson, McIntosh and Pielou, Simpson, and Macintosh uniformity species indexes were calculated in each sampling period. The diversity of aphids was compared by Renyi's diversity ordering method. Estimation of maximum species richness was done using nonparametric indices. Analyzes and calculations were performed using SDR4 software. A total of 8258 individuals were collected from aphids during the whole sampling period, which is belonging to eight species as follows: Diuraphis noxia (Mordvilko, 1913), Ford hirsute (Mordvilko,1928), Rhopalosiphum padi (Linnaeus, 1758), Rhopalosiphum sp., Metopolophium dirhodum (Walker, 1849), Sipha elegans (Del Guercio, 1905), Sipha sp. and Sitobion avenae (Fabricius, 1775). The most abundant species were the Russian wheat aphid, D. noxia and the rose-grass aphid, M. dirhodum, with 53.05 and 43.47 percent of the total aphid individuals respectively. Non-parametric methods of estimating species richness showed that additional sampling would yield at most 12 wheat aphid species in Saman wheat fields. A discussion was provided on species richness and species composition of wheat aphids during time in Saman region and also compared to other studied regions in Iran.