The Occurrence Regularity And Habitat Landscape Analysis Of Simulium Maculatum In The Lower Irtysh River In Xin Jiang

Simulium(Byssodon) maculatum is one of the important medical pests found worldwide.It spreads many diseases and causes much harm along the lower Irtysh River in Xinjiang where it is considered the major pest species. In this paper, we investigated the habitat distribution, landscape analysis, biological characteristics, rules for population occurrence,and the effectiveness of three different insect traps for Simulium maculatum along the lower Irtysh River of Xinjiang. The population dynamics, the overwintering generation, the annual life history, and the distribution of habitats were documented. Trapping effectiveness using three different methods and the landscape analysis of Simulium maculatum in different habitats was studied. The results are as follows.1. There are two generations of Simulium maculatum at 185 Regiment in the lower Irtysh River of Xinjiang in one year. The larvae overwinter by hiding in the river sludge. They move to weeds and river floats in later April of the next year.2. Three different insect collecting methods were compared for sampling Simulium maculatum. The differences among the three insect traps of Simulium maculatum adults were striking: the insect net trap was best, and the lamp trap was worse than the human-baited net trap.3. The population circadian rhythm of Simulium maculatum assessed by insect traps was similar across three different habitats at the 185 Regiment. Main insect activity occurred one hour after sunrise and sunset.4. The generations of adults are not easy to distinguish in determining the population dynamics of Simulium maculatum. Except for the overwintering adults that occur in large numbers and concentrations, the later generations seriously overlap. The first generation of adults occur from early June to middle July and the second generations of adults occur from middle July to late August. Larvae began to overwinter with the temperature decreases starting in early October.5. Investigation of the habitats of Simulium maculatum in the lower Irtysh River of Xinjiang revealed that Simulium maculatum were distributed in each grape production area inthe lower Irtysh River. The 185 regiment was especially affected by this pest and normal life was seriously disturbed. The habitats of Simulium maculatum at the 185 Regiment were concentrated in rivers with higher velocity、higher dissolved oxygen、higher pH、and at higher altitude. The habitats of Simulium maculatum were concentrated in those rivers with shallow depth and cool temperatures in other places along the lower Irtysh River of Xinjiang. The regression forecast equation for Simulium maculatum larvae in habitat at the 185 Regiment was established.