关键词:  拟步甲科昆虫, 物种多样性, 分布格局, 地形因子, 北祁连山

Abstract: 【Aim】 Tenebrionid beetles are a group of ground-dwelling insects with strong adaptability, complex feeding habits and robust reproductive capabilities. The impact of topographic factors on the distribution of tenebrionid beetles in the northern Qilian Mountains, northwestern China was analyzed, aiming to reveal the diversity distribution patterns of tenebrionid beetles under different topographic conditions. 【Methods】 During July-August, 2022, 65 sampling sites were selected across four altitude gradients in the northern Qilian Mountains region: 1 000-2 000, 2 000-3 000, 3 000-4 000, and above 4 000 m. Active trapping method was employed to investigate the species composition and distribution of tenebrionid beetles. Canonical correspondence analysis (CCA) and curve regression fitting were utilized to analyze the relationships between the diversity distribution of tenebrionid beetles and topographic factors in the northern Qilian Mountains. 【Results】 A total of 5 682 adult tenebrionid beetles, belonging to 124 species of 34 genera, were identified and counted. Among them, Anatolica potanini and Scleropatrum horridum horridum were the dominant species, accounting for 14.4% and 24.8% of the total captured individuals, respectively. The Shannon-Wiener diversity index and Simpson dominance index of tenebrionid beetles were the highest at the altitudes between 2 000-3 000 m, the Margalef’s richness index of tenebrionid beetles was the highest at the altitudes between 1 000-2 000 m, and the Pielou’s evenness index of tenebrionid beetles was the highest at the altitudes between 3 000-4 000 m. At the altitudes above 4 000 m, only a few sciophilous and hygrophilous species of Blaptini and Platyscelidini were found. CCA result showed that altitude and slope had significant effects on the distribution pattern of tenebrionid beetles, with altitude having the highest explanatory power. The Margalef’s richness index and Shannon-Wiener diversity index of tenebrionid beetles showed significant linear relationships with altitude. The Margalef’s richness index of tenebrionid beetles was significantly negatively correlated with slope. The individual number of the dominant species A. potanini showed no significant correlation with any of the five topographic factors, and A. potanini was distributed near the origin of the CCA ordination axis, indicating its widespread distribution in the Northern Qilian Mountains. The individual number of the dominant species S. horridum horridum was only significantly negatively correlated with altitude. The plane curvature of tenebrionid beetles showed a significant normal curve distribution relationship with their individual numbers. 【Conclusion】 The distribution pattern of tenebrionid beetles in the northern Qilian Mountains is influenced by a combination of multiple topographic factors, with altitude being the dominant factor.

Key words: Tenebrionid beetles, species diversity, distribution pattern, topographic factors, northern Qilian Mountains