河西走廊中部戈壁地表甲虫群落动态变化及其影响因素

地表甲虫是戈壁主要的地表昆虫类群, 但我们对其种属组成和活动节律的认识还很有限。2018-2020年1-12月我们利用陷阱法对河西走廊中部典型砾质戈壁地表甲虫种类及数量进行了连续观测, 并测定了该区降水和温度。本文研究发现: (1)戈壁地表甲虫由步甲科、叶甲科、象甲科、粪金龟科和拟步甲科5科21种组成, 阿小鳖甲(Microdera kraatzi alashanica)、戈壁琵甲(Blaps gobiensis)和波笨粪金龟(Lethrus potanini)是优势地表甲虫种; (2)戈壁地表甲虫活动节律存在明显年季变异, 地表甲虫的活动期在3-10月, 地表甲虫活动密度的最大值出现在4-7月, 而物种丰富度的最大值均在5月出现; (3)降水增多的2019年地表甲虫的活动密度明显增加, 且2019年地表甲虫物种丰富度和多样性指数显著高于2018年; (4)地表甲虫的取食类型和个体大小影响它们的活动节律, 降水增多的年份提高了植食性的象甲科和部分拟步甲科的活动密度, 而一些拟步甲科的活动密度对降水的响应存在一定的滞后性; (5)降水和温度变化强烈影响地表甲虫活动节律, 地表甲虫的个体数和物种数与月降水量和月平均温度呈显著的二次曲线和指数关系, 植食性和捕食性甲虫对降水及温度变化响应较腐食性甲虫敏感, 大甲虫对降水变化的响应较中甲虫和小甲虫敏感。总之, 降水及温度变化影响了戈壁地表甲虫的活动节律, 而不同地表甲虫种对二者的响应因其生理生态特征不同而异, 从而影响了地表甲虫群落动态变化规律。

Dynamic change of ground-dwelling beetle community in a gobi desert of the middle of Hexi Corridor and its influencing factors

Aims: The purpose of the study is to further understand the species/genus composition and activity rhythms of ground-dwelling beetles of gobi.Methods: From January to December during 2018 and 2020, the number of individuals and species of ground-dwelling beetles in a gobi desert of the Hexi Corridor were continuously observed with pitfall traps, and the climatic elements of the region were observed.Results: (1) Ground-dwelling beetles of the gobi were composed of 21 species from 5 families, including carabid, chrysomelid, curculionid, geotrupid and tenebrionid, and Microdera kraatzi alashanica, Blaps gobiensis and Lethrus potanini were the dominant species; (2) The activity rhythm of ground-dwelling beetles in gobi had obvious seasonal variations. The activity period of ground-dwelling beetles were from March to October, the activity density of ground-dwelling beetles peaked in April to July, and the species richness of ground-dwelling beetles peaked in May; (3) The activity density of ground-dwelling beetles increased significantly in 2019 with increased precipitation, and the species richness and diversity index of ground-dwelling beetles decreased significantly in 2018 with decreased precipitation; (4) The type of feeding and individuals size of ground-dwelling beetles affected their activity rhythm. The years of increased precipitation increased the activity density of the curculionid of phytophagous and some species of the tenebrionid, and the response of the activity density of some species of tenebrionid showed a certain hysteresis with precipitation; (5) The change of precipitation and temperature strongly affected the activity rhythm of ground-dwelling beetles. The number of individuals and species of ground-dwelling beetles had a significant quadratic and exponential relationship with monthly average precipitation and temperature. The response of phytophagous and predatory beetles to the change of precipitation and temperature were more sensitive than those of beetles of saprophagy, the response of large beetles to the change of precipitation were more sensitive than those of medium and small beetles.Conclusion: The change of precipitation and temperature affect the activity rhythm of gobi ground-dwelling beetles, and the responses of different ground-dwelling beetle species to them are different due to their different physiological and ecological characteristics, which affect the dynamic changes of the ground-dwelling beetles communities.