桃园捕食性节肢动物群落结构及动态研究

【目的】探讨桃园捕食性节肢动物群落特征、结构组成及动态规律,为桃园害虫防治提供依据。【方法】在西北农林科技大学实验站选择树龄5~6年的桃园为调查对象,系统调查园内节肢动物群落的种类和数量,测定群落的相对丰富度、多样性指数(H')、均匀度指数(E)及优势集中性指数(C)等指标,研究园内捕食性节肢动物群落的变化规律。【结果】桃园捕食性节肢动物群落的多样性指数和均匀度指数表现为高-低-高-低的趋势;群落优势度(B)与优势集中性指数呈现低-高-低趋势。食蚜蝇、蜘蛛、瓢虫、步甲和草蛉是桃园主要捕食性节肢动物亚群落。大灰食蚜蝇Metasyrphus corollae和黑带食蚜蝇Episyrphus balteata是食蚜蝇亚群落的优势种群,5月中旬至6月下旬是其发生高峰期;龟纹瓢虫Propylaea japonica是瓢虫亚群落的优势种群,5月中旬至7月下旬是其发生高峰期,随后数量维持在较低水平;龟纹瓢虫鼎斑变型和锚斑变型是桃园最常见的色斑变型,分别占49.6%和29%;蜘蛛亚群落主要包括皿蛛、蟹蛛和球蛛类群,5月上中旬、8月中下旬和10月中旬是其发生高峰期;步甲亚群落的发生高峰期为5月上旬至6月下旬,随后维持在较低的水平;中华草蛉Chrysoperla sinica为草蛉亚群落的优势种群,6月上旬至8月上旬是其发生高峰期。【结论】桃园捕食性节肢动物主要包括捕食性蜘蛛、食蚜蝇、捕食性瓢虫、步甲和草蛉5个亚群落,不同天敌亚群落的结构特征随着季节和气温的变化而相互演替,共同发挥控制害虫的作用。

Community structure and population dynamics of predacious arthropods in peach orchards

Objectives] The habits, community structure and population dynamics of predacious arthropod communities in peach orchards was investigated to improve pest control methods. Methodsl Five to six year old peach orchards were selected in Northwest A＆F University＇s experimental farm as study sites. The species and numbers of predacious arthropod communities in selected orchards were systematically investigated by measuring the relative species abundances, dominant, species diversity, evenness and dominance. Results] The diversity and evenness index showed a high-low-high-low tread, and the dominance index and index of dominant concentration were a low-high-low tread. The syrphid fly, spider, ladybeetle, carabid beetle and lacewing were the predominant predacious arthropod sub-communities in peach orchards. Metasyrphus corollae and Episyrphus balteata were the dominant species of the syrphid fly sub-community, which reached peak abundance in middle May to late June. Propylaea japonica was the main species of the coccinellid sub-community, with a population peak beginning in middle May to late July. P.japonica ab. tessellata and ab. ancora were the most common color variants of this species in peach orchards, accounting for 49.6% and 29% of the population, respectively. Linyphiidae, Thomisidae and Theridiidae were the dominant groups of the spider sub-community, which peaked in early and middle May, middle and late August as well as mid-October. The peak of the carabid sub-community occurred from early May to late June. Chrysoperla sinica was the predominant species of the lacewing sub-community, which reached peak abundance in early June to early August. Conelusion] The predacious arthropod community in peach orchards was mainly comprised of spider, syrphid fly, predacious ladybeetle, carabid beetle and lacewing sub-communities. The structural characteristics of different predacious arthropod sub-communities varied with season and temperature, which played a major role in the control of insect pests.