Weiser Erlandson L A, Obrycki J J
Department of Entomology, Iowa State University, Ames, IA 50011 Texas A&M University-Central Texas, Department of Science and Mathematics, Killeen, TX 76549
Department of Entomology, Iowa State University, Ames, IA 50011 University of Kentucky, Department of Entomology, Lexington, KY 40546-0091.
J Insect Sci. 2015 Aug 28;15(1). doi: 10.1093/jisesa/iev097. Print 2015.
Adults and nymphs of Empoasca fabae Harris (Hemiptera: Cicadellidae) and adults of predatory species in the families Coccinellidae, Anthocoridae, Nabidae, Chrysopidae, and Hemerobiidae were sampled in Iowa alfalfa fields from June to September in 1999 and 2000. The relationship between each predatory taxa and E. fabae was examined using regression analysis. In 2000, all predators were found to be positively correlated with the presence of E. fabae during all periods sampled and most likely contributed to mortality. Orius insidiosus (Say) (Hemiptera: Anthoridae) was the most numerous insect predatory species; population numbers ranged from 0 to 1 and 0.1 to 3.7 adults per 0.25 m(2) in 1999 and 2000, respectively. Partial life tables were constructed for E. fabae nymphs for two alfalfa-growing periods. Nymphs were grouped into three age intervals: first and second, third and fourth, and fifth instars. For the first alfalfa growing period examined, E. fabae nymphal mortality was 70% in 1999 and 49% in 2000. During the last growing period of each season (August-September), total nymphal mortality was relatively low (<25%). Adult E. fabae density ranged from 5.4 to 25.6 and 1.4-9.2 per 0.25 m(2) in 1999 and 2000, respectively. E. fabae population peaks were similar for each age interval in all growing periods. This study provides further information on the population dynamics of E. fabae and its relationship with select predatory species in Iowa alfalfa fields.
1999年和2000年6月至9月期间，在美国爱荷华州的苜蓿田中采集了豆叶蝉（Empoasca fabae Harris，半翅目：叶蝉科）的成虫和若虫，以及瓢虫科、花蝽科、姬蝽科、草蛉科和褐蛉科捕食性物种的成虫。使用回归分析研究了每个捕食性类群与豆叶蝉之间的关系。2000年，在所有采样时期都发现所有捕食者与豆叶蝉的存在呈正相关，并且很可能导致了豆叶蝉的死亡。暗黑赤眼蜂（Orius insidiosus (Say)，半翅目：花蝽科）是数量最多的捕食性昆虫物种；1999年和2000年每0.25平方米的成虫数量分别为0至1只和0.1至3.7只。为两个苜蓿生长时期的豆叶蝉若虫构建了部分生命表。若虫被分为三个龄期区间：一龄和二龄、三龄和四龄以及五龄。在所研究的第一个苜蓿生长时期，1999年豆叶蝉若虫死亡率为70%，2000年为49%。在每个季节的最后一个生长时期（8月至9月），若虫总死亡率相对较低（<25%）。1999年和2000年豆叶蝉成虫密度分别为每0.25平方米5.4至25.6只和1.4至9.2只。在所有生长时期，每个龄期区间的豆叶蝉种群峰值相似。本研究提供了关于爱荷华州苜蓿田中豆叶蝉种群动态及其与选定捕食性物种关系的更多信息。
