Diversity and phenology of epigeal Coleoptera assemblages in lettuce and tomato crops in Northern Buenos Aires province, Argentina

Abstract Epigeic coleopteran species are linked by complex trophic webs and implicated in several ecosystem services for agriculture. Although there are reports of ground-dwelling Coleopterans inhabiting main extensive agroecosystems, their assemblages in horticultural crops in Argentina have been little explored. We examined the community structure of epigeal Coleoptera assemblages of Curculionidae, Carabidae, Staphylinidae and Coccinellidae species, in lettuce and tomato crops located in Northern Buenos Aires province, over a 3-year sampling period (2010 to 2013) by using pit-fall traps. Crop species and cycles, and phytosanitary measures (conventional and organic farming), were main factors considered as influencing the insect species composition, abundance and seasonal occurrence in the assemblages. Seventy coleopteran species were identified. The curculionids Ceutorhynchini sp. and Phyrdenus muriceus (Germar), the carabid Scarithes anthracinus Dejean, the coccinelid Eriopis connexa (Germar) and the staphylinids Aleochara sp. and Aleochara obscurus Bernhauer are the most common species in lettuce and tomato crops in the region studied. Especially the carabids, staphylinids and E. connexa are known act as natural enemies of several pests in the agroecosystems studied. Coleopteran assemblages found in lettuce differed from those associated to tomato crops, being the cropping season the main factor that influenced the community structure.

摘要：表栖鞘翅目昆虫（epigeic coleopteran）依托复杂的食物网形成关联，并参与多项农业生态系统服务功能。尽管已有研究报道地表栖居鞘翅目昆虫栖息于主要粗放型农业生态系统，但阿根廷园艺作物生境中的该类群群落却鲜有研究。本研究于2010至2013年的3年采样周期内，采用地坑陷阱（pit-fall traps）法，对布宜诺斯艾利斯省北部地区生菜与番茄田中的象甲科（Curculionidae）、步甲科（Carabidae）、隐翅虫科（Staphylinidae）及瓢虫科（Coccinellidae）的表栖鞘翅目类群群落结构开展调查。研究将作物种类、生育周期及植物保护措施（常规耕作与有机耕作）列为影响该类群昆虫物种组成、种群丰度及季节发生动态的主要因素。本次调查共鉴定出70种鞘翅目昆虫，其中象甲科的Ceutorhynchini sp.与Phyrdenus muriceus (Germar)、步甲科的Scarithes anthracinus Dejean、瓢虫科的Eriopis connexa (Germar)以及隐翅虫科的Aleochara sp.和Aleochara obscurus Bernhauer为该研究区域生菜与番茄田中最为常见的物种类群。其中步甲科、隐翅虫科昆虫及E. connexa已被证实为本次研究涉及的农业生态系统中多种害虫的天敌。生菜田中的鞘翅目类群群落与番茄田中的类群群落存在显著分异，作物种植季为影响群落结构的核心因素。