POPULATION DYNAMICS OF Hypothenemus hampei (Coleoptera: Scolytidae) IN AGROFORESTRY AND MONOCULTURE SYSTEMS OF CONILON COFFEE IN THE SOUTHERN PORTION OF THE STATE OF AMAZONAS, BRAZIL

ABSTRACT Hypothenemus hampei is the main coffee pest in the Amazon and worldwide. Although coffee cultivation exists in the State of Amazonas, there is no information regarding the behavior of this species population in this region of Brazil. Since the Amazon region is a favorable environment for H. hampei, the present study aimed to investigate this insect population in the following cultivation systems implanted in the municipality of Humaitá, Southern Amazonas: i) coffee in native forest (CNF), ii) coffee intercropped with cupuaçu and açaí (native Brazilian fruits) (CCA) and iii) coffee in monoculture (MC). Also, the climatic and phenological parameters of the plant were used in relation with the population dynamics of the insect. For that, ten baited traps were installed in each field for the monthly sampling of the H. hampei population from July/2018 to June/2019. The highest population abundance of the insect was observed during the coffee flowering season, mainly in monoculture crops, when compared to the other intercropped fields. The total mean value of the insect population observed in the three environments evaluated was highest in August/2018, with a recorded value of 1749. The increase in rainfall indexes occurred simultaneously with a decrease in the insect population; this coincides with the end of the flowering season (October/2018, 161.8 mm) and the beginning of grain formation (November/2018, 234.8 mm). The lowest abundance of the insect observed in the coffee fields in native forest, with an abundance of 83 (CNF), indicates that the local biodiversity disfavors the population size of the pest in the environment. These results suggest that phenological phases of conilon coffee and the influence of climatic conditions can result in changes in the population dynamics of the H. hampei. Coffee agroforestry systems are more promising to maintain this population at low levels.摘要 咖啡果小蠹（Hypothenemus hampei）是亚马孙地区乃至全球范围内的主要咖啡害虫。尽管巴西亚马孙州境内已有咖啡种植，但针对该区域内该物种的种群行为特征，目前尚无公开研究数据。鉴于亚马孙地区为咖啡果小蠹的适宜生存环境，本研究旨在对亚马孙州南部乌马提市（Humaitá）的三种咖啡种植模式下的咖啡果小蠹种群展开调查：i) 原生林套种咖啡（CNF），ii) 与库普阿苏树（cupuaçu）及阿萨伊棕榈（açaí，巴西本土水果树种）间作的咖啡种植园（CCA），iii) 咖啡单作农田（MC）。此外，本研究还结合植株物候参数与气候因子，分析了该昆虫的种群动态变化。为开展研究，本研究于2018年7月至2019年6月期间，在每个样地布设10个诱捕器，按月采集咖啡果小蠹种群样本。观测结果显示，该害虫的种群丰度峰值出现在咖啡花期，其中单作农田的种群数量显著高于其他间作模式样地。三种评估种植环境下观测到的昆虫种群总平均值以2018年8月为最高，记录值为1749。降雨量的上升与昆虫种群数量的下降同步发生，这一时间节点与咖啡花期结束（2018年10月，降雨量161.8 mm）及籽粒形成期启动（2018年11月，降雨量234.8 mm）相吻合。原生林套种咖啡样地的害虫种群丰度最低，仅为83（CNF），表明当地的生物多样性会抑制该害虫的种群规模。本研究结果表明，科尼隆咖啡（conilon coffee）的物候阶段与气候条件的共同作用，可改变咖啡果小蠹的种群动态，而咖啡农林业系统更有助于将该害虫种群维持在较低水平。