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）是亚马逊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，但目前尚无针对该区域内该物种种群行为特征的相关研究数据。鉴于亚马逊地区是咖啡果小蠹的适宜滋生环境，本研究旨在对亚马孙州南部乌马伊塔市的三种种植模式下的该昆虫种群展开调查：i) 原生林内种植咖啡（CNF），ii) 与古布阿苏果、阿萨伊果（均为巴西本土水果）间作的咖啡（CCA），以及iii) 单一栽培咖啡（MC）。同时，本研究结合植株的气候参数与物候参数，分析其与该昆虫种群动态的关联。
为此，研究团队于2018年7月至2019年6月期间，在每个样地布设10个诱饵诱捕器，按月采集咖啡果小蠹的种群样本。结果显示，相较于其他间作样地，单一栽培样地的昆虫种群丰度在咖啡花期达到峰值。三种评估样地中，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。降雨量的增加与昆虫种群数量的下降同步发生，这与花期结束（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）的时间节点完全吻合。原生林内种植咖啡样地的昆虫丰度最低，仅为83（CNF），这表明当地的生物多样性可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。咖啡农林业系统更有助于将该害虫的种群维持在较低水平。