Circadian feeding rhythm of green-belly stink bug in corn cultivation

Abstract: The objective of this work was to evaluate the circadian feeding rhythm of the green-belly stink bug (Dichelops melacanthus) on corn (Zea mays), and to correlate it with meteorological parameters. The experiments were conducted in corn fields in the first (summer) and second (fall) crop seasons, in the municipality of Chapecó, in the state of Santa Catarina, Brazil. Plants in the V3 and V5 stages were covered with cages and infested with adults of D. melacanthus. After 24 hours of acclimation, the number of insects feeding on the plant stem was counted every three hours (at 6:00, 9:00, 12:00, 15:00, 18:00, 21:00, and 0:00 h). At night, a red led flashlight was used to visualize the insects without interfering with their behavior. Meteorological parameters were monitored and correlated to the number of insects feeding on the plants. In the first and second crop seasons, the number of insects feeding on the corn stem differed among evaluation times, with peak in the afternoon, in the evening, and at night. Few insects were found feeding at 6:00 and 9:00 h. There was a positive correlation between air temperature and feeding in both seasons. In milder temperature regions, the preferred feeding time of D. melacanthus on corn is during the afternoon, evening, and night hours, which should be taken into account for a precise management of this insect.摘要：本研究旨在评估绿腹蝽（Dichelops melacanthus）在玉米（Zea mays）上的昼夜取食节律，并将其与气象参数进行关联分析。试验于巴西圣卡塔琳娜州沙佩科市的玉米田开展，覆盖第一季（夏季）与第二季（秋季）作物季。将处于V3、V5生育期的玉米植株用笼罩覆盖，并接种绿腹蝽成虫。经过24小时的适应期后，每3小时（即6:00、9:00、12:00、15:00、18:00、21:00及0:00）统计一次取食植株茎秆的昆虫数量。夜间采用红色LED手电筒观察昆虫，以避免干扰其行为。同时监测气象参数，并与植株上的取食昆虫数量进行相关性分析。结果显示，两个作物季中，玉米茎秆上的取食昆虫数量随评估时间存在显著差异，取食高峰出现在下午、傍晚及夜间；6:00与9:00时段的取食昆虫数量极少。两个季候中，气温与取食昆虫数量均呈正相关。在温度较为温和的区域，绿腹蝽在玉米上的偏好取食时段为下午、傍晚及夜间，该结论可为该害虫的精准防控提供参考依据。