Investigating the impacts of field-realistic exposure to a neonicotinoid pesticide on bumblebee foraging, homing ability and colony growth

The ability to forage and return home is essential to the success of bees as both foragers and pollinators. Pesticide exposure may cause behavioural changes that interfere with these processes, with consequences for colony persistence and delivery of pollination services. We investigated the impact of chronic exposure (5–43 days) to field-realistic levels of a neonicotinoid insecticide (2·4 ppb thiamethoxam) on foraging ability, homing success and colony size using radio frequency identification (RFID) technology in free-flying bumblebee colonies. Individual foragers from pesticide-exposed colonies carried out longer foraging bouts than untreated controls (68 vs. 55 min). Pesticide-exposed bees also brought back pollen less frequently than controls indicating reduced foraging performance. A higher proportion of bees from pesticide-exposed colonies returned when released 1 km from their nests; this is potentially related to increased orientation experience during longer foraging bouts...觅食与归巢能力，是蜜蜂兼具觅食者与授粉者双重功能并维系种群存续的核心关键。农药暴露可引发蜜蜂行为改变，干扰上述两项过程，进而对蜂群存续与授粉服务供给产生不利影响。本研究借助射频识别（Radio Frequency Identification, RFID）技术，针对自由飞行的熊蜂蜂群，探究了新烟碱类杀虫剂（Neonicotinoid Insecticide）噻虫嗪（Thiamethoxam）在田间实际暴露浓度为2.4 ppb的情况下，为期5至43天的慢性暴露对其觅食能力、归巢成功率及蜂群规模的影响。农药暴露组蜂群的单个觅食工蜂，其单次觅食时长较未处理对照组更长（68分钟 vs 55分钟）。此外，农药暴露组蜜蜂带回花粉的频率同样低于对照组，提示其觅食性能有所下降。在距蜂巢1公里处释放后，农药暴露组蜂群的蜜蜂归巢比例更高；这一现象或与更长觅食时长所积累的定向经验提升有关……