Negative effects of neonicotinoids on male honeybee survival, behaviour and physiology in the field

1. Agricultural chemicals such as neonicotinoid insecticides are believed
to be one important factor responsible for the recent reduction in health
of pollinating insects like the western honeybee (Apis mellifera).
However, effects of neonicotinoids on male (drone) honeybee health remain
severely understudied. 2. We examined for the first time the
multi-dimensional effects of field-realistic concentrations of two common
neonicotinoid insecticides (thiamethoxam and clothianidin) on drone
honeybee survival, behaviour, and physiology using individuals reared and
maintained as adults in the field. 3. Our data showed that neonicotinoids
reduced honeybee drone survival by 51%, increased drifting behaviour to
non-maternal colonies by 100%, delayed flight activities by three days,
and reduced number of living sperm by 28%. However, they did not influence
the sperm concentration produced by the drones, the strength of the
drone’s maternal colonies, or the total number of drones produced by those
colonies. 4. ‘Policy implications’: Our study demonstrated that
neonicotinoids can elicit a diverse array of lethal (survival) and
sub-lethal (behaviour, reproductive physiology) effects on male honeybees
(Apis mellifera) in the field. These findings should be considered by
policy makers looking to adopt and implement science-based, holistic risk
assessments to more comprehensively assess effects of chemicals on
important ecosystem service providing insects like the honeybee. To date,
risk assessment schemes do not specifically address potential effects on
male bees.

1. 新烟碱类杀虫剂（neonicotinoid insecticides）等农用化学品被认为是近期传粉昆虫（如西方蜜蜂（Apis mellifera））健康水平下降的重要诱因之一。然而，新烟碱类杀虫剂对雄蜂（drone）健康的影响迄今仍未得到充分研究。
2. 本研究首次针对两种常见新烟碱类杀虫剂——噻虫嗪（thiamethoxam）与噻虫胺（clothianidin）的田间真实浓度，通过野外繁育并饲养至成虫的雄蜂个体，探究其对蜜蜂雄蜂存活、行为及生理的多维度影响。
3. 研究数据显示，新烟碱类杀虫剂可使蜜蜂雄蜂的存活率降低51%，使其向非亲代蜂群的迷巢行为增加100%，延迟其飞行活动达3天，并使存活精子数量减少28%。但该类杀虫剂并不会影响雄蜂的精子浓度、雄蜂亲代蜂群的群势，亦不会影响这些蜂群所繁育的雄蜂总数量。
4. 政策启示：本研究证实，在野外环境中，新烟碱类杀虫剂可对西方蜜蜂（Apis mellifera）雄蜂产生一系列多样化的致死（存活相关）与亚致死（行为、生殖生理）效应。对于希望采用并实施基于科学的整体性风险评估体系，以更全面评估化学品对蜜蜂这类重要生态系统服务提供者的影响的政策制定者而言，本研究结果应予以重视。截至目前，现有的风险评估体系并未专门针对雄蜂的潜在受影响情况进行考量。