Favaro Riccardo, Garrido Paula Melisa, Bruno Daniele, Braglia Chiara, Alberoni Daniele, Baffoni Loredana, Tettamanti Gianluca, Porrini Martin Pablo, Di Gioia Diana, Angeli Sergio
Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen, Bolzano, Italy.
Instituto de Investigaciones en Producción Sanidad y Ambiente (IIPROSAM), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Centro Científico Tecnológico Mar del Plata, CONICET, Centro de Asociación Simple CIC PBA, Mar del Plata, Argentina; Centro de Investigaciones en Abejas Sociales, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.
Sci Total Environ. 2023 Dec 20;905:167277. doi: 10.1016/j.scitotenv.2023.167277. Epub 2023 Sep 21.
Fungicides, insecticides and herbicides are widely used in agriculture to counteract pathogens and pests. Several of these molecules are toxic to non-target organisms such as pollinators and their lethal dose can be lowered if applied as a mixture. They can cause large and unpredictable problems, spanning from behavioural changes to alterations in the gut. The present work aimed at understanding the synergistic effects on honeybees of a combined in-hive exposure to sub-lethal doses of the insecticide thiacloprid and the fungicide penconazole. A multidisciplinary approach was used: honeybee mortality upon exposure was initially tested in cage, and the colonies development monitored. Morphological and ultrastructural analyses via light and transmission electron microscopy were carried out on the gut of larvae and forager honeybees. Moreover, the main pollen foraging sources and the fungal gut microbiota were studied using Next Generation Sequencing; the gut core bacterial taxa were quantified via qPCR. The mortality test showed a negative effect on honeybee survival when exposed to agrochemicals and their mixture in cage but not confirmed at colony level. Microscopy analyses on the gut epithelium indicated no appreciable morphological changes in larvae, newly emerged and forager honeybees exposed in field to the agrochemicals. Nevertheless, the gut microbial profile showed a reduction of Bombilactobacillus and an increase of Lactobacillus and total fungi upon mixture application. Finally, we highlighted for the first time a significant honeybee diet change after pesticide exposure: penconazole, alone or in mixture, significantly altered the pollen foraging preference, with honeybees preferring Hedera pollen. Overall, our in-hive results showed no severe effects upon administration of sublethal doses of thiacloprid and penconazole but indicate a change in honeybees foraging preference. A possible explanation can be that the different nutritional profile of the pollen may offer better recovery chances to honeybees.
杀菌剂、杀虫剂和除草剂在农业中被广泛用于对抗病原体和害虫。其中一些分子对传粉者等非目标生物有毒，如果混合使用，其致死剂量可能会降低。它们会引发从行为改变到肠道变化等一系列重大且不可预测的问题。本研究旨在了解蜂巢内亚致死剂量的杀虫剂噻虫啉和杀菌剂戊唑醇联合暴露对蜜蜂的协同作用。我们采用了多学科方法：首先在笼子里测试暴露后蜜蜂的死亡率，并监测蜂群的发展情况。通过光学显微镜和透射电子显微镜对幼虫和觅食蜜蜂的肠道进行了形态学和超微结构分析。此外，利用下一代测序技术研究了主要的花粉觅食来源和肠道真菌微生物群；通过定量聚合酶链反应对肠道核心细菌类群进行了定量分析。死亡率测试表明，在笼子里接触农用化学品及其混合物时，对蜜蜂的存活有负面影响，但在蜂群层面未得到证实。对肠道上皮的显微镜分析表明，在田间接触农用化学品的幼虫、新羽化蜜蜂和觅食蜜蜂的肠道没有明显的形态变化。然而，肠道微生物谱显示，混合使用后，双歧乳杆菌减少，乳酸杆菌和总真菌增加。最后，我们首次强调了农药暴露后蜜蜂饮食的显著变化：戊唑醇单独使用或混合使用时，会显著改变花粉觅食偏好，蜜蜂更喜欢常春藤花粉。总体而言，我们在蜂巢内的研究结果表明，给予亚致死剂量的噻虫啉和戊唑醇不会产生严重影响，但表明蜜蜂的觅食偏好发生了变化。一个可能的解释是，花粉不同的营养成分可能为蜜蜂提供了更好的恢复机会。
