Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil.
Laboratory of Pathology and Microbial Control, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil.
Chemosphere. 2022 Jan;287(Pt 2):132147. doi: 10.1016/j.chemosphere.2021.132147. Epub 2021 Sep 2.
Pathogenic fungi have been used worldwide to control crop pests and are assumed to pose negligible threats to the survival of pollinators. Although eusocial stingless bees provide essential pollination services and might be exposed to these biopesticides in tropical agroecosystems, there is a substantial knowledge gap regarding the side effects of fungal pathogens on behavioural traits that are crucial for colony functioning, such as guarding behaviour. Here, we evaluated the effect of Beauveria bassiana on the sophisticated kin recognition system of Tetragonisca angustula, a bee with morphologically specialized entrance guards. By combining behavioural assays and chemical analyses, we show that guards detect pathogen-exposed nestmates, preventing them from accessing nests. Furthermore, cuticular profiles of pathogen-exposed foragers contained significantly lower amounts of linear alkanes than the unexposed ones. Such chemical cues associated with fungal conidia may potentially trigger aggression towards pathogen-exposed bees, preventing pathogen spread into and among colonies. This is the first demonstration that this highly abundant native bee seems to respond in a much more adaptive way to a potentially infectious threat, outweighing the costs of losing foraging workforce when reducing the chances of fungal pathogen outbreaks within their colonies, than honeybees do.
病原真菌已被广泛用于防治作物害虫，人们认为其对传粉媒介的生存不会造成重大威胁。尽管共生无刺蜜蜂为热带农业生态系统提供了重要的授粉服务，并且可能会接触到这些生物农药，但对于真菌病原体对行为特征的副作用，我们的了解还存在很大的空白，而这些行为特征对于群体功能至关重要，例如防御行为。在这里，我们评估了球孢白僵菌对 Tetragonisca angustula 复杂亲缘识别系统的影响，Tetragonisca angustula 是一种具有形态特化入口守卫的蜜蜂。通过结合行为分析和化学分析，我们发现守卫可以检测到暴露于病原体的巢内同伴，并阻止它们进入巢穴。此外，暴露于病原体的觅食者的表皮特征图谱中线性烷烃的含量明显低于未暴露的觅食者。与真菌分生孢子相关的这些化学线索可能会引发对暴露于病原体的蜜蜂的攻击，从而防止病原体在群体内部和之间传播。这是第一个证明这种高度丰富的本地蜜蜂似乎对潜在传染性威胁做出更适应反应的例子，它超过了因失去觅食劳动力而造成的损失，从而降低了其群体中真菌病原体爆发的可能性，这比蜜蜂的反应更有效。
