García-Robledo Carlos, Dierick Diego, Manser Konstantine
University of Connecticut, Department of Ecology and Evolutionary Biology, Storrs, CT 06269-3043.
Organization for Tropical Studies, La Selva Biological Station, Las Horquetas, Sarapiqui 41003, Heredia, Costa Rica.
Proc Natl Acad Sci U S A. 2025 Feb 4;122(5):e2419214122. doi: 10.1073/pnas.2419214122. Epub 2025 Jan 27.
Electric fields in terrestrial environments are used by caterpillars to detect their predators, as foraging cues by pollinators, and facilitate ballooning by spiders. This study shows that electric fields facilitate transportation and detection of hummingbirds in a guild of tropical phoretic mites. Hummingbird flower mites feed on nectar and pollen and complete their life cycle inside flowers. Mites colonize new flowers by hitching rides on hummingbird beaks. Flower mites emerge from hummingbird nostrils and disembark when the beak touches a flower. We tested whether flower mites are attracted to unmodulated electrostatic, or to modulated electric fields with amplitudes and frequencies in the range of those previously reported for hummingbirds. In a laboratory setup, mites were only attracted to modulated electric fields. In a choice experiment between positive or negative polarities, mites almost instantaneously chose positive charges, but only when the field was modulated. Mites display questing behavior, moving their front legs toward an electrostatic source. In experiments where we removed one or both front leg tarsi, we show that modulated fields are detected by sensory structures present in the front legs. We also show that flower mites use electrostatic attraction to bridge the gap to the beaks of hummingbirds, for a few milliseconds becoming one of the fastest terrestrial organisms. Our results confirm that hummingbird flower mites evolved an additional sensory modality - electroreception - to quickly detect hummingbirds and use electrostatics to facilitate transportation onto their hosts.
陆地环境中的电场被毛虫用来探测捕食者，被传粉者用作觅食线索，并帮助蜘蛛进行气球状飘浮。这项研究表明，电场有助于热带携播螨类群落中蜂鸟的迁移和探测。蜂鸟花螨以花蜜和花粉为食，并在花朵内完成其生命周期。螨类通过搭乘蜂鸟的喙来定殖新的花朵。花螨从蜂鸟的鼻孔中出来，当喙接触到花朵时便会下车。我们测试了花螨是否会被未调制的静电场吸引，或者是否会被幅度和频率在先前报道的蜂鸟范围内的调制电场吸引。在实验室设置中，螨类只被调制电场吸引。在正极性或负极性之间的选择实验中，螨类几乎瞬间选择了正电荷，但前提是电场被调制。螨类表现出探寻行为，将它们的前腿朝向静电源移动。在我们移除一条或两条前腿跗节的实验中，我们表明调制电场是由前腿中存在的感觉结构检测到的。我们还表明，花螨利用静电吸引来弥合与蜂鸟喙之间的间隙，在几毫秒内成为地球上最快的生物之一。我们的结果证实，蜂鸟花螨进化出了一种额外的感觉方式——电感受——以快速探测蜂鸟，并利用静电作用来促进它们迁移到宿主身上。
