Evolutionary Biology, Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
Curr Biol. 2013 Jan 7;23(1):76-82. doi: 10.1016/j.cub.2012.11.034. Epub 2012 Dec 13.
To fight infectious diseases, host immune defenses are employed at multiple levels. Sanitary behavior, such as pathogen avoidance and removal, acts as a first line of defense to prevent infection before activation of the physiological immune system. Insect societies have evolved a wide range of collective hygiene measures and intensive health care toward pathogen-exposed group members. One of the most common behaviors is allogrooming, in which nestmates remove infectious particles from the body surfaces of exposed individuals. Here we show that, in invasive garden ants, grooming of fungus-exposed brood is effective beyond the sheer mechanical removal of fungal conidiospores; it also includes chemical disinfection through the application of poison produced by the ants themselves. Formic acid is the main active component of the poison. It inhibits fungal growth of conidiospores remaining on the brood surface after grooming and also those collected in the mouth of the grooming ant. This dual function is achieved by uptake of the poison droplet into the mouth through acidopore self-grooming and subsequent application onto the infectious brood via brood grooming. This extraordinary behavior extends the current understanding of grooming and the establishment of social immunity in insect societies.
为了对抗传染病，宿主的免疫防御系统在多个层面发挥作用。卫生行为，如病原体的避免和清除，作为第一道防线，可以在生理免疫系统激活之前防止感染。昆虫社会已经进化出了广泛的集体卫生措施和对暴露于病原体的群体成员的密集保健措施。其中最常见的行为之一是同种梳理，在这种行为中，巢友会从暴露个体的身体表面清除传染性颗粒。在这里，我们表明，在入侵花园蚂蚁中，对真菌暴露的幼虫进行梳理不仅可以通过机械方式清除真菌分生孢子，而且还可以通过应用蚂蚁自身产生的毒素进行化学消毒。甲酸是这种毒素的主要活性成分。它可以抑制梳理后留在幼虫表面的分生孢子的真菌生长，也可以抑制从梳理蚂蚁口中收集到的分生孢子的真菌生长。这种双重功能是通过酸孔自我梳理将毒滴吸入口腔，然后通过幼虫梳理将其应用于感染性幼虫来实现的。这种非凡的行为扩展了我们对昆虫社会中梳理行为和社会免疫建立的理解。
