Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
J Evol Biol. 2011 May;24(5):954-64. doi: 10.1111/j.1420-9101.2011.02230.x. Epub 2011 Feb 10.
Parasites can cause extensive damage to animal societies in which many related individuals frequently interact. In response, social animals have evolved diverse individual and collective defences. Here, we measured the expression and efficiency of self-grooming and allo-grooming when workers of the ant Formica selysi were contaminated with spores of the fungal entomopathogen Metarhizium anisopliae. The amount of self-grooming increased in the presence of fungal spores, which shows that the ants are able to detect the risk of infection. In contrast, the amount of allo-grooming did not depend on fungal contamination. Workers groomed all nestmate workers that were re-introduced into their groups. The amount of allo-grooming towards noncontaminated individuals was higher when the group had been previously exposed to the pathogen. Allo-grooming decreased the number of fungal spores on the surface of contaminated workers, but did not prevent infection in the conditions tested (high dose of spores and late allo-grooming). The rate of disease transmission to groomers and other nestmates was extremely low. The systematic allo-grooming of all individuals returning to the colony, be they contaminated or not, is probably a simple but robust prophylactic defence preventing the spread of fungal diseases in insect societies.
寄生虫会对许多相关个体经常相互作用的动物社会造成广泛的破坏。作为回应，社会性动物已经进化出了多种个体和集体防御机制。在这里，我们测量了当蚂蚁 Formica selysi 的工蚁被真菌昆虫病原体绿僵菌的孢子污染时，自我梳理和同种梳理的表达和效率。在真菌孢子存在的情况下，自我梳理的数量增加，这表明蚂蚁能够检测到感染的风险。相比之下，同种梳理的数量并不取决于真菌的污染。工蚁会梳理所有重新引入群体的同种工蚁。当群体以前接触过病原体时，对未受污染个体的同种梳理量更高。同种梳理减少了受污染工蚁表面的真菌孢子数量，但在测试的条件下（孢子高剂量和同种梳理时间晚）并没有阻止感染。疾病传播给梳理者和其他巢内同伴的速度非常低。系统地梳理所有返回群体的个体，无论它们是否受到污染，可能是一种简单但强大的预防措施，防止真菌病在昆虫社会中传播。
