Disease management in two sympatric Apterostigma fungus-growing ants for control the parasitic fungus Escovopsis

Antagonistic interactions between host and parasites are often embedded in
networks of interacting species, in which hosts may be attacked by
competing parasites species, and parasites may infect more than one host
species. To better understand the evolution of host defenses and parasite
counter defenses in the context of a multihost, multiparasite system, we
studied two sympatric species, of congeneric fungus-growing ants (Attini)
species and their symbiotic fungal cultivars, which are attacked by
multiple morphotypes of parasitic fungi in the genus, Escovopsis. To
assess whether closely-related ant species and their cultured fungi are
evolving defenses against the same or different parasitic strains, we
characterized Escovopsis that were isolated from colonies of sympatric
Apterostigma dentigerum and A. pilosum. We assessed in vitro and in vivo
interactions of these parasites with their hosts. While the ant cultivars
are parasitized by similar Escovopsis spp., the frequency of infection by
these pathogens differs between the two ant species. The ability of the
host fungi to suppress Escovopsis growth, as well as ant defensive
responses towards the parasites, differ depending on the parasite strain
and on the host ant species.

宿主与寄生生物之间的拮抗互作往往嵌入于物种互作网络之中：在此类网络中，宿主可能受到多种竞争型寄生生物物种的侵染，而寄生生物也可感染不止一种宿主物种。为更深入阐释多宿主-多寄生生物系统框架下宿主防御与寄生生物反防御的演化机制，我们选取了两种同域分布的近缘菌培蚁（Attini，菌培蚁族）物种及其共生真菌栽培类群作为研究对象，此类宿主会受到埃斯科沃氏霉属（Escovopsis）下多种形态型寄生真菌的侵染。为探究近缘蚁类及其栽培真菌是否演化出针对同一或不同寄生菌株的防御机制，我们对从同域分布的钝齿无柄蚁（Apterostigma dentigerum）与柔毛无柄蚁（A. pilosum）蚁巢中分离得到的埃斯科沃氏霉进行了特征分析。我们评估了这些寄生生物与其宿主的体外（in vitro）与体内（in vivo）互作情况。尽管两种蚁类的栽培真菌均被相似的埃斯科沃氏霉类群（Escovopsis spp.）寄生，但此类病原体的侵染频率在两种蚁类之间存在显著差异。宿主真菌抑制埃斯科沃氏霉生长的能力，以及蚁类针对寄生生物的防御反应，均因寄生菌株与宿主蚁类物种的不同而存在差异。