All known fungus-growing ants (tribe Attini) are obligately symbiotic with their cultivated fungi. The fungal cultivars of “lower” attine ants are facultative symbionts, capable of living apart from ants, whereas the fungal cultivars of “higher” attine ants, including leaf-cutting genera Atta and Acromyrmex, are highly specialized, obligate symbionts. Since higher attine ants and fungi are derived from lower attine ants and fungi, understanding the evolutionary transition from lower to higher attine agriculture requires understanding the historical sequence of change in both ants and fungi. The biology of the poorly known ant genus Mycetagroicus is of special interest in this regard because it occupies a phylogenetic position intermediate between lower and higher ant agriculture. Here, based on the excavations of four nests in Pará, Brazil, we report the first biological data for the recently described species Mycetagroicus inflatus, including the first descriptions of Mycetagroicus males and larvae. Like M. cerradensis, the only other species in the genus for which nesting biology is known, the garden chambers of M.inflatus are unusually deep and the garden is most likely relocated vertically in rainy and dry seasons. Due to the proximity of nests to the Araguaia River, it is likely that even the uppermost chambers and nest entrances of M. inflatus are submerged during the rainy season. Most remarkably, all three examined colonies of M. inflatus cultivate the same fungal species as their congener, M. cerradensis, over 1,000 km away, raising the possibility of long-term symbiont fidelity spanning speciation events within the genus.

中文翻译：

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巢建筑、真菌花园、真菌生长蚂蚁 Mycetagroicus inflatus Brandão 和 Mayhé-Nunes 的蚁后、雄性和幼虫

所有已知的真菌生长蚂蚁（部落 Attini）都必然与其栽培的真菌共生。“低等”蚂蚁的真菌品种是兼性共生体，能够与蚂蚁分开生活，而“高等”蚂蚁的真菌品种，包括切叶属 Atta 和 Acromyrmex，是高度特化的专性共生体。由于高等蚂蚁和真菌源自低等蚂蚁和真菌，因此了解从低等到高等阿廷农业的进化转变需要了解蚂蚁和真菌的历史变化顺序。鲜为人知的蚂蚁属 Mycetagroicus 的生物学在这方面特别令人感兴趣，因为它占据了低级和高级蚂蚁农业之间的系统发育位置。在这里，基于在巴西帕拉的四个巢穴的挖掘，我们报告了最近描述的 Mycetagroicus inflatus 物种的第一个生物学数据，包括对 Mycetagroicus 雄性和幼虫的首次描述。与该属中唯一已知筑巢生物学的其他物种 M. cerradensis 一样，M.inflatus 的花园室异常深，花园很可能在雨季和旱季垂直迁移。由于巢穴靠近阿拉瓜亚河，在雨季，即使是 M. inflatus 最上面的房间和巢穴入口也很可能被淹没。最值得注意的是，所有三个被检查的 M. inflatus 菌落都与它们的同源物 M. cerradensis 在 1,000 公里之外培育了相同的真菌物种，这增加了该属内跨越物种形成事件的长期共生体保真度的可能性。