Tachia guianensis (Gentianaceae), a Neotropical understory myrmecophyte, shelters ant colonies in its hollow trunks and branches (domatia). In turn, it is protected from defoliators and obtains nutrients from ant-produced wastes (myrmecotrophy). Aiming to verify if seasonality influences nitrogen assimilation via ant wastes using the stable isotope nitrogen-15, we first studied Tachia ’s phenology and its seasonal leaf production, and then the life cycle of its two more frequent guest ant species. We found that leaf production was much higher during the rainy than the dry season. Mature guest ant colonies produced sexuals regardless of the season and the net weight of the waste piles inside the domatia did not vary between seasons, so that the availability of nutrients to their host plant is steady year-long. By providing the two most frequent mutualistic guest ant species with food enriched with nitrogen-15, we showed that Tachia individuals assimilate more nitrogen from ant wastes during the rainy season, when the plant is physiologically active, compared to the dry season. Thus, one can deduce that the increase in nitrogen assimilation during the rainy season is determined by the increase in Tachia ’s physiological activity during that season. Information gathered through a bibliographic compilation confirms that none of the 15 ant species known to be associated with myrmecophytes for which the life cycle was studied is characterized by seasonal reproduction (which would result in fluctuating waste production). The same is true for 49.7% of 167 tropical ant species (seasonal production for the remaining species). We concluded that, in contrast to the non-seasonal ant colony reproductive cycle, Tachia ’s phenology determines the myrmecotrophic assimilation rate.

中文翻译：

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季节性影响新热带 myrmecophyte 由蚂蚁介导的养分获取（myrmecotrophy）

Tachia guianensis（龙胆科）是一种新热带林下植物，在其空心的树干和树枝（domatia）中为蚁群提供庇护。反过来，它免受落叶者的侵害，并从蚂蚁产生的废物中获取营养（myrmecotrophy）。为了验证季节性是否通过使用稳定同位素氮 15 的蚂蚁排泄物影响氮同化，我们首先研究了 Tachia 的物候学和它的季节性叶片生产，然后研究了它的两个更频繁的客蚁物种的生命周期。我们发现雨季的叶子产量比旱季高得多。成熟的客蚁群无论季节如何都会产生有性蚁群，而且蚁巢内垃圾堆的净重在不同季节之间没有变化，因此寄主植物的养分供应稳定一年。通过为两种最常见的互惠客蚁物种提供富含氮 15 的食物，我们表明与旱季相比，大甲个体在雨季从蚂蚁排泄物中吸收更多的氮，此时植物生理活跃。因此，可以推断出雨季氮同化的增加是由该季节大甲藻生理活动的增加决定的。通过书目汇编收集的信息证实，在研究生命周期的 15 种已知与食蚁兽相关的蚂蚁物种中，没有一种具有季节性繁殖的特征（这会导致废物产量波动）。167 种热带蚂蚁物种中的 49.7%（其余物种的季节性生产）也是如此。我们得出的结论是，