Myotis levis (yellowish myotis) is a small Neotropical insectivorous vespertilionid bat that provides valuable ecosystem services, such as control of disease vectors and agricultural pests. Aiming to describe the fluctuations of the reproductive organs throughout the year, the gonads and epididymis from 124 adult bats were histologically evaluated. These animals were captured in Santuário do Caraça, Minas Gerais, Brazil. After the initial screening, six bats per reproductive stage (in a representative month) had specific organs harvested for further investigation. The gonads, epididymis, accessory sex gland and brown adipose tissue were collected for biometric analyses. Furthermore, yellowish myotis testis was evaluated through histomorphometric and molecular assays, whereas blood samples were collected for hormonal analyses. The data were compared among the reproductive stages and correlated with rainfall distribution. As a result, we demonstrated that yellowish myotis presented a seasonal reproduction showing testis regression and rest, resembling the pattern exhibited by temperate-zone vespertilionid bats. During the Mature stage, after the peak of rainfall distribution, yellowish myotis testicles were fully developed for gamete production and maximum testosterone synthesis. These findings indicate a significant influence of this environmental factor on yellowish myotis reproduction. Following that, the accessory sex gland, brown adipose tissue and epididymis weights increased in the Regressed stage. The epididymis sperm storage occurred for at least 8 months and was observed in the Regressed, Rest and beginning of the Maturing stage. This reproductive fluctuation is interesting because the reactivation of the gonads coincided with the least amount of sperm in the epididymis.

中文翻译：

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在环境背景下对新热带精子储存 vespertilionid 蝙蝠（Myotis levis）的雄性生殖形态功能评估

Myotis levis（黄色 myotis）是一种小型的新热带食虫 vespertilionid 蝙蝠，可提供宝贵的生态系统服务，例如控制病媒和农业害虫。为了描述全年生殖器官的波动，对124只成年蝙蝠的性腺和附睾进行了组织学评估。这些动物是在巴西米纳斯吉拉斯州的 Santuário do Caraça 捕获的。在初步筛选后，每个繁殖阶段（代表性月份）的六只蝙蝠都收获了特定器官以供进一步调查。收集性腺、附睾、副性腺和棕色脂肪组织用于生物特征分析。此外，黄色肌炎睾丸通过组织形态计量学和分子分析进行评估，同时收集血液样本用于激素分析。数据在繁殖阶段之间进行比较，并与降雨分布相关。结果，我们证明黄色肌炎呈现出季节性繁殖，显示睾丸退化和休息，类似于温带 vespertilionid 蝙蝠所表现出的模式。在成熟期，降雨分布高峰过后，黄色肌炎睾丸完全发育，用于配子产生和最大的睾酮合成。这些发现表明这种环境因素对黄色肌炎的繁殖有显着影响。之后，在回归阶段，副性腺、棕色脂肪组织和附睾的重量增加。附睾精子储存发生至少8个月，并在退化、静止和成熟期开始时观察到。