Abstract：
Although the order Rodentia does not present a high risk of extinction compared to mammals as a whole, several families demonstrate high levels of threat and/or data deficiency, therefore highlighting the need for targeted research and the application of ecological and reproductive data to the development of conservation actions. The order Rodentia, the largest among mammals, includes 9 families, and the family Cricetidae is the most diverse of the Brazilian rodents. In Brazil, 12 of the 16 genera of Oecomys are found. Oecomys bicolor is known in Brazil as the \'arboreal rat\' and is, found in dry, deciduous and tropical forests. The mean body weight of Oecomys bicolor was 35.8 g and the gonadal, tubular and epithelial somatic indexes were, 0.53%, 0.47% and 0.37%, respectively. Seminiferous tubules volume density was 89.72% and the mitotic and meiotic indexes corresponded to 8.59 and 2.45 cells, respectively, and the yield of spermatogenesis was 23.83 cells. The intertubular compartment represented 10.28% of the testis parenchyma and around 5% of the interstitial space was occupied by Leydig cells, whose number per gram of testis was 11.10 × 107 cells. By evaluating the biometric and histomorphometric characteristics of the testis, there is evidence that this species has a high investment in reproduction. Due to the high contribution of the seminiferous epithelium and the intertubular compartment in this species, compared to the others of the same family, it is possible to infer that the species Oecomys bicolor has a promiscuous reproductive behaviour.
摘要：
尽管与整个哺乳动物相比，啮齿动物的灭绝风险不高，几个家庭表现出高度的威胁和/或数据不足，因此，强调需要有针对性的研究以及将生态和生殖数据应用于保护行动的发展。该命令罗塔多,哺乳动物中最大的，包括9个家庭，Cricetidae家族是巴西啮齿动物中最多样化的。在巴西,发现了16属中的12个。oecomysbicolor在巴西被称为“树栖大鼠”，在干燥中发现，落叶和热带森林。双色Oecomys的平均体重为35.8g，性腺，管状和上皮体细胞指数为，0.53%，0.47%和0.37%，分别。生精小管体积密度为89.72％，有丝分裂和减数分裂指数对应于8.59和2.45细胞。分别,精子发生细胞产量为23.83个。管间隔室占睾丸实质的10.28％，间质空间的约5％被Leydig细胞占据。每克睾丸数量为11.10×107个细胞。通过评估睾丸的生物特征和组织形态特征，有证据表明，这个物种在繁殖方面有很高的投资。由于该物种中生精上皮和管间隔室的贡献很大，与同一个家庭的其他人相比，可以推断，双色oecomys物种具有混杂的生殖行为。
