Photoperiodism has been shown to be an important synchronizer of seasonal reproduction in many rodent species in the wild; it is a reliable cue as in the southern hemisphere it coincides with the onset of rainfall and hence the availability of food resources for maximal reproductive success. The photoperiodic effect on the reproductive status of the Namibian gerbil, Gerbilliscus cf. leucogaster from central Namibia was investigated. Twenty adult males were exposed to a long-day length (16L:8D), while further 20 adult males were subjected to a short-day length (SD:8L:16D); all for a period of 3 months. Testicular mass per gram body mass, testicular volume and seminiferous tubule diameters were used to assess the effect of photoperiod on gonadal development. Body mass did not significantly differ between the two photoperiodic regimes. The testicular mass per gram of body mass was significantly heavier for the males maintained on a long photoperiod compared to those on a short photoperiod. Similarly, testicular volume and seminiferous tubule diameter were greater in males maintained on a long-day cycle compared to those on the short-day cycle. These findings suggest that G. cf. leucogaster is photoresponsive to day length changes. Photoperiodic changes in the semi-arid habitats can be used to herald the onset of reproduction as it often acts in concert with other proximate cues in desert rodents, but is a constant environmental cue that does not change from year to year, unlike rainfall patterns.

中文翻译：

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对纳米比亚沙鼠的雄性腺的光周期作用，比照。来自纳米比亚中部的leucogaster

在许多野生啮齿动物中，光周期作用已被证明是季节性繁殖的重要同步剂。这是一个可靠的提示，因为在南半球，它恰逢降雨的开始，因此也有获得最大繁殖成功所需的粮食资源。在纳米比亚沙鼠的繁殖状况的影响光周期，Gerbilliscus参见 白带对来自纳米比亚中部的人进行了调查。20名成年男性暴露于长日照中（16L：8D），另外20名成年男性暴露于短日照中（SD：8L：16D）；全部为期3个月。每克体重的睾丸质量，睾丸体积和生精小管直径用于评估光周期对性腺发育的影响。两种光周期方案之间的体重没有显着差异。与在短光周期的男性相比，长光周期的男性的每克体重的睾丸质量显着增加。同样，长日周期维持的雄性睾丸体积和生精小管直径比短日周期维持的雄性更大。这些发现表明，G。白带对日长变化有光响应。半干旱生境中的光周期变化可以预示繁殖的开始，因为它经常与沙漠鼠类中的其他邻近线索协同作用，但它是一个恒定的环境线索，与降雨模式不同，它每年都不会改变。