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Archive data were analyzed concerning the reproduction of yellow steppe lemmings (Eolagurus luteus) in the Moscow Zoo. We used information referring to E. luteus pairs that existed during two periods: 2008–2013 (first colony) and 2017–2020 (second colony). All breeding partners in the first colony had at least one common ancestor (they originated from two females and one male) and thus were closely related to each other. The degree of relatedness of partners in the second colony was much lower. The founders of that colony were five females and five males that had originated from four pairs of unrelated individuals live-trapped in the Zaisan Basin. We conducted a comparative assessment of the life expectancy and reproductive parameters of adult yellow steppe lemmings and the survival of their offspring in two colonies, that is, we observed the effect of different degrees of inbreeding on such parameters. We also assessed the effect of female age on those values. We assigned the females to two age categories: younger (age of 15–59 days by the time of pair establishment) and older (age of 60–701 days) category. The results of statistical analysis confirmed the significant influence of the degree of relatedness of partners on the proportion of reproducing females, the number of litters per pair, the number of survived pups per pair, the mean number of pups per litter, the inter-birth interval, the female life expectancy, and the period of pair existence. The influence of female age on these parameters was insignificant. Our data provide evidence for a pronounced inbreeding depression in the first captive colony of the yellow steppe lemming. [ABSTRACT FROM AUTHOR]

Eolagurus luteus (yellow steppe lemming Eolagurus luteus Eversmann, 1840) is a keystone species in the desert steppe of northern Xinjiang, one of the regions most affected by global climate change. Their behavior of eating grassland vegetation and digging holes has resulted in the reduction of grassland vegetation and soil erosion in northern Xinjiang, which has seriously affected the ecological balance of the grassland in northern Xinjiang, and pathogens carried by E. luteus pose a great threat to human health. Climate change exacerbates the uncertainty of the outbreak of E. luteus. Predicting the suitable habitat area of this species under climate change scenarios will help farmers and herders deal with the potential threat of an E. luteus outbreak. In this study, 117 actual occurrence points of E. luteus were used, and 24 climate models, 6 soil factors and 3 topographic factors from the Coupled Model Intercomparison Project (CMIP6) were taken into account. Combining the MaxEnt model and the overlay analysis function of ArcGIS software, the potential geographic distribution of E. luteus in 2030 and 2050 for the green development path (SSP126), the intermediate development path (SSP245), the regional competition path (SSP370), and the high development path (SSP585) was predicted. The change trend of the suitable area and distribution pattern of E. luteus in Xinjiang under future climate conditions was analyzed, and the main environmental factors affecting the distribution of E. luteus are discussed. The results show that the average area under curve (AUC) and true skill statistics (TSS) of the MaxEnt model are 0.993 and 0.8816, respectively, indicating that the model has a good prediction effect. The analysis of environmental factors showed that the main environmental factors affecting the potential geographical distribution of E. luteus are average annual temperature, isotherm, average temperature in the wettest quarter, average temperature in the driest quarter, and precipitation variation coefficient. With the increase of radiation intensity and time, the suitable areas of E. luteus will continue to decrease. Especially in the 2050s under the SSP585 scenario, the middle and high suitable areas will decrease by 2.58 × 104 km2 and 1.52 × 104 km2, respectively. Although the potential habitat area of E. luteus is shrinking, the future threat of E. luteus to grassland ecological security and human health should not be underestimated due to ecological adaptation of the community and the frequent occurrence of extreme weather. Therefore, studying changes in the potential geographic distribution of E. luteus under climate change scenarios and developing appropriate monitoring programs are of great importance for grassland ecological security and human health. This study fills in the gaps in the study of the potential geographical distribution of E. luteus and provides methodological and literature support for the study of the potential geographical distribution of other rodents. [ABSTRACT FROM AUTHOR]

The study detected common ultrastructure of pigmented epithelium cells of Eolagurus luteus and other mammals and described its features characteristic of this species. Stages of interactions between the pigmented epithelium cells and external segments of retinal rod cells were studied. Migration of the external segments to the apical zone of a pigmented epithelium cell was observed. A pigmented epithelium cell was characterized by the presence of tubular endoplasmic reticulum and electron dense cytoplasm with processes directed to the retina. Multilamellar formations were detected, regarded as the initial stages of the myeloid body formation. These structures were characterized by periodicity of layers of ~4.2 and ~13.3 nm. The periodicity of layers in the formed myeloid body was ~23 nm. Interactions between the external segments and cells of pigmented epithelium, leading to formation of myeloid bodies, and the signifi cance of this process for normal work of retinal elements are discussed. [ABSTRACT FROM AUTHOR]