Data from: DNA metabarcoding diet analysis for species with parapatric versus sympatric distribution: a case study on subterranean rodents

Closely related sympatric species commonly develop different ecological strategies to avoid competition. Ctenomys minutus and C. flamarioni are subterranean rodents parapatrically distributed in the southern Brazilian coastal plain, showing a narrow sympatric zone. To gain understanding on food preferences and possible competition for food resources, we evaluated their diet composition performing DNA metabarcoding analyzes of 67 C. minutus and 100 C. flamarioni scat samples, collected along the species geographical ranges. Thirteen plant families, mainly represented by Poaceae, Araliaceae, Asteraceae and Fabaceae, were identified in the diet of C. minutus. For C. flamarioni, 10 families were recovered, with a predominance of Poaceae, Araliaceae and Asteraceae. A significant correlation between diet composition and geographical distance was detected in C. minutus, whereas the diet of C. flamarioni was quite homogeneous throughout its geographical distribution. No significant differences were observed between males and females of each species. However, differences in diet composition between species were evident according to multivariate analysis. Our results suggest some level of diet partitioning between C. flamarioni and C. minutus in the sympatric region. While the first species is more specialized on few plant items, the second showed a more varied and heterogeneous diet pattern among individuals. These differences might have been developed to avoid competition in the region of co-occurrence. Resource availability in the environment also seems to influence food choices. Our data indicate that C. minutus and C. flamarioni are generalist species, but that some preference for Poaceae, Asteraceae and Araliaceae families can be suggested for both rodents.

亲缘关系密切的同域分布物种通常会演化出不同的生态策略以规避种间竞争。栉鼠属的Ctenomys minutus与C. flamarioni为地下啮齿类，在巴西南部沿海平原呈邻域分布，二者存在狭窄的同域分布重叠区。为探明二者的食物偏好及潜在的食物资源竞争情况，我们沿两个物种的地理分布范围采集样本，通过DNA元条形码（DNA metabarcoding）技术分析了67份C. minutus与100份C. flamarioni的粪便样本，以评估其饮食组成。在C. minutus的饮食中，共鉴定出13个植物科，其中以禾本科（Poaceae）、五加科（Araliaceae）、菊科（Asteraceae）和豆科（Fabaceae）为主；而C. flamarioni的饮食中则鉴定出10个植物科，优势类群为禾本科、五加科与菊科。在C. minutus中，我们检测到饮食组成与地理距离之间存在显著相关性；而C. flamarioni的饮食组成在其整个地理分布范围内均较为均质。两个物种的雌雄个体间均未检测到显著的饮食差异，但通过多变量分析可见，两个物种间的饮食组成存在显著差异。本研究结果表明，在同域分布重叠区内，C. flamarioni与C. minutus之间存在一定程度的饮食生态位分化：其中C. flamarioni对少数植物类群的取食更为特化，而C. minutus的个体间饮食模式则更为多样且异质性更强。这些差异可能是为了在同域共存区域规避种间竞争而演化形成的。环境中的资源可获得性似乎也会对食物选择产生影响。本研究数据显示，C. minutus与C. flamarioni均为广食性物种，但二者均表现出对禾本科、菊科与五加科植物的取食偏好。