Walker Faith M, Taylor Andrea C, Sunnucks Paul
Australian Centre for Biodiversity Analysis, Conservation and Management, School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
Mol Ecol. 2007 Jan;16(1):199-208. doi: 10.1111/j.1365-294X.2006.03131.x.
Spatiotemporal distributions of key resources are hypothesized to underpin sociobiological patterns. Burrow availability and quality is of paramount importance to fossorial animals. The southern hairy-nosed wombat (Lasiorhinus latifrons) burrows in both hard and friable soils. Theoretical and empirical studies suggest that the harder substrate should promote closer geographical clustering of burrows than in softer soils. Clustered burrows are expected to be associated with larger group sizes. If sociality is driven by constraint rather than advantage, patterns of spatial and temporal distribution of animals within and among groups may show indications of avoidance or even antagonism, and 'making the best of a bad job' via positive kin associations to offset the disadvantages of high-density living. To test these ideas, we compared warren relatedness and social structure of L. latifrons on friable soils (Nullarbor Plain) and hard calcrete (Brookfield Conservation Park, BCP). Individuals were sampled by noninvasive collection of hairs for genotyping to identify individuals and to estimate their space-use and associative behaviour with respect to relatedness. Burrows in calcrete were indeed more clumped, and warren and group size larger. Differences in spatiotemporal organization and relatedness structure between sites were in the expected direction: (i) Nullarbor males associated and shared warrens less than at BCP; and (ii) Nullarbor spatial relatedness patterning data were not consistent with proposed female breeding dispersal, in contrast to those at BCP. Under Nullarbor (low density) conditions, cooperation or tolerance between males may be less advantageous, and accessing or digging burrows should be less of a constraint for juvenile females.
关键资源的时空分布被认为是社会生物学模式的基础。洞穴的可用性和质量对穴居动物至关重要。南方毛鼻袋熊（Lasiorhinus latifrons）会在坚硬和易碎的土壤中挖掘洞穴。理论和实证研究表明，较硬的基质相比较软的土壤应会促使洞穴在地理上更紧密地聚集。预计聚集的洞穴会与更大的群体规模相关联。如果社会性是由限制而非优势驱动的，那么群体内部和群体之间动物的空间和时间分布模式可能会显示出回避甚至对抗的迹象，并且会通过积极的亲属关联来“在不利情况下尽力而为”，以抵消高密度生活的不利之处。为了验证这些观点，我们比较了南方毛鼻袋熊在易碎土壤（纳拉伯平原）和坚硬钙质结砾岩（布鲁克菲尔德自然保护公园，BCP）上的洞穴亲缘关系和社会结构。通过非侵入性采集毛发进行基因分型来对个体进行采样，以识别个体，并估计它们在亲缘关系方面的空间利用和关联行为。钙质结砾岩中的洞穴确实更密集，洞穴群和群体规模也更大。不同地点之间时空组织和亲缘关系结构的差异符合预期方向：（i）纳拉伯平原的雄性之间关联和共享洞穴的情况比在BCP少；（ii）与BCP的情况相反，纳拉伯平原的空间亲缘关系模式数据与所提出的雌性繁殖扩散不一致。在纳拉伯平原（低密度）条件下，雄性之间的合作或容忍可能不太有利，而且对于幼年雌性来说，进入或挖掘洞穴应该不太受限制。
