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Burrowing organisms augment the availability of important resources for other species. The gopher tortoise (Gopherus polyphemus) is a keystone excavator in open canopy pine-forest ecosystems in the southeastern United States because its burrows are utilized by over 360 species. Across its range, the gopher tortoise is declining, which is thought to negatively affect burrow-associated species and ecosystem functionality. The nine-banded armadillo (Dasypus novemcinctus) is another burrower of similar size that has become syntopically distributed with the gopher tortoise as a result of range expansion. Recent studies have documented vertebrates utilizing armadillo burrows, linking armadillo burrowing to support of local biodiversity similar to the gopher tortoise. We sought to determine the potential for ecological redundancy between gopher tortoises and armadillos and test quantitatively for differences in associate events at their burrows in a mixed-pine–hardwood forest where they co-occur. Using motion activated game cameras to monitor burrows, we compared metrics of vertebrate occurrence between armadillo and tortoise burrows and examined the effects of environmental variables using a series of regression models. A total of 40 vertebrate taxa were observed visiting burrows between October 2019 and December 2020. Richness, diversity, and community composition were not significantly different between the two burrow types. However, associate event counts were significantly greater at tortoise burrows. Burrow and microhabitat variables had varying effects on associate event counts, with consistently positive effects for tortoise burrows, active burrows, and increased richness of tree species, while negative effects were detected for increased canopy cover as well as increased proportions of hardwood trees. Our study provides a framework for testing redundancy of function between syntopic ecosystem engineers, adds to the growing body of work on the ecological significance of armadillo range expansion, and identifies aspects of the habitat that cause fluctuations in the importance of burrows for associate species. [ABSTRACT FROM AUTHOR]

The nine-banded armadillo (Dasypus novemcinctus) is unique among mammals because females produce litters of genetically identical quadruplets via monozygotic polyembryony. This unusual form of reproduction could have profound impacts on the spatial genetic structure of populations of armadillos, but at present it is unclear whether littermates remain together as adults, or if sex-biased dispersal occurs. The goal of our study was to determine whether fine-scale spatial genetic structure (FSGS) within a population of armadillos diminishes with age (i.e., from juvenile to adult due to the dispersal of littermates away from one another), and if the degree of FSGS for a given age class differs between the sexes. We obtained genotype data at seven microsatellite DNA loci for 421 individuals in a wild population of armadillos inhabiting the Yazoo National Wildlife Refuge in western Mississippi. Correlogram analyses based on measures of spatial genetic autocorrelation showed weak but significant FSGS that was driven by positive spatial genetic autocorrelation among both male and female juveniles and adult males, but not adult females. Positive spatial genetic autocorrelation among adult males could be due to either female-biased dispersal or high variance in male reproductive success. Further work is required to discriminate between these two possibilities. [ABSTRACT FROM AUTHOR]

The nine-banded armadillo ( Dasypus novemcinctus) is the only known nonhuman reservoir of Mycobacterium leprae, the causative agent of Hansen's disease or leprosy. We conducted a 6-yr study on a wild population of armadillos in western Mississippi that was exposed to M. leprae to evaluate the importance of demographic and spatial risk factors on individual antibody status. We found that spatially derived covariates were not predictive of antibody status. Furthermore, analyses revealed no evidence of clustering by antibody-positive individuals. Lactating females and adult males had higher odds of being antibody positive than did nonlactating females. No juveniles or yearlings were antibody positive. Results of these analyses support the hypothesis that M. leprae infection patterns are spatially homogeneous within this armadillo population. Further research related to movement patterns, contact among individuals, antibody status, and environmental factors could help address hypotheses related to the role of environmental transmission on M. leprae infection and the mechanisms underlying the differential infection patterns among demographic groups. [ABSTRACT FROM AUTHOR]