Comparisons between nine-banded armadillo (Dasypus novemcinctus) populations in Brazil and the United States

We compared characteristics of a population of nine-banded armadillos (Dasypus novemcinctus) studied in the southern United States with a population found in the Atlantic coastal rainforest of Brazil. Adult armadillos in Brazil weighed less than those in the U.S., but when weight was accounted for, did not differ in other measures of body size. However, juveniles in the U.S. were proportionately bigger than those in Brazil. Armadillos in Brazil were less abundant (numbers sighted per h of observation) and were active later at night than those in the U.S. Adult sex-ratios were male-biased in both populations. Finally, there was no significant difference in the incidence of littermate associations observed in the two populations, but groups of juveniles (which included non-littermates) were observed more frequently in the U.S. Many of these differences may be due to the fact that armadillos are hunted extensively in Brazil but not in the United States

Comparisons between nine-banded armadillo (Dasypus novemcinctus) populations in Brazil and the United States

We compared characteristics of a population of nine-banded armadillos (Dasypus novemcinctus) studied in the soulhem Uniled States with a population found in the Atlanlic coastal rainforest of Brazil. Adult armadillos in Brazil weighed less than Ihose in Ihe U.S., but when weight was accounted for, did not differ in: other measures of body size. However, juveniles in Ihe U.S. were proportionately bigger!han Ihose in Brazil. Armadillos in Brazil were less abundant (numbers sighted per h of observation) and were active laler al night .!han Ihose in the U.S. Adult sex-ratios were male-biased in bolh populations: Finally, there was no significant difference in Ihe incidence of litterrnate associations observed in Ihe two populations, but groups of juveniles (which included non-Iitterrnates) were observed more frequently in tbe U.S. Many of these differences may be due 10 the fact that armadillos are hunted extensively in Brazil but not in the United States.We compared characteristics of a population of nine-banded armadillos (Dasypus novemcinctus) studied in the soulhem Uniled States with a population found in the Atlanlic coastal rainforest of Brazil. Adult armadillos in Brazil weighed less than Ihose in Ihe U.S., but when weight was accounted for, did not differ in: other measures of body size. However, juveniles in Ihe U.S. were proportionately bigger!han Ihose in Brazil. Armadillos in Brazil were less abundant (numbers sighted per h of observation) and were active laler al night .!han Ihose in the U.S. Adult sex-ratios were male-biased in bolh populations: Finally, there was no significant difference in Ihe incidence of litterrnate associations observed in Ihe two populations, but groups of juveniles (which included non-Iitterrnates) were observed more frequently in tbe U.S. Many of Ihese differences may be due 10 the fact that armadillos are hunted extensively in Brazil but not in the United States

Research on armadillos: a review and prospectus

A detailed analysis of 1,039 scientific studies of extant armadillos (Xenarthra: Cingulata, Dasypodidae) published in the last 25 years (1989?2013) revealed substantial biases in coverage, including taxonomically, the locales where field studies were conducted, and in the topics investigated.  Examination of the number of other publications that cited each paper revealed that 470 (45%) papers had been cited no more than 10 times, 249 (24%) had never been cited, and 112 (11%) were not even found in the Google ScholarTM database.  The most heavily cited papers were molecular phylogenetic analyses that often used tissues from one or more species of armadillo but were not about the animals per se.  Thus, it appears that research on armadillos is plagued by numerous gaps in coverage, and is not reaching a wide audience.  These data indicate obvious opportunities for future research.  In addition, recent findings suggest that even relatively well-studied phenomena may require re-examination.  Here we review recent advances in the study of armadillos and highlight promising areas for future work.  One critical need is for a thorough systematic revision of Dasypodidae to be completed.  This will make it possible to prioritize those species and populations most in need of study.  Additionally, more long-term field studies of populations of marked individuals are required.  Although there are many important and interesting questions waiting to be answered, the small number of researchers currently conducting studies of armadillos, particularly in the wild, means that progress will be slow.Un análisis detallado de 1.039 estudios científicos sobre armadillos actuales (Xenarthra: Cingulata, Dasypodidae), que fueron publicados en los últimos 25 años (1989–2013), mostró que existen considerables sesgos en la cobertura, incluyendo la taxonomía, los lugares donde se realizaron los estudios de campo, y en los temas estudiados. El análisis de la cantidad de otros trabajos que citaron las publicaciones de armadillos mostró que 470 (45%) de los artículos fueron citado no más de 10 veces, 249 (24%) nunca habían sido citado y 112 (11%) ni siquiera fueron encontrado en la base de datos de Google Scholar. Las publicaciones citadas con mayor frecuencia describían análisis filogenéticos moleculares que generalmente utilizaban tejidos de una o más especies de armadillos, pero no trataban de los armadillos per se. Pareciera, entonces, que la investigación en armadillos está plagada de numerosos vacíos en la cobertura y no está alcanzando una amplia audiencia. Estos datos indican claras oportunidades para futuras investigaciones. Adicionalmente, recientes hallazgos sugieren que incluso las peculiaridades relativamente bien estudiadas podrían requerir de análisis adicionales. En este trabajo revisamos recientes avances en el estudio de los armadillos y resaltamos áreas prometedoras para futuras investigaciones. Una de las necesidades críticas es el desarrollo de una detallada revisión sistemática de los Dasypodidae que permitirá priorizar las especies y poblaciones con mayor necesidad de investigación. Adicionalmente, se requieren de estudios a largo plazo que involucren poblaciones de individuos marcados. Si bien existen muchas preguntas importantes e interesantes que esperan ser respondidas, el reducido número de investigadores que actualmente desarrollan estudios sobre armadillos, especialmente a campo, parece prever que será un proceso lento.Fil: Loughry, W. J.. Valdosta State University; Estados UnidosFil: Superina, Mariella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: McDonough, Colleen M.. Valdosta State University; Estados UnidosFil: Abba, Agustin Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; Argentin

Burrow charaderistics and habitat assodations of armadillos in Brazil and the United States of America

We censused and measured armadillo burrows in ten 10 m x 40 m plots in each of four habitat types at a study site in northern Florida and one in the Atlantic coastal rainforest of Brazi!. The nine-banded armadillo (Dasypus novemcinctus) was the only species of armadillo found in Florida, but several additional species were present in Brazil. Burrows were more numerous but smaller in Brazil than in the U. S., probably due to the inelusion of burrows dug by the smaller congener D. septemcinctus. In Brazil, burrows were larger and more numerous in swamp and forest habitats than in grass)and or disturbed areas, suggestíng that D. novemcinctus is found primarily in forests and swamps while D. septemcinctus is located in the other areas. This was supported by data from sightíngs of live animals. In Florida, burrows were more numerous in hardwood hammocks than in wetlands, fields or upland pine areas, but burrow dimensions did not vary across habitat types. In Florida, armadillos were seen more frequently than expected in hammocks and wetlands and less frequently thlll1 expected in fields and upland pine areas. There were also age (juvenile versus adult), sex, and yearly differences in habita! use in Florida. Biomass, abundance, and species diversity of terrestrial invertebrates did not vary significantly between habitat types in Florida, suggestíng that habitat associatíons of armadillos were not influenced by prey availability.We censused and measured armadillo burrows in ten 10 m x 40 m plots in each of four habitat types at a study site in northern Florida and one in the Atlantic coastal rainforest of Brazi!. The nine-banded armadillo (Dasypus novemcinctus) was the only species of armadillo found in Florida, but several additional species were present in Brazil. Burrows were more numerous but smaller in Brazil than in the U. S., probably due to the inelusion of burrows dug by the smaller congener D. septemcinctus. In Brazil, burrows were larger and more numerous in swamp and forest habitats than in grass)and or disturbed areas, suggestíng that D. novemcinctus is found primarily in forests and swamps while D. septemcinctus is located in the other areas. This was supported by data from sightíngs of live animals. In Florida, burrows were more numerous in hardwood hammocks than in wetlands, fields or upland pine areas, but burrow dimensions did not vary across habitat types. In Florida, armadillos were seen more frequently than expected in hammocks and wetlands and less frequently thlll1 expected in fields and upland pine areas. There were also age (juvenile versus adult), sex, and yearly differences in habita! use in Florida. Biomass, abundance, and species diversity of terrestrial invertebrates did not vary significantly between habitat types in Florida, suggestíng that habitat associatíons of armadillos were not influenced by prey availability

Correlates of reproductive success in a population of nine-banded armadillos

We used microsatellite DNA markers to identify the putative parents of 69 litters of nine-banded armadillos (Dasypus novemcinctus) over 4 years. Male and female parents did not differ in any measure of body size in comparisons with nonparents. However, males observed paired with a female were significantly larger than unpaired males, although paired females were the same size as unpaired females. Females categorized as possibly lactating were significantly larger than females that were either definitely lactating or definitely not lactating. There was no evidence of assortative mating: body-size measurements of mothers were not significantly correlated with those of fathers. Nine-banded armadillos give birth to litters of genetically identical quadruplets. Mothers (but not fathers) of female litters were significantly larger than mothers of male litters, and maternal (but not paternal) body size was positively correlated with the number of surviving young within years, but not cumulatively. There were no differences in dates of birth between male and female litters, nor were there any significant relationships between birth date and maternal body size. Body size of either parent was not correlated with the body sizes of their offspring. Cumulative and yearly reproductive success did not differ between reproductively successful males and females. Average reproductive success (which included apparently unsuccessful individuals) also did not differ between males and females. The majority of adults in the population apparently failed to produce any surviving offspring, and even those that did usually did so in only 1 of the 4 years. This low reproductive success is unexpected, given the rapid and successful range extension of this species throughout the southeastern United States in this century

Is leprosy spreading among nine-banded armadillos in the southeastern United States?

International audienceIn the United States, nine-banded armadillo (Dasypus novemcinctus) populations are derived from two sources: (1) a continuous range expansion from Mexico led to western populations, some of which, particularly along the western Gulf Coast and west side of the Mississippi River delta, exhibit persistently high rates of leprosy infection, and (2) a small group of animals released from captivity in Florida gave rise to eastern populations that were all considered leprosy free. Given that western and eastern populations have now merged, an important question becomes, to what extent is leprosy spreading into formerly uninfected populations? To answer this question, we sampled 500 animals from populations in Mississippi, Alabama, and Georgia. Analyses of nuclear microsatellite DNA markers confirmed the historic link between source populations from Texas and Florida, but did not permit resolution of the extent to which these intermediate populations represented eastern versus western gene pools. Prevalence of leprosy was determined by screening blood samples for the presence of antibodies against Mycobacterium leprae and via polymerase chain reaction amplification of armadillo tissues to detect M. leprae DNA. The proportion of infected individuals within each population varied from 0% to 10%. Although rare, a number of positive individuals were identified in eastern sites previously considered uninfected. This indicates leprosy may be spreading eastward and calls into question hypotheses proposing leprosy infection is confined because of ecologic constraints to areas west of the Mississippi River

Population Dynamics and Range Expansion in Nine-Banded Armadillos

<div><p>Understanding why certain species can successfully colonize new areas while others do not is a central question in ecology. The nine-banded armadillo (<i>Dasypus novemcinctus</i>) is a conspicuous example of a successful invader, having colonized much of the southern United States in the last 200 years. We used 15 years (1992–2006) of capture-mark-recapture data from a population of armadillos in northern Florida in order to estimate, and examine relationships among, various demographic parameters that may have contributed to this ongoing range expansion. Modeling across a range of values for γ, the probability of juveniles surviving in the population until first capture, we found that population growth rates varied from 0.80 for γ = 0.1, to 1.03 for γ = 1.0. Growth rates approached 1.0 only when γ ≥0.80, a situation that might not occur commonly because of the high rate of disappearance of juveniles. Net reproductive rate increased linearly with γ, but life expectancy (estimated at 3 years) was independent of γ. We also found that growth rates were lower during a 3-year period of hardwood removal that removed preferred habitat than in the years preceding or following. Life-table response experiment (LTRE) analysis indicated the decrease in growth rate during logging was primarily due to changes in survival rates of adults. Likewise, elasticity analyses of both deterministic and stochastic population growth rates revealed that survival parameters were more influential on population growth than were those related to reproduction. Collectively, our results are consistent with recent theories regarding biological invasions which posit that populations no longer at the leading edge of range expansion do not exhibit strong positive growth rates, and that high reproductive output is less critical in predicting the likelihood of successful invasion than are life-history strategies that emphasize allocation of resources to future, as opposed to current, reproduction.</p></div