Identification of an attractant for the nine-banded armadillo, Dasypus novemcinctus

Leishmania (Viannia) naiffi Lainson & Shaw 1989

Just over 30 years ago, a new species of Leishmania of the subgenus Leishmania (Viannia) was described infecting the armadillo Dasypus novemcinctus; then, a report of human infection followed. From the Brazilian Amazon and apparently restricted to this region and its close borders, Leishmania (Viannia) naiffi has been characterized as a species that grows easily in axenic culture medium and causes few to no lesions after inoculation in experimental animal models. Results in the last decade indicate the occurrence of L. naiffi in vectors and human infections, including a report of therapeutic failure possibly associated with Leishmania RNA virus 1. Overall, such accounts suggest that the parasite is more dispersed and the disease less self-healing than previously expected.

Aroma-dillo or Area-dillo? An examination of armadillos' sensory modality bias

Many species of armadillo demonstrate impressive navigation abilities and may compensate for poor eyesight with a strong sense of smell. We examined which modality four three-banded armadillos and one hairy armadillo prioritized when two cues (olfactory or spatial) previously associated with reward were put in conflict. The armadillos learned to approach one of two locations - each paired with a distinctive scent - for reward. When the scent cues were reversed, the armadillos demonstrated a strong bias for attending to the location cue over the scent cue. Therefore, a follow-up test presented them with the same scents and assessed their spontaneous preferences. Although the armadillos did not show an immediate preference for the previously rewarded scent, they did learn to discriminate two novel scents when they were placed in a circular arena containing two tins - each scented with a unique scent. They learned to selectively open the tins containing reward based on scent. This result indicates that their bias towards location cues was not due to an inability to discriminate between scents. Armadillos may attend to either location or scent but may prioritize location when both cues are equally predictive.

Food preference of nine-banded armadillo (Dasypus novemcinctus, Linnaeus, 1758) under human care

This study aims to evaluate the food preference of nine banded armadillos kept in captivity, exposed to four different diets: Diet 1 (D1) - dry dog food and ground beef; Diet 2 (D2) - dry dog food, ground beef, and chicken eggs; Diet 3 (D3) - dog food, ground beef, bananas, and papaya; Diet 4 (D4) - dog food, ground beef, chicken eggs, banana, and papaya. To this end, an experiment was carried out for five weeks, the first four of which were for preliminary management and the fifth week for data collection. Frequency of consumption, total intake for each diet, and intake ratio were evaluated. The dietary preference was higher for the diets with a higher protein percentage (D1 and D2), mainly D2, which presented increased demand and intake starting on the fourth day of observation. In second day of observation, D1 presented the higher intake ratio, but D2 gradually replaced it. The diet containing the lowest protein rate (D3) was the least favored on all observation days and evaluations. In conclusion, the food preference of ex-situ armadillos seems to be related to the inclusion of greater amounts of protein, particularly that of animal origin, with eggs being the most appreciated ingredient in this study.

Ecosystem services provided by armadillos

Awareness of the natural ecological processes provided by organisms that benefit human well-being has significantly progressed towards the goal of making conservation a mainstream value. Identifying different services and the species that provide them is a vital first step for the management and maintenance of these so-called ecosystem services. Herein, we specifically address the armadillos, which play key functional roles in terrestrial ecosystems, including as ecosystem engineers, predators, and vectors of invertebrates and nutrients, although these roles have often been overlooked. Armadillos can control pests, disperse seeds, and be effective sentinels of potential disease outbreaks or bioindicators of environmental contaminants. They also supply important material (meat, medicines) and non-material (learning, inspiration) contributions all over the Americas. We identify key gaps in the understanding of ecosystem services provided by armadillos and areas for future research required to clarify their functional role in terrestrial ecosystems and the services they supply. Such information will produce powerful arguments for armadillo conservation.

Leishmania naiffi and Leishmania guyanensis reference genomes highlight genome structure and gene evolution in the Viannia subgenus

The unicellular protozoan parasite Leishmania causes the neglected tropical disease leishmaniasis, affecting 12 million people in 98 countries. In South America, where the Viannia subgenus predominates, so far only L. (Viannia) braziliensis and L. (V.) panamensis have been sequenced, assembled and annotated as reference genomes. Addressing this deficit in molecular information can inform species typing, epidemiological monitoring and clinical treatment. Here, L. (V.) naiffi and L. (V.) guyanensis genomic DNA was sequenced to assemble these two genomes as draft references from short sequence reads. The methods used were tested using short sequence reads for L. braziliensis M2904 against its published reference as a comparison. This assembly and annotation pipeline identified 70 additional genes not annotated on the original M2904 reference. Phylogenetic and evolutionary comparisons of L. guyanensis and L. naiffi with 10 other Viannia genomes revealed four traits common to all Viannia: aneuploidy, 22 orthologous groups of genes absent in other Leishmania subgenera, elevated TATE transposon copies and a high NADH-dependent fumarate reductase gene copy number. Within the Viannia, there were limited structural changes in genome architecture specific to individual species: a 45 Kb amplification on chromosome 34 was present in all bar L. lainsoni, L. naiffi had a higher copy number of the virulence factor leishmanolysin, and laboratory isolate L. shawi M8408 had a possible minichromosome derived from the 3' end of chromosome 34. This combination of genome assembly, phylogenetics and comparative analysis across an extended panel of diverse Viannia has uncovered new insights into the origin and evolution of this subgenus and can help improve diagnostics for leishmaniasis surveillance.