The evolution of mass raiding has allowed army ants to become dominant arthropod predators in the tropics. Although a century of research has led to many discoveries about behavioural, morphological and physiological adaptations in army ants, almost nothing is known about the molecular basis of army ant biology. Here we report the genome of the iconic New World army ant Eciton burchellii, and show that it is unusually compact, with a reduced gene complement relative to other ants. In contrast to this overall reduction, a particular gene subfamily (9-exon ORs) expressed predominantly in female antennae is expanded. This subfamily has previously been linked to the recognition of hydrocarbons, key olfactory cues used in insect communication and prey discrimination. Confocal microscopy of the brain showed a corresponding expansion in a putative hydrocarbon response centre within the antennal lobe, while scanning electron microscopy of the antenna revealed a particularly high density of hydrocarbon-sensitive sensory hairs. E. burchellii shares these features with its predatory and more cryptic relative, the clonal raider ant. By integrating genomic, transcriptomic and anatomical analyses in a comparative context, our work thus provides evidence that army ants and their relatives possess a suite of modifications in the chemosensory system that may be involved in behavioural coordination and prey selection during social predation. It also lays the groundwork for future studies of army ant biology at the molecular level.
Ants , Adaptation, Physiological , Animals , Ants/genetics , Female , Genome , Genomics , Predatory Behavior
Rhinella marina is a toad native to South America that has been introduced in the Antilles, likely carrying high loads of microorganisms, potentially impacting local community diversity. The amphibian skin is involved in pathogen defense and its microbiota has been relatively well studied, however, research focusing on the cane toad microbiota is lacking. We hypothesize that the skin microbial communities will differ between toads inhabiting different geographical regions in Central America and the Caribbean. To test our hypothesis, we compared the microbiota of three populations of R. cf. marina toads, two from Costa Rican (native) and one Puerto Rican (exotic) locations. In Costa Rica, we collected 11 toads, 7 in Sarapiquí and 4 from Turrialba while in Puerto Rico, 10 animals were collected in Santa Ana. Separate swab samples were collected from the dorsal and ventral sites resulting in 42 samples. We found significant differences in the structure of the microbial communities between Puerto Rico and Costa Rica. We detected as much as 35 different phyla; however, communities were dominated by Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Alpha diversity and richness were significantly higher in toads from Puerto Rico and betadiversity revealed significant differences between the microbiota samples from the two countries. At the genus level, we found in Santa Ana, Puerto Rico, a high dominance of Kokuria, Niabella, and Rhodobacteraceae, while in Costa Rica we found Halomonas and Pseudomonas in Sarapiquí, and Acinetobacter and Citrobacter in Turrialba. This is the first report of Niabella associated with the amphibian skin. The core microbiome represented 128 Operational Taxonomic Units (OTUs) mainly from five genera shared among all samples, which may represent the symbiotic Rhinella's skin. These results provide insights into the habitat-induced microbial changes facing this amphibian species. The differences in the microbial diversity in Puerto Rican toads compared to those in Costa Rica provide additional evidence of the geographically induced patterns in the amphibian skin microbiome, and highlight the importance of discussing the microbial tradeoffs in the colonization of new ecosystems.
Antecedentes. Las prisiones implican situaciones de riesgo, que pueden generar comportamientos suicidas, puesto que la privación de la libertad impacta de manera significativa a los sujetos que experimentan esta condición. Objetivo. Caracterizar el riesgo suicida en población carcelaria masculina del Tolima, Colombia. Materiales y métodos. Se realizó una investigación cuantitativa, descriptiva y transversal. Se tomó una muestra de 122 internos a quienes se les aplicaron dos instrumentos de evaluación: el ISO-30, que mide el riesgo suicida y un cuestionario sociodemográfico. Resultados. Se encontró que el 16,4% de la población presenta un riesgo suicida alto. El 22,2% de los que habían hecho intentos previos de suicidio presentaron un riesgo alto, frente al 15,9% de los que no lo habían hecho. Al revisar el riesgo y la escolaridad, se halló que el nivel de riesgo disminuye al aumentar el nivel educativo; igual situación se encuentra entre los que tienen pareja e hijos, convirtiéndose estas tres variables en posibles factores protectores. Conclusiones. Se encontraron niveles de ideación suicida superiores a los hallados en población general. También se identifica una relación directa entre la red social y familiar y la protección frente al riesgo suicida.
Background. Prisons involve risk, which can generate suicidal behavior, since the imprisonment hits significantly to subjects who experience this condition. Objective. The aim of this investigation was to characterize suicide risk in male prison population of the department of Tolima, Colombia. Materials and methods. Quantitative, descriptive and transversal study. With a sample of 122 inmates were applied two evaluation instruments: ISO-30 measuring suicide risk and a social-demographic questionnaire. Results. 16.4% of the population has a high suicide risk. 22.2% of those who had made previous suicide attempts had shown a high risk, compared with 15.9% of those who had not. When reviewing the risk and schooling, it was found that the level of risk decreases with increasing educational level, the same situation is done among those with partners and children making these three variables on potential protective factors. Conclusions. Higher levels of suicidal ideation were found to those found in the general population. A direct relationship between the social and family network is identified and also protection against suicide risk.
