Fast acrobatic maneuvers enable arboreal spiders to hunt dangerous prey.

Spiders, the most specious taxon of predators, have evolved an astounding range of predatory strategies, including group hunting, specialized silk traps, pheromone-loaded bolas, and aggressive mimicry. Spiders that hunt prey defended with behavioral, mechanical, or chemical means are under additional selection pressure to avoid injury and death. Ants are considered dangerous because they can harm or kill their predators, but some groups of spiders, such as the Theridiidae, have a very high diversification of ant-hunting species and strategies [J. Liu et al., Mol. Phylogenet. Evol. 94, 658-675 (2016)]. Here, we provide detailed behavioral analyses of the highly acrobatic Australian ant-slayer spider, Euryopis umbilicata (Theridiidae), that captures much larger and defended Camponotus ants on vertical tree trunks. The hunting sequence consists of ritualized steps performed within split seconds, resulting in an exceptionally high prey capture success rate.

El cuidado humanizado en los futuros enfermeros del sur de Chile / The humanized care in the nursing futures of south Chile

OBJETIVO: Reconocer la percepción que tienen estudiantes de enfermería, en una Universidad del sur de Chile, respecto de los cuidados humanizados que entregan durante el año 2018. MATERIAL Y MÉTODO: Estudio cuantitativo, transversal, no experimental realizado en 2018 en 197 estudiantes, entre 18 y 25 años, de segundo a quinto año de enfermería, se autoadministra instrumento validado basado en los comportamientos humanizados: Caring Efficacy Scale (CES). RESULTADOS: El 73% de los futuros enfermeros poseen un alto grado de percepción de cuidados humanizados, el 26% una percepción regular y solo el 1% posee un bajo nivel de percepción de cuidados humanizados de su atención. Además, se comprobó que no existe diferencia en el género al momento de entregar cuidados humanizados y que a mayor nivel académico la percepción de cuidados humanizados también aumenta. CONCLUSIÓN: Al analizar las variables entre los comportamientos positivos y negativos, en relación con el género, se pudo comprobar que no existe significancia; sin embargo, en relación al nivel académico, se pudo determinar que mientras mayor es el nivel académico, mayor es la percepción del cuidado humanizado que poseen los estudiantes de enfermería.

OBJECTIVE: To recognize the perception that nursing student shave, in a University of southern Chile, regarding the humanized care they deliver during 2018. MATERIAL AND METHOD: Quantitative, cross-sectional, non-experimental study conducted in 2018 in 197 students, among 18 and 25 years, from second to fifth year of nursing, validated instrument is self-administered based on humanized behaviors: Caring Efficacy Scale (CES). RESULTS: 73% of future nurses have a high degree of perception of humanized care, 26% have a regular perception and only 1% have a low level of perception of humanized care of their care. In addition, it was found that there is no difference in gender when delivering humanized care and that at a higher academic level the perception of humanized care also increases. CONCLUSION: When analyzing the variables between positive and negative behaviors, in relation to gender, it was found that there is no significance; However, in relation to the academic level, it was determined that the higher the academic level, the greater the perception of the humanized care that nursing students possess.

Ontogeny of learning walks and the acquisition of landmark information in desert ants, Cataglyphis fortis.

At the beginning of their foraging lives, desert ants (Cataglyphis fortis) are for the first time exposed to the visual world within which they henceforth must accomplish their navigational tasks. Their habitat, North African salt pans, is barren, and the nest entrance, a tiny hole in the ground, is almost invisible. Although natural landmarks are scarce and the ants mainly depend on path integration for returning to the starting point, they can also learn and use landmarks successfully to navigate through their largely featureless habitat. Here, we studied how the ants acquire this information at the beginning of their outdoor lives within a nest-surrounding array of three artificial black cylinders. Individually marked 'newcomers' exhibit a characteristic sequence of learning walks. The meandering learning walks covering all directions of the compass first occur only within a few centimeters of the nest entrance, but then increasingly widen, until after three to seven learning walks, foraging starts. When displaced to a distant test field in which an identical array of landmarks has been installed, the ants shift their search density peaks more closely to the fictive goal position, the more learning walks they have performed. These results suggest that learning of a visual landmark panorama around a goal is a gradual rather than an instantaneous process.