Ballooning is an aerial dispersal mechanism commonly used by spiders, primarily observed in small adults and juveniles of some species. Spiders can navigate through the air by deploying silk threads, covering varying distances. During the last decades, there has been increased attention to spider aerial dispersal studies, and different use of terminologies associated with ballooning. We surveyed research literature on aerial dispersal studies from 1966 up to 2024 to assess the variances in the number of studies on these topics and analyse the use of pre-ballooning and ballooning terms. We found a total of 216 research articles containing pre-ballooning behaviour terms such as ‘tip-toe’/ ‘tiptoe’/ ‘tiptoeing’ (n = 17), ‘drop on dragline’/ ‘dropping on dragline’ (n = 15) and terms such as ‘ballooning’ (n = 146), ‘rappel/rappelling/bridging’ (n = 74), ‘aerial dispersal’ (n = 104), ″aerial dispersion″ (n = 15), or ″aeronautic behaviour″ (n = 7). These studies were distributed into 192 research articles, 9 reviews, 3 book chapters, and 7 into other categories. Spider families with the most reports of ballooning were Linyphiidae, Theridiidae, and Araneidae. Tiptoeing is considered an indicator of ballooning behaviour; however, according to our results, there are some differences in the use of the concepts ‘drop on dragline/dropping on a dragline’ and ‘rappelling’ as pre-ballooning, ballooning or non-ballooning behaviours. We discuss the importance of fine-scaled behavioural descriptions of ballooning and the need to homogenize the criteria to smooth the way for future studies of this phenomenon in spiders.
Las poblaciones de guanaco en Argentina sufrieron una drástica disminución durante el siglo XX que empezó a revertirse en los últimos 30 años. A pesar de esto, la provincia de Buenos Aires aún posee solamente pequeñas poblaciones relictuales en dos reservas naturales ubicadas al sudoeste de la provincia. Reportamos registros de dos nuevas posibles áreas de presencia a largo plazo de guanaco en el partido de Patagones, por fuera de áreas protegidas. Estas nuevas áreas contribuyen a plantear la necesidad de mayor exploración en la zona, enfocada en establecimientos productivos, para favorecer la conservación de esta especie y la coexistencia con la ganadería.
This study introduces a novel non-linear real-time filter based on the concept of Free Energy, which is applied to estimate the state of mobile robots in dynamic environments. By leveraging the principles of Bayesian inference, the proposed Free Energy Filter aims to minimize prediction errors between the observed and estimated trajectories. The approach extends existing non-linear filtering techniques, incorporating elements such as the Fokker-Planck equation. The simulation results demonstrate the effectiveness of this method in improving the control accuracy of unicycle robots equipped with the Bessel controller. The study also discusses comparisons with traditional Kalman filtering, highlighting the advantages of the proposed approach in adapting to noisy and uncertain conditions.
Despite the remoteness of the Antarctic continent and Southern Ocean, microplastic (MPs) contamination has been evidenced in recent years. However, the deep-sea compartments of the Southern Ocean are yet to be investigated. In the present study, we conducted a baseline MP assessment of the deep-sea waters and bottom sediments of the Bransfield Strait, Antarctica. A low abundance of suspected MPs was found. The average MP abundances in bottom sediments and water samples were 0.09 MPs/g (range of 0 to 0.2 MPs/g) and 7.00 MPs/L (range of 0 to 16 MPs/L), respectively. The majority of the particles were fibers identified as cellulose, although polyethylene terephthalate (PET) and polyacrylonitrile (PAN) was also detected. These results suggest low MP contamination levels in the Southern Ocean's deepest environmental compartments. However, future studies must aim to investigate the smallest MP fractions and, if possible, nanoplastic (<1 μm) contamination in these remote compartments.
The COVID-19 pandemic induced an unprecedented flow of single-use plastics, mostly in the form of face masks. As significant amounts of face masks reached coastal environments, concerns regarding the impacts were raised. The present chapter deals with the release of microplastics and nanoplastics (MPs/PNPs), including the amount, characteristics, and analytical approaches, associated with face masks. Additionally, the current understanding of their ecotoxicological implications was summarized and discussed. Overall, face masks have been demonstrated to be a significant source of MPs/PNPs, with estimations reaching millions of particles released per mask, as well as growth-related sublethal effects on aquatic organisms. Nevertheless, some various uncertainties and questions remain unanswered.
