What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology

The species diversity of entomophilous plants and flower-visiting insects is sustained in the field margins of sunflower crops

Field margins are key landscape features sustaining biodiversity in farmland mosaics and through that, ecosystem services. However, agricultural intensification has encouraged fencerow removal to enlarge cropping areas, reducing farmland biodiversity and its associated ecosystems services. In the present work, we assess the role of field margins in retaining farmland biodiversity across the sunflower cropping area of Argentina. Flower-visiting insects and entomophilous plants were intensively sampled along the margins of sunflower fields, in eight locations across eastern Argentina. We recorded 149 species of flowering plants and 247 species of flower-visitors. Plants and arthropods were mostly natives. Most of the floral visitors captured provide ecosystem services to agriculture. Our results show that many species of beneficial insects and native plants occur in semi-natural linear features in the intensively managed farmland of Argentina. Field margins may constitute the last refugia of native plant species and their associated fauna in farmland mosaics. Conservation of field margins in Argentine farmland may therefore be essential for preserving biodiversity and associated ecosystem services.Fil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Poggio, Santiago Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal; Argentin