Population structure and diversity of an invasive pine needle pathogen reflects anthropogenic activity

Dothistroma septosporum is a haploid fungal pathogen that causes a serious needle blight disease of pines, particularly as an invasive alien species on Pinus radiata in the Southern Hemisphere. During the course of the last two decades, the pathogen has also incited unexpected epidemics on native and non-native pine hosts in the Northern Hemisphere. Although the biology and ecology of the pathogen has been well documented, there is a distinct lack of knowledge regarding its movement or genetic diversity in many of the countries where it is found. In this study we determined the global population diversity and structure of 458 isolates of D. septosporum from 14 countries on six continents using microsatellite markers. Populations of the pathogen in the Northern Hemisphere, where pines are native, displayed high genetic diversities and included both mating types. Most of the populations from Europe showed evidence for random mating, little population differentiation and gene flow between countries. Populations in North America (USA) and Asia (Bhutan) were genetically distinct but migration between these continents and Europe was evident. In the Southern Hemisphere, the population structure and diversity of D. septosporum reflected the anthropogenic history of the introduction and establishment of plantation forestry, particularly with Pinus radiata. Three introductory lineages in the Southern Hemisphere were observed. Countries in Africa, that have had the longest history of pine introductions, displayed the greatest diversity in the pathogen population, indicating multiple introductions. More recent introductions have occurred separately in South America and Australasia where the pathogen population is currently reproducing clonally due to the presence of only one mating type.The Department of Science and Technology (DST)/National Research Foundation (NRF), the Tree Protection Co-operative Programme (TPCP), the Claude Leon Foundation and the THRIP initiative of the Department of Trade and Industry, South Africa.http://onlinelibrary.wiley.comjournal/10.1002/(ISSN)2045-7758am201

Three Decades of Subterranean Acoustic Communication Studies

The subterranean environment has strongly influenced the evolution of the sensory biology of subterranean rodents. While dark and monotonous tunnels have led to reductions in the visual capabilities of some species, other senses appear to be highly developed in contrast. Among them, the emission of acoustic and seismic signals plays a major role in communication and alertness of subterranean mammals. In this chapter, the ecological and evolutionary conditions that influence the characteristics of vibrational communication in subterranean rodents are reviewed. First, the characteristics of rodents’ burrows and how they dictate the methods used to study subterranean communication are discussed. Second, the properties and roles of vocalizations and seismic signals in subterranean species are examined, including the main hypotheses about the evolution of these signals. Third, what is understood about social and vocal complexity in subterranean rodents is summarized and the similarities and differences in the vocal repertoires of social and solitary groups are analyzed. The chapter ends with a short summary and a consideration of future challenges in the field of subterranean acoustic communication in rodents.Fil: Schleich, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Francescoli Gilardini, Gabriel Enrique. Universidad de la República; Urugua