Barcelona, ¿ciudad del miedo?: urbanismo "preventivo" y control del espacio público

Peer Reviewe

Hybridization and extensive mitochondrial introgression among fire salamanders in peninsular Italy

Discordance between mitochondrial and nuclear patterns of population genetic structure is providing key insights into the eco-evolutionary dynamics between and within species, and their assessment is highly relevant to biodiversity monitoring practices based on DNA barcoding approaches. Here, we investigate the population genetic structure of the fire salamander Salamandra salamandra in peninsular Italy. Both mitochondrial and nuclear markers clearly identified two main population groups. However, nuclear and mitochondrial zones of geographic transition between groups were located 600 km from one another. Recent population declines in central Italy partially erased the genetic imprints of past hybridization dynamics. However, the overall pattern of genetic variation, together with morphological and fossil data, suggest that a rampant mitochondrial introgression triggered the observed mitonuclear discordance, following a post-glacial secondary contact between lineages. Our results clearly show the major role played by reticulate evolution in shaping the structure of Salamandra salamandra populations and, together with similar findings in other regions of the species’ range, contribute to identify the fire salamander as a particularly intriguing case to investigate the complexity of mechanisms triggering patterns of mitonuclear discordance in animals

Evidence of reinforcement of premating isolation between two species of the genus Ochthebius (Coleoptera : Hydraenidae)

The increase in premating reproductive isolation between recently diverged and potentially interbreeding taxa resulting from selection against hybridization (reinforcement) is one of the most contentious issues in evolutionary biology. After many years of debate, its plausibility under various conditions has been shown by theoretical studies and some cases have been documented. At present, interest is arising about the frequency and importance of reinforcement in nature. Ochthebius quadricollis and Ochthebius sp. A are two hydraenid beetles inhabiting marine rock pools in the Mediterranean basin. By molecular analysis of a contact zone between the two species along the Italian Tyrrhenian coast, full reproductive isolation between the two species was evidenced. However, the finding of introgressed specimens at some diagnostic loci suggested that gene flow occurred in the past but then ceased. In this article, by analyzing species composition of mating couples collected in sympatric localities, we show the existence of strong assortative mating between the two species in nature. In laboratory multiple-choice mating trials, sympatric populations showed greater assortative mating than allopatric populations. Reinforcement is suggested as the most parsimonious hypothesis to explain the evolution of discriminative mate recognition systems occurring among O. quadricollis and Ochthebius sp. A under sympatric, but not allopatric, populations

Dynamics of mtDNA introgression during species range expansion. Insights from an experimental longitudinal study

Introgressive hybridization represents one of the long-lasting debated genetic consequences of species range expansion. Mitochondrial DNA has been shown to heavily introgress between interbreeding animal species that meet in new sympatric areas and, often, asymmetric introgression from local to the colonizing populations has been observed. Disentangling among the evolutionary and ecological processes that might shape this pattern remains difficult, because they continuously act across time and space. In this context, long-term studies can be of paramount importance. Here, we investigated the dynamics of mitochondrial introgression between two mosquito species (Aedes mariae and Ae. zammitii ) during a colonization event that started in 1986 after a translocation experiment. By analyzing 1,659 individuals across 25 years, we showed that introgression occurred earlier and at a higher frequency in the introduced than in the local species, showing a pattern of asymmetric introgression. Throughout time, introgression increased slowly in the local species, becoming reciprocal at most sites. The rare opportunity to investigate the pattern of introgression across time during a range expansion along with the characteristics of our study-system allowed us to support a role of demographic dynamics in determining the observed introgression pattern

L'immagine della città del futuro nella letteratura distopica della prima metà del '900

The contemporary city, threatened by uncontrolled population growth and the rapid increase of poverty, is not the only possible scenario for future wars and ecological collapse but seems also to have become the catalyst for a collective fear: the topos of final disaster. The negative image of this future, as represented by literature and film, seems to refer to an older iconographic repertoire and often, this decadent representation of the city, matches with the pessimistic visions of the late-Victorian literature. The ruins of the industrial cities like Detroit, today converted into archaeological areas, remind us the grandeur of the ancient capitals of fallen empires. This essay analyses some of the mechanisms that led to the transformation of the contemporary city using the different scenarios that literature has used to represent its negative and distorted future. Repeatedly, the history of architecture has speculated on the importance of the relationship between Utopía and urban space. On the contrary, Dystopia, a literary genre born in the late nineteenth century and used to describe unwanted and aberrant societies of the future, seems to have been consigned to the marginal role of mass entertainment. lnstead, the dystopian genre offers interesting resources to understand the present. Nowadays in Western culture, Dystopia seems to have definitely replaced Utopia as a way to reflect upon the present. This research undertakes a historical journey through the rise and fall of the myth of progress. lt analyses the city of the future through literary works. The first part is concemed with the creation of the image of the future city, thoroughly transformed by scientific and technological achievements. This phase begins with the publication of "New Atlantis'', by Francis Bacon (1621), and finishes with "Les cinq cents millions de la Begum", by J. Veme (1879). The literature of the last two decades of the twentieth century is characterized, instead, by darker views. The myth of progress, built by the bourgeoisie, is gradually eclipsed by the fear of the class conflict outbreak, the demographic boom and the decline of the old colonial empires. Science and technology cease to play a positive, utopian role to become potentially destructive forces. This is the moment when the literary representation of the future city moves from a positive view of the technological achievements towards a negative one, from utopía to totalitarian dystopia. lt is during the 1920's with the publication of 'We", by Y. Zamjatin, that modern dystopia starts. This novel, set in a completely transparent city, anticipates the birth of an invisible power whose aim is the total control of citizen's lives. As well as utopia embodies collective desires and hopes through certain urban models, dystopia has its own ways to embody fears and nightmares. To this literary genre corresponds a precise type of city, thoroughly restrained, segregated and hierarchical. Besides Dystopia is also a caricature of the Utopia of Organization. Dystopian cities are designed as a result of a critical analysis of the new approaches of urbanism, born out of the ashes of the French Revolution. In this belief system, Architecture is seen as a "bio-political technology", a "devise to produce individuals", so as to improve humankind through mind control and physical conditioning.La ciudad contemporánea, amenazada por el crecimiento demográfico sin control y el aumento acelerado de la pobreza, posible escenario de futuras guerras y del colapso ecológico, parece haberse convertido hoy en el catalizador de todo miedo colectivo, en topos definitivo del desastre. Sin embargo, la imagen negativa de su futuro, tal como la representan la literatura y el cine, parece recurrir a un repertorio iconográfico más antiguo. Muchas veces, su representación decadente coincide con las visiones pesimistas de la literatura tardo-victoriana. Las ruinas de metrópolis industriales como Detroit traen a la memoria la grandiosidad de las antiguas capitales de los imperios caídos, convertidas hoy en áreas arqueológicas. Esta investigación analiza algunos de los mecanismos que guían la transformación de la ciudad contemporánea tomando como herramientas las distintas maneras en las que la literatura ha representado su imagen futura de manera distorsionada y negativa. En muchas ocasiones, la historia de la arquitectura ha reflexionado sobre la importancia de la relación entre la utopía y la construcción del espacio urbano. Por el contrario, la distopía, género literario surgido hacia finales del siglo XIX y volcado en la descripción de sociedades futuras indeseadas y desviadas, parecía haber quedado relegada a la función marginal del entretenimiento de masas. Sin embargo, el género distópico ofrece interesantes claves de lectura para entender el presente. En la cultura occidental, la distopía parece haber substituido definitivamente a la utopía como herramienta de crítica del presente. A través del análisis de obras literarias que ofrecen una representación de la ciudad del futuro, la investigación emprende un recorrido histórico por el auge y el declive del mito del progreso. El primer momento corresponde a la construcción de la imagen de una ciudad del futuro radicalmente transformada por las conquistas de la ciencia y la tecnología. Esta etapa empieza con la publicación de "New Atlantis", de F. Bacon (1621), y se cierra con "Les cinq cents millions de la Begum", de J . Veme (1879). En cambio, la literatura de las dos últimas décadas del siglo xx se caracteriza por miradas más sombrías. El mito del progreso construido por la burguesía queda progresivamente eclipsado por el miedo al estallido de los conflictos de clase, por la explosión demográfica y la decadencia de los viejos imperios coloniales. Ciencia y tecnología dejan de desempeñar un papel positivo, utópico, y se convierten en fuerzas potencialmente destructivas. Es en este momento cuando se materializa la transición, en la representación literaria de la ciudad del futuro, de una visión positiva de las conquistas tecnológicas hacia una visión negativa, de la utopía tecnológica a la distopía totalitaria. En los años veinte, la publicación de "We", de Y. Zamjatin, novela ambientada en una ciudad completamente transparente, da comienzo a la distopía moderna, relato anticipatorio del nacimiento de un poder invisible dirigido al control total de la vida de la ciudadanía. Así como a la utopía le correspondían determinados modelos urbanos que encarnaban deseos y esperanzas colectivas, la distopía posee su proprio «juego espacial» en la transposición de miedos y pesadillas. A este género literario le corresponde una determinada forma de ciudad, rígidamente vigilada, segregada y jerarquizada. La distopía es también una caricatura de la utopía del orden. Sus ciudades son dibujadas a partir de una lectura crítica de las renovaciones propuestas por el urbanismo a partir de la Revolución Francesa. En la distopía, la arquitectura asume la función de «máquina para la fabricación de individuos», de tecnología biopolítica para la mejora de la especie humana a través de su condicionamiento tanto físico como moralLa città contemporanea, minacciata dalla crescita demografica fuori controllo e dall'aumento vertiginoso della povertà, possibile scenario di guerre future e del collasso ecologico, sembra si sia trasformata oggi nel catalizzatore di qualsiasi paura collettiva, in topos definitivo del disastro. Nonostante ciò, l'immagine negativa del suo futuro, così come viene rappresentata nella letteratura e nel cinema, sembra ricorrere ad un repertorio iconografico più antico. Spesso, la sua rappresentazione decadente coincide con le visioni pessimiste della letteratura tardo-vittoriana. Le rovine delle metropoli industriali come Detroit ricordano la grandiosità delle antiche capitali degli imperi caduti, trasformate oggi in aree archeologiche. Questa ricerca analizza alcuni dei meccanismi che guidano la trasformazione della città contemporanea, usando come strumenti i distinti modi in cui la letteratura ha rappresentato la sua immagine futura in maniera distorta e negativa. In numerose occasioni, la storia dell'architettura ha riflettuto sull'importanza della relazione esistente fra utopia e costruzione dello spazio urbano. Al contrario, la distopia, genere letterario sorto verso la fine del XIX secolo e riguardante la descrizione di società future indesiderabili e degenerate, sembra sia rimasta confinata alla funzione marginale di spettacolo di massa. Nonostante ciò, il genere distopico offre interessanti chiavi di lettura per comprendere il presente. Nella cultura occidentale, la distopia sembra aver sostituito definitivamente l'utopia come strumento di critica del presente. Attraverso l'analisi di opere letterarie che offrono una rappresentazione della città del futuro, la ricerca affronta un percorso storico dall'auge al declino del mito del progresso. Il primo momento corrisponde alla costruzione dell'immagine della città del futuro radicalmente trasformata dalle conquiste della scienza e della tecnologia. Questa tappa comincia con la pubblicazione di "New Atlantis", di F. Bacon (1621), y si chiude con "Les cinq cents millions de la Begum", di J. Verne (1879). Invece, la letteratura delle due ultime decadi del XIX secolo si caratterizza per un atteggiamento più negativo. Il mito del del progresso costruito dalla borghesia, viene progressivamente eclissato dalla paura per lo scoppio dei conflitti di classe, per l'esplosione demografica e la decadenza dei vecchi imperi coloniali. Scienza e tecnologia cessano di compiere un ruolo positivo, utopico, e si trasformano in forze potenzialmente distruttive. È in questo momento che avviene il passaggio, nella rappresentazione letteraria della città del futuro, da una visione positiva delle conquiste tecnologiche ad una visione negativa, dalla utopia tecnologica alla distopia totalitaria. Negli anni Venti, la pubblicazione di "We", di Y. Zamjatin, romanzo ambientato in una città interamente trasparente, da inizio alla distopia moderna, racconto anticipatore della nascita di un potere invisibile, volto al controllo totale della vita della cittadinanza. Così come all'utopia corrispondevano determinati modelli urbani che incarnavano desideri e speranze collettive, la distopia possiede il proprio “gioco spaziale”, trasposizione di paure ed incubi. A questo genere letterario corrisponde una determinata forma di città, rigidamente controllata, segregata e gerarchizzata. La distopia è anche una caricatura dell'utopia dell'ordine. Le sue città sono disegnate mediante una lettura critica dei rinnovamenti proposti dall'urbanistica dalla Rivoluzione Francese in poi. Nella distopia, l'architettura assume la funzione di “macchina per fabbricare individui”, di tecnologia biopolítica per migliorare la specie umana mediante il suo condizionamento sia fisico che morale

Cannibalism in temporary waters. Simulations and laboratory experiments revealed the role of spatial shape in the mosquito Aedes albopictus

Cannibalism is a commonly observed phenomenon in arthropod species having relevant consequences for population dynamics and individual fitness. It is a context-dependent behaviour and an understanding of the factors affecting cannibalism rate is crucial to highlight its ecological relevance. In mosquitoes, cannibalism between larval stages has been widely documented, and the role of density, food availability and length of contact between individuals also ascertained. However, although mosquitoes can develop in temporary water habitats with very heterogeneous topologies, the role of the site shape where cannibals and victims co-occur has been instead overlooked. In this paper, we investigated this issue by using a simulation approach and laboratory cannibalism experiments between old (third- and fourth-instars) and young (first-instar) larvae of the tiger mosquito Aedes albopictus. Three virtual spaces with different shapes were simulated and the number of larval encounters was estimated in each one to assess whether the spatial shape affected the number of encounters between cannibal and victims. Then, experimental trials in containers with similar shapes to those used in the simulations were performed, and the cannibalism rate was estimated at 24 and 48h. Our results showed that the spatial shape plays a role on cannibalism interactions, affecting the number of encounters between individuals. Indeed, in the experimental trials performed, we observed the highest cannibalism rate in the container with the highest number of encounters predicted by the simulations. Interestingly, we found also that spatial shape can affect cannibalism not only by affecting the number of encounters, but also the number of encounters ªfavorableº for cannibalistic events. Temporary waters are inhabited by several species other than mosquitoes. Our results, showing an influence of the spatial shape on cannibalism in Ae. albopictus larvae, add a new critical factor to those affecting ecological interactions in these habitats

Exon-intron structure and sequence variation of the calreticulin gene among Rhipicephalus sanguineus group ticks

Background: Calreticulin proteins (CRTs) are important components of tick saliva, which is involved in the blood meal success, pathogen transmission and host allergic responses. The characterization of the genes encoding for salivary proteins, such as CRTs, is pivotal to understand the mechanisms of tick-host interaction during blood meal and to develop tick control strategies based on their inhibition. In hard ticks, crt genes were shown to have only one intron with conserved position among species. In this study we investigated the exon-intron structure and variation of the crt gene in Rhipicephalus spp. ticks in order to assess the crt exon-intron structure and the potential utility of crt gene as a molecular marker. Methods: We sequenced the exon-intron region of crt gene in ticks belonging to so-called tropical and temperate lineages of Rhipicephalus sanguineus (sensu lato), Rhipicephalus sp. I, Rhipicephalus sp. III, Rhipicephalus sp. IV, R. guilhoni, R. muhsamae and R. turanicus. Genetic divergence and phylogenetic relationships between the sequences obtained were estimated. Results: All individuals belonging to the tropical lineage of R. sanguineus (s. l.), R. guilhoni, R. muhsamae, R. turanicus, Rhipicephalus sp. III and Rhipicephalus sp. IV analysed showed crt intron-present alleles. However, both crt intron-present and intron-absent alleles were found in Rhipicephalus sp. I and the temperate lineage of R. sanguineus (s. l.), showing the occurrence of an intraspecific intron presence-absence polymorphism. Phylogenetic relationships among the crt intron-present sequences showed distinct lineages for all taxa, with the tropical and temperate lineages of R. sanguineus (s. l.) being more closely related to each other. Conclusions: We expanded previous studies about the characterization of crt gene in hard ticks. Our results highlighted a previously overlooked variation in the crt structure among Rhipicephalus spp., and among hard ticks in general. Notably, the intron presence/absence polymorphism observed herein can be a candidate study-system to investigate the early stages of intron gain/loss before fixation at species level and some debated questions about intron evolution. Finally, the sequence variation observed supports the suitability of the crt gene for molecular recognition of Rhipicephalus spp. and for phylogenetic studies in association with other markers

Biological compatibility between two temperate lineages of brown dog ticks, Rhipicephalus sanguineus (sensu lato)

Background: The brown dog tick Rhipicephalus sanguineus (sensu stricto) is reputed to be the most widespread tick of domestic dogs worldwide and has also been implicated in the transmission of many pathogens to dogs and humans. For more than two centuries, Rh. sanguineus (s.s.) was regarded as a single taxon, even considering its poor original description and the inexistence of a type specimen. However, genetic and crossbreeding experiments have indicated the existence of at least two distinct taxa within this name: the so-called "temperate" and "tropical" lineages of Rh. sanguineus (sensu lato). Recent genetic studies have also demonstrated the existence of additional lineages of Rh. sanguineus (s.l.) in Europe and Asia. Herein, we assessed the biological compatibility between two lineages of Rh. sanguineus (s.l.) found in southern Europe, namely Rhipicephalus sp. I (from Italy) and Rhipicephalus sp. II (from Portugal). Methods: Ticks morphologically identified as Rh. sanguineus (s.l.) were collected in southern Portugal and southern Italy. Tick colonies were established and crossbreeding experiments conducted. Morphological, biological and genetic analyses were conducted. Results: Crossbreeding experiments confirmed that ticks from the two studied lineages were able to mate and generate fertile hybrids. Hybrid adult ticks always presented the same genotype of the mother, confirming maternal inheritance of mtDNA. However, larvae and nymphs originated from Rhipicephalus sp. I females presented mtDNA genotype of either Rhipicephalus sp. I or Rhipicephalus sp. II, suggesting the occurrence of paternal inheritance or mitochondrial heteroplasmy. While biologically compatible, these lineages are distinct genetically and phenotypically. Conclusions: The temperate lineages of Rh. sanguineus (s.l.) studied herein are biologically compatible and genetic data obtained from both pure and hybrid lines indicate the occurrence of paternal inheritance or mitochondrial heteroplasmy. This study opens new research avenues and raises question regarding the usefulness of genetic data and crossbreeding experiments as criteria for the definition of cryptic species in ticks

The choreography of the chemical defensome response to insecticide stress: insights into the Anopheles stephensi transcriptome using RNA-Seq

Animals respond to chemical stress with an array of gene families and pathways termed "chemical defensome". In arthropods, despite many defensome genes have been detected, how their activation is arranged during toxic exposure remains poorly understood. Here, we sequenced the transcriptome of Anopheles stephensi larvae exposed for six, 24 and 48 hours to the LD50 dose of the insecticide permethrin to monitor transcriptional changes of defensome genes across time. A total of 177 genes involved in insecticide defense were differentially expressed (DE) in at least one time-point, including genes encoding for Phase 0, I, II, III and antioxidant enzymes and for Heat Shock and Cuticular Proteins. Three major patterns emerged throughout time. First, most of DE genes were down-regulated at all time-points, suggesting a reallocation of energetic resources during insecticide stress. Second, single genes and clusters of genes turn off and on from six to 48 hours of treatment, showing a modulated response across time. Third, the number of up-regulated genes peaked at six hours and then decreased during exposure. Our results give a first picture of how defensome gene families respond against toxicants and provide a valuable resource for understanding how defensome genes work together during insecticide stress

Identification and Detection of a Novel Point Mutation in the Chitin Synthase Gene of Culex Pipiens Associated With Diflubenzuron Resistance

Diflubenzuron (DFB) is one of the most used insecticides in mosquito larval control including that of Culex pipiens, the proven vector of the recent West Nile Virus epidemics in Europe. Two mutations (I1043L and I1043M) in the chitin synthase (CHS) putative binding site of DFB have been previously reported in Cx. pipiens from Italy and associated with high levels of resistance against this larvicide