Variation in body size and metamorphic traits of Iberian spadefoot toads over a short geographic distance

Determinants of geographic variation in body size are often poorly understood, especially in organisms with complex life cycles. We examined patterns of adult body size and metamorphic traits variation in Iberian spadefoot toad (Pelobates cultripes) populations, which exhibit an extreme reduction in adult body size, 71.6% reduction in body mass, within just about 30 km at south-western Spain. We hypothesized that size at and time to metamorphosis would be predictive of the spatial pattern observed in adult body size. Larvae from eight populations were raised in a common garden experiment at two different larval densities that allow to differentiate whether population divergence was genetically based or was simply a reflection of environmental variation and, in addition, whether this population divergence was modulated by differing crowding larval environments. Larger adult size populations had higher larval growth rates, attaining larger sizes at metamorphosis, and exhibited higher survival than smaller-sized populations at both densities, although accentuated at a low larval density. These population differences appeared to be consistent once embryo size variation was controlled for, suggesting that this phenotypic divergence is not due to maternal effects. Our results suggest considerable genetic differentiation in metamorphic traits that parallels and may be a causal determinant of geographic variation in adult body size. © 2008 The Authors.Peer Reviewe

Differential morphology and jumping performance of newly metamorphosed frogs of the hybridogenetic Rana esculenta complex

Closely related clonal and sexual populations may coexist in spite of the theorized lower potential for the evolution of clonal genotypes. Water frogs of the Rana esculenta complex have hemiclonal inheritance but most populations coexist with one of the recombinant parental species. We examine whether hemiclonal lineages may counterbalance their limitations of genetic variability by the adoption of one or more non-exclusive mechanisms: the general-purpose genotype or the frozen niche-variation model. Three coexisting hemiclones of the hybrid R. esculenta (GUT1, GUT2, GUT3) and both parental species (syntopic R. lessonae and allopatric R. ridibunda) were raised at two larval densities to examine morphological traits affecting jumping performance at the time of metamorphosis and size-independent jumping ability tested at three temperatures. Hind leg length and body mass at metamorphosis, traits that explain most of the variance in jumping performance, differed across hemiclones of R. esculenta. Metamorphs of hemiclone GUT1 had the longest hindlimbs and were bigger than metamorphs of the other hemiclones at low larval density but not at high density. Size adjusted jumping performance exhibited a significant genotype by larval density interaction. Metamorphs of GUT1 showed maximal jumping performance when raised at low larval density but at high density metamorphs of GUT2 were the best jumpers. In addition, within particular traits, differences were found between hemiclones across densities. These results appear to be consistent with both frozen niche-variation model and the general-purpose genotype model. Comparison with parental species revealed syntopic R. lessonae was smaller than hemiclones at metamorphosis but conversely exhibited better size-adjusted jumping performance when raised at low larval density. Temperature affected size-adjusted jumping performance only for frogs raised at low larval density but not for those raised at high larval densities. There was no significant temperature by hemiclone interaction.Peer Reviewe

Can age and growth patterns explain the geographical variation in the body size of two toad species?

Determining both the age structure and growth pattern allows to establish the causal factors, environmental and/or genetic, that eventually may be responsible for the observed pattern of divergence. We examined the variation in age structure and growth pattern across populations of two toad species, Pelobates cultripes and Epidalea calamita that exhibit a geographic variation in body size in southern Spain. For both species, populations differed in mean age but age structure did not correlate with body size variation across populations. Although the population with the youngest females found for E. calamita was the smallest in body size, the oldest males for both species were found in a small body size population. The growth pattern fit well to a von Bertalanffy growth model and interdemic divergence were found for both the asymptotic body size (Sm ) and the growth coefficients (k). As expected, Large-Bodied populations of both species attained higher Sm but, Small-Bodied population had higher, although non significantly different, k growth coefficients. Also, the Small-Bodied population attained sexual maturity sooner but had also high longevity. The observed pattern may reflect both environmental variations in resources availability affecting body size observed across populations, but also different growth and maturity pathways that may respond to contrasting selective pressures.Fil: Marangoni, Federico. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Tejedo, Miguel. Consejo Superior de Investigaciones Científicas; EspañaFil: Cogalniceanu, Dan. Universitatea Ovidius din Constanta; Rumani

Extreme reduction in body size and reproductive output associated with sandy substrates in two anuran species

Geographic variation in body size and reproductive traits has been reported in a wide range of organisms, including amphibians. Most studies have focused on latitudinal and/or altitudinal variation where differences in temperature and duration of the growing season are the main causes for population divergence. We describe a steep variation in body size and reproductive traits in two anuran species in southwestern Spain, associated with changes in the geological substrate. Pelobates cultripes and Bufo calamita (= Epidalea calamita) drastically reduced their size (a 71.6% and 76.1% reduction in body mass for P. cultripes and B. calamita, respectively) in just about 60 km. This extreme size reduction was more pronounced at the boundary between two different geological substrates (hercinic and sandy soil). Mean clutch mass, egg size, and clutch size were all smaller in B. calamita populations in the sandy environment. Likewise, clutch mass and egg size were both smaller in sandy P. cultripes populations. We observed a negative correlation between size-adjusted fecundity and egg size for both species, suggesting the existence of a reproductive trade-off that could explain the differences in reproductive allocation between populations and species. In P. cultripes, small-bodied populations had relatively higher fecundities and smaller eggs than large-bodied ones, whereas in B. calamita populations from the sandy area we found both populations with high fecundity and small eggs, and populations with low fecundity and large eggs. Common environmental effects associated with the sandy substrate produce a similar reduction in size in both toad species. © 2008 Koninklijke Brill NV, Leiden.Peer Reviewe

Can amphibians take the heat? Vulnerability to climate warming in subtropical and temperate larval amphibian communities

Predicting the biodiversity impacts of global warming implies that we know where and with what magnitude these impacts will be encountered. Amphibians are currently the most threatened vertebrates, mainly due to habitat loss and to emerging infectious diseases. Global warming may further exacerbate their decline in the near future, although the impact might vary geographically. We predicted that subtropical amphibians should be relatively susceptible to warming‐induced extinctions because their upper critical thermal limits (CT max) might be only slightly higher than maximum pond temperatures (T max). We tested this prediction by measuring CT max and T max for 47 larval amphibian species from two thermally distinct subtropical communities (the warm community of the Gran Chaco and the cool community of Atlantic Forest, northern Argentina), as well as from one European temperate community. Upper thermal tolerances of tadpoles were positively correlated (controlling for phylogeny) with maximum pond temperatures, although the slope was steeper in subtropical than in temperate species. CT max values were lowest in temperate species and highest in the subtropical warm community, which paradoxically, had very low warming tolerance (CT max–T max) and therefore may be prone to future local extinction from acute thermal stress if rising pond T max soon exceeds their CT max. Canopy‐protected subtropical cool species have larger warming tolerance and thus should be less impacted by peak temperatures. Temperate species are relatively secure to warming impacts, except for late breeders with low thermal tolerance, which may be exposed to physiological thermal stress in the coming years.Agencia Española de Cooperación y Desarrollo (AECID)Ministerio de Ciencia e Innovación de España CGL2009-12767-C02-02 y CGL2008-04814- C02-02Ministerio de Educación y Cultura de España. Beca postdoctoral MEC2007-0944Ministerio de Ciencia e Innovación de España. Beca posdoctoral de Juan de la Cierv

Variation in upper thermal tolerance among 19 species from temperate wetlands

Communities usually possess a multitude of interconnected trophic interactions within food webs. Their regulation generally depends on a balance between bottom-up and top-down effects. However, if sensitivity to temperature varies among species, rising temperatures may change trophic interactions via direct and indirect effects. We examined the critical thermal maximum (CTmax) of 19 species from temperate wetlands (insect predators, amphibian larvae, zooplankton and amphipods) and determined if they vary in their sensitivity to warming temperatures. CTmax differed between the groups, with predatory insects having higher CTmax than amphibians (both herbivorous larval anurans and predatory larval salamanders), amphipods and zooplankton. In a scenario of global warming, these differences in thermal tolerance may affect top-down and bottom-up processes, particularly considering that insect predators are more likely to maintain or improve their performance at higher temperatures, which could lead to increased predation rates on the herbivores in the food web. Further studies are needed to understand how the energy flows through communities, how species’ energy budgets may change and whether other physiological and behavioral responses (such as phenotypic plasticity and thermoregulation) can buffer or increase these changes in the top-down regulation of wetland food webs.U.S. National Science Foundation 0716149Ministerio de Ciencia e Innovación CGL2009-12767-C02-02Ministerio de Economía y Competitividad CGL201240246C0201, CGL2017-86924-

Molecular evidence for cryptic candidate species in Iberian Pelodytes (Anura, Pelodytidae)

Species delineation is a central topic in evolutionary biology, with current efforts focused on developing efficient analytical tools to extract the most information from molecular data and provide objective and repeatable results. In this paper we use a multilocus dataset (mtDNA and two nuclear markers) in a geographically comprehensive population sample across Iberia and Western Europe to delineate candidate species in a morphologically cryptic species group, Parsley frogs (genus Pelodytes). Pelodytes is the sole extant representative of an ancient, historically widely distributed anuran clade that currently includes three species: P. caucasicus in the Caucasus; P. punctatus in Western Europe, from Portugal to North-Western Italy; and P. ibericus in Southern Iberia. Phylogenetic analyses recovered four major well-supported haplotype clades in Western Europe, corresponding to well demarcated geographical subdivisions and exhibiting contrasting demographic histories. Splitting times date back to the Plio-Pleistocene and are very close in time. Species-tree analyses recovered one of these species lineages, corresponding to P. ibericus (lineage B). , as the sister taxon to the other three major species lineages, distributed respectively in: western Iberian Peninsula, along the Atlantic coast and part of central Portugal (lineage A); Central and Eastern Spain (lineage C); and North-eastern Spain, France and North-western Italy (lineage D). The latter is in turn subdivided into two sub-clades, one in SE France and NW Italy and the other one from NE Spain to NW France, suggesting the existence of a Mediterranean-Atlantic corridor along the Garonne river. An information theory-based validation approach implemented in SpedeSTEM supports an arrangement of four candidate species, suggesting the need for a taxonomic revision of Western European Pelodytes.This work was supported through Project “Genomics and Evolutionary Biology” cofinanced by North Portugal Regional Operational Programme 2007/2013 (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF); the Program Operacional Factores de Competitividade (COMPETE), and by national funds from Fundação para a Ciência e a Tecnologia (FCT), through the research Projects PTDC/BIA-BEC/099915/2008 and PTDC/BIA-BEC/105083/2008 to HG and FS, respectively; and grants CGL2008-04271-C02-01/BOS and CGL2011-28300 (Ministerio de Ciencia e Innovación, Ministerio de Economía y Competitividad, Spain, and FEDER) and PPII10-0097- 4200 (Junta de Comunidades de Castilla la Mancha and FEDER) to IMS, who was funded by Project “Biodiversity, Ecology and Global Change”, co-financed by North Portugal Regional Operational Programme 2007/2013 (ON.2–O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF) and is currently supported by funding from the Spanish Severo Ochoa Program (SEV-2012-0262). Additional funds were provided by grants: “Anfibios Endémicos de Andalucía” (Consejería de Medio Ambiente, Junta de Andalucía, Spain), and CGL2005-02931/BOS (Ministerio de Ciencia e Innovación, Spain) to MT. JDR is supported by a PhD grant from FCT (SFRH/BD/70631/2010), HG and FS are supported by postdoctoral grants from FCT (SFRH/BPD/26555/2006 and SFRH/BPD/87721/2012, respectively) and TSN by a research grant (BI) from ICETA/UP.Peer Reviewe

El simulador VBS-2 para la instrucción de una Unidad de Infantería Ligera

Actualmente, la simulación constituye una herramienta fundamental para la preparación e Instrucción del personal en Unidades, debido a que permite entrenar y homogenizar procedimientos antes de ponerlos en práctica sobre el terreno. Esto sin duda, permite reducir el coste económico y el impacto medioambiental que las actividades militares producen. No obstante, como tecnología todavía en desarrollo debido a su reciente incorporación, existe una gran reticencia por parte de algunos de los componentes de las Fuerzas Armadas que todavía consideran que estos nuevos métodos no son del todo fiables y eficaces. Es por ello que el objetivo de este Trabajo de Fin de Grado es conocer y demostrar de forma objetiva que se puede confiar en la utilización de este tipo de medios para apoyar la tarea de instruir a nuestros Soldados para el combate. Para ello se ha realizado el estudio de las posibilidades y de los componentes del simulador Virtual Battlespace 2 (VBS2), implementado en un gran número de Unidades y que permite el desarrollo de procedimientos para la realización de misiones de cualquier tipo de escenario y con un sinfín de materiales que el Mando puede utilizar. Particularmente el trabajo se ha desarrollado en el Batallón de Infantería Motorizado Barcelona II/62. Éste se inició con la recopilación y análisis de documentación para poder conocer los distintos tipos de simuladores que existen en el Ejército de Tierra para después centrarse en el VBS2. Tras descubrir en que consiste este simulador y sus partes más importantes, se han diseñado y realizado una serie de entrevistas a personal especializado del Batallón con el fin de conocer la opinión y ciertos aspectos concretos relacionados con el VBS2 en base al puesto táctico y funciones que desarrollan este personal en la Unidad. Con sus respuestas se han extraído una serie de conclusiones relevantes que se han analizado por entrevistado además de aquellos aspectos que compartían todos ellos. Seguidamente, se ha realizado la preparación y diseño de un ejercicio programado con el fin de poder ver cómo afecta la utilización del simulador en la Instrucción de una Unidad de Infantería Ligera, en este caso la Segunda Compañía de fusiles. Para ello se ha escogido y planeado un procedimiento táctico el cual se les ha explicado de manera teórica a toda la Compañía. Sin embargo, la Primera Sección puso en práctica dicho procedimiento con la realización de dos sesiones en el simulador VBS2. Más tarde, se trasladó el ejercicio al campo de maniobras donde ambas Secciones lo realizaron sobre el terreno. A partir de una lista de objetivos previamente realizada en base a este procedimiento, se anotaron las diferencias que se observaron entre ambos grupos, explicando más tarde otras discrepancias particulares observadas sobre el terreno. De todas estas observaciones se han extraído a su vez unas conclusiones del ejercicio programado. A continuación, aprovechando las sesiones realizadas en el ejercicio programado, se han encuestado a 26 personas pertenecientes a las escalas de Tropa y 6 Cuadros de Mando, todos ellos Sargentos, de la Segunda Compañía de fusiles del Batallón, con el objetivo de descubrir que opinión les merece a los principales usuarios de este simulador, aspecto a tener en cuenta si se quiere mejorar su rendimiento y eficiencia. A partir de los resultados se ha realizado un análisis descriptivo destacando aquellas preguntas y datos importantes para extraer una serie de conclusiones. Finalmente, se exponen las conclusiones de todo el trabajo realizado con una propuesta que pretende mejorar el problema principal que se detecta, así como la propuesta de futuras líneas de trabajo acerca de este simulador.<br /

Niche models at inter- and intraspecific levels reveal hierarchical niche differentiation in midwife toads

Variation and population structure play key roles in the speciation process, but adaptive intraspecific genetic variation is commonly ignored when forecasting species niches. Amphibians serve as excellent models for testing how climate and local adaptations shape species distributions due to physiological and dispersal constraints and long generational times. In this study, we analysed the climatic factors driving the evolution of the genus Alytes at inter- and intraspecific levels that may limit realized niches. We tested for both differences among the five recognized species and among intraspecific clades for three of the species (Alytes obstetricans, A. cisternasii, and A. dickhilleni). We employed ecological niche models with an ordination approach to perform niche overlap analyses and test hypotheses of niche conservatism or divergence. Our results showed strong differences in the environmental variables affecting species climatic requirements. At the interspecific level, tests of equivalence and similarity revealed that sister species were non-identical in their environmental niches, although they neither were entirely dissimilar. This pattern was also consistent at the intraspecific level, with the exception of A. cisternasii, whose clades appeared to have experienced a lower degree of niche divergence than clades of the other species. In conclusion, our results support that Alytes toads, examined at both the intra- and interspecific levels, tend to occupy similar, if not identical, climatic environments

Tolerância e sensibilidade térmica em anfíbios:Thermal tolerance and sensitivity in amphibians

Atualmente vivemos um cenário de alterações climáticas em que se prevê o aumento da temperatura média e da ocorrência de picos de temperatura extrema, entre outros. Sabendo que os anfíbios correspondem a uma parte importante da biodiversidade mundial e que estes possuem um número de características fisiológicas, ecológicas e de história de vida que os tornam bastante susceptíveis a mudanças no ambiente, é fundamental conseguir identificar as espécies/comunidades mais vulneráveis ao aquecimento global. Assim, o estudo da tolerância e da sensibilidade térmica das espécies, e em particular dos anfíbios, é muito importante quando se pretende prever o impacto que o aumento das temperaturas poderá ter na fauna e flora do planeta.We are currently living in a scenario of climate change in which the rise of the average environmental temperatures and the increase of events of extreme temperature peaks is forecasted, among others. The study of the thermal tolerance and sensitivity is very important, particularly in amphibians, when forecasting the impact of rising temperatures on both the fauna and flora of the world. Knowing that amphibians are an essential part of the world’s terrestrial and aquatic biodiversity, and that they possess a series of ecophysiological characteristics and life history traits, which makes them very susceptible to environmental changes, it is essential to identify the species/communities that are more vulnerable to global warming.Fil: Katzenberger, Marco. Consejo Superior de Investigaciones Científicas; EspañaFil: Tejedo, Miguel. Consejo Superior de Investigaciones Científicas; EspañaFil: Duarte, Helder. Consejo Superior de Investigaciones Científicas; EspañaFil: Marangoni, Federico. Universidad Nacional del Nordeste; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Beltran, Juan Francisco. Universidad de Sevilla; Españ