"From Natural History Museums to the African less explored regions"
Natural History collections are the repository of herpetological data since the eighteenth century. This data, in form of specimens, photos and documentation, play a critical role in growth of our knowledge regarding the diversity and distribution of herpetofauna, as well as contribute to modern research – from integrative taxonomy approaches, distribution modelling, anatomy, genomics, etc. In this presentation, I’ll present my experience dealing with these collections, with the aim of reviewing the herpetofauna diversity of two African countries – Angola and São Tomé & Principe. Combining data from historical collections and recent field work, I’ve been able to provide important insights on the hidden herpetological diversity of these regions, describe new species to science and provide baseline data for future research and conservation actions.
"The morphometric revolution in herpetology: synergies that advance our understanding of phenotypes"
The fast development of technical tools of geometric morphometrics for describing organismal morphology and of refined methods for testing hypotheses about its relation to other traits has brought a revolution to our understanding of phenotypic evolution. Building on technological advances that allow us to accurately capture small-scale variation in body structures, we are producing large amounts of high-dimensional morphological data, moving towards the era of big-data in morphometrics. Together with these advances in data acquisition, ground-breaking analytical procedures are continuously developed to provide robust solutions for the statistical analysis of these multidimensional data in light of organismal function, ecology and evolution. Remarkably, herps have long served as major model organisms for both methodological studies pushing forward the fields of morphometrics; and for empirical investigation that addressed key questions in ecology and evolution. Due to their wide geographical distribution, and their diverse life habits, these organisms have served as major models for studies that consider individual-level variation to investigate developmental processes and how these might be affected by humanly induced change; through population- and species-level studies concerned with linking shape variation across space to its underlying causes; and up to macroevolutionary diversity across wide timescales. I will discuss how such studies have drastically changed our way of exploring phenotypic evolution, and how they are expected to develop towards new avenues of inquiry further enhancing our understanding of the remarkable diversity of amphibians and reptiles.
"Parental decision-making in poison frogs"
Reproductive behaviour, like courtship, intra-sexual competition, inter-sexual mate choice, and parental care, are key determinants of individual fitness. In my research group we aim to understand the ecological factors that have shaped highly specialised and complex behaviours at the individual as well as the population level. Dendrobatid frogs exhibit elaborate and complex social behaviours, including territoriality, courtship, and parental care. In the last years we used the dendrobatid frog Allobates femoralis as a model to study the ecological and cognitive aspects of reproductive behaviour. This species is characterised by high male territoriality and predominantly male care in terms of tadpole transport from terrestrial clutches to aquatic deposition sites. A logistic keystone of my research was the establishment of an experimental frog population on a river island. We used the colonization phase to evaluate the use of microsatellite markers for genetic mark–recapture studies across amphibian life. We were could track individual tadpoles via their unique ‘genetic fingerprint’ throughout metamorphosis until adulthood, an approach that will be of substantial value for future studies on amphibian population ecology and evolution. Using molecular parentage analysis, we further established cross-generational pedigrees and reconstructed tadpole transport trajectories that allowed us to identify decision rules for tadpole deposition. The combination of behavioural observations, clutch manipulations and cross-fostering experiments, as well as individual tracking show that these little forest frogs are very thoughtful parents, exhibit excellent navigation and orientation abilities, as well as behavioural flexibility across various contexts.
"Integrative research to understand the reproductive polymorphism in Salamandra: evolving from water to terrestrial reproduction"
Reproductive diversity is one of the hallmarks of amphibians. Current classifications identity a few dozens of reproductive modes that are based on a set of characters (e.g. parental care strategies, oviposition site and clutch characteristics, duration of development, stage and size of hatchlings). The skip of the aquatic stage (i.e. terrestrialization) is the most remarkable reproductive shift in amphibians, which typically exhibit a biphasic life cycle with an aquatic larval stage. Viviparity is considered an adaptive innovation with two strategies: (i) larviparity (aquatic larvae) and (ii) pueriparity (terrestrial newborns). The Palearctic Salamandra-Lycisalamandra group is a unique viviparous clade in urodeles, with intra-specific reproductive polymorphism in two sister species: Salamandra salamandra and Salamandra algira. This group provides a remarkable opportunity to understand the evolution of a key reproductive innovation (i.e. pueriparity) that likely originated in response to strong selective pressures and involves profound phenotypic, ecological, and genetic changes. I will present an overview of an integrative research line studying the reproductive polymorphism in Salamandra, which benefits from team-work skills investigating specific questions and hypotheses. Specifically, I will highlight some past and ongoing studies exploring the distribution and potential drivers of pueriparity, phenotypic and genetic changes between reproductive modes and some eco-evolutionary consequences underlying this evolutionary novelty.
"Broad-scale impacts of invasive predators on amphibian communities"
Gentile Francesco Ficetola, Mattia Falaschi, Mathieu Denoel, Martina Muraro, Elia Lo Parrino, Simone Giachello, Daisy Pensotti, Chiara Gibertini, Andrea Dalpasso, Mathieu Denoel, Raoul Manenti
Invasive predators are a major conservation issue, yet their role on broad-scale amphibian decline remains controversial. By conducting several long-term, broad-scale monitoring programmes, we documented how invasive predators (predatory fish and crayfish) have multifaceted impacts on amphibian populations. Introduced fish species cause a loss of amphibian occupancy, and in some environments can determine broad-scale declines, with particularly strong impacts on paedomorphic species and the rapid loss of some species and of intra-specific diversity. In the last decades. The American crayfish Procambarus clarkii is quickly expanding its range at the global scale, causing the decline of multiple species. Dynamic occupancy modelling allowed to identify the processes through which the crayfish impacts amphibian populations. In some cases the crayfish caused extinctions in invaded wetlands but, for the majority of species, the effects of the crayfish mostly occurred at the meta-population levels. In invaded landscapes, colonization rate was significantly lower, and local extinctions were not compensated by recolonization, thus causing more negative population trends in the areas invaded by the crayfish. The control of invasive species is essential for the long-term conservation of amphibian populations, and to avoid that this invader further expands his range. However, patch-scale management of the impact of invasive species are insufficient. Predicting and controlling the long-term interplay between invasive and native populations require landscape-level approaches accounting for the complexity of spatial interactions.
"Effects of climate change on Liolaemidae"
The diversity of habitats, a consequence of the formation of the Andes mountain range has resulted in a great variety of environments in South America, and has allowed the development of numerous species with particularities in their ecology and physiology. The lizard family Liolaemidae is widely distributed, from central Peru, southward through Bolivia, western Paraguay, Chile and Argentina to northern Tierra del Fuego, and eastwards along the Atlantic coast of southern Brazil, Uruguay and Argentina, at elevations ranging from sea level to over 6000 m a.s.l. Here we analyze how abiotic factors (geography, climate) and biotic factors (oviparity vs. viviparity and affinity to the substrate) explain the variation in body temperature of field activity (Tb), preferred temperature (Tp), hours of restriction and potential hours of activity in lizards. The reconstruction of the ancestral character of the family Liolaemidae shows changes in Tb in the last ~ 20 thousand years that correspond to environmental changes, while Tp has a lower evolutionary rate than Tb, remains more stable and 3 °C higher than Tb and air temperature. The difference observed between Tb and Tp results in a wide thermal safety margin (TSM) in particular in viviparous species to cope with the increase in environmental temperatures due to climate change. The rapid increase in ambient temperatures over the next 50 to 80 years, combined with the anthropogenic impact caused by habitat loss, is expected to lead to the extirpation and extinction in particular of oviparous species located at low altitudes in arid systems.
Ronis da Silveira
(more info soon)
"Amphibians in ecotoxicology: the need for alternatives to animal experimentation"
Amphibians are amongst the most threatened group of vertebrates; the IUCN lists approximately 41% of the species as being threatened of extinction. The causes for such a drastic decline are manyfold, including habitat loss and fragmentation, diseases, pollution, among others. Following such worldwide decline, in the past decades the use of amphibians in scientific research increased vastly, namely, to understand the impacts that pollution may cause on them for conservation purposes. Given the high diversity (e.g. species, reproduction, life history, life modes) of this group, it is important to understand their biology to ensure their welfare while using them for animal experimentation. Adding to this, most available standard toxicity assays used to assess the effects that chemical contamination may cause to amphibians involve animal experimentation. This makes difficult their risk assessment considering the increasing amount of chemicals to be tested and the ethical issues involved. Thus, the need to develop non-animal alternatives for amphibians has been acknowledge by the scientific community and regulatory agencies. Accordingly, this lecture will focus on such needs and on new non-animal approaches that are being developed to support risk assessment of chemicals to amphibians.