GEDA conference on Lizards !

Dr. A. Rotger will give a seminar on the ecology and life-history of the Balearic Wall lizard at the Visitor Centre of Carbrera National Park in Colonia St Jordi. 

The seminar is free and for all public. Friday 19/04/2024, 19h - Colonia St Jordi.

New Publication on Lilfordi's lizard genome!

Gomez-Garrido, J., Cruz, F., Alioto, S.T., Feiner, N., Uller, T., Gut, M., Sanchez Escudero, I., Tavecchia, G., Rotger, A., Otalora Acevedo, K., and Baldo,  L., 2023 Chromosome-level genome assembly of Lilford’s wall lizard, Podarcis lilfordi (Günther, 1874) from the Balearic Islands (Spain), DNA Research,  https://doi.org/10.1093/dnares/dsad008      

Abstract: The Mediterranean lizard Podarcis lilfordi is an emblematic species of the Balearic Islands. The extensive phenotypic diversity among extant isolated populations makes the species a great insular model system for eco-evolutionary studies, as well as a challenging target for conservation management plans. Here we report the first high quality chromosome-level assembly and annotation of the P. lilfordi genome, along with its mitogenome, based on a mixed sequencing strategy (10X Genomics linked reads, Oxford Nanopore Technologies long reads and Hi-C scaffolding) coupled with extensive transcriptomic data (Illumina and PacBio). 

 The genome assembly (1.5 Gb) is highly contiguous (N50 = 90 Mb) and complete, with 99% of the sequence assigned to candidate chromosomal sequences and >97% gene completeness. We annotated a total of 25,663 protein-coding genes translating into 38,615 proteins. Comparison to the genome of the related species Podarcis muralis revealed substantial similarity in genome size, annotation metrics, repeat content, and a strong collinearity, despite their evolutionary distance (~18-20 MYA). This genome expands the repertoire of available reptilian genomes and will facilitate the exploration of the molecular and evolutionary processes underlying the extraordinary phenotypic diversity of this insular species, while providing a critical resource for conservation genomics.

New publication on Lilford's lizard microbiota!

Baldo L, Tavecchia G, Rotger A, Igual JM, Riera JL. 2023. Insular holobionts: persistence and seasonal plasticity of the Balearic wall lizard (Podarcis lilfordi) gut microbiota. PeerJ 11:e14511 https://doi.org/10.7717/peerj.14511

Summary:Background: Integrative studies of animals and associated microbial assemblages (i.e., the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Insular vertebrates provide ideal natural systems to understand patterns of host-gut microbiota coevolution, the resilience and plasticity these microbial communities over temporal and spatial scales, and ultimately their role in the host ecological adaptation.  

Methods:Here we used the endemic Balearic wall lizard Podarcis lilfordi to dissect the drivers of the microbial diversity within and across host allopatric populations/islets. By focusing on three extensively studied populations/islets of Mallorca (Spain) and fecal sampling from individually identified lizards along two years (both in spring and autumn), we sorted out the effect of islet, sex, life stage, year and season on the microbiota composition. We further related microbiota diversity to host genetics, trophic ecology and expected annual metabolic changes. 

Photo: G. Tavecchia

Results:All the three populations showed a remarkable conservation of the major microbial taxonomic profile, while carrying their unique microbial signature at finer level of taxonomic resolution (Amplicon Sequence Variants (ASVs)). Microbiota distances across populations were compatible with both host genetics (based on microsatellites) and trophic niche distances (based on stable isotopes and fecal content). Within populations, a large proportion of ASVs (30–50%) were recurrently found along the four sampling dates. The microbial diversity was strongly marked by seasonality, with no sex effect and a marginal life stage and annual effect. The microbiota showed seasonal fluctuations along the two sampled years, primarily due to changes in the relative abundances of fermentative bacteria (mostly families Lachnospiraceae and Ruminococcaceae), without any major compositional turnover. 

Conclusions:These results support a large resilience of the major compositional aspects of the P. lilfordi gut microbiota over the short-term evolutionary divergence of their host allopatric populations (<10,000 years), but also indicate an undergoing process of parallel diversification of the both host and associated gut microbes. Predictable seasonal dynamics in microbiota diversity suggests a role of microbiota plasticity in the lizards’ metabolic adaptation to their resource-constrained insular environments. Overall, our study supports the need for longitudinal and integrative studies of host and associated microbes in natural systems

New Publication on Lizard Body size differences!

Rotger, A., Igual, J.M., Genovart, M., [...], Tavecchia, G. 2021.  Contrasting Adult Body-Size in Sister Populations of the Balearic Lizard, Podarcis lilfordi (Günther 1874) Suggests Anthropogenic Selective Pressures. Herpethological Monograph  35: 53-64. https://doi.org/10.1655/HERPMONOGRAPHS-D-19-00005 

Summary: Recently isolated populations offer a good biological model to infer the evolutionary forces responsible for the current divergences across populations. We coupled genetic, morphometric, ecological, and demographic analyses from three island populations of the endemic Balearic Wall Lizard, Podarcis lilfordi, (Balearic archipelago, Spain) to infer the mechanisms underlying the observed differences in body size. For each population, we described plant community structure, derived a biotic capacity index, and used individual-based data on 1369 lizards captured and released during 6 yr (2009–2015) to estimate population density and body growth patterns.

We used genetic data collected on 80 individuals (∼27 for each population) to infer genetic divergences across islets and population history. Body size divergences cannot be explained by the ecological or population characteristics. Individual growth was slower in the smallest island, where lizards reached the largest average body size. In addition to having the highest density, results suggested that resource availability does not constrain asymptotic body size, but the speed at which individuals reach it does. The Approximate Bayesian Computation used to infer population history from genetic data supported the occurrence of two bottlenecks in the islet with the highest anthropogenic footprint. We emphasize the need to integrate ecological and genetic data and the importance of considering the effects of past human disturbance as an additional force in being able to model present island fauna.

New Publication on Lizard evolutionary demography

Rotger, A., Igual, J.M. and Tavecchia, G., 2020,  Contrasting size-dependent life-history straegy in an insular lizard. Current Zoology, https://doi.org/10.1093/cz/zoaa019

Abstract: In many species with continuous growth, body size is an important driver of life-history tactics and its relative importance is thought to reflect the spatio-temporal variability of selective pressures. We developed a deterministic size-dependent integral projection model (IPM) for three insular neighbouring lizard populations with contrasting adult body sizes to investigate how size-related selective pressures can influence lizard life-history tactics. 

Photo; G. Tavecchia

 For each population, we broke down differences in population growth rates into contributions from size-dependent body growth, survival, and fecundity. A life table response experiment (LTRE) was used to compare the population dynamics of the three populations and quantify the contributions of intrinsic demographic coefficients of each population to the population growth rate (λ). Perturbation analyses revealed that the largest adults contributed the most to the population growth rate, but this was not true in the population with the smallest adults and size-independent fertility. Although we were not able to identify a single factor responsible for this difference, the combination of the demographic model on a continuous trait coupled with a life table response experiment analysis revealed how sister populations of the same species follow different life strategies and showed different compensatory mechanisms among survival, individual body growth and fertility.Our results indicate that body size can play a contrasting role even in closely related and closely spaced populations.

A press note (in Spanish) here

New publication on Lilfordi's lizard !

Santamaría, S., Enoksen, C. A., Olsen, J., Tavecchia, G., Rotger, A., Igual, J.M. and Traveset A. 2019.Diet composition of the lizard Podarcis lilfordi (Lacertidae) on two small islands: an individual-resource network approach. Current Zoology, https://doi.org/10.1093/cz/zoz028

Abstract: Despite it is widely accepted that intrapopulation variation is fundamental to ecological and evolutionary processes, this level of information has only recently been included into network analysis of species/population interactions. When done, it has revealed non-random patterns in the distribution of trophic resources. Nestedness in resource use among individuals is the most recurrent observed pattern, often accompanied by an absence of modularity, but no previous studies examine bipartite modularity. We use network analysis to describe the diet composition of the Balearic endemic lizard Podarcis lilfordi in two islets at population and individual levels, based on the occurrence of food items in fecal samples.
Our objectives are to 1) compare niche structure at both levels, 2) characterize niche partition using nestedness and modularity, and 3) assess how size, sex, season, and spatial location influence niche structure. At population-level niche width was wide, but narrow at the level of the individual. Both islet networks were nested, indicating similar ranking of the food preferences among individuals, but also modular, which was partially explained by seasonality. Sex and body size did not notably affect diet composition. Large niche overlap and therefore possibly relaxed competition were observed among females in one of the islets and during spring on both islets. Likewise, higher modularity in autumn suggests that higher competition could lead to specialization in both populations, because resources are usually scarce in this season. The absence of spatial location influence on niche might respond to fine-grained spatio-temporally distribution of food resources. Behavioral traits, not included in this study, could also influence resource partitioning.

Spring lizard campaign 2018: first day!

The spring lizard campaign 2018 has began with a first sunny day and 58 individuals caught, photographed and released. Nearly all were old firends.

Award by the Spanish Society of Evolutionary Biology !

The work on the evolutionary demography of the Belearic Wall lizard by A. Rotger presented at the VI Congress of the Spanish Society of Evolutionary Biology was awarded with the 2nd prize for the best scientific poster. 


Well done Andreu!