A study of colour patterns leading to mimicry in bumblebees

Bumblebees represent one of the best examples of Müllerian mimicry, the convergence of colour patterns among species that serve as warning signal to predators. The aim ofthis study is to identify the colorimetric variables that best indicate similarities in different body parts of these insects. We examined hair colour patterns with spectroscopy analyses and evaluated measurement error (intra-individual variability), inter-individual and inter-specific variation in three cryptic species (Bombus terrestris, B. magnus, B. lucorum) collected in the Cantabrian Mountains (North Western Spain). We obtained 23 reflectance parameters in four different segmental sclerites (collar, scutellum, second abdominal tergite and tail) in 10 individuals per species (totalling 27600 measurements). Our results showed that these species co-occur in 40% -57% of sampling plots, being significant the positive association between B. lucorumand B. magnus. The variables that showed lower measurement error were ¿Mean brightness¿, ¿Intensity¿, ¿Chroma¿ and ¿Contrast¿ in all segments. With respect to biological differences, a high inter-individual variation in tail and scutellum were found through all species, especially in B. lucorumscutellum in the more repeatable variables. Differences between species were often of similar magnitude or only a bit higher than differences within species, especially for the variables associated with brightness and hue. Our study identifies the colour parameters and body segments that best reflect colour biological variability and that may serve to quantify the amount of convergence among species in studies of Müllerian mimicr

Evolutionary conservation of within-family biodiversity patterns

The raw data set has been deposited in the Digital CSIC repository (https://doi.org/ 10.20350/digitalCSIC/10529)The tendency for species to retain their ancestral biological properties has been widely demonstrated, but the effect of phylogenetic constraints when progressing from species to ensemble-level properties requires further assessment. Here we test whether community-level patterns (environmental shifts in local species richness and turnover) are phylogenetically conserved, assessing whether their similarity across different families of lichens, insects, and birds is dictated by the relatedness of these families. We show a significant phylogenetic signal in the shape of the species richness-elevation curve and the decay of community similarity with elevation: closely related families share community patterns within the three major taxa. Phylogenetic influences are partly explained by similarities among families in conserved traits defining body plan and interactions, implying a scaling of phylogenetic effects from the organismal to the community level. Consequently, the phylogenetic signal in community-level patterns informs about how the historical legacy of a taxon and shared responses among related taxa to similar environments contribute to community assembly and diversity patterns.This work was funded by grants CGL2014-53899-P/AEI/FEDER.UE and CGL2017-85191-P/AEI/FEDER.UE of the Spanish Ministry of Science, Innovation and Universities, and grant IDI/2018/000151 of Principado de AsturiasPeer reviewe

Survey & Traits Datasets

We compiled datasets using own data and literature data of surveys carried out in the Cantabrian Mountains, NW Spain, and a dataset of functional traits of the species of surveys. In Survey Datasets, data are presented as Site (Row) x Species (Column) matrices in which 1 indicate presence and 0 absence of a given species in a given site; habitat and geographic information are provided in additional columns. In Trait Datasets, data are presented as Species (Row) x Trait (Column) matrices.N

Selection for functional performance in the evolution of cuticle hardening mechanisms in insects

Calcified tissues have repeatedly evolved in many animal lineages and show a tremendous diversity of forms and functions. The cuticle of many insects is enriched with elements other than Calcium, a strategy of hardening that is taxonomically widespread but apparently poorly variable among clades. Here, we investigate the evolutionary potential of the enrichment with metals in insect cuticle at different biological levels. We combined experimental evidence of Zinc content variation in the mandibles of a target species (Chorthippus cazurroi [Bolívar]) with phylogenetic comparative analyses among grasshopper species. We found that mandibular Zinc content was repeatable among related individuals and was associated with an indicator of fitness, so there was potential for adaptive variation. Among species, Zinc enrichment evolved as a consequence of environmental and dietary influences on the physical function of the jaw (cutting and chewing), suggesting a role of natural selection in environmental fit. However, there were also important within and transgenerational environmental sources of similarity among individuals. These environmental influences, along with the tight relationship with biomechanics, may limit the potential for diversification of this hardening mechanism. This work provides novel insights into the diversification of biological structures and the link between evolutionary capacity and intra- and interspecific variation.We were supported by grants 4278 of the British Ecological Society, CGL2017-85191-P/AEI/FEDER.UE from the Spanish Ministry of Science and Innovation, LIQUENES from FICYT and EDP-HC Energía, and IDI/2018/000151 from Principado de Asturias.Peer reviewe

Data from: Selection for functional performance in the evolution of cuticle hardening mechanisms in insects

[Methods] We measured Zinc content and strengths of grasshopper mandibles, by means of scanning electron microscope and calibrated multifocus pictures. We used biological and ecological information obtained from field and experimental data on the grasshopper species inhabiting the Cantabrian Mountains (NW Spain). [Usage Notes] The different datasets of the study can be found in separate sheets. An informative title on sheet content has been given to each sheet. In tables, column names refer to the variable measured (and the unit of measurement).Calcified tissues have repeatedly evolved in many animal lineages and show a tremendous diversity of forms and functions. The cuticle of many insects is enriched with elements other than Calcium, a strategy of hardening that is taxonomically widespread but apparently poorly variable among clades. Here, we investigate the evolutionary potential of the enrichment with metals in insect cuticle at different biological levels. We combined experimental evidence of Zinc content variation in the mandibles of a target species (Chorthippus cazurroi) with phylogenetic comparative analyses among grasshopper species. We found that mandibular Zinc content was repeatable among related individuals and was associated with an indicator of fitness, so there was potential for adaptive variation. Among species, Zinc enrichment evolved as a consequence of environmental and dietary influences on the physical function of the jaw (cutting and chewing), suggesting a role of natural selection in environmental fit. However, there were also important within and transgenerational environmental sources of similarity among individuals. These environmental influences, along with the tight relationship with biomechanics, may limit the potential for diversification of this hardening mechanism. This work provides novel insights into the diversification of biological structures and the link between evolutionary capacity and intra and interspecific variation.Ministerio de Ciencia e Innovación, Award: CGL2017-85191-P/AEI/FEDER.UE. Gobierno del Principado de Asturias, Award: IDI/2018/000151. British Ecological Society, Award: 4278. FYCIT Asturias.Peer reviewe

The roles of geography, climate and sexual selection in driving divergence among insect populations on mountaintops

Aim Analysing the drivers of intraspecific variation and how reproductive barriers arise is an essential step to infer the mechanisms of biogeographic differentiation. In populations of a specialized alpine species, we explore the role of geography and climate in the divergence of genetic, morphological and acoustic characters, and analyse the functional consequences of variation on mate choice. Taxon Chorthippus cazurroi (Orthoptera: Caelifera, Acrididae, Gomphocerinae). Location The entire distribution of the species (23 populations from six massifs of the Cantabrian Mountains, NW Spain). Methods First, we analysed the extent of intraspecific spatial divergence and the covariation among climatic niche, genetic (mtDNA), acoustic (song structure) and morphological (body size) traits. Then, we analysed the consequences of phenotypic variation by means of a crossing experiment among populations from different elevations. This served to test for differences in sexual selection among body size‐divergent populations and for the relationship between male traits, female preference and reproduction. Results Genetic, morphologic and acoustic divergence increased with geographic distance. Female morphology was also affected by climate variation, while male one tightly covaried with the song differentiation. Females more closely approached males investing more time in song activities, but weakly responded to the rest of acoustic features and morphological variation. They also distanced themselves slightly more from males from different populations, although this behaviour did not lead to clear differences in reproductive parameters. Main conclusions The process of colonization of mountain massifs has led to significant genetic and phenotypic changes in C. cazurroi. Phenotypic divergence does not constitute a strong intrinsic barrier to reproduction and is largely unpaired from female preference, overall suggesting that sexual selection is a minor actor in the process of differentiation as compared, for instance, to drift. This does not exclude that traits associated with individual condition are under strong selection and, therefore, do not vary so extensively. This study dismisses the idea that alpine specialists with narrow distributions lack genetic and phenotypic variability, and highlights the importance of synthesizing biogeographic and experimental approaches to obtain stronger and deeper inferences about the dynamics and mechanisms of biological differentiation.Funding for this study was provided by grant 4278 of the British Ecological Society, grants CGL2011‐28177, CGL2014‐53899‐P and CGL2017‐85191‐P from the Spanish Ministry of Economy, Industry and Competitiveness, and grant LIQUENES 2014 from FICYT and edp‐HC Energía.Peer reviewe