Diversification linked to larval host plant in the butterfly Eumedonia eumedon

It is widely accepted that the relationship between phytophagous insects and their host plants influences insect diversification. However, studies addressed at documenting host-associated genetic differentiation (HAD) and the mechanisms that drive reproductive isolation in host-associated lineages (or host races) are still scarce relative to insect diversity. To uncover further evidence on the HAD processes in Lepidoptera, we investigated the genetic structure of the geranium argus butterfly (Eumedonia eumedon) and tested for isolation by ecology (IBE) vs. isolation by distance (IBD). Genomic data revealed an array of host races (three of them in the same mountain range, the Cantabrian Mountains, northern Iberia) at apparently distinct levels of reproductive isolation. We found a pattern of IBE mediated by HAD at both local and European scales, in which genetic differentiation between populations and individuals correlated significantly with the taxonomic relatedness of the host plants. IBD was significant only when considered at the wider European scale. We hypothesize that, locally, HAD between Geranium-feeding populations was caused (at least partially) by allochrony, that is via adaptation of adult flight time to the flowering period of each host plant species. Nevertheless, the potential reproductive isolation between populations using Erodium and populations using Geranium cannot be explained by allochrony or IBD, and other mechanisms are expected to be at play.Peer reviewe

Rise and fall of island butterfly diversity : understanding genetic differentiation and extinction in a highly diverse archipelago

Aim. We describe fine-scale diversity patterns of the entire butterfly fauna occurring on the Tuscan Archipelago. By assessing the traits associated with population diversification, haplotype uniqueness and extinction, we aim to identify the factors determining the origin and maintenance of genetic diversity, and population vulnerability to environmental changes. Location. Tuscan Archipelago, Sardinia, Tuscany (Italy) and Corsica (France). Methods. We built a mtDNA dataset (1,303 COI sequences) for the 52 butterfly species reported in the Archipelago, also including specimens from neighbouring areas, and compiled data on 12 species traits and on the apparent extinction of species from the main islands. We calculated indices that measure genetic differentiation, and using phylogenetic regressions we evaluated the relationships between these indices and species traits. Finally, we inferred which traits are associated with disappearance of species on individual islands using phylogenetic regression. Results. The overall spatial pattern of genetic diversity corresponded with the proximity of the areas, but strong contrasts were also identified between geographically close areas. Together with the island endemics, several common and widespread species had a high genetic diversification among islands and mainland. Phylogenetic regressions revealed that smaller-sized, more specialized species, with a preference for drier regions, displayed greater genetic structure and/or haplotype uniqueness. Species that disappeared from islands had a higher population diversification. Capraia has experienced a notable loss of diversity, which significantly affected species with shorter flight periods. Main conclusions. Tuscan island butterflies are characterized by strong genetic contrasts and species differ in their contribution to the overall genetic diversity. By ranking the species for their contribution to genetic diversity and identifying the traits linked to the emergence and maintenance of diversity, we have developed a valuable tool for prioritizing populations as targets for monitoring and conservation action. The dataset constructed also represents a valuable resource for testing biogeographical hypotheses

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Data from: A mirage of cryptic species: genomics uncover striking mito-nuclear discordance in the butterfly Thymelicus sylvestris

Mitochondrial DNA (mtDNA) sequencing has led to an unprecedented rise in the identification of cryptic species. However, it is widely acknowledged that nuclear DNA (nuDNA) sequence data are also necessary to properly define species boundaries. Next generation sequencing techniques provide a wealth of nuclear genomic data, which can be used to ascertain both the evolutionary history and taxonomic status of putative cryptic species. Here, we focus on the intriguing case of the butterfly Thymelicus sylvestris (Lepidoptera: Hesperiidae). We identified six deeply diverged mitochondrial lineages; three distributed all across Europe and found in sympatry, suggesting a potential case of cryptic species. We then sequenced these six lineages using double-digest restriction-site associated DNA sequencing (ddRADseq). Nuclear genomic loci contradicted mtDNA patterns and genotypes generally clustered according to geography, i.e., a pattern expected under the assumption of postglacial recolonization from different refugia. Further analyses indicated that this strong mtDNA/nuDNA discrepancy cannot be explained by incomplete lineage sorting, sex-biased asymmetries, NUMTs, natural selection, introgression or Wolbachia-mediated genetic sweeps. We suggest that this mito-nuclear discordance was caused by long periods of geographic isolation followed by range expansions, homogenizing the nuclear but not the mitochondrial genome. These results highlight T. sylvestris as a potential case of multiple despeciation and/or lineage fusion events. We finally argue, since mtDNA and nuDNA do not necessarily follow the same mechanisms of evolution, their respective evolutionary history reflects complementary aspects of past demographic and biogeographic events

Can species endure massive introgression? Genomic evidence of asymmetric geneflow in Melitaea butterflies

Datasets and phylogenies used in the paper 'Can species endure massive introgression? Genomic evidence of asymmetric geneflow in Melitaea butterflies'</p

A mirage of cryptic species:genomics uncover striking mitonuclear discordance in the butterfly Thymelicus sylvestris

Abstract Mitochondrial DNA (mtDNA) sequencing has led to an unprecedented rise in the identification of cryptic species. However, it is widely acknowledged that nuclear DNA (nuDNA) sequence data are also necessary to properly define species boundaries. Next generation sequencing techniques provide a wealth of nuclear genomic data, which can be used to ascertain both the evolutionary history and taxonomic status of putative cryptic species. Here, we focus on the intriguing case of the butterfly Thymelicus sylvestris (Lepidoptera: Hesperiidae). We identified six deeply diverged mitochondrial lineages; three distributed all across Europe and found in sympatry, suggesting a potential case of cryptic species. We then sequenced these six lineages using double‐digest restriction‐site associated DNA sequencing (ddRADseq). Nuclear genomic loci contradicted mtDNA patterns and genotypes generally clustered according to geography, i.e., a pattern expected under the assumption of postglacial recolonization from different refugia. Further analyses indicated that this strong mtDNA/nuDNA discrepancy cannot be explained by incomplete lineage sorting, sex‐biased asymmetries, NUMTs, natural selection, introgression or Wolbachia‐mediated genetic sweeps. We suggest that this mitonuclear discordance was caused by long periods of geographic isolation followed by range expansions, homogenizing the nuclear but not the mitochondrial genome. These results highlight T. sylvestris as a potential case of multiple despeciation and/or lineage fusion events. We finally argue, since mtDNA and nuDNA do not necessarily follow the same mechanisms of evolution, their respective evolutionary history reflects complementary aspects of past demographic and biogeographic events

Hybridization fuelled diversification in Spialia butterflies

The importance of hybridization and introgression is well documented in the evolution of plants but, in insects, their role is not fully understood. Given the fact that insects are the most diverse group of organisms, assessing the impact of reticulation events on their evolution may be key to comprehend the emergence of such remarkable diversity. Here, we used an insect model, the Spialia butterflies, to gather genomic evidence of hybridization as a promoter of novel diversity. By using double-digest RADseq (ddRADseq), we explored the phylogenetic relationships between Spialia orbifer, S. rosae and S. sertorius, and documented two independent events of interspecific gene flow. Our data support that the Iberian endemism S. rosae probably received genetic material from S. orbifer in both mitochondrial and nuclear DNA, which could have contributed to a shift in the ecological preferences of S. rosae. We also show that admixture between S. sertorius and S. orbifer probably occurred in Italy. As a result, the admixed Sicilian populations of S. orbifer are differentiated from the rest of populations both genetically and morphologically, and display signatures of reproductive character displacement in the male genitalia. Additionally, our analyses indicated that genetic material from S. orbifer is present in S. sertorius along the Italian Peninsula. Our findings add to the view that hybridization is a pervasive phenomenon in nature and in butterflies in particular, with important consequences for evolution due to the emergence of novel phenotypes.Financial support was provided by projects PID2019-107078GB-I00 funded by MCIN/AEI/10.13039/501100011033 and 2017-SGR-991 funded by Generalitat de Catalunya to R.V., by grant BES-2017-080641, funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” to J.C.H. and by the project “Ricerca e conservazione sugli Impollinatori dell’Arcipelago Toscano e divulgazione sui Lepidotteri del parco” to L.D. Computational resources used by D.K. were supplied by the project "e-Infrastruktura CZ" (e-INFRA LM2018140) provided within the program Projects of Large Research, Development and Innovations Infrastructures.Peer reviewe

Diversification linked to larval host plant in the butterfly Eumedonia eumedon

Abstract It is widely accepted that the relationship between phytophagous insects and their host plants influences insect diversification. However, studies addressed at documenting host-associated genetic differentiation (HAD) and the mechanisms that drive reproductive isolation in host-associated lineages (or host races) are still scarce relative to insect diversity. To uncover further evidence on the HAD processes in Lepidoptera, we investigated the genetic structure of the geranium argus butterfly (Eumedonia eumedon) and tested for isolation by ecology (IBE) vs. isolation by distance (IBD). Genomic data revealed an array of host races (three of them in the same mountain range, the Cantabrian Mountains, northern Iberia) at apparently distinct levels of reproductive isolation. We found a pattern of IBE mediated by HAD at both local and European scales, in which genetic differentiation between populations and individuals correlated significantly with the taxonomic relatedness of the host plants. IBD was significant only when considered at the wider European scale. We hypothesize that, locally, HAD between Geranium-feeding populations was caused (at least partially) by allochrony, that is via adaptation of adult flight time to the flowering period of each host plant species. Nevertheless, the potential reproductive isolation between populations using Erodium and populations using Geranium cannot be explained by allochrony or IBD, and other mechanisms are expected to be at play

Genetic assessment and climate modelling of the Iberian specialist butterfly Euchloe bazae (Lepidoptera: Pieridae)

Abstract Although both positive (expansion of thermophilous species) and negative effects (retraction of cold-adapted species) have been attributed to global warming, range shifts may be constrained by the ecological traits of species. This can be especially true for highly specialised organisms like the Spanish Greenish Black-tip (Euchloe bazae), an Iberian endemic specialist of semiarid steppes with a debated taxonomic and conservation status. Here, we first seek to clarify the taxonomic status of this butterfly and its populations by using multilocus phylogenetic inference. Then, we update its distribution range and employ ecological niche modelling, combined with other sources of data, to re-evaluate its conservation status. Our results confirm E. bazae as a well-differentiated species with one of the most restricted distribution ranges among the European butterflies. We demonstrate that its two disjunct populations, regarded as subspecies, are genetically differentiated and should be treated as independent management units. Climate models under two future emission scenarios suggest an increase of the area climatically suitable. However, the suitability of the areas currently occupied is estimated to decrease, meaning that rapid range shifts could be required for the survival of the species. Given the presumably low dispersal capabilities of E. bazae, its current restricted distribution, high degree of population fragmentation (divided in two distant populations), low intrapopulation genetic variability, decline in extension and abundance, low densities, high yearly fluctuations, and numerous threats to its habitat, we consider that their populations are extremely fragile and we propose to consider it ‘Endangered’ [EN B1ab(i,ii,iii,iv); B2ab(i,ii,iii,iv)]

Rapid colour shift by reproductive character displacement in Cupido butterflies

Abstract Reproductive character displacement occurs when competition for successful breeding imposes a divergent selection on the interacting species, causing a divergence of reproductive traits. Here, we show that a disputed butterfly taxon is actually a case of male wing colour shift, apparently produced by reproductive character displacement. Using double digest restriction‐site associated DNA sequencing and mitochondrial DNA sequencing we studied four butterfly taxa of the subgenus Cupido (Lepidoptera: Lycaenidae): Cupido minimus and the taxon carswelli, both characterized by brown males and females, plus C. lorquinii and C. osiris, both with blue males and brown females. Unexpectedly, taxa carswelli and C. lorquinii were close to indistinguishable based on our genomic and mitochondrial data, despite displaying strikingly different male coloration. In addition, we report and analysed a brown male within the C. lorquinii range, which demonstrates that the brown morph occurs at very low frequency in C. lorquinii. Such evidence strongly suggests that carswelli is conspecific with C. lorquinii and represents populations with a fixed male brown colour morph. Considering that these brown populations occur in sympatry with or very close to the blue C. osiris, and that the blue C. lorquinii populations never do, we propose that the taxon carswelli could have lost the blue colour due to reproductive character displacement with C. osiris. Since male colour is important for conspecific recognition during courtship, we hypothesize that the observed colour shift may eventually trigger incipient speciation between blue and brown populations. Male colour seems to be an evolutionarily labile character in the Polyommatinae, and the mechanism described here might be at work in the wide diversification of this subfamily of butterflies