Diversity, biogeography and chromosomal evolution in european butterflies

Tesis doctoral de Vlad Eugen Dinca

The butterflies of europe are arguably the best studied group of invertebrates. However, given the diversity of the group, there are many questions still awaiting answers, and much work needs yet to be done until our knowledge on the european butterfly fauna becomes satisfactory. In this work, we selected several key case studies to address topics related to european butterflies. The most relevant findings of these studies are: romania is the first country in the world having a comprehensive dna barcode reference database for butterflies. Dna barcoding allows the reliable identification of 90% of the romanian butterfly species. The remaining taxa can be identified up to species-pair level and, in some cases, involve species with controversial taxonomy or that hybridize regularly. dna barcoding appears to be more effective in the identification of romanian butterflies compared to external morphology (wing pattern), and comparable to internal morphology (male genitalia). the high levels of intraspecific divergence (>2%) found within eight species (including cases of lineages occurring in sympatry), suggest potential cryptic diversity and highlight the need for deeper studies using multiple sources of data. in some cases, dna barcoding provides population-level resolution, which highlights its potential applications as a complementary tool for conservation-oriented efforts, given the fact that it could facilitate comparative studies of genetic diversity and help to delineate subspecific taxonomic units of conservation importance. given the taxon coverage (both in terms of species and number of samples), and the parallel morphological study, our results provide an accurate estimation of dna barcoding success across temperate europe. a region-oriented dna barcoding strategy would foster the applicability of the method by providing non-specialists with a reliable identification tool, long before the worldwide barcoding initiative will have completely accomplished its goals. based on a population discovered in the southern carpathians (romania), the european endemic erebia oeme is recorded for the first time in the carpathian chain. The species is likely to be very local in the carpathians, but its presence may have also passed unnoticed due to external similarity with erebia medusa, from which it can be reliably distinguished based on genitalic examination, but also through dna barcoding. the common and widespread butterfly leptidea sinapis is the species with the highest (excluding polyploidy) chromosome number variability recorded in any metazoan (2n=56-106). This variation is actually comparable with the highest known level of within-genus karyotype variability. the chromosome number variation of l. Sinapis follows a longitudinally-oriented cline (2n=106 in spain to 2n=56 in eastern kazakhstan), which indicates either the direction of selective pressure involved in its formation, the direction of population dispersal, or both of these processes. given that (i) the different chromosomal races of l. Sinapis belong to the same species, (ii) intrapopulation chromosome number polymorphism exists, (iii) the chromosome number range overlaps between some populations separated by hundreds of kilometers, (iv) the species currently has a virtually continuous distribution and there were no obvious barriers for its continuous distribution in the past, (v) the species has a rather homogenous genetic structure, and (vi) chromosomal heterozygotes are abundant, this represents the first clearly documented case of rapid and massive within-species accumulation of multiple chromosomal rearrangements changing the number of chromosomes. This case offers a rare opportunity to study this process before drift, dispersal, selection, extinction and speciation erase the traces of microevolutionary events and just leave the final picture of a pronounced interspecific chromosomal difference. we showed that what has been formerly called the cryptic species pair leptidea sinapis – l. Reali actually comprises a triplet of species. The new species, l. Juvernica, is sister to the other two, is apparently synmorphic with l. Reali, and its reliable identification needs to be based on molecular or chromosomal data. the discovery of l. Juvernica is the first european case of a new butterfly species found within a pair of already acknowledged and intensively studied cryptic species. Its discovery requires a complete re-evaluation of all current knowledge on the species pair l. Sinapis – l. Reali, which has become an emerging model in the study of speciation in cryptic species. polyommatus celina is recorded for the first time in europe, where it occurs on several west mediterranean islands (balearics, sardinia, sicily, lipari), as well as across much of spain. The species is genetically distant from p. Icarus since it is more closely related to several other polyommatus taxa. Despite high similarities in external morphology, geometric morphometry of the male genitalia correlates well with genetic data, supporting the distinctness of the two taxa. polyommatus icarus and p. Celina display a complex biogeographical pattern that involves several cycles of vicariance, expansion and contraction in the mediterranean for both species. Polyommatus icarus appears to have had several glacial refugia (iberia, crete), but the main palaearctic lineage appears to have been expanding in a east-west direction. The lineage of p. Celina conserved on several west mediterranean islands diverged approximately 0.5 mya and might represent the outcome of an ancestral lineage that was once distributed across the mediterranean. Specimens occurring in iberia are the product of a recent colonization event from north africa. The invading palaearctic lineage of p. Icarus and the north african p. Celina form contact zones in the south of the iberian peninsula, but the two species appear to completely exclude each other on islands. despite the fact that european butterflies are the best studied group of invertebrates in the world, large parts of the continent are still lacking good quality data. This is well exemplified by our findings: l. Juvernica – new for science, p. Celina – new for europe, e. Oeme – first record in the carpathian chain, p. Andromedae – second area of occurrence in the carpathians, and several new records of butterfly and moth species poorly known in romania or even europe.

 

Datos académicos de la tesis doctoral «Diversity, biogeography and chromosomal evolution in european butterflies«

  • Título de la tesis:  Diversity, biogeography and chromosomal evolution in european butterflies
  • Autor:  Vlad Eugen Dinca
  • Universidad:  Autónoma de barcelona
  • Fecha de lectura de la tesis:  01/04/2011

 

Dirección y tribunal

  • Director de la tesis
    • Roger Vila Ujaldón
  • Tribunal
    • Presidente del tribunal: Miguel López munguira
    • joan Pons pons (vocal)
    • (vocal)
    • (vocal)

 

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