Genetic variability on worldwide populations of the scale insect Pulvinariella mesembryanthemi

The South African scale insect Pulvinariella mesembryanthemi was introduced worldwide in several coastal areas with Mediterranean climate, probably through infested plants of Carpobrotus sp. Its high host specificity and its capacity to produce severe damages in the invasive Carpobrotus sp. plants makes this insect a potential biocontrol agent. To test the efficiency and host range of insects used for biocontrol, population genetic studies can help to unravel cryptic complexes and intraspecific diversity. In this study we performed a genetic analysis including native and exotic populations of P. mesembryanthemi, through Sanger sequencing of mitochondrial (cytochrome c oxidase I, COI) and ribosomal (D2–D3 expansion segments of the large subunit ribosomal RNA gene 28S) gene fragments. Accidentally, an endosymbiont was sequenced with one of the pair of primers used. The exotic populations of the insect did not show any variability among populations for both studied genes, which suggest a common origin of all studied introduced populations. Contrastingly, native populations showed high variability and seemed to be a cryptic species complex. Moreover, the Gauteng populations (from NE South Africa) were phylogenetically the closest to the exotic ones, suggesting that the exotic populations could be original from somewhere near this area. An endosymbiont of P. mesembryanthemi was detected, and the sequenced coxA gene was similar to that of the Rickettsiaceae family from the α-Proteobacteria, and close to other insect endosymbionts. To the best of our knowledge, this was the first mention of this endosymbiont in P. mesembryanthemi, although α-Proteobacteria endosymbionts have been reported for other sap-sucking insects.info:eu-repo/semantics/publishedVersio

A review of the distribution and ecology of the elusive Brown Hairstreak butterfly Thecla betulae (Lepidoptera, Lycaenidae) in the Iberian Peninsula

The Brown Hairstreak (Thecla betulae L.) is one of the least observed butterflies of the Palaearctic region, even though its distribution spans from Portugal in the west, to Russia and Korea in the far east. Adults are arboreal and seldom descend to ground level. As a result, this species is mostly monitored via the detection of eggs on the food plant during wintertime. In the Iberian Peninsula, this species was largely unknown until very recently, but a recent burst of regional studies in Spain has begun bridging this gap. However, their focused nature and a still incomplete knowledge on T. betulae in Portugal promoted the need for an integrative study at the Iberian scale. Here, we carried out a full literature review on the distribution, ecology and behaviour of T. betulae in Portugal and Spain. Complemented with field work in Portugal, we revealed an almost continuous distribution in the northern third of Iberia, whilst populations further south are mostly mountain-bound. In order to help with future discovery of new populations, we built a species-distribution model relating its occurrence with bioclimatic variables. This model accurately explains the current known occupation of the territory and highlights other areas where the species may potentially be found. Finally, we found evidence of a broadening of the species’ niche through the local use of an hitherto unknown food plant. This study sets a new knowledge baseline for future works and conservation of T. betulae through southern Europe.info:eu-repo/semantics/publishedVersio

Ancient divergence, a crisis of salt and another of ice shaped the evolution of the west Mediterranean butterfly Euchloe tagis

The Mediterranean region is an extremely complex hotspot where, since the Miocene, extensive geological, habitat and climate changes have taken place, alternating between warm and cold periods. These phenomena have taken a toll on the genetic composition of species, and surviving lineages have often adapted locally and diverged to the point of (complete) speciation. To study these phenomena, in this study we used one of the most enigmatic butterflies, the Portuguese dappled white, Euchloe tagis, a west Mediterranean endemic with fragmented, morphologically differentiated populations whose status have long been disputed. Even its affiliations with other Anthocharidini are largely unresolved. We used mitochondrial and nuclear markers under a phylogenetic and phylogeographical framework to evaluate its placement among relatives and population differentiation, reconstructing its evolutionary history. We found that this species had a Miocene origin ~15 Mya and was nearest to Euchloe s.s. and Elphinstonia. Its populations showed high genetic diversity but all coalesced to 5.3 Mya, when European and all but one African population diverged. Our multiple findings concerning the evolution of E. tagis through a changing, narrow habitable area might provide a more general perspective on how species survive within this hotspot of paramount importance.info:eu-repo/semantics/publishedVersio

Biologia e genética da conservação da branca-portuguesa, Euchloe tagis (Hübner, 1804) em Portugal

Tese de mestrado. Biologia (Biologia da Conservação). Universidade de Lisboa, Faculdade de Ciências, 2009A Branca-Portuguesa é uma espécie de borboleta (Insecta, Lepidoptera) cuja distribuição abarca a região Atlântico-Mediterrânica entre Portugal e Itália, Marrocos e Argélia, em núcleos fragmentados e divergentes do ponto de vista morfológico. O isolamento das suas populações advém fundamentalmente da sua especificidade ecológica na dependência de solos calcários onde se desenvolve um matagal mediterrânico de fácies calcícola e das plantas de que se alimentam as lagartas, as Assembleias. Este estudo, apoiado na importância das borboletas como elementos basilares nos ecossistemas, bem como na importância que a sua promoção representa para a conservação dos seus habitats, tem origem na lacuna de conhecimento existente sobre esta espécie em Portugal. A nível nacional, até ao presente apenas era conhecida uma única população, na Serra da Arrábida. A sinergia entre os dados cartográficos de distribuição dos calcários e das plantas alimentícias permitiu criar um mapa de distribuição potencial da espécie em Portugal e o trabalho de campo comprovou a existência de populações previamente desconhecidas no Alentejo e no Maciço Calcário Estremenho. Todos os locais de ocorrência partilham uma gama de características fundamentais para a sua subsistência. Através do seguimento e caracterização de todas as fases do seu ciclo-de-vida preencheu-se também uma outra lacuna de conhecimento. Através de um marcador molecular mitocondrial pretendeu-se avaliar o grau de diferenciação genética das populações europeias da espécie bem como inferir a sua história filogeográfica. E. tagis apresenta uma elevada diversidade genética não estruturada segundo a taxonomia e terá subsistido na Península durante o Quaternário em isolados policêntricos que sucessivamente entraram em contacto, tornando o padrão filogeográfico difuso. Com todos estes dados foi possível confrontar informação multidisciplinar para a conservação da Branca-Portuguesa, relevando-se a sua importância como espécie “guarda-chuva” e bio-indicadora de qualidade ecológica, podendo ser integrada, a par de outras espécies prioritárias como “espécie bandeira” dos seus habitats.The Portuguese Dappled White is a butterfly (Insecta, Lepidoptera) whose distribution encompasses fragmented and morphologically distinct populations in the Atlantico-Mediterranean region from Portugal to Italy, Morocco and Algeria. This fragmentation arises fundamentally from its ecological specificity, depending on limestone soils where a lush Mediterranean calcicole scrubland develops, which is also where its caterpillar foodplants, Candytufts, are to be found. This study has its origin in the absolute lack of knowledge regarding this species in Portugal and is supported by the keystone importance of butterflies for ecosystems and of their promotion towards the conservation of their habitats. At the national level, until now only one population was known to thrive, at Serra da Arrábida. The synergy between cartographic data of the distribution of both limestone soils and the butterfly’s foodplants made possible the production of a potential distribution map for the species in Portugal and subsequent fieldwork unveiled the existence of previously unknown populations in Alentejo and the Maciço Calcário Estremenho. An E. tagis site holds a number of fundamental characters which allow its survival. Through the rearing and description of its early-stages, a knowledge gap was filled-in. With the use of a molecular mitochondrial marker it was possible to evaluate the degree of genetic divergence among the European populations of E. tagis and infer its phylogeography. This species exhibits a high genetic diversity, albeit not structured according to current taxonomy and probably has thrived in the Península during the entire Quaternary in polycentric isolates with subsequent migration between them making the general phylogeographical pattern diffuse. With these data we could confront multidisciplinary information towards the conservation of the Portuguese-Dappled-White, emphasizing its importance as an umbrella species and a bio-indicator of ecological quality. Together with other charismatic, priority species it can also be a good flagship species for its habitats

Testing drivers of acoustic divergence in cicadas (Cicadidae: Tettigettalna )

Divergence in acoustic signals may have a crucial role in the speciation process of ani-mals that rely on sound for intra-specific recognition and mate attraction. The acous-tic adaptation hypothesis (AAH) postulates that signals should diverge according to the physical properties of the signalling environment. To be efficient, signals should maximize transmission and decrease degradation. To test which drivers of divergence exert the most influence in a speciose group of insects, we used a phylogenetic ap-proach to the evolution of acoustic signals in the cicada genus Tettigettalna, inves-tigating the relationship between acoustic traits (and their mode of evolution) and body size, climate and micro-/macro- habitat usage. Different traits showed different evolutionary paths. While acoustic divergence was generally independent of phyloge-netic history, some temporal variables’ divergence was associated with genetic drift. We found support for ecological adaptation at the temporal but not the spectral level. Temporal patterns are correlated with micro- and macro- habitat usage and tempera-ture stochasticity in ways that run against the AAH predictions, degrading signals more easily. These traits are likely to have evolved as an anti- predator strategy in conspicuous environments and low-density populations. Our results support a role of ecological selection, not excluding a likely role of sexual selection in the evolution of Tettigettalna calling songs, which should be further investigated in an integrative approach.info:eu-repo/semantics/publishedVersio

Integrative analysis reveals the divergence and speciation between sister Sooty Copper butterflies Lycaena bleusei and L. tityrus

The comparison of closely related taxa is cornerstone in biology, as understanding mechanisms leading up to differentiation in relation to extant shared characters are powerful tools in interpreting the evolutionary process. Hotspots of biodiversity such as the west-Mediterranean, where many lineages meet are ideal grounds to study these processes. We set to explore the interesting example of Sooty Copper butterflies: widespread Eurasian Lycaena tityrus (Poda, 1761) comes into contact in Iberia with closely related and local endemic, L. bleusei (Oberthür, 1884), which hasn’t always been considered a distinct species. An integrative analysis was designed, combining the use of extensive molecular data (five genes), geometric morphometrics analyses, verified and up-to-date distribution data, and environmental niche modelling, aimed at deciphering their true relationship, their placement within European Lycaena and trace their evolutionary history. We revealed several levels of differentiation: L. bleusei and L. tityrus appear to be reciprocally monophyletic independent gene-pools, distinct in all genes analysed, having mutually diverged 4.8 Ma ago. L. tityrus but not L. bleusei, further displays a genetic structure compatible with several glacial refugia, where populations assignable to infraspecific taxa surface. Conversely, L. bleusei shows a loss in mtDNA diversity in relation to nuDNA. Morphological analyses differentiate both species according to size and shape but also discriminate strong seasonal and sexual traits and a geographical phenotype segregation in L. tityrus. Finally, updated distribution and its modelling for current and glacial timeframes reveal both species respond differently to environmental variables, defining a mostly parapatric distribution and an overlapping belt where sympatry was recovered. During the last glacial maximum, a wider expansion in L. bleusei distribution explains current isolated populations. Our study highlights the importance of gathering several lines of evidence when deciphering the relationships between closely related populations in the fringe of cryptic species realm.info:eu-repo/semantics/publishedVersio

The effect of the Messinian salinity crisis on the early diversification of the Tettigettalna cicadas

The current distribution patterns of many Mediterranean species are often a consequence of large and impactful past geoclimatic events, such as the Messinian Salinity Crisis (MSC) and the Quaternary glacial cycles. Cicadas are flying insects with poor dispersal ability, which have experienced intense local differentiation in the Mediterranean, where the genus Tettigettalna has surfaced as a biogeographic model. The genus includes 10 species with species-specific calling songs but identical morphology. All Tettigettalna species are restricted to Southern Iberia, with the exception of T. estrellae (northwest Iberia), the widespread T. argentata (mainly Iberia, France and Italy), and T. afroamissa (Morocco). With an expanded genetic dataset involving nuclear (EF1α) and mitochondrial (5′ and 3′ COI and ATP) loci, we reconstructed the phylogeny of the genus and estimated divergence dates for Tettigettalna species under a Bayesian framework. Phylogeny with the new mitochondrial dataset was in agreement with previous studies, whereas the nuclear EF1α supported T. josei and T. afroamissa as monophyletic clades but lacked resolution to resolve the remaining taxa. Some sister taxa share mitochondrial haplotypes, hinting for incomplete lineage sorting. Estimates of divergence time settled T. josei as the earliest diverging lineage, likely as a pre- or early-MSC event. As for the origin of T. afroamissa in Morocco, though time estimates could not entirely rule out post-MSC dispersal, the most likely scenario points to isolation of African Tettigettalna after the reopening of the strait of Gibraltar. The Pleistocene glaciations that followed likely impacted on the diversification of the remaining species of the genus in southern Iberia refugia.info:eu-repo/semantics/submittedVersio

Population genomics of Bombus terrestris reveals high but unstructured genetic diversity in a potential glacial refugium

Ongoing climate change is expected to cause an increase in temperature and a reduction of precipitation levels in the Mediterranean region, which might cause changes in many species distributions. These effects negatively influence species gene pools, decreasing genetic variability and adaptive potential. Here, we use mitochondrial DNA and RADseq to analyse population genetic structure and genetic diversity of the bumblebee species Bombus terrestris (subspecies Bombus terrestris lusitanicus), in the Iberian Peninsula. Although this subspecies shows a panmictic pattern of population structure across Iberia and beyond, we found differentiation between subspecies B. t. lusitanicus and B. t. africanus, probably caused by the existence of barriers to gene flow between Iberia and North Africa. Furthermore, the results revealed that the Iberian Peninsula harbours a large fraction of B. terrestris intraspecific genetic variation, with the highest number of mitochondrial haplotypes found when compared with any other region in Europe studied so far, suggesting a potential role for the Iberian Peninsula as a glacial refugium. Our findings strengthen the idea that Iberia is a very important source of diversity for the global genetic pool of this species, because rare alleles might play a role in population resilience against human- or climate-mediated changes.info:eu-repo/semantics/publishedVersio

Population structure, adaptation and divergence of the meadow spittlebug, Philaenus spumarius (Hemiptera, Aphrophoridae), revealed by genomic and morphological data

Understanding patterns of population differentiation and gene flow in insect vectors of plant diseases is crucial for the implementation of management programs of disease. We investigated morphological and genome-wide variation across the distribution range of the spittlebug Philaenus spumarius (Linnaeus, 1758) (Hemiptera, Auchenorrhyncha, Aphrophoridae), presently the most important vector of the plant pathogenic bacterium Xylella fastidiosa Wells et al., 1987 in Europe. We found genome-wide divergence between P. spumarius and a very closely related species, P. tesselatus Melichar, 1899, at RAD sequencing markers. The two species may be identified by the morphology of male genitalia but are not differentiated at mitochondrial COI, making DNA barcoding with this gene ineffective. This highlights the importance of using integrative approaches in taxonomy. We detected admixture between P. tesselatus from Morocco and P. spumarius from the Iberian Peninsula, suggesting gene-flow between them. Within P. spumarius, we found a pattern of isolation-by-distance in European populations, likely acting alongside other factors restricting gene flow. Varying levels of co-occurrence of different lineages, showing heterogeneous levels of admixture, suggest other isolation mechanisms. The transatlantic populations of North America and Azores were genetically closer to the British population analyzed here, suggesting an origin from North-Western Europe, as already detected with mitochondrial DNA. Nevertheless, these may have been produced through different colonization events. We detected SNPs with signatures of positive selection associated with environmental variables, especially related to extremes and range variation in temperature and precipitation. The population genomics approach provided new insights into the patterns of divergence, gene flow and adaptation in these spittlebugs and led to several hypotheses that require further local investigation.Peer reviewe