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Habel J.C.,Invertebrate Biology | Reuter M.,Luneburg University | Drees C.,Luneburg University | Pfaender J.,Alexander Koenig Research Museum
Journal of Insect Conservation

Isolated populations represent one of the main focuses in conservation biology. Long-term isolation often causes losses of genetic diversity and as a consequence might reduce individual fitness. Morphometric characters can be used as suitable markers to analyse ecological stress and individual fitness of local populations. Asymmetry in bilateral symmetry is used as a measure for developmental instability of populations and is often negatively correlated with population size and low genetic diversity. As a study system, we selected the endangered butterfly Parnassius apollo, which occurs in small and isolated remnant populations in Central Europe, but also in fairly large metapopulations in the Alps. We analysed wing morphometrics (shape and size characters) of 812 individuals representing (1) already extinct, (2) highly isolated and (3) still interconnected populations. Seventeen landmarks on veins were used to analyse morphological variances in the wing shape. Our data show significant deviations between landmarks on the left and right wing side within individuals and strong morphological variance among individuals. The highest morphological variability could be found for individuals in the Alps, however, the level of asymmetry was very similar for all populations analysed. The higher morphological variability found in the Alps can be interpreted as a consequence of the higher level of the genetic diversity detectable for this region. Analysis on morphological variance of P. apollo individuals of the Mosel valley using time series ranging from 1895 until today showed no significant rise in asymmetry and no decline of morphological variability over time, although, anthropogenic habitat destruction has caused severe bottlenecks in this population. © 2011 Springer Science+Business Media B.V. Source

Husemann M.,Baylor University | Namkung S.,Baylor University | Habel J.C.,Invertebrate Biology | Danley P.D.,Baylor University | Hochkirch A.,University of Trier
Zoologica Scripta

Historically, morphological traits have been used to examine the relationships of distantly related taxa with global distributions. The use of such traits, however, may be misleading and may not provide the resolution needed to distinguish various hypotheses that may explain the distribution patterns of widely distributed taxa. One such taxon, the Oedipodine grasshoppers, contains two tribes principally defined by wing morphologies: the Bryodemini have broad wings whereas Sphingonotini are narrow-winged. Through the use of morphological features alone, hypotheses concerning the evolution of these tribes cannot be distinguished. To differentiate hypotheses that may explain the distribution of Oedipodines, such as vicariance, natural dispersal and anthropogenic translocation, we used two mitochondrial and three nuclear gene fragments to reconstruct the phylogenetic relationships within and between the two tribes, and employed a molecular clock to evaluate the hypotheses of vicariance and dispersal. Our results clearly reject monophyly of the tribes and revealed monophyletic Old and New World clades, which is in agreement with previous molecular studies. The split between both clades was dated at 35Ma (±12Ma). This clearly rejects the vicariance hypothesis and supports a single invasion via the Beringian land bridge. In addition, our data clearly show that the similarities in wing morphology used for distinguishing both tribes are the result of at least one convergent event. Our study shows that interpretations of relationships based on the currently accepted taxonomy in the study groups will be error prone. We suggest that future revisions that consider our findings are required. © 2012 The Authors. Zoologica Scripta © 2012 The Norwegian Academy of Science and Letters. Source

Habel J.C.,Invertebrate Biology | Zachos F.E.,Natural History Museum Vienna
Biodiversity and Conservation

Habitats often show similar present structuring, but contrasting histories: habitats occur naturally fragmented due to abiotic or biotic factors over long time periods, but may also have become fragmented only recently through transformation from interconnected to highly fragmented habitats within short time periods. Species and populations being faced with such contrasting habitat scenarios also show contrasting responses at species and intraspecific level. Organisms and populations from naturally fragmented habitats may show a reduction in their genetic load (purging) due to purifying selection in isolation. In contrast, sudden habitat transformations from interconnected to highly fragmented structures and the resulting transition from gene flow or panmixia to strong population differentiation often have negative effects on biota; while species occur in interconnected population networks (maintaining a high proportion of genetic diversity), a sudden breakdown of gene flow may lead to a severe loss of genetic diversity and the manifestation of weakly deleterious alleles. In consequence, fragmented habitats need not have a negative impact on species per se, but the history of habitat structures, particularly fast transformation processes, may severely affect the persistence and fitness of species. © 2012 Springer Science+Business Media B.V. Source

Habel J.C.,Invertebrate Biology | Engler J.O.,University of Trier | Engler J.O.,Zoological Research Museum Alexander Koenig | Rodder D.,Zoological Research Museum Alexander Koenig | Schmitt T.,University of Trier
Conservation Genetics

The intensification of agricultural land use over wide parts of Europe has led to the decline of semi-natural habitats, such as extensively used meadows, with those that remain often being small and isolated. These rapid changes in land use during recent decades have strongly affected populations inhabiting these ecosystems. Increasing habitat deterioration and declining permeability of the surrounding landscape matrix disrupt the gene flow within metapopulations. The burnet moth species Zygaena loti has suffered strongly from recent habitat fragmentation, as reflected by its declining abundance. We have studied its population genetic structure and found a high level of genetic diversity in some of the populations analysed, while others display low genetic diversity and a lack of heterozygosity. Zygaena loti was formerly highly abundant in meadows and along the skirts of forests. However, the species is currently restricted to isolated habitat remnants, which is reflected by the high genetic divergence among populations (F ST: 0. 136). Species distribution modelling as well as the spatial examination of panmictic clusters within the study area strongly support a scattered population structure for this species. We suggest that populations with a high level of genetic diversity still represent the former genetic structure of interconnected populations, while populations with low numbers of alleles, high F IS values, and a lack of heterozygosity display the negative effects of reduced interconnectivity. A continuous exchange of individuals is necessary to maintain high genetic variability. Based on these results, we draw the general conclusion that more common taxa with originally large population networks and high genetic diversity suffer stronger from sudden habitat fragmentation than highly specialised species with lower genetic diversity which have persisted in isolated patches for long periods of time. © 2011 Springer Science+Business Media B.V. Source

Habel J.C.,Invertebrate Biology | Engler J.O.,University of Trier | Rodder D.,Zoologisches Forschungsmuseum Alexander Koenig | Schmitt T.,University of Trier
Conservation Genetics

Species often respond differently to identical environmental changes. Such different responses might be the consequence of varying ecological requirements and tolerances of specialists compared to generalists. We selected two closely related burnet moth species with contrasting ecological requirements: Zygaena carniolica is restricted to semi-natural calcareous grasslands and represents a stenotopic taxon, while Zygaena viciae occurs more widespread at extensively used meadows forming larger metapopulations. To examine different responses to recent habitat fragmentation, we analysed genetic and morphologic variation between populations of these two Zygaenid species in western Germany and adjoining areas in France and Luxembourg. Our data indicate contrasting genetic and morphologic patterns for both species: the genetic differentiation among populations is lower for Z. carniolica (F ST: 0.049) compared to Z. viciae (F ST: 0.058). The genetic diversity for Z. carniolica is rather low and homogeneously distributed over all populations, while Z. viciae has more alleles, which are unevenly distributed and often restricted to single populations, as shown by GENELAND models. The level of morphologic variance among and within (e. g. asymmetry) individuals is low for Z. carniolica, but much higher for Z. viciae. We conclude that these contrasting patterns mirror opposite responses on recent habitat degradation and associated loss of interconnectivity as a result of habitat destruction and land-use intensification. The data suggest that species like Z. viciae, with (historically) higher abundances suffer even stronger under the recent habitat loss. Morphologic asymmetry and genetic differentiation in the latter species rises, while diversity declines. More specialised taxa occurring in naturally isolated habitats (indicated by Species Distribution Models) feature an originally lower level of genetic diversity, and thus the impact of habitat decline on species' persistence is less dramatic, as shown for Z. carniolica. Hence, we conclude that past and recent occurrence pattern has to be taken into account when interpreting data in the light of conservation measures. © 2012 Springer Science+Business Media B.V. Source

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