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Carol D Von Dohlen - One of the best experts on this subject based on the ideXlab platform.
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phylogeny of the dragonfly genus sympetrum odonata Libellulidae
Organisms Diversity & Evolution, 2012Co-Authors: Erik M Pilgrim, Carol D Von DohlenAbstract:The libellulid dragonfly genus Sympetrum has been recognized since 1833, but lacks any morphological synapomorphies to unite the taxon. Previous researchers have disagreed over which species belong in Sympetrum, bringing the monophyly of the genus into question. We use DNA sequence data from 6 genetic loci (16S, tRNA-valine, 12S, elongation factor 1 alpha, cytochrome oxidase subunit I, and the second internal transcribed spacer region) and 25 morphological characters (mainly genitalic) to test the monophyly of Sympetrum with Bayesian inference and maximum likelihood analyses. Under Bayesian inference, all Sympetrum species included in this study form a clade, which also contains the Hawaiian monotypic genus Nesogonia, often considered a close relative of Sympetrum. Phylogenetic analyses also reveal at least six strongly supported clades (treated as species groups) within Sympetrum, but relationships between these species groups remain unresolved or unsupported. Although the relationships between Sympetrum species groups remain unresolved, several species groups include taxa from multiple biogeographic regions/continents, and the species group sister to the rest of Sympetrum contains migratory species from the New World and Africa. This pattern suggests a complex biogeographic history in Sympetrum shaped by vicariance and dispersal. Preliminary estimates of the divergence dates of Sympetrum species groups outline a rapid radiation of the groups approximately 32-38 million years ago, possibly influenced by cooling and drying climates of the late Eocene and early Oligocene.
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phylogeny of the sympetrinae odonata Libellulidae further evidence of the homoplasious nature of wing venation
Systematic Entomology, 2008Co-Authors: Erik M Pilgrim, Carol D Von DohlenAbstract:Sympetrinae is the largest subfamily of the diverse dragonfly family Libellulidae. This subfamily, like most libellulid subfamilies, is defined currently by a few wing venation characters, none of which are synapomorphies for the taxon. In this study, we used DNA sequence data from the nuclear locus elongation factor-1a and the mitochondrial loci 16S and 12S rRNA, together with 38 wing venation characters, to test the monophyly of the Sympetrinae and several other libellulid subfamilies. No analysis recovered Sympetrinae as mono- phyletic, partly because of the position of Leucorrhinia (of the subfamily Leucorrhininae) as a strongly supported sister to Sympetrum (of Sympetrinae) in all analyses. The subfamilies Brachydiplactinae, Leucorrhininae, Trameinae and Trithemistinae were also found not to be monophyletic. Libellulinae was the only subfamily supported strongly as monophyletic. Consistency indices and retention indices of wing venation characters used to define various subfamilies were closer to zero than unity, showing that many of these characters were homoplasious, and therefore not useful for a classification scheme within Libellulidae.
Erik M Pilgrim - One of the best experts on this subject based on the ideXlab platform.
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phylogeny of the dragonfly genus sympetrum odonata Libellulidae
Organisms Diversity & Evolution, 2012Co-Authors: Erik M Pilgrim, Carol D Von DohlenAbstract:The libellulid dragonfly genus Sympetrum has been recognized since 1833, but lacks any morphological synapomorphies to unite the taxon. Previous researchers have disagreed over which species belong in Sympetrum, bringing the monophyly of the genus into question. We use DNA sequence data from 6 genetic loci (16S, tRNA-valine, 12S, elongation factor 1 alpha, cytochrome oxidase subunit I, and the second internal transcribed spacer region) and 25 morphological characters (mainly genitalic) to test the monophyly of Sympetrum with Bayesian inference and maximum likelihood analyses. Under Bayesian inference, all Sympetrum species included in this study form a clade, which also contains the Hawaiian monotypic genus Nesogonia, often considered a close relative of Sympetrum. Phylogenetic analyses also reveal at least six strongly supported clades (treated as species groups) within Sympetrum, but relationships between these species groups remain unresolved or unsupported. Although the relationships between Sympetrum species groups remain unresolved, several species groups include taxa from multiple biogeographic regions/continents, and the species group sister to the rest of Sympetrum contains migratory species from the New World and Africa. This pattern suggests a complex biogeographic history in Sympetrum shaped by vicariance and dispersal. Preliminary estimates of the divergence dates of Sympetrum species groups outline a rapid radiation of the groups approximately 32-38 million years ago, possibly influenced by cooling and drying climates of the late Eocene and early Oligocene.
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phylogeny of the sympetrinae odonata Libellulidae further evidence of the homoplasious nature of wing venation
Systematic Entomology, 2008Co-Authors: Erik M Pilgrim, Carol D Von DohlenAbstract:Sympetrinae is the largest subfamily of the diverse dragonfly family Libellulidae. This subfamily, like most libellulid subfamilies, is defined currently by a few wing venation characters, none of which are synapomorphies for the taxon. In this study, we used DNA sequence data from the nuclear locus elongation factor-1a and the mitochondrial loci 16S and 12S rRNA, together with 38 wing venation characters, to test the monophyly of the Sympetrinae and several other libellulid subfamilies. No analysis recovered Sympetrinae as mono- phyletic, partly because of the position of Leucorrhinia (of the subfamily Leucorrhininae) as a strongly supported sister to Sympetrum (of Sympetrinae) in all analyses. The subfamilies Brachydiplactinae, Leucorrhininae, Trameinae and Trithemistinae were also found not to be monophyletic. Libellulinae was the only subfamily supported strongly as monophyletic. Consistency indices and retention indices of wing venation characters used to define various subfamilies were closer to zero than unity, showing that many of these characters were homoplasious, and therefore not useful for a classification scheme within Libellulidae.
Kamilla Koch - One of the best experts on this subject based on the ideXlab platform.
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inflexible versus flexible the influence of temperature and photoperiod on pre and post eyespot development time in Libellulidae odonata
Physiological Entomology, 2016Co-Authors: Lisa Hesse, Joachim Falk, Kamilla KochAbstract:Temperature and photoperiod are important environmental parameters for organisms. The present study tests the hypothesis that, during embryogenesis, temperature and photoperiod influence pre- and post-eyespot development time in dragonflies of the family Libellulidae differently. Eggs are used from eight species (five different genera, from Africa/Europe, and lentic/lotic habitat preferences). The eggs are reared under different constant or fluctuating temperature and light conditions. There are no general species-specific degree-days for pre- or the post-eyespot development in these species. In all study species, the variance within and between the treatments of the duration in days and the degree-days of pre-eyespot development is lower than that of post-eyespot development. Pre-eyespot development appears to be less flexible in its reaction to environmental influences. By contrast, post-eyespot development appears to react more flexibly to environmental influences. All eight species show the same pattern. This indicates strongly that this flexibility is a general pattern in Libellulidae that might help the species within this family to cope successfully with variations in environmental conditions. Because eyespot development and katatrepsis occur close to each other, the above-described pattern might also appear in other odonates and in other insect groups that exhibit katatrepsis. For all of them, it is essential for survival to match the time of hatching with adequate external temperature and photoperiodic conditions.
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Inflexible versus flexible: the influence of temperature and photoperiod on pre‐ and post‐eyespot development time in Libellulidae (Odonata)
Physiological Entomology, 2016Co-Authors: Lisa Hesse, Joachim Falk, Kamilla KochAbstract:Temperature and photoperiod are important environmental parameters for organisms. The present study tests the hypothesis that, during embryogenesis, temperature and photoperiod influence pre- and post-eyespot development time in dragonflies of the family Libellulidae differently. Eggs are used from eight species (five different genera, from Africa/Europe, and lentic/lotic habitat preferences). The eggs are reared under different constant or fluctuating temperature and light conditions. There are no general species-specific degree-days for pre- or the post-eyespot development in these species. In all study species, the variance within and between the treatments of the duration in days and the degree-days of pre-eyespot development is lower than that of post-eyespot development. Pre-eyespot development appears to be less flexible in its reaction to environmental influences. By contrast, post-eyespot development appears to react more flexibly to environmental influences. All eight species show the same pattern. This indicates strongly that this flexibility is a general pattern in Libellulidae that might help the species within this family to cope successfully with variations in environmental conditions. Because eyespot development and katatrepsis occur close to each other, the above-described pattern might also appear in other odonates and in other insect groups that exhibit katatrepsis. For all of them, it is essential for survival to match the time of hatching with adequate external temperature and photoperiodic conditions.
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influence of temperature and photoperiod on embryonic development in the dragonfly sympetrum striolatum odonata Libellulidae
Physiological Entomology, 2015Co-Authors: Kamilla KochAbstract:Temperature and photoperiod play major roles in insect ecology. Many insect species have fixed degree-days for embryogenesis, with minimum and maximum temperature thresholds for egg and larval development and hatching. Often, photoperiodic changes trigger the transfer into the next life-cycle stadium. However, it is not known whether this distinct pattern also exist in a species with a high level of phenotypic plasticity in life-history traits. In the present study, eggs of the dragonfly Sympetrum striolatum Charpentier (Odonata: Libellulidae) are reared under different constant and fluctuating temperatures and photoperiodic conditions in several laboratory and field experiments. In general, and as expected, higher temperatures cause faster egg development. However, no general temperature or light-days for eyespot development and hatching are found. The minimum temperature thresholds are distinguished for survival (2 °C), embryogenesis (6 °C) and larval hatching (above 6 °C). Low winter temperatures synchronize hatching. Above 36 °C, no eyespots are visible and no larvae hatch. In laboratory experiments, light is neither necessary for eyespot development, nor for hatching. By contrast to the laboratory experiments, the field experiment show that naturally changing temperature and photoperiod play a significant role in the seasonal regulation of embryonic development. The post-eyespot development is more variable and influenced by temperature and photoperiod than the pre-eyespot development. This developmental plasticity at the end of the embryogenesis might be a general pattern in the Libellulidae, helping them to cope with variation in environmental conditions.
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Morphology of follicle cells of Libellulidae (Odonata)
International Journal of Odonatology, 2011Co-Authors: Kamilla Koch, Nadine Fuchs, Göran SahlénAbstract:In libellulids, mature oocyte size varies within and between individual ovaries. The regulating mechanism is not yet understood. Variations in the contents of the follicle cells, and thereby their ability to secrete material into the oocyte, might explain some of the observed differences in oocyte size. We therefore investigated the follicle cell surface, the interstitial space width between follicle cells and between follicle cells and oocytes, the number of nuclei, and the cell compartment proportions using scanning and transmission electron microscopy. In all investigated species, the follicle cells were covered by a basal lamina. We found cytoplasmic microvilli and septate junctions. As we could not find any pores or other structures on the cell surface, endocytosis seems to be the only mechanism transporting material into the follicle cells. Larger follicle cells had larger interstitial gaps between follicle cells and oocytes, larger nuclei and a larger mitochondrial area. Larger interstitial spaces between follicle cells and oocytes may afford more room that can be filled with material from the follicle cell layer. More mitochondria could provide more energy/ATP needed for the transport of the material. The quantity of free ribosomes and the mean number of nuclei seemed to be even more important to the productivity of the follicle cell. All these variations in cell contents cause productivity differences among follicle cells and may explain some of the size differences between oocytes within individual ovaries in libellulids.
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continuous and stepwise oocyte production in Libellulidae anisoptera
Odonatologica, 2010Co-Authors: Maria Karlsson, Göran Sahlén, Kamilla KochAbstract:Compared to other insect groups, libellulids have a rather high mean number of ovarioles. In addition, the mean ovariole diameter differs greatly between and within species. In general, 2 different types of ovariole arrangement exist: (1) all developing oocytes mature and equal in size; in some species without, and in others with, surrounding connective tissue and (2) oocytes displaying gradual maturation, with only the outermost ovarioles mature. These differences have ecological consequences: the first arrangement occurs in spp. that have stepwise egg production. These spp. will lay one or more clutches, after which an interclutch interval of ovariole regrowth follows. Spp. with the second arrangement have continuous egg production and are able to lay at least some eggs all the time, reducing the length of interclutch intervals. However, no direct connection between mate-guarding strategies and ovariole arrangements can be seen. Nevertheless, it is believed that the process of ovariole maturation differs between these groups. It is concluded that ovary morphology in libellulids may exhibit evolutionary fixed traits, although the whole picture still remains complex. The ovariole arrangement may have a crucial impact on the reproductive ecology of the species.
Stanislav N Gorb - One of the best experts on this subject based on the ideXlab platform.
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the probability of wing damage in the dragonfly sympetrum vulgatum anisoptera Libellulidae a field study
Biology Open, 2017Co-Authors: H Rajabi, Veronica Schroeter, Shahab Eshghi, Stanislav N GorbAbstract:ABSTRACT Dragonfly wings resist millions of cycles of dynamic loading in their lifespan. During their operation, the wings are subjected to relatively high mechanical stresses. They further experience accidental collisions which result from the insects9 daily activities, such as foraging, mating and fighting with other individuals. All these factors may lead to irreversible wing damage. Here, for the first time, we collected qualitative and quantitative data to systematically investigate the occurrence of damage in dragonfly wings in nature. The results obtained from the analysis of 119 wings from >30 individual Sympetrum vulgatum (Anisoptera: Libellulidae), collected at the second half of their flight period, indicate a high risk of damage in both fore- and hindwings. Statistical analyses show no significant difference between the extent of damage in fore- and hindwings, or between male and female dragonflies. However, we observe a considerable difference in the probability of damage in different wing regions. The wing damage is found to mainly result from two failure modes: wear and fracture.
Gunther Fleck - One of the best experts on this subject based on the ideXlab platform.
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The larva of the genus Misagria Kirby, 1889 (Odonata: Libellulidae).
Zootaxa, 2019Co-Authors: Gunther Fleck, Ulisses Gaspar NeissAbstract:: The ultimate stadium of Misagria parana Kirby, 1889 is described and illustrated for the first time based on reared material. The larva was hitherto unknown for the genus. Based on M. parana, M. divergens Westfall, 1992 and M. cf. calverti a larval generic diagnosis is given. Larva of the genus Misagria Kirby, 1889 is briefly compared to the strongly similar larvae of the Neotropical genera Cannaphila Kirby, 1889, and Dasythemis Karsch, 1889. Larvae of Misagria can be separated from those of Dasythemis by the number of palpal setae (seven in Misagria vs four in Dasythemis) and by the shape of ventral tarsal setae (trifid setae present in Misagria), and from those of Cannaphila by the number of palpal setae (seven vs five or six) and the chaetotaxy of middorsal abdominal segments (segments three to nine with a diffuse clump of long setae in Misagria vs no diffuse clump in Cannaphila).
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larval and molecular characters help to solve phylogenetic puzzles in the highly diverse dragonfly family Libellulidae insecta odonata anisoptera the tetrathemistinae are a polyphyletic group
Organisms Diversity & Evolution, 2008Co-Authors: Gunther Fleck, Manuela Brenk, Bernhard MisofAbstract:Abstract The systematics of the dragonfly family Libellulidae remains an unsolved puzzle. The classification into subfamilies relies primarily on wing venational characters, as is the case for most systematic hypotheses on dragonflies. In this study, we show that the discovery of unknown libellulid larvae can change tremendously our views on phylogenetic relationships. The larvae of the genera Micromacromia Karsch, 1889 and Allorhizucha Karsch, 1889 are described and illustrated. They are briefly compared with the larva of Neodythemis Karsch, 1889. The larvae of A. klingi Karsch, 1889 and N. africana Fraser, 1954 are extremely similar. The larva of M. camerunica Karsch, 1889 displays well developed dorsal hooks on abdominal segments 4–8, which distinguishes it from other closely allied genera. Micromacromia, Allorhizucha and Neodythemis are traditionally placed within the Tetrathemistinae, but their larvae strongly resemble those in the subfamily Libellulinae. Larval morphological studies and a molecular analysis based on mitochondrial SSU, LSU and tRNA valine imply that Micromacromia, Allorhizucha and Neodythemis have to be placed in the subfamily Libellulinae. Consequently, the subfamily Tetrathemistinae becomes a polyphyletic group. Our analysis suggests that imaginal characters, and in particular wing venation, are much more often prone to homoplasious evolution than previously anticipated. Taxonomic or systematic works predominantly based on wing venation might be in need of substantial revision, at least within this dragonfly family, presumably even in the whole suborder Anisoptera, based on independent character sets like larval and molecular data.
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la larve du genre cyanothemis ris 1915 odonata anisoptera Libellulidae consequences phylogenetiques
Annales De La Societe Entomologique De France, 2004Co-Authors: Gunther FleckAbstract:Resume La larve du genre Cyanothemis Ris, 1915 est decrite et illustree pour la premiere fois. L’etude des adultes et des larves des genres Lepthemis Hagen, 1861, Rhodothemis Ris, 1911 et Cyanothemis Ris, 1915 suggere qu’ils sont etroitement apparentes, comblant ainsi une lacune phylogenetique vieille de presque un siecle. Le genre Acisoma Rambur, 1842, bien que plus derive, doit egalement etre considere appartenir au clade (Cyanothemis + Lepthemis + Rhodothemis). Les genres Nannophya Rambur, 1842 et Nannothemis Brauer, 1868 places traditionnellement dans les Brachydiplacinae et non dans les Sympetrinae pourraient etre les adelphotaxons du clade (Acisoma + Cyanothemis + Lepthemis + Rhodothemis). Lutilisation de la nervation alaire, jusqu’alors preponderante, montre certaines limites dans la systematique et la phylogenie des Libellulidae.