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11. Initial preference of oviposition sites: discrimination between living and dead plant material in Sympecma fusca and Coenagrion caerulescens (Odonata: Lestidae, Coenagrionidae)

Creator:
Martens, Andreas
Type:
article, model:article, and TEXT
Subject:
Odonata, Zygoptera, Lestidae, Coenagrionidae, Sympecma fusca, Coenagrion caerulescens, reproductive behaviour, oviposition site selection, and aggregation behaviour
Language:
English
Description:
Sympecma fusca and Coenagrion caerulescens mainly deposit their eggs into floating dead parts of emergent plants. In their initial choice of oviposition site (selection of landing site) S. fusca does not distinguish between fresh and dead plant material, whereas C. caerulescens significantly prefers dead material. In S. fusca, the missing discrimination of the plant condition in the choice of the landing site is explained by its oviposition period in the beginning of the vegetation period when the green plant material is rare. C. caerulescens reproduces in summer and finds dead and living plants side by side. I suggest that in the latter species an early recognition of dead material is advantageous because of the reduction of the expense in searching.
Rights:
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12. Latitudinal variation in morphology in two sympatric damselfly species with contrasting range dynamics (Odonata: Coenagrionidae)

Creator:
Hassall, Christopher, Thompson, David J., and Harvey, Ian F.
Type:
article, model:article, and TEXT
Subject:
Dragonfly, Odonata, Coenagrionidae, morphology, range shift, United Kingdom, body size, temperature, and voltinism
Language:
English
Description:
Geographic range expansion is one of the best documented macroecological consequences of climate change. A concomitant change in morphology has been demonstrated in some species. The relationship between latitudinal variation in morphology (e.g. Bergmann's rule) and the morphological consequences of microevolutionary pressures at expanding range margins have received little attention in the literature. Here we compare morphology of males of two Palaearctic damselfly (Odonata: Zygoptera) species, Coenagrion puella (Linnaeus, 1758) and Pyrrhosoma nymphula (Sulzer, 1776). C. puella has recently expanded its range from the north of England into Scotland. P. nymphula does not exhibit a range margin in the United Kingdom and has established populations in northern Scotland. We demonstrate evidence for spatially correlated variation in body size across the sampling sites between the two species but a deviation in patterns of dispersal-related morphology. P. nymphula exhibited very weak relationships between dispersal-related morphology (wing loading and thorax : abdomen mass ratio) and latitude. However, the more southerly-distributed C. puella exhibited strong relationships between mass investment in dispersal-related morphology and latitude. These trends appear to indicate compensatory growth patterns in cooler environments like those demonstrated for other species. The limits of this compensation for conditions that are close to the limits of a species' tolerance may contribute to the determination of the range margin. Greater variation in morphology towards the range margin has been observed in previous studies in Odonata. As such, the location of the sampling sites relative to the range margin of each species (closer in C. puella than P. nymphula) is highlighted as a potential contributing factor to the variation observed.
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13. Merlax bohemicus gen. n., sp. n. , a new fossil dragonfly from the Lower Miocene of northern Bohemia (Odoanta: Aeshnidae)

Creator:
Prokop, Jakub and Nel, André
Type:
article, model:article, and TEXT
Subject:
Odonata, Aeshnidae, Anactini, adult, new genus, fossil, Lower Miocene, Czech Republic, and Europe
Language:
English
Description:
Two aeshnid dragonflies are described from the Lower Miocene deposits in the Bílina mine in the north of the Czech Republic, including a new genus and species of Anactini, Merlax bohemicus gen. n., sp. n., and a further specimen assigned to the genus Aeshna.
Rights:
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14. Molecular taxonomy of the Sympetrum vulgatum (Odonata: Libellulidae) complex in the West Palaearctic

Creator:
Hinojosa, Joan C., Martín, Ricard, Maynou, Xavier, and Vila, Roger
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, vážky, fylogeografie, Odonata, phylogeography, Libellulidae, Sympetrum vulgatum, molecular systematics, molecular taxonomy, mitochondrial DNA, nuclear DNA, 2, and 59
Language:
English
Description:
The Sympetrum vulgatum (Linnaeus, 1758) complex is composed of the subspecies S. vulgatum vulgatum, S. vulgatum decoloratum (Selys, 1884) and S. vulgatum ibericum Ocharan, 1985 in the West Palaearctic. These taxa have parapatric distributions and noticeable morphological differences in colour and body size, and their taxonomic status is debated. Here we revise the systematics of this group using molecular taxonomy, including molecular analyses of mitochondrial (cytochrome c oxidase subunit I, COI) and nuclear (internal transcribed spacer, ITS1) DNA taking into account known morphological differences. Each subspecies has a unique and differentiated COI haplotype, although divergences among them are low (0.4% maximum uncorrected p-distance). The subspecies are not differentiated by the nuclear marker ITS1. The genetic results for these taxa contrast with the deep divergence of the sister species S. striolatum (Charpentier, 1840). Given current evidence, we propose to maintain the subspecific status of the S. vulgatum complex and hypothesize their biogeographical history. It is likely that the three subspecies became isolated during one of the latest glacial periods, each in a different refugium: S. vulgatum ibericum possibly occupied the Iberian Peninsula, S. vulgatum vulgatum the Balkan Peninsula or territories further east and S. vulgatum decoloratum Anatolia., Joan C. Hinojosa, Ricard Martín, Xavier Maynou, Roger Vila., and Obsahuje bibliografii
Rights:
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15. Motorway as a barrier to dispersal of the threatened dragonfly Sympetrum depressiusculum (Odonata: Libellulidae): consequence of mortality or crossing avoidance?

Creator:
Šigutová, Hana, Filip Harabiš, Hykel, Michal, and Aleš Dolný
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, vážky, chování živočichů, úmrtnost, Odonata, animal behavior, mortality, Libellulidae, dispersal barrier, dragonflies, habitat fragmentation, 2, and 59
Language:
English
Description:
Infrastructure is one of the main causes of landscape fragmentation, which results in isolation and loss of populations. Although the negative effect of roads on insects is well documented, only a minority of studies has focused on roads in the context of barriers to dispersal. Flying species in particular have been neglected. We investigated the effect of a four-lane motorway as a barrier to the movement of an isolated population of the threatened dragonfly Sympetrum depressiusculum in an agricultural landscape in Central Europe. Generalized additive models were used to assess the motorway's effect on (i) the distribution of adult dragonflies in patches of terrestrial habitat surrounding their natal site, and (ii) individual flight behaviour (i.e. willingness or unwillingness to cross the motorway). Movement patterns of marked adults throughout the landscape were also investigated. During one season, significantly fewer adults were found at patches located on the far side of the motorway, indicating it has a barrier effect. Observations on flight behaviour revealed no apparent effect of the motorway. The possible barrier effect for the species studied was therefore presumed to be a consequence of road mortality. Our results indicate that the motorway may influence the dispersal of this threatened species of dragonfly, which is a habitat specialist with particular requirements for its terrestrial environment. Negative effects on other species with similar behaviour and strategy can be presumed. When establishing new habitats, carrying out reintroductions or translocations, it is necessary to consider that roadways may reduce population size and affect population dynamics by limiting dispersal., Hana Šigutová, Filip Harabiš, Michal Hykel, Aleš Dolný., and Obsahuje bibliografii
Rights:
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16. Population structure and speciation in the dragonfly Sympetrum striolatum/nigrescens (Odonata: Libellulidae): An analysis using AFLP markers

Creator:
Parkes, Katherine A., Amos, William, Moore, Norman W., Hoffman, Joseph I. , and Moore, Janet
Type:
article, model:article, and TEXT
Subject:
Gene flow, STRUCTURE, morphotypes, dragonfly, Odonata, and Sympetrum striolatum/nigrescens
Language:
English
Description:
There has been a long-standing debate as to whether Sympetrum striolatum (Charpentier, 1840) and the darker northern form, S. nigrescens (Lucas, 1912) should be recognised as separate species of dragonfly. Here we address this question using genetic analysis based on AFLP markers and samples collected from sites across the species' United Kingdom range. The program STRUCTURE finds no support for specific status. Instead, it reveals strong patterns of divergence between populations sampled from Scottish islands and those on the mainland, suggesting that salt water is a major barrier to gene flow. Thus, the dark form is quite likely to reflect a beneficial polymorphism that allows individuals to take advantage of short periods of warmer weather. Our AFLP markers appear to be very rapidly evolving, showing little or no overlap between congeneric species, and hence are ideally suited to answering questions relating to the levels of gene flow among populations within species.
Rights:
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17. Sex- and morph-specific predation risk: Colour or behaviour dependency?

Creator:
Van Gossum, Hans, Adriaens, Tim, Dumont, Henri, and Stoks, Robby
Type:
article, model:article, and TEXT
Subject:
Behaviour, colour, Odonata, Enallagma cyathigerum, damselfly, detection, polymorphism, andro-, gynomorphs, predation, and survival
Language:
English
Description:
The coexistence of discrete morphs within a species, with one morph more conspicuous than the other(s) is often thought to result from both sexual selection and predation. In many damselflies, sexual dimorphism occurs jointly with multiple female colour morphs. Typically, one morph is coloured like the male (andromorph), while the other(s) is not (gynomorph(s)). The mechanisms contributing to the maintenance of such female polymorphism in damselflies remain poorly understood, especially the role of predation. We tested the detectability of two different female colour morphs of the damselfly, Enallagma cyathigerum, using human observers as model predators; andromorphs were detected more frequently than gynomorphs. Field data on mortality of males and the two different female morphs due to predation or drowning were also collected, and these observations support morph-specific mortality. In natural populations predation risk was higher in males than females; gynomorphs, however, were more prone to predation than andromorphs. Differences in behaviour between morphs, rather than colour, may explain this result.
Rights:
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18. The development of sexual differences in body size in Odonata in relation to mating systems

Creator:
Serrano-Meneses, Martin-Alejandro, Azpilicueta-Amorín, Mónica, Székely, Tamás, and Córdoba-Aguilar, Alex
Type:
article, model:article, and TEXT
Subject:
Odonata, Anisoptera, Anax imperator, Cordulegaster boltonii, Onychogomphus uncatus, Oxygastra curtisii, Zygoptera, Cercion lindeni, Ischnura graellsii, Platycnemis acutipennis, and sexual size dimorphism
Language:
English
Description:
Adult body size is the result of important environmental, maternal and/or genetic effects acting on animals during development. Here we investigate how sexual size dimorphism (SSD) develops in seven species of Odonata: Anax imperator, Cordulegaster boltonii, Onychogomphus uncatus, Oxygastra curtisii (Anisoptera), Cercion lindeni, Ischnura graellsii and Platycnemis acutipennis (Zygoptera). SSD of both the last larval and adult stages of the same individuals, which were reared under laboratory conditions, was measured. The aims were to investigate (i) whether SSD develops during the larval stage, (ii) the direction of larval and adult SSD, and (iii) whether the direction of adult SSD can be predicted by the mating system of a given species (e.g. males of territorial species being larger than females and the opposite for non-territorial species). We found that although larval differences in size may be present between the sexes, these are not necessarily shown in the adult stage (they may change or disappear). Also, the mating system was not related to patterns of adult SSD. Differences in SSD in larvae may be caused by differential use of resources via differential niche-utilisation or sex-specific growth patterns. We highlight the fact that sexual selection favouring large male size and fecundity selection, which selects for large females may be acting on the observed patterns in SSD in adults.
Rights:
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19. The life cycles of Boyeria irene and Onychogomphus uncatus (Odonata: Aeshnidae, Gomphidae) in western Spain: a biometric study

Creator:
Velasco-Villanueva, Tatiana , Campos, Francisco , Norling, Ulf , and Ferreras-Romero, Manuel
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Odonata, Aeshnidae, Gomphidae, dragonfly, Boyeria irene, Onychogomphus uncatus, life cycle, permanent streams, larval sizes, seasonal regulation, voltinism, and Spain
Language:
English
Description:
Co-occurrence of species with similar trophic requirements, such as odonates, seems to depend both on them occupying different microhabitats and differing in their life-cycles. The life cycles of the dragonflies Boyeria irene and Onychogomphus uncatus were studied in two consecutive years, mainly by systematic sampling of larvae in seven permanent head courses that constitute the upper basin of the River Águeda, western Spain, in the central part of the ranges of these two species. The size ranges of the last five larval stadia of both species were established based on biometric data. The eggs of the egg-overwintering aeshnid hatched in late spring and early summer and for the gomphid hatching peaked in middle-late summer. Both species showed mixed voltinism with "cohort splitting". B. irene had a dominant three-year development (partivoltinism), with some developing in two years (semivoltinism). O. uncatus requires four, sometimes three years to complete development (all partivoltine). B. irene larvae spent the winter before emergence in the last three, maybe four stadia, as a "summer species". O. uncatus mainly behaved as a "spring species", most larvae spending the last winter in the final larval stadium.
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20. Voltinism and larval growth pattern in Coenagrion mercuriale (Odonata: Coenagrionidae) at its northern range margin

Creator:
Purse, Bethan V. and Thompson, David J.
Type:
article, model:article, and TEXT
Subject:
Odonata, Coenagrion mercuriale, Pyrrhosoma nymphula, seasonal regulation, diapause, voltinism, larval growth, and intraspecific predation
Language:
English
Description:
Voltinism and larval growth pattern were investigated in an edge-of-range population of Coenagrion mercuriale. Coenagrion mercuriale is semi-voltine in Britain and growth is inhibited in winter. The 2nd year group overwinters in a range of instars between the antepenultimate and final instar consistent with the early, asynchronous emergence pattern of this species. A facultative autumnal diapause in the penultimate instar is the most likely mode of seasonal regulation. The broad size distribution of larvae produced by this growth pattern was wider than that found in co-occurring populations of Pyrrhosoma nymphula, a "spring" species with synchronous emergence. The broad size distributions may lead to considerable intraspecific interference between C. mercuriale larvae. Sex ratio in the last three larval instars of C. mercuriale did not differ significantly from unity. A laboratory investigation of the effect of temperature and photoperiod on growth and diapause in C. mercuriale is recommended to determine whether high minimum temperature thresholds for development limit both the width of the temporal niche and microhabitat use by this species at its range margin.
Rights:
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