Allometry of Defense: Predator Shift Alters Ontogenetic Growth Patterns in an Antipredator Trait

Predation is a major factor driving prey trait diversification and promoting ecological speciation. Consequently, antipredator traits are widely studied among prey species. However, comparative studies that examine how different predators shape the ontogenetic growth of antipredator traits are scarce. In larval dragonflies, abdominal spines are effective traits against predatory fish in fish lakes, which prefer larger prey. However, defensive spines increase mortality in habitats dominated by invertebrate predators (invertebrate lakes), which prefer smaller prey. Thus, species from fish lakes may accelerate spine growth at a later body size compared to species from invertebrate lakes when growing into the preferred prey size range of predatory fish. In this study, we constructed the allometric relationship between spine length and body size and compared the inflexion point of those growth curves in five species of Leucorrhinia dragonfly larvae. We found that fish-lake Leucorrhinia species accelerated spine growth at a larger body size than congenerics from invertebrate lakes. Further, rather than extending spine length constantly through development, fish-lake species rapidly accelerated spine growth at a larger body size. This is likely to be adaptive for avoiding invertebrate predation at an early life stage, which are also present in fish lakes, though in smaller numbers. Our results highlight that comparative studies of ontogenetic patterns in antipredator traits might be essential to develop an integrated understanding of predator–prey interactions

Conservation focused topsoil removal in calcareous fens – field experiences from northern Brandenburg

Abstract: The natural park „Uckermärkische Seen“ is outstanding due to precious brownmoss dominated calcareous fens. None of them are undisturbed or virgin. Even in the remote areas of northern Brandenburg peatlands suffer from permanent water shortage. They have been drained or show considerable deficiency of water due to human influences in catchment areas. To counteract succession expensive management is implemented since several decades, but necessary funds are threatened to run dry. As a further step to create small scale hideaways for endangered species conservation was focused on topsoil removal within two peatlands. This report presents practical experiences and offers first impressions of vegetation development within these newly developed sites. Two years after the measures altogether 87 vascular plant species and 9 moss species were recorded in the peat cutting areas. The numbers of species within those sites were between 15 and 50. The most frequent species were Phragmites australis, Carex rostrata, C. elata, Juncus articulatus, Utricularia minor, Menyanthes trifoliata, Chara vulgaris und C. intermedia.Zusammenfassung: Der Naturpark „Uckermärkische Seen“ zeichnet sich durch wertvolle, für Brandenburg bedeutsame, von Braunmoosen geprägte Kalkflachmoore aus. Keines dieser Moore blieb jedoch ungestört oder naturnah. Sie wurden entwässert oder weisen aufgrund des gestörten Landschaftswasserhaushaltes erhebliche Wasserdefizite auf. Durch aufwendige Pflege wird der Sukzession auf ausgewählten Flächen seit Jahrzehnten entgegengewirkt. Die finanziellen Mittel hierfür drohen jedoch bald zu versiegen. Um zumindest kleinflächig sichere Refugien für bedrohte Arten zu schaffen, wurden je drei Flachabtorfungen á 1000 m² in zwei Mooren angelegt. In diesem Beitrag werden praktische Erfahrungen und erste Eindrücke zur Vegetationsentwicklung auf den sechs zunächst vegetationsfreien Flächen wiedergegeben. Nach zwei Jahren wurden in den neu angelegten Flächen insgesamt 87 Samenpflanzen- und 9 Moosarten festgestellt. Die Artenzahl der Gefäßpflanzen lag dabei zwischen 15 und 50. Die höchste Stetigkeit erreichten Phragmites australis, Carex rostrata, C. elata, Juncus articulatus, Utricularia minor, Menyanthes trifoliata, Chara vulgaris und C. intermedia.DFG, SUB Göttingen, DGMTresearc

Vergleichende ökologische Untersuchungen an Epitheca bimaculata Charpentier 1825 im Saarland und in der Uckermark (Odonata: Corduliidae).

Zwischen 1988 und 1998 wurde diese als sehr selten geltende Art im Saarland (Südwestdeutschland) und in der Uckermark (Nordostdeutschland) an über 100 Gewässern entdeckt (Trockur & Mauersberger in prep.). Ein großer Teil der Habitate der Art in diesen beiden Regionen wurde in Bezug auf zahlreiche Parameter untersucht und verglichen. - Im Saarland besiedelt die Art eutrophe bis polytrophe künstliche Altwässer, Kiesgruben und Fischteiche in der Auenlandschaft. In der Uckermark handelt es sich bei den meisten Fundorten um eutrophe, natürliche Kleinseen vorwiegend in Endmoränennähe. Als hervorstechende Merkmale der Epitheca-Gewässer in beiden Gebieten dürfen gelten: - stehende Gewässer geringer Größe: 85% der Fundgewässer sind kleiner als 10 ha, 63% unter 4 ha; - relativ flache, zumeist ungeschichtete Wasserkörper: Maximaltiefe zwischen 1,1 und 12 m (91% unter 8 m, 67% zwischen 2 und 6 m), nur 12% mit vollständiger Temperaturschichtung; - sommerliches Sauerstoffdefizit in der Tiefe: nur wenige Gewässer besitzen noch über 2 mg/l O2 unterhalb 4 m Tiefe; - von Phytoplankton getrübte, eutrophe bis polytrophe Gewässer: Fortpflanzungsnachweise gelangen an Gewässern mit mittleren Sichttiefen zwischen 0,5 und 3,1 m (68% mit Sichttiefen unter 2 m); - Strukturen für Männchenreviere und als Eiablagesubstrat: ausgedehnte Schwimmblatt- oder oberflächennahe Submersvegetation (an 80% der Gewässer), seltener auch umgestürzte Bäume oder Röhrichthalme; - alle Gewässer sind von Ufergehölzen und/oder von Wald umgeben, in dem Laubbäume dominieren; - alle Gewässer weisen Fischbestände auf; - die Libellengemeinschaften werden von Orthetrum cancellatum, Cordulia aenea und Erythromma-Arten dominiert; die Besiedlungsdichte von Aeshniden ist zumeist gering. - Bisher mehrfach in der Literatur als charakteristisch genannte Gewässertypen können somit nicht als die wichtigen Epitheca-Habitate angesehen werden: große Klarwasserseen oder schwach saure Moorweiher. Als typischen Primärlebensraum der Art in Europa sehen wir Auengewässer und Kleinseen an, in denen ein nicht zu geringer Fischbestand die Biozönose steuert.StichwörterCorduliidae, limnology, Uckermark, Saarland Germany, co-existence, fish, habitat structure, broad-leavered tree, forest, water vegetation, dragonfly community, lake, flood plain, optimal habitat, primary habitat, threat, negative factor.Between 1988 and 1998, more than a hundred habitats of the supposedly rare corduliid dragonfly Epitheca bimaculata were studied in the western parts of the Saarland (SW- Germany), in the adjacent parts of Luxembourg and France (especially the valleys of the rivers Saar and Mosel) and in the Uckermark ('Biosphärenreservat Schorfheide-Chorin', NE- Germany). In the Saarland, the species inhabits eutrophic to polytrophic artificial backwaters, gravelpits and fish-ponds, whereas in the Uckermark it occurs in small natural, predominantly eutrophic lakes. Relevant characteristics of the Epitheca-habitats in both regions were the following: - still waters of small area: 85% of the habitats were less than 10 ha, 63% less than 4 ha; - relatively shallow water body without distinct stratification: maximum water depth between 1.1 and 12 m (91% less than 8 m, 67% between 2 and 6 m, only 12% with complete temperature stratification; - low oxygen content in deeper strata: usually less than 2 mg O2/l below 4 m; - water clouded by phytoplankton, eutrophic to polytrophic: breeding sites between 0.5 and 3.1 m median Secchi-depth (68% with visibility of less than 2 m); - water surface with abundant floating or submerged vegetation, more rarely also tree trunks or reed: substrates for oviposition and habitats of the younger larvae; - water surrounded by shrubs and/or deciduous woodland; - water inhabited by fish populations; - the dragonfly communities are dominated by Orthetrum cancellatum, Cordulia aenea and Erythromma species; aeshnids usually occur a low densities. - The typica habitats of Epitheca in central and western Europe are not large, oligotrophic lakes or slightly acetous bog ponds, but still waters in the flood plain (river lagoons or gravel pits) and small lakes inhabited by fish populations.KeywordsCorduliidae, limnology, Uckermark, Saarland Germany, co-existence, fish, habitat structure, broad-leavered tree, forest, water vegetation, dragonfly community, lake, flood plain, optimal habitat, primary habitat, threat, negative factor

Allometry of Defense: Predator Shift Alters Ontogenetic Growth Patterns in an Antipredator Trait

Predation is a major factor driving prey trait diversification and promoting ecological speciation. Consequently, antipredator traits are widely studied among prey species. However, comparative studies that examine how different predators shape the ontogenetic growth of antipredator traits are scarce. In larval dragonflies, abdominal spines are effective traits against predatory fish in fish lakes, which prefer larger prey. However, defensive spines increase mortality in habitats dominated by invertebrate predators (invertebrate lakes), which prefer smaller prey. Thus, species from fish lakes may accelerate spine growth at a later body size compared to species from invertebrate lakes when growing into the preferred prey size range of predatory fish. In this study, we constructed the allometric relationship between spine length and body size and compared the inflexion point of those growth curves in five species of Leucorrhinia dragonfly larvae. We found that fish-lake Leucorrhinia species accelerated spine growth at a larger body size than congenerics from invertebrate lakes. Further, rather than extending spine length constantly through development, fish-lake species rapidly accelerated spine growth at a larger body size. This is likely to be adaptive for avoiding invertebrate predation at an early life stage, which are also present in fish lakes, though in smaller numbers. Our results highlight that comparative studies of ontogenetic patterns in antipredator traits might be essential to develop an integrated understanding of predator–prey interactions

Data from: Relaxed predation results in reduced phenotypic integration in a suite of dragonflies

While changes in magnitude of single traits responding to selective agents have been studied intensively, little is known about selection shaping networks of traits and their patterns of co-variation. However, this is central for our understanding of phenotypic evolution since traits are embedded in a multivariate environment with selection affecting a multitude of traits simultaneously rather than individually. Here, we investigate inter- and intraspecific patterns of trait integration (trait correlations) in the larval abdomen of dragonflies as a response to a change in predator selection. Species of the dragonfly genus Leucorrhinia underwent a larval habitat shift from predatory fish to predatory dragonfly dominated lakes with an associated relaxation in selection pressure from fish predation. Our results indicate that the habitat-shift induced relaxed selection pressure caused phenotypic integration of abdominal traits to be reduced. Intraspecific findings matched patterns comparing species from both habitats with higher abdominal integration in response to predatory fish. This higher integration is probably a result of faster burst swimming speed. The abdomen holds the necessary morphological machinery to successfully evade predatory fish via burst swimming. Hence, abdominal traits have to function in a tight coordinated manner, since maladaptive variation and consequently non-optimal burst swimming would cause increased mortality. In predatory dragonfly dominated lakes no such strong link between burst swimming and mortality is present. Our findings highlight the importance of studying multivariate trait relationships as a response to selection for understanding patterns of phenotypic diversification

Mikolajewski et al. JEB

Abdominal measures for phenotypic integration in Leucorrhinia-species

Scientific an Art Collections: TUD Dresden University of Technology

The extensive natural science and engineering collections as well as the important art collection of TU Dresden document almost 200 years of history of knowledge transfer and generation and are important testimonies to our university identity. Exhibits from the early 19th century connect the history of scientific knowledge with the research of our present and even influence future technologies when object-based evidence forms the basis for innovative research approaches.:5 Preface 7 KIRSTEN VINCENZ The collections of TUD Dresden University of Technology – tradition and new perspectives 17 KLAUS MAUERSBERGER The historical development of the collections at the TUD Dresden University of Technology 23 LUTZ GRAEFE The Collection of Astronomic-Geodetic Instruments 35 FRANK MÜLLER The Botanical Collection 47 MARINA LIENERT · CARIS-PETRA HEIDEL The Medical-Historical Collection 57 HORST HARTMANN · KIRSTEN VINCENZ The Dye Collection 69 DANIEL LORDICK The Collection of Mathematical Models 81 MANFRED F. BUCHROITHNER · WOLF GÜNTHER KOCH The Cartographic Collection 93 KLAUS MAUERSBERGER The “elektron” Collection of Communication Engineering and Precision Technology 105 RÜDIGER HOFFMANN The Historical Acoustic-Phonetic Collection 117 ECKHARD BENDIN The Color Research & Theory Collection 129 CHRISTIAN WÖLFEL · JENS KRZYWINSKI The Industrial Design Collection 139 GWENDOLIN KREMER · MARIA OBENAUS The Art Collections – living testimony of the University’s history 155 KLAUS MAUERSBERGER* The Collection “Doctors, Patients and Disease in Art” 169 JÖRG ZAUN Scientific and Art Collections – an Overview Scope · Location · Contacts 190 Literature and Sources 196 Index of Names 199 Authors 200 Publishing Detail