Hansruedi Wildermuth

Boyeria irene larvae of different stages sampled at several localities in the headwaters of the Gardon River, Southern France, frequently showed malformations and injuries in their anal pyramid. The majority of these were broken or imperfectly regenerated tips of the anal spines. To quantify this phenomenon in a standardized way, exuviae of B. iren...

Damselflies and dragonflies are well-known hosts of the West Palaearctic biting midge Forcipomyia paludis . Females of this ectoparasitic dipteran mainly cling to the host’s wings, sucking hemolymph from the wing veins. The midges are firmly attached to the wing surface with specialized tarsi, thus not being flung away during the host’s flight mane...

The female of the biting midge Forcipomyia paludis is a dipteran ectoparasite of West Palaearctic damselflies and dragonflies, sucking haemolymph mainly from wing veins of their hosts. This tiny midge remains firmly attached to the wings even during fast flight and aerial fight maneuvers as shown in the present paper by field studies of the large d...

Among the 75 dragonflies species assessed in Switzerland, 27 (36 %) are red listed according to the IUCN criteria. Half of the red list-species (13: 48 %) colonise fens and raised bogs and the second half inhabit other habitats: springs, small brooks and ditches, as well rivers with slow flows, small standing waterbodies and gravel shores of la...

Among the 75 dragonflies species assessed in Switzerland, 27 (36 %) are red listed according to the IUCN criteria. Half of the red list-species (13: 48 %) colonise fens and raised bogs and the second half inhabit other habitats: springs, small brooks and ditches, as well rivers with slow flows, small standing waterbodies and gravel shores of la...

Among the 75 dragonflies species assessed in Switzerland, 27 (36 %) are red listed according to the IUCN criteria. Half of the red list-species (13: 48 %) colonise fens and raised bogs and the second half inhabit other habitats: springs, small brooks and ditches, as well rivers with slow flows, small standing waterbodies and gravel shores of lakes....

A gynandromorphic individual of Trithemis aurora is reported from a garden in Palakkad district, Kerala state, India. Its eyes, thorax, legs, wings, and abdomen show mosaic gynandromorphy. The abdomen is mostly gynochromic with the tip bearing female appendages. Detailed study of the specimen shows that female characters predominate but significant...

The final instar larvae of the two species of the southern African gomphid genus Ceratogomphus, the South African endemic C. triceraticus and the more widespread C. pictus, are compared based on exuviae. Main differences are the shapes of the prementum and of the last abdominal segments, giving C. pictus a more slender and pointed appearance. Cerat...

Colonisation and dispersal behaviour of Coenagrion scitulum in Switzerland-facts and evidence (Odonata: Coenagrionidae)-In Europe, C. scitulum is mainly distributed in the Mediterranean area. Since the 1990s the species has extended its range north-and eastwards successively. In Switzerland, it established itself since 2002. Based on comprehensive...

The biting midge Forcipomyia paludis (Macfie, 1936) was found parasitizing seven Odonata species and subspecies in Georgia, southern Caucasus ecoregion, ca 1 800 km east of the nearest known occurrence in Europe. It is suggested that the distribution of this species ranges continuously from Ireland and Spain to the Caucasus. Three new host species...

Death feigning, sometimes designated as thanatosis, reflex immobilization, tonic immobility or faking death is generally assumed a last-resort antipredator defence, attempting to avoid being killed and consumed. Recently, faking death has also been claimed to exist with respect to sexual conflict in Odonata. Here we review a number of published cas...

In his 1958 book the well-known Swiss artist and odonatologist Paul-André Robert depicted a male Sympetrum striolatum adopting obelisk posture that might be interpreted as either warming-up or avoiding heat. We analysed the watercolour based on circumstantial evidence such as direction of irradiation, landscape, locality and season and we conclude...

The Kingfisher Alcedo atthis as dragonfly hunter (Aves: Alcedinidae; Odonata) – The Common Kingfisher mainly feeds on small fish and to a lesser extent on aquatic arthropods caught by plunge-diving. As little is known about the Kingfisher’s insect nutrition we investigated the captured prey on photos and video films and analysed the contents of pel...

Paul-André Robert (1901-1977), peintre et naturaliste suisse, a écrit et illustré plusieurs livres faisant autorité sur l’histoire naturelle. Il est bien connu en Europe pour son ouvrage « Les Libellules », paru en 1958. Sa monographie monumentale des larves des libellules d’Europe, commencée à l’âge de 16 ans, est cependant bien moins connue. Ce m...

Unguarded oviposition of Coenagrion scitulum (Odonata: Coenagrionidae)-A single ovi-positing female C. scitulum was observed at a small water body in Lower Austria in July 2016. This is presumably the first documented case of unguarded oviposition without immediately preceded copulation in a Coenagrion species.

Behavioural thermoregulation in Leucorrhinia pectoralis and L. rubicunda (Odonata: Li-bellulidae)-Libellulids are perchers that control their body temperature-in contrast to the endothermic fliers-during their activity periods at sunny sites mainly by perch selection and body posture. Hitherto, thermoregulation in Libellulidae was studied only in a...

Comparative functional morphology of vein joints in Odonata.

Onze ans après la première édition des Libellules de France, Belgique et Luxembourg, publication dorénavant épuisée, nous proposons ici la seconde édition de cet ouvrage, renforcée par l’intégration de la Confédération Helvétique. Tout en veillant à rester dans le même esprit que la première édition et l’ensemble de la collection Parthénope, l’ouvr...

A hitherto unknown swarming flight behaviour of Libellula quadrimaculata that included spectacular waterfall-like manoeuvres was observed and photographically documented in May and June 2015 in the steppes of the Kazakh Uplands. This unusual flight behaviour was connected to communal roosting aggregation. It is analysed and compared with common hyp...

A hitherto unknown swarming flight behaviour of Libellula quadrimaculata that included spectacular waterfall-like manoeuvres was observed and photographically documented in May and June 2015 in the steppes of the Kazakh Uplands. This unusual flight behaviour was connected to communal roosting aggregation. It is analysed and compared with common hyp...

German vernacular names for several species of Mediterranean dragonflies (Odonata) – German vernacular names are available for nearly all western Palaearctic odonate species. The meaning of these names, beginning from Schiemenz (1953), was mainly explained by Wildermuth & Martens (2014). The German translation of Dijkstra & Lewington (2014) expande...

Water mites on the wings of Sympetrum meridionale: an analysis of the 2013 records in Germany (Acari: Hydrachnidia; Odonata: Libellulidae) – During an extensive survey of Sym­ petrum meridionale in Germany parasitism of this species by the water mite Arrenurus papillator was recorded on the basis of photographic documents. The localities of para-si...

A male Libellula depressa was observed to mistake a dark-green passenger coach for a water body thus establishing his territory over the surface of the vehicle and using the radio antenna as perch. A videopolarimetric analysis of the car body showed that the light reflected from the bonnet was highly and horizontally polarized with rather similar p...

The biting midge Forcipomyia (Pterobosca) paludis is the only ceratopogonid species known to parasitise Odonata imagines in Europe. In this study, based mainly on the analysis of about 200 photographically documented cases, data on host species, parasite load and undisturbed position on the odonate body were analysed. The list of hitherto known hos...

Females of Forcipomyia paludis were studied microscopically during their feeding action on Odonata wings where they were mostly attached to main veins in the basal half of the wings. In some individuals rhythmic nodding of the head was noted. Conspicuously many midges lifted the abdominal tip every one or two minutes and from the anus fast growing...

Various methods for measuring the success of conservation actions and for evaluating aquatic habitats are outlined, based on quantifi ed dragonfl y monitoring. Th ey are discussed with respect to their practicability and information value, counts of adult males and especially of exuviae yielding the most valuable results. Th ese are presented by ac...

In a heterogeneous environment, males of Somatochlora flavomaculata regularly occupy site-fixed locations away from water, adjacent to vertical landscape elements, and to a lesser extent, also at water, i.e. at oviposition sites. Territories both over land and over water are typically patrolled by continuous site-fixed flights. These places serve a...

Artenschutz konzentriert sich bei den Libellen weitgehend auf Biotopschutz, d.h. auf die Erhaltung und Förderung der Gewässer, in denen ihre Larven sich entwickeln. Der Schwerpunkt des Leitfadens liegt deshalb auf den Lebensräumen. Die entsprechenden Kapitel sind nach einem einheitlichen Raster aufgebaut. In einem ersten Teil werden die Biotoptypen...

Dans le cas des libellules, la protection des espèces se concentre surtout sur la protection des habitats, c.-à-d. sur l’entretien et la conservation des cours et plans d’eau dans lesquels leurs larves se développent. Le guide met donc l’accent sur les milieux. Les chapitres qui leur sont consacrés sont tous rédigés selon le même schéma. Une premiè...

Due to the destruction of its primary habitats, the West Palaearctic libellulid Orthetrum coerulescens has suffered much decline in central Europe. However, at the regional scale it has survived in a variety of secondary habitat, such as draining ditches. In order to find adequate measures for its conservation and promotion, habitat use and habitat...

1. We observed that the dragonfly species Sympetrum flaveolum , S. striolatum , S. sanguineum , S. meridionale and S. danae were attracted by polished black gravestones in a Hungarian cemetery. 2. The insects showed the same behaviour as at water: (i) they perched persistently in the immediate vicinity of the chosen gravestones and defended their p...

Terrestrial mites as parasites of dragonflies: infestation of Ortherum coerulescens by Leptus sp. (Odonata: Libellulidae; Parasitengona: Erythraeidae) — During the 2001 flying season 110 mites of the genus Leptus were recorded on adults in five of six local populations of O. coeru- lescens in the Swiss Jura mountains. Of the host individuals 72.8 %...

A singular observation of an adult Tettigonia viridissima (Tettigoniidae) that captured a female Eutolmus rufibarbis (Asilidae) sucking a male Lestes sponsa (Lestidae) is reported. The reciprocal predation of Odonata, Asilidae, and Saltatoria (Ensifera, Caelifera) hitherto recorded in Europe is compiled and augmented by unpublished data on asilids...

A breeding pair of the Three-toed Woodpecker was recorded from mid-April until the end of June 2005 in the hilly region in the east of the Canton of Zurich, c. 22 km from the next breeding site in the northern Prealps. The drumming place was situated on a ridge at 922 m a.s.l. and consisted of a group of dead and partly broken conifers within a mix...

Based on all available data, the former and present distribution in Europe is presented and critically analysed. The sp. is extinct or has only survived at single or small clustered and isolated localities in many parts of the western borderlands of its former Eurasian area that extended from Belgium to Japan. It is continuously declining, especial...

The study describes how the aquatic flora and fauna could be protected and promoted by suitable shaping and management, using the example of the 'Drumlinlandschaft Zürcher Oberlauf', which is the relic of an originally wide-stretched moorland in the Swiss Midland. After abandoning the extensive use of bedding and peat around 1950 the peat cuttings...

The reproductive behaviour in relation to structural habitat resources was studied at mountain bogs of the Central Alps (Tyrol, Austria). The ♂ ♂ searched for mates at small clearings in coniferous forests where numerous scattered oviposition sites were hidden in dense vegetation, using 3 tactics: (1) they scanned the oviposition sites by slow flig...

Site attachment and displacement of adult Somatochlora alpestris were studied by means of mark-release-resighting during two years at two clusters of ponds (A, B) ca 8 km distant from each other on opposite slopes of Prättigau Valley in the Swiss Alps. Data on 127 marked tenerals in 1998 and 92 in 2000 at (A) were obtained. Additionally, in 1998, 1...

Heavy infestation by water mites in Cordulia aenea (Hydrachnida: Arrenurus; Odonata: Corduliidae). – A population of C. aenea heavily parasitized by larvae of Arrenurus sp.was found at a moorland lake in northern Germany in May 2002. The parasites attached in clusters, mainly to the pleural membrane ventrally on abdominal segments 7, 8 and 9. The f...

SUMMARY 1. Based on the findings that some dragonflies prefer either ‘dark’ or ‘bright’ water (as perceived by the human eye viewing downwards perpendicularly to the water surface), while others choose both types of water bodies in which to lay their eggs, the question arises: How can dragonflies distinguish a bright from a dark pond from far away,...

In the course of a 2-yr mark-resighting study on S. alpestris at 2000 m a.s.l. in the Central Alps of Switzerland snow fell during the beginning of the reproductive period in July 2000. The snow cover was up to 30 cm thick and remained for about 8 days. Only 3% of the individuals marked as tenerals and 4% of those marked as matures before the cold...

The model describes a management mode enabling the establishment of a mosaic of all succession stages, with changes in space and time on a confined area. By offering different succession stages at the same time it is intended to provide permanent habitats for a high diversity of aquatic organisms. The model simulates the fictitious dynamics of smal...

Reflex immobilization in dragonfly larvae (Odonata)-Larv ae of 18 Eu­ropean Anisoptera species, mainly final instar, were studied with respect to re­flex immobilization (RI). In Brachytron pratense, Somatochlora flavomaculata. S. meridionalis and S. metallica RI revealed an obligatory reaction to disturbance in the water. An additional 4 species ex...

150 sites with occurrence of S. alpestris were surveyed in Switzerland and new records integrated in an actualized distribution map comprising 322 localities. The sp, only occurs in the alpine region and is not found in the Jura mountains. The data on the vertical distribution are summarized in altitude and climatic categories, differentiated with...

In search of receptive females, the males of many corduliids patrol over open water. Additionally, some species exhibit localized patrol flights also over terrestrial sites. In open fen habitats, Somatochlora flavomaculata may be an extreme case in this respect as it conspicuously patrols often away from water. In consideration of its possible func...

The population dynamics of Leucorrhinia pectoralis and two sympatric ubiquitous species (Libellula quadrimaculata, Aeshna cyanea) were investigated in Switzerland. Size of the population emerging from the study site varied from year to year by as much as a factor of 10, and within a single pond by as much as a factor of 100. Exuviae of L. pectorali...

Hemianax ephippiger, found for the first time last century, has been recorded again in Switzerland. A mature male was caught in May 1989, followed in August, by massive emergence of hundreds specimens. Specimens presumably flew from Africa, with the help of the air current. -from English summary

SUMMARY Thin sections, freeze-etch preparations and carbon replicas of Thermoactinomyces vulgaris sporangia and endospores were examined in the electron microscope. The outer spore coat contained parallel arrays of long fibrous striations spaced at about 5 nm; there appeared to be several layers with a different orientation of the fibres in each. T...

The ultrastructure of the surface membranes of the spores and aerial hyphae of S. glaucescens and S. acrimycini was studied by means of electron microscopy of air-dried whole mounts, thin sections, negative stainings and freezeetchings. The delicate sheath which envelopes the spore walls produces long protruding appendages which have previously bee...

The fine structure of the surface membrane which covers the cell walls of spores and aerial hyphae of S. viridochromogenes was investigated by means of electron microscopy of air-dried whole mounts, thin sections, negative stainings and freeze-etchings. The delicate sheath of the spores, which is responsible for the surface features, exhibits consp...

The fine structure of the plasma membrane and the mesosomes of Streptomyces coelicolor was studied by means of serial sections of aerial mycelium fixed in glutaraldehyde and osmium tetroxide, by negative staining of intact cells and cell fragments, and by freeze-etching. The plasma membrane as seen in freezeetch preparations showed the typical feat...

The fine structure of the cell envelopes of vegetative aerial hyphae and spores of Streptomyces coelicolor was studied by means of freeze-etching and negative staining. The walls of both hyphal cells and spores appeared smooth or slightly granular without any periodic substructure. The thin surface layer surrounding the cell wall consisted of a del...

It is generally assumed that in multicellular organisms the diversity of the different cell types is the result of different gene activity which becomes manifest in the course of development. This theoretical concept of cell differentiation was developed on the basis of results obtained from a relatively small number of suitable experimental system...

Surmmary Sporulation-defective mutants were isolated on the basis of altered colonial coloration. The mutants were classified into a number of morphological classes by means of phase-contrast and electron microscopy. Some mutants lacking sporulation septa, the special septa that lead to spore delimitation and separation in the wild-type, or differi...

The anatomy of individual colonies of Streptomyces coelicolor was studied at various developmental stages in situ by means of surface-impressions and thin sections. Young colonies consisted of substrate mycelium composed of a loose network of hyphae with uniform appearance. The uppermost cells produced the very closely packed hyphae of the aerial m...

The fine structure of the morphological events during sporulation in Streptomyces coelicolor grown on chemically defined medium was studied in electron micrographs of thin sections. During vegetative growth the young hyphae were divided into long cells by cross-walls which formed in a way comparable to those in certain other Gram-positive bacteria....

The application of a simple negative staining technique and freeze-etching has revealed detailed information on the species-specific surface structure of spores and aerial hyphae of streptomycetes.