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Insect migration redistributes enormous quantities of biomass, nutrients and species globally. A subset of insect migrants perform extreme long-distance journeys, requiring specialized morphological, physiological and behavioral adaptations. The migratory globe skimmer dragonfly (Pantala flavescens) is hypothesized to migrate from India across the Indian Ocean to East Africa in the autumn, with a subsequent generation thought to return to India from East Africa the following spring. Using an energetic flight model and wind trajectory analysis, we evaluate the dynamics of this proposed transoceanic migration, which is considered to be the longest regular non-stop migratory flight when accounting for body size. The energetic flight model suggests that a mixed strategy of gliding and active flapping would allow a globe skimmer to stay airborne for up to 230–286 h, assuming that the metabolic rate of gliding flight is close to that of resting. If engaged in continuous active flapping flight only, the flight time is severely reduced to ∼4 h. Relying only on self-powered flight (combining active flapping and gliding), a globe skimmer could cross the Indian Ocean, but the migration would have to occur where the ocean crossing is shortest, at an exceptionally fast gliding speed and with little headwind. Consequently, we deem this scenario unlikely and suggest that wind assistance is essential for the crossing. The wind trajectory analysis reveals intra- and inter-seasonal differences in availability of favorable tailwinds, with only 15.2% of simulated migration trajectories successfully reaching land in autumn but 40.9% in spring, taking on average 127 and 55 h respectively. Thus, there is a pronounced requirement on dragonflies to be able to select favorable winds, especially in autumn. In conclusion, a multi-generational, migratory circuit of the Indian Ocean by the globe skimmer is shown to be achievable, provided that advanced adaptations in physiological endurance, behavior and wind selection ability are present. Given that migration over the Indian Ocean would be heavily dependent on the assistance of favorable winds, occurring during a relatively narrow time window, the proposed flyway is potentially susceptible to disruption, if wind system patterns were to be affected by climatic change.
Innerhalb der Proteinfamilien der Antistasine und der Hirudine konnte ein breites Spektrum von Faktoren identifiziert werden. Obwohl die Funktionen dieser Hirudin-ähnlichen Faktoren (HLF) aus Hirudo sp. und Hirudinaria manillensis, sowie des Antistasin-ähnlichen Faktors (ALF) aus Hirudo verbana, bis zu diesem Zeitpunkt unbekannt waren, könnte der hohe Grad an Übereinstimmung zu den Antistasinen bzw. Hirudinen bezüglich ihrer Genstruktur und Aminosäuresequenzen auf eine Anpassung der Blutegel auf ihr Wirtsspektrum hindeuten. So ist es mit der funktionellen Charakterisierung von rekombinanten Formen dieser Speicheldrüsenproteine möglich, die Frage zu beantworten, weshalb der Blutegel nicht nur einen potenten Inhibitor für die jeweiligen Faktoren der Blutgerinnung in seinen Speicheldrüsen sekretiert, sondern wohl möglich eine Vielzahl variierender Faktoren vorliegen.
Abstract
Aim
Species ranges are highly dynamic, shifting in space and time as a result of complex ecological and evolutionary processes. Disentangling the relative contribution of both processes is challenging but of primary importance for forecasting species distributions under climate change. Here, we use the spectacular range expansion (ca. 1000 km poleward shift within 10 years) of the butterfly Pieris mannii to unravel the factors underlying range dynamics, specifically the role of (i) niche evolution (changes in host‐plant preference and acceptance) and (ii) ecological processes (climate change).
Location
Provence‐Alpes‐Côte d’Azur, France; North Rhine‐Westphalia, Rhineland‐Palatinate and Hesse, Germany.
Taxon
Insect and angiosperms.
Methods
We employed a combination of (i) common garden experiments, based on replicated populations from the species’ historical and newly established range and host‐plant species representative for each distribution range, co‐occurrence analyses and (ii) grid‐based correlative species distribution modelling (SDM) using Maxent.
Results
We observed changes in oviposition preference, with females from the newly established populations showing reduced host‐plant specialization and also an overall increased fecundity. These changes in behaviour and life history may have enabled using a broader range of habitats and thus facilitated the recent range expansion. In contrast, our results indicate that the range expansion is unlikely to be directly caused by anthropogenic climate change, as the range was not constrained by climate in the first place.
Main conclusions
We conclude that evolution of a broader dietary niche rather than climate change is associated with the rapid range expansion, and discuss potential indirect consequences of climate change as trigger for the genetic differences found. Our study thus illustrates the importance of species interactions in shaping species distributions and range shifts, and draws attention to indirect effects of climate change. Embracing this complexity is likely the key to a better understanding of range dynamics.
Organisms often employ ecophysiological strategies to exploit environmental conditions and ensure bio-energetic success. However, the many complexities involved in the differential expression and flexibility of these strategies are rarely fully understood. Therefore, for the first time, using a three-part cross-disciplinary laboratory experimental analysis, we investigated the diversity and plasticity of photoresponsive traits employed by one family of environmentally contrasting, ecologically important phytoflagellates. The results demonstrated an extensive inter-species phenotypic diversity of behavioural, physiological, and compositional photoresponse across the Chlamydomonadaceae, and a multifaceted intra-species phenotypic plasticity, involving a broad range of beneficial photoacclimation strategies, often attributable to environmental predisposition and phylogenetic differentiation. Deceptively diverse and sophisticated strong (population and individual cell) behavioural photoresponses were observed, with divergence from a general preference for low light (and flexibility) dictated by intra-familial differences in typical habitat (salinity and trophy) and phylogeny. Notably, contrasting lower, narrow, and flexible compared with higher, broad, and stable preferences were observed in freshwater vs. brackish and marine species. Complex diversity and plasticity in physiological and compositional photoresponses were also discovered. Metabolic characteristics (such as growth rates, respiratory costs and photosynthetic capacity, efficiency, compensation and saturation points) varied elaborately with species, typical habitat (often varying more in eutrophic species, such as Chlamydomonas reinhardtii), and culture irradiance (adjusting to optimise energy acquisition and suggesting some propensity for low light). Considerable variations in intracellular pigment and biochemical composition were also recorded. Photosynthetic and accessory pigments (such as chlorophyll a, xanthophyll-cycle components, chlorophyll a:b and chlorophyll a:carotenoid ratios, fatty acid content and saturation ratios) varied with phylogeny and typical habitat (to attune photosystem ratios in different trophic conditions and to optimise shade adaptation, photoprotection, and thylakoid architecture, particularly in freshwater environments), and changed with irradiance (as reaction and harvesting centres adjusted to modulate absorption and quantum yield). The complex, concomitant nature of the results also advocated an integrative approach in future investigations. Overall, these nuanced, diverse, and flexible photoresponsive traits will greatly contribute to the functional ecology of these organisms, addressing environmental heterogeneity and potentially shaping individual fitness, spatial and temporal distribution, prevalence, and ecosystem dynamics.
Abstract
Sander lucioperca is an organism of growing importance for the aquaculture industry. Nonetheless, the rearing of S. lucioperca larvae is proving to be a difficult task as it is facing a high mortality rate during hatching and the change to exogenous feeding. To gain insight into growth patterns during this period, the authors analysed pikeperch embryos and larvae from 9 days before hatching to 17 days after hatch. Hereby they were able to describe a natural development by using close to natural conditions based on using a direct flow‐through supply of lake fresh water on specimens from a local wild population. The results show that between the early embryonic stages a steady growth was visible. Nonetheless, in between hatching and the start of exogenous feeding, a phase of growth stagnation took place. In the following larval stages, an increased growth with large size variations between individual specimens appeared. Both factors are conspicuous as they can indicate a starting point for cannibalism. With this analysis, the authors can provide a fundament to support the upcoming research on S. lucioperca and aid to optimize size‐sorting procedures for a higher survival of pikeperch stock in aquaculture.
The modification of male pedipalps into secondary sexual intromittent organs is one of the hallmark characteristics of spiders, yet understanding the development and evolution of male genitalia across the order remains a challenging prospect. The embolus – the sclerite bearing the efferent spermatic duct or spermophor, and used to deliver sperm directly to the female genitalia during copulation – has always been considered the single unambiguously homologous palpal sclerite shared by all spider species, fundamental to the bauplan of the order and to the evolution and functional morphology of spider reproductive systems. Indeed, after two centuries of comparative research on spider reproduction, the presence of a single spermophor and embolus on each of a male spider’s two pedipalps remains a central tenet of evolutionary arachnology. Our findings challenge this premise, and reveal a remarkable twin intromittent organ sperm transfer system in a lineage of Australian palpimanoid spiders, characterized by a bifurcate spermophor and the presence of two efferent ducts leading to a pair of embolic sclerites on each pedipalp. This is the first time such a remarkable conformation has been observed in any group of arachnids with direct sperm transfer, complicating our understanding of palpal sclerite homologies, and challenging ideas about the evolution of spider genitalia.
Abstract
Nervous system development has been intensely studied in insects (especially Drosophila melanogaster), providing detailed insights into the genetic regulatory network governing the formation and maintenance of the neural stem cells (neuroblasts) and the differentiation of their progeny. Despite notable advances over the last two decades, neurogenesis in other arthropod groups remains by comparison less well understood, hampering finer resolution of evolutionary cell type transformations and changes in the genetic regulatory network in some branches of the arthropod tree of life. Although the neurogenic cellular machinery in malacostracan crustaceans is well described morphologically, its genetic molecular characterization is pending. To address this, we established an in situ hybridization protocol for the crayfish Procambarus virginalis and studied embryonic expression patterns of a suite of key genes, encompassing three SoxB group transcription factors, two achaete–scute homologs, a Snail family member, the differentiation determinants Prospero and Brain tumor, and the neuron marker Elav. We document cell type expression patterns with notable similarities to insects and branchiopod crustaceans, lending further support to the homology of hexapod–crustacean neuroblasts and their cell lineages. Remarkably, in the crayfish head region, cell emigration from the neuroectoderm coupled with gene expression data points to a neuroblast‐independent initial phase of brain neurogenesis. Further, SoxB group expression patterns suggest an involvement of Dichaete in segmentation, in concordance with insects. Our target gene set is a promising starting point for further embryonic studies, as well as for the molecular genetic characterization of subregions and cell types in the neurogenic systems in the adult crayfish brain.
Currently, poleward range expansions are observed in many taxa, often in response to anthropogenic climate change. At the expanding front, populations likely face cooler and more variable temperature conditions, imposing thermal selection. This may result in changes in trait means or plasticity, the relative contribution of which is not well understood. We, here, investigate evolutionary change in range‐expanding populations of the butterfly Pieris mannii, by comparing populations from the core and the newly established northern range under laboratory conditions. We observed both changes in trait means and in thermal reaction norms. Range‐expanding populations showed a more rapid development, potentially indicative of counter‐gradient variation and an increased cold tolerance compared with core populations. Genotype‐environment interactions prevailed in all associated traits, such that the above differences were restricted to cooler environmental conditions. In range‐expanding populations, plasticity was decreased in developmental traits enabling relatively rapid growth even under cooler conditions but increased in cold tolerance arguably promoting higher activity under thermally challenging conditions. Notably, these changes must have occurred within a time period of ca. 10 years only. Our results suggest, in line with contemporary theory, that the evolution of plasticity may play a hitherto underestimated role for adaptation to climatic variation. However, rather than generally increased or decreased levels of plasticity, our results indicate fine‐tuned, trait‐specific evolutionary responses to increase fitness in novel environments.
1. Anthropogenic climate change is a substantial threat to global biodiversity. It may affect insect herbivores directly and indirectly. Indirect effects are, among others, mediated by climate‐change induced variation in host‐plant quality. Although being potentially important, little is known on the significance of such indirect effects and on interactions among environmental stressors in plant–herbivore interactions.
2. To simulate the potential impact of climate change, we investigated effects of host‐plant temperature and soil moisture on herbivore performance in the tropical butterfly Bicyclus anynana under laboratory conditions.
3. Maize grown at high temperatures or under wet conditions reduced herbivore performance, indicated by decreased body mass, storage reserves, phenoloxidase activity, and increased development time. Temperature and soil moisture acted largely independent of one another. Detrimental effects of the high plant temperature were restricted to males, indicating a higher vulnerability of this sex to environmental stress.
4. In nature, B. anynana might be threatened by increasing temperatures during the wet season negatively affecting host‐plant quality. Our study shows that herbivore performance can be substantially affected by indirect effects mediated through changes in host‐plant quality, which deserves more attention in the current era of global climate change.
Abstract
Social organisation in species with fluctuating population sizes can change with density. Therefore, information on (future) density obtained during early life stages may be associated with social behaviour. Olfactory cues may carry important social information. We investigated whether early life experience of different experimental densities was subsequently associated with differences in attraction to adult conspecific odours. We used common voles (Microtus arvalis), a rodent species undergoing extreme density fluctuations. We found that individuals originating from high experimental density populations kept in large outdoor enclosures invested more time in inspecting conspecific olfactory cues than individuals from low‐density populations. Generally, voles from both treatments spent more time with the olfactory cues than expected by chance and did not differ in their latency to approach the odour samples. Our findings indicate either that early experience affects odour sensitivity or that animals evaluate the social information contained in conspecific odours differently, depending on their early life experience of conspecific density.
Abstract
The two important mechanisms influencing the response of phytoplankton communities to alterations of abiotic factors in their environment are difficult to distinguish: species sorting resulting from a change in interspecific competitive pressure, and phenotypic plasticity (here explicitly physiological plasticity i.e. species‐specific physiological adjustment). A shift in species composition as well as physiological adjustments in species can lead to changes in fatty acid composition that determine the food quality for zooplankton consumers.
We used phytoplankton communities consisting of five species and exposed them to two different light intensities, two light conditions (constant and variable), and two levels of phosphorus supply. Changes in fatty acid and species composition were analyzed. We compared community pairs differing in one factor by calculating the Bray‐Curtis similarity index for the composition of both variables. Comparing the Bray‐Curtis similarity index of the species composition with the index of the fatty acid composition was used to estimate the effects of species sorting and physiological plasticity.
Changes in nutrient supply influenced fatty acid responses based on species sorting and physiological plasticity the most. On one hand, the relevance of physiological plasticity was highest at cultivation in different nutrient supplies but the same light environment. Conversely with low nutrients species sorting appeared to dominate the response to changes in light, while at high nutrients physiological plasticity appeared to influence the response. Overall, under low phosphorus supply the communities showed a lower total fatty acid content per carbon and had increased proportions of saturated and monounsaturated fatty acids. Instead, communities in low light produced more of eicosapentaenoic acid.
Our results suggest that the relevance of species sorting and physiological plasticity in shaping the community response highly depends on the environmental factors that influence the system. Nutrient supply had the largest effect, while light had more limited conditional effects. However, all of these factors are important in shaping the food quality of the phytoplankton community for higher trophic levels.
In Germany, basic data on the biology, ecology and distribution of rare mosquito species are insufficiently recorded leading to knowledge gaps, for example regarding their vector potential. The introduction of new mosquito species and of the pathogens they transmit has increased the risk of diseases previously uncommon in Germany. These circumstances have led to increased efforts within the past 10 years to better understand the spatio-temporal occurrence and underlying habitat binding of mosquito species and to predict their future distribution, particularly with regard to the changing climatic conditions and changing landscape. A reliable morphological and genetic identification was lacking for several native mosquito species, which forms the basis for any robust monitoring within mosquito surveillance programs or insect conservation projects.
The aim of this thesis was to gain detailed knowledge on the current spatial and temporal occurrence, the habitat binding, and morphological and genetic features with regard to species identification for the non-native species Aedes albopictus (Skuse, 1895), the native species of the Aedes Annulipes Group, and the native and rare species Aedes refiki Medschid, 1928, Culex martinii Medschid, 1930 and Culiseta ochroptera (Peus, 1935).
The thesis compares the suitability of the local climate for the persistence of the species Aedes albopictus sporadically observed in Jena (Thuringia) from 2015 to 2018 with two populations in southern Germany. The focus was on the analysis of extreme winter temperatures and the duration below selected temperature thresholds. In addition to critical temperature conditions, aquatic habitat conditions were of importance. The results of this study suggest that the population could become established in the long term.
Through the monitoring conducted for this thesis, the very rare mosquito species Aedes refiki, Culex martinii in Thuringia and Culiseta ochroptera were rediscovered at several sites in northern and eastern Germany. It was possible to add new information on habitat binding, distribution and abundance for the considered mosquito species. The survival of these rare native mosquito species depends on the preservation of a few remaining habitats. In addition, it can be assumed that these species will become even rarer with future climate change in Germany and, therefore, should be considered endangered. In contrast, other mosquito species could benefit from an increase in average temperatures or precipitation in individual cases.
Due to the contribution to species identification, difficulties in the morphological and genetic identification of selected mosquito species native to Germany could be dispelled. Three forms each were assigned to the known morphological variants of Aedes refiki and Culiseta ochroptera and their peculiarities were described, as well as a new character for species identification was highlighted in the case of Culiseta ochroptera. Generated CO1 mtDNA sequences provide the first DNA-barcodes of Aedes refiki and Culex martinii for Germany.
In five native mosquito species of the Aedes Annulipes Group, twenty types of aberrant tarsal claws were illustrated and described in their morphology. Morphological peculiarities and an asymmetrical occurrence of the aberrant claw types were observed and possible causes for their development were discussed. Together with the development of a basic blueprint of mosquito tarsal claws, the results opened another field of research for the taxonomy, developmental biology and aquatic ecology of arthropods.
Das alpha-Toxin (Hla) von Staphylococcus aureus (S. aureus) spielt eine bedeutende Rolle bei S. aureus-induzierten Pneumonien. Hla bindet zunächst als Monomer an die Plasmamembran eukaryotischer Wirtszellen und assoziiert sich zu heptameren Transmembranporen. Die Sensitivität gegenüber dem Toxin ist bei verschiedenen Atemwegsepithelzelllinien unterschiedlich ausgeprägt. Die Gründe dafür sind bis jetzt nicht vollends verstanden. Mögliche Faktoren, die einen Einfluss auf die Hla-Sensitivität der Zellen haben, könnten die Rezeptordichte und Effizienz der Porenbildung sowie die Entsorgung von Poren aus der PM durch Internalisierung und Degradation (lysosomal, proteasomal) oder durch Ausschleusung von extrazellulären Vesikeln in den Extrazellularraum sein.
Ziel dieser Arbeit war es, die Bedeutung der Faktoren, die einen Einfluss auf die Toxin-Sensitivität von Wirtszellen haben könnten, am Beispiel der drei Atemwegs-Modellzelllinien 16HBE14o-, S9 sowie A549 genauer zu untersuchen.
Dabei konnte gezeigt werden, dass die Menge an rHla, allem voran die Abundanz der Heptamere in der Plasmamembran der Zellen, einen starken Einfluss auf die Toxinsensitivität (gemessen an der Rate parazellulärer Lückenbildung in den Zellverbänden) der Zelllinien hat. Diese Ergebnisse korrelierten am besten mit der Häufigkeit des potenziellen Hla-Rezeptors ADAM10 in der Plasmamembran der drei Zelltypen, aber auch das Phospholipid Sphingomyelin scheint ebenfalls einen Einfluss auf die Hla-Sensitivität der Zellen zu haben. Die Zellgröße, der für die Hla-Vorpore stabilisierende Faktor Caveolin-1, Integrin α5β1 als weiterer möglicher Hla-Rezeptor und die Lipide Phosphatidylcholin/-serin zeigten dagegen keine Korrelation zur Hla-Sensitivität der drei Atemwegsepithelzelllinien. Das Lipid Phosphatidylethanolamin wies zwar das gleiche Muster wie das des Sphingomyelins bei den Zelllinien auf, jedoch muss eine mögliche Bedeutung des Lipids in der Hla-Bindung und/oder -Heptamerisierung erst noch untersucht werden.
Untersuchungen der Internalisierung des Toxins zeigten, dass von den drei Atemwegsepithelzelllinien nur die S9-Zellen in der Lage waren die rHla-Heptamere effizient zu internalisieren. Dabei konnte unter Verwendung der rHla-Mutante rH35L, die keine Transmembranpore ausbilden kann, gezeigt werden, dass die Internalisierung der Toxin-Heptamere wahrscheinlich Poren-unabhängig geschieht. Durch die Überprüfung des rHla-Abbaus in S9-Zellen nach Inhibierung der lysosomalen oder proteasomalen Proteindegradation konnte ein Abbau des Toxins über das Proteasom ausgeschlossen werden. Dagegen scheint der lysosomale Weg von entscheidender Bedeutung für die Hla-Heptamer-Degradation zu sein. Eine saure Hydrolyse der Protease-resistenten Toxin-Heptamere in rHla-Monomere konnte allerdings nicht nachgewiesen werden und scheint somit bei dem lysosomalen Abbau keine Rolle zu spielen. Präparierte extrazelluläre Vesikel von rHla-behandelten S9-Zellen zeigten zudem, dass eine Entsorgung des Toxins über Exosomen und/oder Mikrovesikel ebenfalls bei diesen Zellen möglich zu sein scheint. Der primäre Weg der Hla-Prozessierung ist bei den S9-Zellen dennoch der lysosomale Abbau.
Midges are small mosquitoes that can transmit pathogens to susceptible hosts through their blood-sucking act. They are known as biological vectors that can transmit the bluetongue virus (BTV) and the Schmallenberg virus (SBV) to ruminants, among others. Various vector control measures can be used to curtail the spread of the virus during an epidemic. However, for effective vector measures, it is essential to have profound knowledge of the role of biting midges as vectors, as well as their biology and phenology. For several years, midges were not in the focus of research and there are still considerable gaps in knowledge. Therefore, the present work examines various aspects of biting midges of the genus Culicoides, whose function as vectors of the Schmallenberg virus was already proven at the beginning of the project.
The aim of the first part of this work was to determine the percentage of infected midges in various German areas in order to determine the influence of Culicoides midges within the virus epidemic. For this purpose, samples, collected during 2011 and 2012 as part of monitoring projects, were analysed. Additionally, in early 2013, various farms in southern and eastern regions of Germany, where SBV was considered to be largely absent, were equipped with UV traps. The small number of virus-positive samples did not allow a more precise assessment of the viral spread in culicoid midges. Instead, it revealed the importance to conduct targeted samplings of its vectors during an acute outbreak. Additionally, the presented results and statements made by several animal owners, gave reason to believe, that SBV must have affected the southern and eastern parts of Germany earlier than actually assumed. This would consequently have led to an increased immunity in host animals, which provides a reasonable explanation for the low positive values and is in agrement with the statements made by various farmers.
The second part of this work identifies the conditions and surrounding factors under which acute SBV diseases emerged in ruminants in the cold winter months of 2012/2013. After the diagnosis of several acute SBV infections of sheep in a sheep pen in Mecklenburg-Western Pomerania, culicoid midge activity could be proven. This demonstrates that, suitable conditions for its vectors given, an infection of SBV can also take place during wintertime. A more detailed analysis of the surrounding conditions revealed, that the outdoor temperatures during infection were consistently at values of at least 5-9 ° C for several consecutive days, which enabled the flight and blood-sucking activity of the midges within
the shelter.
Midge activity during wintertime represents a crucial component in understanding how the virus can outlast the cold season. A constant midge presence could lead to a low but permanent infection rate throughout the cold months, enabling a recurrence of the pathogen the following year. Instead, a longer vector-free timeperiod would point to other mechanisms that allow the virus to re-occur in Germany on a yearly basis. Thus, the acute cases of SBV infections in sheep rose the question of critical threshold temperatures, representing the beginning of midge activity. The investigation of several stables sheltering cattle, horse or sheep addressed potential differences between indoor and outdoor activity and whether the type of host animal has an influence on the beginning of the flight. In the third part of this work, a long vector-free period and several differences in the onset of midge activity between different types of host animals could be detected. It could also be illustrated that the progression of the flight began differently depending on the present type of host animal/type of stable. For all cattle stables and the sheep barn the first midge activity was measured indoors, whereas for horses, culicoid midges were found to become active either at the same time or almost simultaneously inside and outside the animal shelters. This suggests that the horse stables do not represent good breeding sites for midges, which might be attributed to husbandry practices. In addition, it was possible to determine specific threshold temperatures for the different types of host animals and for various midge species. Altogether, the late beginning of flight, measured at the beginning of March, was surprising. This raises more questions of alternative mechanisms enabling the virus to outlast the winter months. The documentation of species-specific threshold temperatures can be a useful tool f.i. within automated large stables to keep indoor temperatures under the threshold value in order to postpone the onset of culicoid activity of various vector species. This may help to prevent virus transmissions during winter or to evoke a delay in spring, making it more difficult for the virus to overwinter.
To be able to start instant defense measures during an ongoing virus epidemic, which is transmitted by Culicoides midges, reducing the ground-living midge larvae offers a promising option during the warm season. For targeted vector control measures, it is important to know the breeding sites of culicoid midge species. Therefore, four agriculturally used biotopes were sampled and compared to four biotopes of a forest-dominated area. The results clearly show that meadows per se are not suitable breeding habitats for Culicoides
spp. Only the influence of livestock animals induces their potential as developmental sites. The various biotopes of the forest-dominated region were less subject to anthropogenic influences. Although fewer individual midges were found here, it displayed a higher biodiversity than the agricultural habitats. These results demonstrate once more the potential of forests in regards to the preservation of biodiversity. In Particular, the alder on fen site revealed most midge species and also the highest number of collected specimens among the studied biotopes. That illustrates the high impact of this specific humid type of habitat in respect to species diversity and the need of its perpetuation.
As part of this work, new breeding sites for a variety of culicoid species were identified and assigned to the usually rather short profiles of known Culicoides species. For one part, previous observations of chosen substrates could be consolidated. Furthermore, new breeding substrates were identified. Additionally, information of abiotic factors such as ph-value, soil moisture or organic compound of all sampled breeding substrates obtained from a soil analysis, extended the knowledge about the species-specific choice of breeding habitats and their characteristical traits. The additional knowledge about potential breeding substrates and their soil factors might be useful for future epidemiological modelling approaches. It can also raise the effectiveness and accuracy of targeted vector control measurements during an epidemic outbreak. Therefore, it may indirectly contribute to the preservation of endangered rare species. However, there is still an enormous need for more research before this goal can be fully achieved.