Impact of the invasive ant Linepithema humile on native ant assemblages on the western slopes of Table Mountain and implications for ant-butterfly associations

The Argentine Ant, Linepithema humile (Hymenoptera: Formicidae), is one of the world's most successful invasive species and invades undisturbed Fynbos habitats in South Africa, displacing native arthropod species and affecting interspecific associations. In order to assess the impact of Li. humile on native ant assemblages and associations between ants and myrmecophilous butterflies (Lepidoptera: Lycaenidae) on the western slopes of Table Mountain (Cape Town, South Africa), adult butterfly density was scored and distribution of food plants were assessed at two sites

Assessing the efficacy of bee promoting measures (Hymenoptera, Apiformes) along an urban-rural gradient

Die Bedeutung von Städten als Refugien für Bestäuber­insekten zeichnet sich zunehmend ab. Bienen spielen eine wichtige Rolle in der Stabilisierung von Ökosystemen, sowohl im ruralen als auch im urbanen Kontext. Während bienenfördernde Maßnahmen vor allem im landwirtschaftlichen bzw. ruralen Kontext untersucht wurden, besteht eine große Wissenslücke in Bezug auf die Effektivität solcher Maßnahmen in urbanen Landschaften. Ziel dieses Übersichtsartikels ist es, einen Überblick über jüngere Forschungsaktivitäten basierend auf der im Peer-Review-Verfahren publizierten Literatur zu geben, um Empfehlungen für zukünftige Forschungsprojekte zum Schließen dieser Wissenslücke abzuleiten. Während Studien zu Saatgutmischungen hauptsächlich auf Ernährungsaspekte abzielen, sind Studien zu Staudenpflanzungen auf vergleichsweise wenige Pflanzentaxa beschränkt. Die Durchführung vergleichbarer Stu­dien zu Effekten von Baumpflanzungen auf Bienenpopulationen wird durch eine geringgradige Methodenstandardisierung erschwert. Der Naturschutzwert künstlicher Niststrukturen in Städten bedarf weiterer Erforschung, insbesondere im Hinblick auf bodennistende Bienen­arten. Während mehrere Fallstudien auf eine Ernährungsfunktion von Gründächern für urbane Bienenpopulationen hindeuten, sind die Ergebnisse bezüglich der vertikalen Isolation von Gründächern nicht eindeutig. Zahlreiche Faktoren wurden identifiziert, die die Diversität und Populationsstruktur im urbanen Raum auf lokaler und Landschaftsebene beeinflussen. Der relevante Landschaftsmaßstab wird in den meisten Fällen durch Radien zwischen 500 und 1000 m repräsentiert. Zukünftige Studien, deren Versuchsaufbau einen kontinuier­lichen und vollständigen Urbanisierungsgradienten berück­sichtigt, werden von Nutzen sein, um die zahlreichen Ergebnisse zu bienenfördernden Maßnahmen in Agrarlandschaften mit den bislang wenigen Ergebnissen in urbanen Landschaften zu vergleichen. Studien, die die genetische Struktur von Bienenpopulationen im Hinblick auf Urbanisierung berücksichtigen, repräsentieren bislang nur einen sehr kleinen Ausschnitt der Bienenvielfalt. Die Weiterentwicklung molekularbiologischer Methoden könnte in naher Zukunft neuartige Werkzeuge zur Bewer­tung des Erfolgs bienenfördernder Maßnahmen im Hinblick auf die Habitatkonnektivität bereitstellen.Cities are emerging as refugia for pollinators, among which bees play a pivotal role for maintaining ecosystem functioning in agricultural and urban settings. While measures to promote bees have been investigated predominantly in the agricultural or rural context, a wide knowledge gap persists with regard to the effectiveness of such measures within urban landscapes. In order to guide research addressing this lack of knowledge, the aim of this perspective paper is to give an overview of the recent research activities based on the published peer-reviewed literature. While research on flower seed mixtures in general focuses on nutritional aspects, studies on plantings of perennial herbs are relatively limited to few plant taxa. Implementation of comparable case studies investigating the effects of tree plantings on bee populations is hampered by a lack of methodological standardization. The conservation value of providing nesting sites in cities needs to be further investigated, in particular concerning ground-nesting bee species. While several case studies indicate a nutritional supporting function of green roofs for urban bee populations, findings with regard to vertical isolation remain equivocal. Various factors driving bee diversity and population structure in the urban context at the local and landscape scale have been identified, the reported relevant landscape scale being represented by radii between 500 and 1000 m in most cases. Future study designs reflecting a continuous and complete gradient of urbanization will be helpful in comparing results on bee promoting measures in agricultural landscapes (which are numerous) to urban settings (which are still encountered much less frequently). Studies looking into the genetic structure of bee populations with regard to urbanization so far represent only a tiny fraction of bee diversity, and the further development of molecular methods could yield novel tools for assessing the success of bee promoting measures in terms of habitat connectivity in the near future

Wildbienen (Hymenoptera, Aculeata: Apiformes) des Mittleren Moseltals: Die Weinbausteillagen im Klotten-Treiser Moseltal

Von 2012 bis 2013 wurden Wildbienen in Weinbausteillagen mittels Sichtfang, Farbschalen und Malaise-Fallen erfasst. Aus 3246 bestimmten Individuen resultierten 159 nachgewiesene Wildbienenarten. Fast ein Drittel der erfassten Arten ist als bestandsgefahrdet zu bezeichnen oder von Bestandsruckgangen betroffen. Im Vergleich mit Erfassungsergebnissen aus dem naheren Umkreis deuten die vorliegenden Ergebnisse auf eine grose Bedeutung der untersuchten Weinbausteillagen als (Teil-)Lebensraume hin, die der regionalen Artenvielfalt der Bienen zugrunde liegen.In 2012 and 2013, the wild bee fauna of vineyards on steep slopes was investigated by means of hand-netting, pan traps and Malaise traps. A total of 3246 individuals was captured and identified, yielding 159 species of wild bees. Almost one third of the species registered is regarded as endangered or shows declining populations. Considering earlier results from nearby study sites, the results of this work underline the importance of steep slopes under viticultural management as (partial) habitats underlying the regional bee species richness

Deposition of dust with active substances in pesticides from treated seeds in adjacent fields during drilling: disentangling the effects of various factors using an 8-year field experiment

The side effects from the use of plant protection products and their potential effects on non-target arthropods (NTAs) such as honey bees, other insects within the vegetation layer and epigeic arthropods nowadays receive more attention. However, uncertainties about the factors driving the deposition of active substances (a.s.) into off-crop areas persist, in particular during sowing of treated seeds. Analysing a highly standardised 8-year field experiment, we assessed the importance of various factors potentially affecting dust drift and deposition of a.s., emitted during the sowing process of treated seeds and deposited on fields adjacent to the drilling field, i.e. on the ground, on flowers, and on nonflowering plant parts. Regarding a.s. deposition, the Heubach a.s. value has a predictive capability, which is independent from all other factors taken into account in this study, and can thus be considered as a scenario-independent measure of potential dust deposition. Petri dish samplers, an established standard method for measuring a.s. deposition, were representative of the results from the plant samplers for a given combination of drilling technique and adjacent crop type. Adjacent crop type is likely to impact on a.s. deposition. The present work will enable a more field-realistic exposure assessment for bees and other NTAs

License to Kill?—Disease Eradication Programs May Not be in Line with the Convention on Biological Diversity

Global human population growth is associated with many problems, such as food and water provision, political conflicts, spread of diseases, and environmental destruction. The mitigation of these problems is mirrored in several global conventions and programs, some of which, however, are conflicting. Here, we discuss the conflicts between biodiversity conservation and disease eradication. Numerous health programs aim at eradicating pathogens, and many focus on the eradication of vectors, such as mosquitos or other parasites. As a case study, we focus on the “Pan African Tsetse and Trypanosomiasis Eradication Campaign,” which aims at eradicating a pathogen (Trypanosoma) as well as its vector, the entire group of tsetse flies (Glossinidae). As the distribution of tsetse flies largely overlaps with the African hotspots of freshwater biodiversity, we argue for a strong consideration of environmental issues when applying vector control measures, especially the aerial applications of insecticides. Furthermore, we want to stimulate discussions on the value of species and whether full eradication of a pathogen or vector is justified at all. Finally, we call for a stronger harmonization of international conventions. Proper environmental impact assessments need to be conducted before control or eradication programs are carried out to minimize negative effects on biodiversity

Improving wild bee monitoring, sampling methods, and conservation

Bees are the most important group of insect pollinators, but their populations are declining. To gain a better understanding of wild bee responses to different stressors (e.g. land-use change) and conservation measures, regional and national monitoring schemes are currently being established in Germany, which is used here as a model region, and in many other countries. We offer perspectives on how to best design future bee monitoring programs with a focus on evaluating the implementation of conservation measures. We discuss different traditional and novel sampling methods, their efficacy depending on research questions and the life-history traits of target species, and how greater standardization of wild bee sampling and monitoring methods can make data more comparable, contributing to the identification of general trends and mechanisms driving bee populations. Furthermore, the potential impact of bee sampling itself on bee populations is discussed