Understanding how anthropogenic activities induce changes in the functional traits of arthropod communities is critical to assessing their ecological consequences. However, we largely lack comprehensive assessments of the long-term impact of global-change drivers on the trait composition of arthropod communities across a large number of species and sites. This knowledge gap critically hampers our ability to predict human-driven impacts on communities and ecosystems. Here, we use a dataset of 1.73 million individuals from 877 species to study how four functionally important traits of carabid beetles and spiders (i.e. body size, duration of activity period, tolerance to drought, and dispersal capacity) have changed at the community level across ~40 years in different types of land use and as a consequence of land use changes (that is, urbanisation and loss of woody vegetation) at the landscape scale in Switzerland. The results show that the mean body size in carabid communities declined in all types of land use, with particularly stronger declines in croplands compared to forests. Furthermore, the length of the activity period and the tolerance to drought of spider communities decreased in most land use types. The average body size of carabid communities in landscapes with increased urbanisation in the last ~40 years tended to decrease. However, the length of the activity period, the tolerance to drought, and the dispersal capacity did not change significantly. Furthermore, urbanisation promoted increases in the average dispersal capacities of spider communities. Additionally, urbanisation favoured spider communities with larger body sizes and longer activity periods. The loss of woody areas at the landscape level was associated with trait shifts to carabid communities with larger body sizes, shorter activity periods, higher drought tolerances and strongly decreased dispersal capacities. Decreases in activity periods and dispersal capacities were also found in spider communities. Our study demonstrates that human-induced changes in land use alter key functional traits of carabid and spider communities in the long term. The detected trait shifts in arthropod communities likely have important consequences for their functional roles in ecosystems.

Natural pest and weed regulation are essential for agricultural production, but the spatial distribution of natural enemies within crop fields and its drivers are mostly unknown. Using 28 datasets comprising 1204 study sites across eight Western and Central European countries, we performed a quantitative synthesis of carabid richness, activity densities and functional traits in relation to field edges (i.e. distance functions). We show that distance functions of carabids strongly depend on carabid functional traits, crop type and, to a lesser extent, adjacent non-crop habitats. Richness of both carnivores and granivores, and activity densities of small and granivorous species decreased towards field interiors, whereas the densities of large species increased. We found strong distance decays in maize and vegetables whereas richness and densities remained more stable in cereals, oilseed crops and legumes. We conclude that carabid assemblages in agricultural landscapes are driven by the complex interplay of crop types, adjacent non-crop habitats and further landscape parameters with great potential for targeted agroecological management. In particular, our synthesis indicates that a higher edge-interior ratio can counter the distance decay of carabid richness per field and thus likely benefits natural pest and weed regulation, hence contributing to agricultural sustainability.

In einer Feldstudie in den Jahren 2016 und 2018 wurde untersucht, ob Bluhstreifen der Saatmischung «Nutzlinge Kohlanbau» am Rand von Kohlfeldern im Schweizer Mittelland rauberische Nutzlinge (Laufund Kurzflugelkafer sowie Spinnen) und Bestauber (Schwebfliegen und Bienen) fordern konnen. In beiden Untersuchungsjahren war die Artenvielfalt der spontanen und angesaten Ackerbegleitflora in den Bluhstreifen durchschnittlich doppelt so hoch wie in den Kohlfeldern. Fallenfange im Zentrum von acht Kohlfeldern und in den dazugehorigen Bluhstreifen am Rand zeigten 2016, dass durch die gesteigerte Artenvielfalt der Begleitpflanzen Bienen, Laufkafer und Spinnen gefordert wurden. Zudem wurde festgestellt, dass ein hoher Bodendeckungsgrad der spontanen Ackerbegleitflora die Schwebfliegen forderte. Im Jahr 2018 zeigte der Direktvergleich zwischen Bluhstreifen und den Randern von sechs Kohlfeldern, dass signifikant mehr Bienenindividuen und -arten und marginal mehr Kurzflugel- und Laufkaferarten in den Bluhstreifen vorkamen. Sowohl 2016 als auch 2018 wurden uber 90 Arten ausschliesslich in den Bluhstreifen festgestellt, rund doppelt so viele wie in den Kohlflachen. Biodiversitatsforderflachen bieten einen periodischen Lebensraum fur diverse rauberische Nutzlinge und Bestauber und konnen somit die positiven Effekte der spontanen Ackerbegleitflora starken, was eine okologische Aufwertung von Produktionsflachen im Kohlanbau ermoglicht.

In conservation biological control, flowers can be used to increase the biological control potential of parasitoids, which benefit from the offered food sources. Besides exhibiting exploitable nectar, flowers should preferably be olfactorily attractive, as highly attractive flowers are easily located, reducing the time spent searching for food and subsequently increasing the per capita host searching efficiency. In this study we thus focused on the olfactory attractiveness of Fagopyrum esculentum Moench (Polygonaceae), Centaurea cyanus L. (Asteraceae) and Vicia sativa L. (Fabaceae) to Cotesia rubecula (Marshall, 1885) (Hymenoptera: Braconidae), a larval parasitoid of the cabbage pest Pieris rapae (Linnaeus, 1758) (Lepidoptera: Pieridae). With a Y-tube olfactometer we found that C. cyanus and to a lesser extent V. sativa successfully attract C. rubecula. Also F. esculentum attracts C. rubecula, but only after a rewarding feeding experience. All three tested flowers seem to be suitable to be exploited in conservation biological control programs to control P. rapae in brassica fields. Even though not every flower offering accessible nectar is also innately attractive, it can still be suitable for conservation biological control purposes as feeding experience can change this attraction. In fact, the application of mixtures containing attractive and rewarding flowers could help increase the success of such programs.

For the restoration of biodiversity in agricultural grasslands, it is essential to understand how management acts as an ecological filter on the resident species. Mowing constitutes such a filter: only species that possess functional traits enabling them to withstand its consequences can persist in the community. We investigated how the timing of mowing modulates this filtering effect for insects. We predicted that two traits drive species responses. Species with larval development within the meadow vegetation will suffer more from mowing than species whose larvae develop in or on the ground, or outside the meadows, while species with a later phenology should benefit from later mowing. We conducted a five-year experiment, replicated at 12 sites across the Swiss lowlands, applying three different mowing regimes to low-intensity hay meadows: (1) first cut of the year not earlier than 15 June (control regime); (2) the first cut delayed until 15 July; and (3) leaving an uncut grass refuge on 10-20% of the meadow area (after earliest first cut on 15 June). Before the first cut in years 4 or 5, we sampled larvae of Lepidoptera and sawflies, and adults of moths, parasitoid wasps, wild bees, hoverflies, ground beetles, and rove beetles. Overall, before the first cut of the year, abundances of species with vegetation-dwelling larvae were higher in meadows with delayed mowing or an uncut grass refuge, with some taxon-specific variation. In contrast, species whose larval development is independent of the meadow vegetation showed no differences in abundance between mowing regimes. Species richness did not differ among regimes. For species with vegetation-dwelling larvae, a fourth-corner analysis showed an association between early phenology and the control regime. No associations were found for the other functional groups. Our results show that slight modifications of mowing regimes, easily implementable in agri-environmental policy schemes, can boost invertebrate abundance, potentially benefitting insectivorous vertebrates.

Les ravageurs des cultures maraicheres bio peuvent etre regules grâce aux surfaces de promotion de la biodiversite. C’est ce que montrent des recherches pluriannuelles prenant comme modele le chou, un de ses ravageurs (noctuelle du chou) et des auxiliaires (parasitoides des oeufs et des larves de la noctuelle). Des bandes fleuries en bordure de parcelles et des plantes compagnes a l’interieur des cultures ont permis de favoriser les auxiliaires. Des especes adaptees aux bandes fleuries ont ete selectionnees sur la base de la litterature specialisee et d’experiences en laboratoire, puis testees lors d’essais en champ. Lors des essais en laboratoire, l’offre en sarrasin, bleuets ou vesces a permis de prolonger la duree de vie des parasitoides de la noctuelle du chou de 43 a 85%. Par rapport au temoin, le parasitage des larves de noctuelle etait de 3 a 6 fois plus eleve. Dans les essais en champ, les bandes fleuries ont permis de doubler le parasitage des oeufs de noctuelle une annee sur deux. Lorsque des bleuets ont ete semes comme plantes compagnes dans les cultures de choux, la predation sur les oeufs de noctuelle a augmente de 8 a 95 % et le parasitage des larves de 35 a 68 %. La diversite des groupes d’auxiliaires a large spectre (carabes, staphylins et araignees) a augmente en moyenne de 46 % dans les bandes fleuries. Avec des plantes compagnes, les choux ont ete, une annee sur deux, plus lourds de 18 % que ceux cultives sans bleuets. Ils presentaient en outre 41 % de moins de feuilles endommagees.

Die Regulation von Schadlingen kann im Bio-Gemusebau mit Hilfe von Biodiversitatsflachen verbessert werden. Dies zeigen mehrjahrige Untersuchungen am Modellsystem Kohl, am Schadling Kohleule und an dessen Ei- und Larvenparasitoiden (Nutzlinge). Gefordert wurden die Nutzlinge durch Bluhstreifen am Feldrand und Beipflanzen innerhalb des Feldes. Geeignete Pflanzen fur die Bluhstreifen wurden aufgrund der Fachliteratur und eigener Laborexperimente ausgewahlt und in Feldversuchen uberpruft. In Laborversuchen verlangerte das Angebot von Buchweizen, Kornblumen oder Futterwicken die Lebensdauer der Kohleulen-Parasitoide um 43 bis 85%. Die Parasitierung der Kohleule-Larven erhohte sich im Vergleich zur Kontrolle um das Drei- bis Sechsfache. In den Feldversuchen erhohten Bluhstreifen die Parasitierung von Kohleuleneiern in einem von zwei Jahren um das Zweifache. Die Kornblume als Beipflanze im Kohlfeld konnte den Frass von Kohleuleneiern um 8 bis 95% und die Parasitierung der Larven um 35 bis 68% steigern. Die Artenvielfalt breit wirksamer Nutzlingsgruppen (Lauf- und Kurzflugelkafer sowie Spinnen) erhohte sich in den Bluhstreifen um durchschnittlich 46%. Kohlkopfe mit Beipflanzen waren in einem von zwei Jahren 18% schwerer als ohne Kornblumen und wiesen 41% weniger Blatter mit Frassspuren auf.

Herbivore-induced plant volatiles (HIPVs) are important cues for female parasitic wasps to find hosts. Here, we investigated the possibility that HIPVs may also serve parasitoids as cues to locate mates. To test this, the odour preferences of four braconid wasps - the gregarious parasitoid Cotesia glomerata (L.) and the solitary parasitoids Cotesia marginiventris (Cresson), Microplitis rufiventris Kokujev and Microplitis mediator (Haliday) - were studied in olfactometers. Each species showed attraction to pheromones but in somewhat different ways. Males of the two Cotesia species were attracted to virgin females, whereas females of M. rufiventris were attracted to virgin males. Male and female M. mediator exhibited attraction to both sexes. Importantly, female and male wasps of all four species were strongly attracted by HIPVs, independent of mating status. In most cases, male wasps were also attracted to intact plants. The wasps preferred the combination of HIPVs and pheromones over plant odours alone, except M. mediator, which appears to mainly use HIPVs for mate location. We discuss the ecological contexts in which the combined use of pheromones and HIPVs by parasitoids can be expected. To our knowledge, this is the first study to show that braconid parasitoids use HIPVs and pheromones in combination to locate mates.

Multi-year studies of the model system 'cabbage', the pest 'cabbage moth' and the latter's egg and larval parasitoids (beneficials) demonstrate how pests can be controlled in vegetable production with the help of tailored biodiversity areas. Beneficials were encouraged by means of flower strips on field margins and companion plants within the field. Suitable plants for the flower strips were selected on the basis of the scientific literature and in-house laboratory experiments, and tested in field trials. In laboratory trials, the provision of buckwheat, cornflowers or common vetch extended the lifespan of the cabbage-moth parasitoids by 43% to 85%. Parasitisation of the cabbage-moth larvae increased three- to six-fold over that of the control. In the field trials, flower strips increased the parasitisation of cabbage moth eggs twofold in one of two years. Used as a companion plant in the cabbage field, cornflowers increased predation on cabbage-moth eggs by 8% to 95 % and the parasitism of the larvae by 35% to 68%. The species diversity of broadly effective groups of beneficials (ground beetles, short-winged beetles and spiders) increased by an average of 46% in the flower strips. In one of two years, cabbage heads grown with companion plants were 18% heavier than those grown without cornflowers, and had 41% fewer leaves with feeding damages.

In cabbage fields parasitoid wasps ( Hymenoptera ) use the eggs or larvae of pest butterflies and moths for their own reproduction, ultimately killing them, playing an important role in the biological plant protection strategy. An efficient way to promote this parasitoids in the crop field is to provide them with flower strips as well as companion plants, e.g. cornflower ( Centaurea cyanus ), that will provide them with food (nectar) and shelter. Between 2007 and 2010 we conducted experiments to test the olfactory attractiveness of different flowers as well as the influence of their nectar on the regulation of the cabbage moth ( Mamestra brassicae ) as well as on the lifespan and parasitation performance of its antagonists (egg and larval parasitoids). Keywords: functional biodiversity, cabbage, flowering plants, natural enemies

This work, which is part of a project called Biocomes (www.biocomes.eu), focuses on the control of the cabbage moth Mamestra brassicae (Linnaeus, 1758) (Lepidoptera: Noctuidae) through mass release of the egg parasitoid Telenomus sp. (Hymenoptera: Scelionidae). In the first year of the project we conducted different experiments to undercover aspects of the biology of this egg parasitoid that could help the creation of an efficient rearing system. Parallel we developed a species specific primer for the molecular species determination. Here we will present the most important results.

In einem zusammenfassenden Beitrag zur Kaferfauna des Furkapasses (2300–2700 m u. M.) wurden 111 Arten zusammengetragen. Der Artenreichtum ist hoch im Vergleich mit anderen Studien in ahnlichen Biotopen in den Schweizer Alpen. Die Funde von Psylliodes schwarzi Weise, 1900, Mycetoporus inaris Luze, 1901 und Cratosilis distinguenda (Baudi, 1859) auf der Alpennordseite sind bemerkenswert.