Enemy Communities Research Articles

Arthropod predator identity and evenness jointly shape the delivery of pest control services.

Maximizing the effectiveness of natural pest control requires a detailed understanding of how service delivery is affected by natural enemy community diversity and composition. Many studies have investigated the effects of natural enemy abundance and species richness on pest control. Studies examining the effects of evenness and species identity are fewer and have produced inconsistent results. Here we test the effects of arthropod predator community evenness and species identity on natural pest control by exposing aphid (Sitobion avenae) colonies in experimental cages to arthropod predator communities that had the same abundance and species richness but differed in evenness and dominant species. We found that the identity of the most dominant species in the arthropod predator community predominantly drove the pest control efficiency. However, additional to the effects of species identity, we also found a causal positive relationship between the evenness of arthropod predator communities and the suppression of pest growth. Our results provide support for the hypothesis that ecosystem service provision is generally a function of the abundance and efficiency of the most dominant species of the service-providing groups. This could partly explain why management practices aiming at promoting abundance of natural enemies often have mixed effects on pest control. Our results also demonstrate that diversity components such as evenness have important additional effects. However, in real-world ecosystems these effects may be obscured because evenness is generally confounded with abundance or species richness in natural enemy predator communities. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Tree species richness around urban red maples reduces pest density but does not enhance biological control

Urban trees often host greater insect pest abundance than trees in rural forests. This may be due, in part, to differences in tree diversity and canopy cover between these settings. Urban trees are often planted in isolation or monoculture, which favors pest accumulation. Gloomy scale, Melanaspis tenebricosa Comstock, is a pest of urban red maples (Acer rubrum L.) that is abundant where impervious surfaces dominate the local landscape. Increasing tree diversity and canopy cover around urban red maples may reduce gloomy scale abundance by supporting natural enemy communities. We investigated the effect that surrounding tree species richness and tree canopy cover had on gloomy scale abundance, natural enemy abundance, and biological control in red maple trees in Raleigh, NC, USA. We collected scales and natural enemies from red maples that spanned a gradient of tree species richness, canopy cover, and impervious surface values. We also measured gloomy scale parasitism and predation of sentinel prey in red maple canopies. Greater tree species richness and canopy cover were associated with lower gloomy scale density. Red maples in diverse settings also hosted fewer scales per natural enemy. Parasitoids were less common in maples in diverse settings, but generalist predator abundance was unaffected by tree diversity. Finally, tree species richness and canopy cover did not increase biological control of scales or sentinel prey. Our findings suggest that higher tree diversity and greater canopy cover may reduce gloomy scale density, but this is not entirely explained by the effects of natural enemies and biological control.

Host–enemy interactions provide limited biotic resistance for a range‐expanding species via reduced apparent competition

AbstractAimAs species' ranges shift poleward in response to anthropogenic change, they may lose antagonistic interactions if they move into less diverse communities, fail to interact with novel populations or species effectively, or if ancestral interacting populations or species fail to shift synchronously. We leveraged a poleward range expansion in a tractable insect host–enemy community to uncover mechanisms by which altered antagonistic interactions between native and recipient communities contributed to ‘high niche opportunities’ (limited biotic resistance) for a range‐expanding insect.LocationNorth America, Pacific Northwest.MethodsWe created quantitative insect host–enemy interaction networks by sampling oak gall wasps on 400 trees of a dominant oak species in the native and expanded range of a range‐expanding gall wasp species. We compared host–enemy network structure between regions. We measured traits (phenology, morphology) of galls and interacting parasitoids, predicting greater trait divergence in the expanded range. We measured function relating to host control and explored if altered interactions and traits contributed to reduced function, or biotic resistance.ResultsInteraction networks had fewer species in the expanded range and lower complementarity of parasitoid assemblages among host species. While networks were more generalized, interactions with the range‐expanding species were more specialized in the expanded range. Specialist enemies effectively tracked the range‐expanding host, and there was reduced apparent competition with co‐occurring hosts by shared generalist enemies. Phenological divergence of enemy assemblages interacting with the range‐expanding and co‐occurring hosts was greater in the expanded range, potentially contributing to weak apparent competition. Biotic resistance was lower in the expanded range, where fewer parasitoids emerged from galls of the range‐expanding host.Main ConclusionsChanges in interactions with generalist enemies created high niche opportunities, and limited biotic resistance, suggesting weak apparent competition may be a mechanism of enemy release for range‐expanding insects embedded within generalist enemy networks.

Enhanced diversity of aquatic macroinvertebrate predators and biological pest control but reduced crop establishment in organic rice farming

Organic farming has been adopted as the main alternative to reduce the environmental impact of intensive agriculture by banning the use of synthetic inputs and bolstering key ecological functions such as biological pest control. Yet the potential cascading effects of farming management on the communities of natural enemies, the provisioning of pest control, and the ultimate impact on crop performance remain poorly explored. This is especially true for semi-aquatic crops such as rice (Oryza sativa, L) that largely depend on aquatic macroinvertebrate predators for biological pest control. Here we performed two consecutive landscape-scale field experiments by combining monthly surveys of macroinvertebrate aquatic predators with both pest predation and seed rice germination trials to assess differences between conventional and organic rice farming in all the above-mentioned issues. Specifically, we selected 6 organic and 6 conventionally managed rice paddies and evaluated differences in i) the diversity of aquatic macroinvertebrate predators (taxa richness and evenness), ii) the infestation level of a seed pest (chironomids larvae), iii) the efficiency of biological pest control provisioning and iv) the impact on germination of rice seeds. Communities of macroinvertebrate aquatic predators were more diverse (taxa richness) and abundant in organic than in conventional fields, yet community evenness was higher in conventionally-managed fields. Accordingly, we found that macroinvertebrate-mediated pest control was markedly more efficient in organic farms during the establishment crop stage. Pest infestation, however, remained also higher in organic farming, most likely because biological pest control in organic fields is not able to outcompete chemical control provided in conventional fields. Finally, the increased infestation level observed in organic fields ultimately resulted in reduced germination rates of rice seeds, thus limiting crop performance. Our results highlight the potential positive effects of pesticide banning in organic rice farming on aquatic macroinvertebrate communities and the consequently improvement of biological pest control provisioning. Yet conditions enhancing biodiversity may also favor pest infestation and ultimately increase crop damage. Management recommendations should therefore account for potential services and disservices associated to organic farming in order to avoid negative yield outcomes for rice farmers.

The relationship between host plant traits and biodiversity across three sympatric seed‐feeding tri‐trophic systems in a tropical region of Brazil

Abstract We describe the diverse community of insect herbivores and parasitoids associated with the seeds and fruits of three sympatric Fabaceae species in Lavras, Minas Gerais, Brazil: Inga vera, Senna multijuga and Leucaena leucocephala. A total of 5353 individual insects, representing 77 different species, were identified via morphology and DNA barcoding. The non‐native L. leucocephala had the least diverse natural enemy community (N = 17 species), while two native species, I. vera and S. multijuga, were more diverse (N = 40 and N = 24 species, respectively). Individuals from the insect order Hymenoptera, a group dominated by parasitoid wasps, were the most diverse recovered from our samples in all hosts. Additionally, individual herbivore and parasitoid species were more likely to be found on a single host, with only four out of the 77 species found in more than one plant species. This includes the generalist agricultural pest herbivore, Lasioderma serricorne, found in two species, and three parasitoids connecting native S. multijuga and non‐native L. leucocephala communities, hinting at recent host shifts. Furthermore, different host plant traits had complex effects on the herbivore and parasitoid communities, where seed number per fruit promoted a propagating effect on the abundance and richness at both higher trophic levels, whereas seed and fruit weight did not. We highlight the importance of including parasitoids in insect community studies because they are highly diverse and provide important ecosystem services. Additional study of the biology, behaviour and distributions of parasitoids would be advantageous to inform conservation and biological control.

Aphidophagous predators in commercial Capsicum cultivars and characterization of their trophic network using stomach content analysis

AbstractViruses and aphids, the most recent vectors of viruses (Hemiptera: Aphididae) of the genera Myzus and Aphis, are the main phytosanitary problems of Capsicum spp. (Solanales: Solanaceae) agricultural systems in Colombia. The incorporation of biological control in integrated pest management (IPM) programmes, which can be used to reduce aphid populations in solanaceous crops, is hampered by the lack of information on the natural enemy community, such as parasitoids, predators and generalist aphidophagous. For this reason, the objective of this research was to determine and characterize the community of generalist aphidophagous (Coccinellidae and Syrphidae) in the cultivation of chilli pepper in south‐western Colombia, and to characterize their diet through stomach content analysis using next‐generation sequencing (NGS) techniques. Two species of Coccinellidae and one species of Syrphidae were the most abundant predators in commercial crops of Capsicum spp. and fed preferentially on aphids that attacked the pepper plants. The characterization of the diet of these predators using molecular tools revealed intraspecific predation, secondary predation of aphid parasitoids and consumption of alternative prey to the aphids attacking the pepper plants. Differences in diet composition were observed between larval and adult coccinellids, and between coccinellids and the hoverfly species studied. The results suggest that dominant predators may be suitable for use in IPM programmes to control aphids in pepper crops, as their diet consists mainly of aphids that attack pepper plants. In addition, these predators can take advantage of the agricultural matrix by feeding on alternative prey in the absence of aphids.

Description of the herbivore and natural enemy community associated with the seeds of an invasive plant in Brazil

Abstract Studies have shown that fruits of plants from the Fabaceae family harbour a diverse community of herbivorous insects and their natural enemies. Despite this observation, we still lack information on the specific interactions within these multi‐trophic communities. Herein, we describe the food web of insects associated with fruits and seeds of Leucaena leucocephala (Fabaceae), an invasive plant in Brazil, and their relationship with plant traits including seed biomass. We found 17 species of insects distributed across three trophic levels. The main herbivore species sampled was Acanthoscelides macrophthalmus (Coleoptera, Chrysomelidae, Bruchinae), which was responsible for most of the seed predation and associated with the highest parasitoid biodiversity (N = 10 species). Four other herbivorous species were lower in abundance, including a previously unreported Lepidopteran species with two parasitoids and one hyperparasitoid associated with it. Seeds with more mass promoted an increase in insect abundance, insect species richness, and the number of links and connectivity. We observed two native parasitoid species, Paracrias pluteus and Stenocorse suldamericanos, shift from herbivores on native plants to herbivores on the invasive L. leucocephala, consistent with a potential host shift. However, more investigation is required to ascertain the effects of recent shifts of native insect communities (on native plants) to non‐native ones and their consequences on plant fitness. Our study contributes to the understanding of the dynamics of communities and food webs in unknown systems, specifically in fruits of an invasive plant, and provides information about the influence of different plant traits on these communities.

The impact of field margins on biological pest control: a meta-analysis

Floral field margins are known to benefit invertebrate species diversity and abundance within agricultural landscapes, but variation in success limits widespread uptake. Understanding how variation within floral field margins can affect certain entomological groupings is lacking but would allow for a more individualised design of margins to enhance biological control. This meta-analysis aims to answer the question; do floral field margins benefit biological pest control over grassy field margins? We found that floral margins significantly benefit the natural enemy community and biological control services, relative to non-floral grass margins. We confirm that field margin type is linked to higher abundance and diversity of natural enemies, lower numbers of herbivorous invertebrate pests, and reduced crop damage. We consider whether specific characterisations of natural enemies and pest communities vary between these margin types, finding key differences in the abundances of aerial and epigeal enemies, the diversity of parasitoid and predatory enemies and pest abundances found in naturally regenerating and sown floral field margins. The finding here cements the implementation of floral field margins as a legitimate control method for crop pests in the face of losses due to pesticides and highlights design and management considerations for the success of floral margins.

Wildflower plantings have mixed effects on insect herbivores and their natural enemies

Flower strips are advocated as a strategy to promote beneficial insects as well as the services they deliver to adjacent crops. Flower strips have, however, often been developed separately for pollinators and natural enemies and, additionally, little consideration has been given to effects on insect herbivores. We sampled insect herbivores, their natural enemies and parasitism of pest eggs using vacuum sampling, sticky cards and egg cards in nine pairs of bee-attractive wildflower plantings and control field borders, as well as in adjacent tomato and watermelon crop fields in Yolo County, California 2015–2016. Control field borders had a higher total number of herbivores on sticky traps than did wildflower plantings, a pattern that was driven by more aphids, hoppers, psyllids and whiteflies, whereas wildflower plantings had more lace bugs and Lygus bugs. The total number of herbivores in the adjacent crop fields did not differ between treatments, but there were more leaf beetles near (at 10 m but not 50 m from) wildflower plantings. Control field borders had a higher total number of predators, driven by more big-eyed bugs, lady beetles and minute pirate bugs, whereas spiders were more common in wildflower plantings. The total number of predators in adjacent crop fields was, however, higher in those next to wildflower plantings, which was driven by more minute pirate bugs. Parasitoid wasps were more common in wildflower plantings and at 10 m but not 50 m into adjacent crop fields. Stink bug egg parasitism rate did not differ between treatments, either in the borders or in the crop fields. In conclusion, wildflower plantings clearly affect the insect herbivore and natural enemy community, but do so in a highly taxon-specific manner, which can lead to both positive and negative outcomes for pest control as a result.

Within-field crop diversity and landscape complexity decrease the abundance of fall armyworm larvae in maize cropping systems

The composition and spatial arrangement of multiple crop and non-crop habitats at a field and landscape levels have the potential to modify the abundance and structure of arthropod communities. In particular, semi-natural habitats can provide important life support functions to a range of natural enemies of agricultural pests. How such traits might affect generalist predators has poorly been considered in complex landscapes dominated by intercropping and trees within a mosaic of small-scale agricultural plots in Africa. The objective of the present study was to test the hypothesis that crop diversity and landscape complexity in maize cropping systems decrease the abundance of crop pests through natural regulation by generalist predators. For this purpose, we monitored the fall armyworm abundance and predation of sentinel larvae by predatory ants across a set of maize fields with contrasted within-field crop diversity and abundance of semi-natural vegetation including trees and shrubs in their surrounding landscape. A negative effect of crop diversity and landscape complexity on FAW abundance, and a species-specific effect on ant abundance, were observed. However, no significant effect of ant abundance or predation on FAW abundance was observed, suggesting that habitat complexity by itself or other natural enemy communities such as parasitoids could play a complementary role to explain FAW abundance in maize crops.

Floral presence and flower identity alter cereal aphid endosymbiont communities on adjacent crops.

Floral plantings adjacent to crops fields can recruit populations of natural enemies by providing flower nectar and non-crop prey to increase natural pest regulation. Observed variation in success rates might be due to changes in the unseen community of endosymbionts hosted by many herbivorous insects, of which some can confer resistance to natural enemies, for example, parasitoid wasps. Reduced insect control may occur if highly protective symbiont combinations increase in frequency via selection effects, and this is expected to be stronger in lower diversity systems.We used a large-scale field trial to analyse the bacterial endosymbiont communities hosted by cereal aphids Sitobion avenae collected along transects into strip plots of barley plants managed by either conventional or integrated (including floral field margins and reduced inputs) methods. In addition, we conducted an outdoor pot experiment to analyse endosymbionts in S. avenae aphids collected on barley plants that were either grown alone or alongside one of three flowering plants, across three time points.In the field, aphids hosted up to four symbionts. The abundance of aphids and parasitoid wasps was reduced towards the middle of all fields while aphid symbiont species richness and diversity decreased into the field in conventional, but not integrated, field-strips. The proportion of aphids hosting different symbiont combinations varied across cropping systems, with distances into the fields, and were correlated with parasitoid wasp abundances.In the pot experiment, aphids hosted up to six symbionts. Flower presence increased natural enemy abundance and diversity, and decreased aphid abundance. The proportion of aphids hosting different symbiont combinations varied across the flower treatment and time, and were correlated with varying abundances of the different specialist parasitoid wasp species recruited by different flowers. Synthesis and applications. Floral plantings and flower identity had community-wide impacts on the combinations of bacterial endosymbionts hosted by herbivorous insects, which correlated with natural enemy diversity and abundance. We recommend that integrated management practices incorporate floral resources within field areas to support a more functionally diverse and resilient natural enemy community to mitigate selection for symbiont-mediated pest resistance throughout the cropping area.

Functional Traits Mediate the Natural Enemy Response to Land Use at the Local Scale

Arthropods are key nodes for the provision of ecosystem services such as pest control, but their response to land-use change is highly variable depending on the scale of analysis and the natural enemies’ life histories. We evaluate the effects of landscape- and local-scale variables of natural enemies’ communities on small-scale agriculture. We consider functional response traits to attain a mechanistic understanding of the effect of land-use changes on the biodiversity and resilience of natural enemies’ communities. Predator and parasitoid arthropods were collected from thirteen raspberry farms to estimate functional diversity, complementarity, and redundancy indices. We found no effects of landscape heterogeneity, local habitat, or management practices on natural enemies’ functional diversity. Regarding resilience, complementarity was high at most of the sites and was not affected by the landscape or local variables. However, redundancy was affected by two management practices. Weed control decreased natural enemies’ abundance as well as the abundance of walker generalist predators and flying specialist parasitoids, while habitat richness decreased flying generalist predators. These results highlight the importance of management when the landscape matrix is heterogeneous. We conclude that small-scale agriculture in a heterogeneous landscape supports a functionally diverse enemy community, potentially promoting the resilience of pest control to land-use change.

Potential of Hedgerows with Aromatic Plants as Reservoirs of Natural Enemies of Pests in Orange Orchards

In the present study, the potential of hedgerows from Mediterranean aromatic plant species, i.e., oregano, rosemary, sage, and savory, in orange field margins to function as reservoirs of natural enemies of citrus pests was tested in comparison to the common management practice of bare soil or weed vegetation. Assessments were based on the abundance and diversity of parasitoid wasps, spiders, and insect predators in the field margins and on the orange trees for two growing seasons. Savory plants harbored more parasitoids compared to weed vegetation and the other aromatic plants (savory > organic rosemary > sage > oregano). Weed vegetation hosted more arachnid predators than the aromatic plants in their first year in the orchard, but this was reversed with their full growth in the following year (most abundant on rosemary). Oregano and sage favor insect predators. The similarity of the natural enemy communities on the field margins and on the orange trees increased with time, indicating the insects' movement from the field margins to the trees. The results support the use of the tested aromatic plant species in conservation practices for targeted groups of beneficial arthropods in orange orchards, also considering the exploitation of suitable wild flowering plants of the weed flora.

Crop diversity and edge density benefit pest suppression through bottom-up and top-down processes, respectively

Agricultural intensification has resulted in the homogenization of agricultural landscapes, leading to the loss of crop and habitat diversity, and a higher rate of chemical inputs in the landscape, negatively impacting natural enemy communities and their ability to provide pest control services. Landscape heterogeneity is thought to benefit predator populations (increasing landscape complementation) and lower pest colonization (decreasing resource concentration); however, few studies have determined the relative importance of these two processes in pest suppression. Here, we tease apart direct and indirect impacts of landscape heterogeneity on experimental populations of soybean aphid excluded from and open to predation, in 23 soybean fields in Manitoba, in 2017 and 2018. Field plant counts and sweep net samples were conducted to determine aphid and predator abundances, respectively, and Malaise traps were used to quantify predator movement into soybean. Landscape effects differed between a soybean aphid outbreak year (2017) versus a non-outbreak year (2018). We found that crop diversity at a 1.5 km radius had negative impacts on aphid colonization during the outbreak year, resulting in greater aphid suppression but no impacts on predator movement. Edge density at a 1.5 km radius increased aphid suppression during the low aphid year. Predator movement and abundance were driven by aphid colonization in soybean, and syrphid and coccinellid abundance were 33-fold and 15-fold more abundant in the high compared to the low aphid year. Thus, our study revealed complementary effects of landscape heterogeneity on aphid suppression: a reduction of resource concentration associated with increased crop diversity and resulting in bottom-up effects during an outbreak, and an increase in landscape complementation associated with increased edge density and top-down control in a low aphid year. Increasing crop diversity seems a promising strategy to mitigate aphid outbreaks without compromising food production.

Tomato Potato Psyllid Bactericera cockerelli (Hemiptera: Triozidae) in Australia: Incursion, Potential Impact and Opportunities for Biological Control.

Incursion and establishment of an exotic pest may threaten natural habitats and disrupt ecosystems. On the other hand, resident natural enemies may play an important role in invasive pest control. Bactericera cockerelli, commonly known as the tomato-potato psyllid, is an exotic pest, first detected on mainland Australia in Perth, Western Australia, in early 2017. B. cockerelli causes direct damage to crops by feeding and indirectly by acting as the vector of the pathogen that causes zebra chip disease in potatoes, although the latter is not present in mainland Australia. At present, Australian growers rely on the frequent use of insecticides to control B. cockerelli, which may lead to a series of negative economic and environmental consequences. The incursion of B. cockerelli also provides a unique opportunity to develop a conservation biological control strategy through strategically targeting existing natural enemy communities. In this review, we consider opportunities to develop biological control strategies for B. cockerelli to alleviate the dependence on synthetic insecticides. We highlight the potential of existing natural enemies to contribute toward regulating populations of B. cockerelli in the field and discuss the challenges ahead to strengthen the key role they can play through conservation biological control.

New Records of Elm Leaf Beetle, Xanthogaleruca luteola, Parasitoids in Colorado, with Notes on Predators

Elm leaf beetle, Xanthogaleruca luteola Müller (Coleoptera: Chrysomelidae), is an invasive pest of elm trees, Ulmus spp. L. Natural enemies are thought to be important in controlling elm leaf beetles, but their natural enemy community is poorly described in many areas of the invaded range. The aim of this research was to identify parasitoids and predators of elm leaf beetle in Colorado, an area with frequent pest outbreaks and where few natural enemies have been described. We present new state records of the egg parasitoid Oomyzus gallerucae Fonscolombe (Hymenoptera: Eulophidae) and the larval-adult parasitoid Erynniopsis antennata Rondani (Diptera: Tachinidae) in Colorado. Parasitism of elm leaf beetle eggs and larvae was <3% during the 2021 sampling season. Both parasitoid species were nearly absent early in the season, and parasitism peaked in late summer. We also identified six species of elm leaf beetle predators, several of which are newly documented to consume elm leaf beetle. Considering the low levels of parasitism and few predators observed in our study, it seems unlikely that natural enemies effectively control elm leaf beetles in Colorado. Additional research is needed to develop effective methods to control this invasive insect pest.

Impact of plant community structure and its diversity on richness and abundance of arthropod aphidophagous natural enemy community

Arthropod natural enemies (ANEs) play an indispensable role in maintaining the balance for plant communities that also significantly affects the ANE diversities not only by supporting herbivorous prey, but also by providing habitats and floral food resources. Studying the diversity of ANEs is thus vital to develop an understanding of sustainable pest control. Relationships of the vegetation diversity (including richness, coverage, and Shannon–Wiener diversity) with associated arthropod aphidophagous natural enemies (AANEs) and their groups under Pinus tabuliformis of different distances were analyzed by non-metric multidimensional scaling (metaMDS). Our results indicated that the vegetation richness affects AANEs at a small scale, while the vegetation structure affects it at a large scale. The richness and abundance of AANEs and the abundance of green lacewings (GLs) and aphid parasitoids (APs) were positively related to neighboring tree richness. But the richness of AANEs and aphidophagous ladybirds (ALs) were negatively associated with nearby tree coverage, as well as AANE richness with close-up shrub coverage, while the abundance of AANEs, ALs, and GLs possessed a negative and hump-shaped relationship with nearby tree coverage, as well as the abundance of AANEs and GLs with close-up shrub coverage. When tree and shrub layers each had approximately half coverage within a vegetation structure, the richness and abundance of AANEs were highest. Similarly, the richness and abundance of AANEs were positively related to neighboring blooming plant richness. However, the richness of AANEs and ALs, and the abundance of AANEs, AL, GL, and APs had a positive association either with the coverage or with the Shannon–Wiener diversity of close-up blooming plants. Half coverage of the tree and shrub layer combined with higher diversities (richness, coverage, and Shannon–Wiener diversity) of blooming plants resulted in low aphid density. The results provide a basis for effectively improving AANE diversity.

Hedgerows have contrasting effects on pollinators and natural enemies and limited spillover effects on apple production

Agricultural intensification has resulted in a decline in insect biodiversity and threatens the provision of valuable ecosystem services. Agri-environment schemes (AESs) have been implemented in an effort to conserve biodiversity on farmland and increase agricultural sustainability, but their effectiveness can vary widely. To better determine which factors influence AES effectiveness, the relative roles of local habitat features, habitat quality, and landscape context need to be further explored. The aim of this study was to determine the most important factors influencing field margin AES effectiveness in commercial apple orchards, in terms of arthropod biodiversity conservation and ecosystem service provision. We surveyed wild bees and aphid natural enemies in field margins and apple trees in 20 orchards, ten bordered by hedgerow field margins (an AES) and ten with herbaceous field margins (no hedgerows present, not an AES). We considered field margin floral resources and the cover of semi-natural habitat in the surrounding landscape as indicators of local habitat quality and landscape context, respectively. We furthermore quantified pollination and pest control as measures of ecosystem service delivery and the relationship between arthropod communities and apple yield (initial and final fruit set) and quality. We found that hedgerow presence strongly predicted both pollinator and natural enemy communities and that these relationships were more pronounced than those with local habitat quality and landscape context. Hedgerows were negatively related to wild bee richness and abundance within the orchard, and positively related to natural enemy richness and abundance at the field margin but not within the orchard. We found no relationships between local and landscape factors and ecosystem service delivery, and no relationship between wild bee communities and apple yield, suggesting that apple is not pollen limited in our study system. There was, however, a negative relationship between natural enemy richness and initial fruit set. We conclude that annually cut hedgerows can benefit the conservation of natural enemies, but have limited arthropod-mediated private benefits for apple production, and likely need to be supplemented with additional local habitat resources for the conservation of wild bees. Our findings indicate that local habitat factors can strongly influence biodiversity regardless of landscape context, but that AESs likely need to be designed with separate biodiversity and ecosystem service targets, and specific taxonomic groups, in mind.

First report on classical biological control releases of the larval parasitoid Ganaspis brasiliensis against Drosophila suzukii in northern Italy

Current management strategy of the invasive fruit fly Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) exploits different tools but relies mainly on chemical control. In the invaded areas, the local natural enemy community mostly consists of generalist pupal parasitoids unable to control the pest efficiently. Conversely, in the pest native area, there are more specialized sympatric larval parasitoids attacking D. suzukii. Following foreign explorations and quarantine risk assessments, the larval endoparasitoid Ganaspis brasiliensis (Ihering) (Hymenoptera: Figitidae) was selected as the best candidate for classical biological control programs. In 2021, the first ever propagative biocontrol program using a Japanese G1 lineage of G. brasiliensis started in Italy. Here we report the results of the first year of releases in the province of Trento (Northeast Italy), wherein G. brasiliensis was released in 12 locations. Pre- and post-release samplings on fresh and fallen fruits were performed around the release points to assess the recapture rate, the impact of the exotic parasitoid on D. suzukii and its potential interactions with local non-target species. After releases, G. brasiliensis was recovered at 50% of the locations. The exotic parasitoid only emerged from D. suzukii, mostly from fresh fruit still on the plant. Post-overwintering monitoring revealed the presence of a four G. brasiliensis individuals at two release locations.

Between Kiev and Venice The cognitive warfare and the Biennale of Venice

The Russia-Ukraine conflict is witnessing the intensive use of information warfare and psychological warfare which are part of the cognitive warfare. The main goal of cognitive warfare is to wage a war on what an enemy community thinks, loves or believes in, by altering its representation of reality and the art is an important asset and domain of the cognitive warfare. The Venice Biennale serves as a major international art exhibition celebrating achievements in contemporary art, architecture, film, theater, and dance. Some experts call it “the Olympics of the art world.” This article provides analysis of the case study of the Biennale of Venice as a theater of cognitive warfare between Russia and Ukraine. It’s still uncertain how the war will end in Ukraine, but at the 2022 Venice art biennale it is clear which side has prevailed on the art and cultural front.