Maltese bats show phylogeographic affiliation with North-Africa : implications for conservation

In the Mediterranean region, cryptic diversity of bats is common. As distinct genetic lineages should be managed independently for conservation, insight into bat phylogeography is important. The Maltese islands are located in the centre of the Mediterranean between North Africa and Sicily and are densely populated. At present, it is thought that at least seven species of bats are native, but phylogeographic affiliations remain largely unexplored. Therefore, we sequenced a ca. 540 bp fragment of the mitochondrial 16S rRNA gene from 23 bats, which were captured during the citizen-science project Akustika. We found two morphologically cryptic lineages common in North Africa, Plecotus gaisleri and a mainly North-African lineage of Hypsugo savii (named Hypsugo cf. darwinii in some recent studies). We also recorded two Pipistrellus species. The P. kuhlii haplotype belonged to a lineage present in North-Africa and across the Mediterranean. Within P. pipistrellus we found two novel haplotypes that clustered within a North-African clade, well distinguished from the European haplotypes. Our results highlight the historic connection between the bat fauna of the Maltese Islands and North Africa. Malta is one of the few regions in the European Union where P. gaisleri and the North-African clades of P. pipistrellus and H. savii occur. Hence, Malta has an exceptionally high responsibility for the conservation of these taxa in Europe

First molecular evidence of an invasive agricultural pest, Drosophila suzukii, in the diet of a common bat, Pipistrellus pipistrellus, in Belgian orchards

Bats are major consumers of arthropods, including many agricultural pest species, and can thus reduce and prevent crop damage. However, few, if any, data is available on the potential role of bats in pest control in central Europe. Evidence that bats prey upon locally important pest species would be an important first step to demonstrate their value to local farmers and facilitate conservation measures. In this pilot study, we used a DNA metabarcoding approach to investigate the diet composition of common pipistrelles and brown long-eared bats captured in orchards in Belgium. We show that the spotted wing drosophila (Drosophila suzukii), one of the most harmful pest species in this region, was part of the diet of common pipistrelles. This pest species was recorded in one of the five samples from common pipistrelles. Our results indicate that bats can be valuable assets for biological pest suppression in West-European orchards, thus setting a path for future studies

Evolutionary Ecology of Plant-Arthropod Interactions in Light of the “Omics” Sciences : A Broad Guide

Funding Information: The project is funded by the European Commission as well as the following national/regional bodies: Formas—the Swedish Research Council for Sustainable Development (grant no: 2020–02376), Academy of Finland (grant no. 344726), Research Foundation—Flanders (grant no. FWO ERANET G0H6520N), and Agencia Estatal de Investigación (grant no. PCI2020-120719-2). Publisher Copyright: Copyright © 2022 De-la-Cruz, Batsleer, Bonte, Diller, Hytönen, Muola, Osorio, Posé, Vandegehuchte and Stenberg.Aboveground plant-arthropod interactions are typically complex, involving herbivores, predators, pollinators, and various other guilds that can strongly affect plant fitness, directly or indirectly, and individually, synergistically, or antagonistically. However, little is known about how ongoing natural selection by these interacting guilds shapes the evolution of plants, i.e., how they affect the differential survival and reproduction of genotypes due to differences in phenotypes in an environment. Recent technological advances, including next-generation sequencing, metabolomics, and gene-editing technologies along with traditional experimental approaches (e.g., quantitative genetics experiments), have enabled far more comprehensive exploration of the genes and traits involved in complex ecological interactions. Connecting different levels of biological organization (genes to communities) will enhance the understanding of evolutionary interactions in complex communities, but this requires a multidisciplinary approach. Here, we review traditional and modern methods and concepts, then highlight future avenues for studying the evolution of plant-arthropod interactions (e.g., plant-herbivore-pollinator interactions). Besides promoting a fundamental understanding of plant-associated arthropod communities’ genetic background and evolution, such knowledge can also help address many current global environmental challenges.Peer reviewe

Evolutionary Ecology of Plant-Arthropod Interactions in Light of the “Omics” Sciences: A Broad Guide

Aboveground plant-arthropod interactions are typically complex, involving herbivores, predators, pollinators, and various other guilds that can strongly affect plant fitness, directly or indirectly, and individually, synergistically, or antagonistically. However, little is known about how ongoing natural selection by these interacting guilds shapes the evolution of plants, i.e., how they affect the differential survival and reproduction of genotypes due to differences in phenotypes in an environment. Recent technological advances, including next-generation sequencing, metabolomics, and gene-editing technologies along with traditional experimental approaches (e.g., quantitative genetics experiments), have enabled far more comprehensive exploration of the genes and traits involved in complex ecological interactions. Connecting different levels of biological organization (genes to communities) will enhance the understanding of evolutionary interactions in complex communities, but this requires a multidisciplinary approach. Here, we review traditional and modern methods and concepts, then highlight future avenues for studying the evolution of plant-arthropod interactions (e.g., plant-herbivore-pollinator interactions). Besides promoting a fundamental understanding of plant-associated arthropod communities’ genetic background and evolution, such knowledge can also help address many current global environmental challenges.</p

Spatial ecology, gene flow and conservation of the digger wasp Bembix rostrata

Beweging is een fundamenteel onderdeel van diverse ecologische processen en bepaalt mee het ontstaan van ruimtelijke patronen zoals de verspreiding van soorten, individuen en genen in de ruimte en tijd. Het omliggende landschap heeft een sterke invloed op beweging en de resulterende patronen. In deze thesis worden in gefragmenteerde duingebieden in België de ruimtelijke patronen en functionele connectiviteit bij de harkwesp (Bembix rostrata) onderzocht. Op verschillende ruimtelijke schalen wordt gekeken naar nestplaatskeuze, nestdensiteit in functie van beheer, landschapsconnectiviteit en populatie-genetische structuren en uitwisseling. De resultaten tonen dat de harkwesp een sterke aantrekking heeft tot soortgenoten tijdens de keuze van een nestplaats, wat wellicht in verband staat met hun gekende plaatstrouw. De resultaten tonen echter ook dat de uitwisseling tussen bestaande populaties weinig beperkt is, want er is vrij veel genetische connectiviteit. In de algemene discussie worden de verbanden tussen de verschillende resultaten besproken in een breed ecologisch kader en relevante inzichten over de ecologie, het gedrag en het behoud van de harkwesp. Beweging van de harkwesp op verschillende ruimtelijke schalen heeft een fundamentele invloed op ruimtelijke patronen binnen populaties en hoe populaties in verbinding staan in een landschap en tussen regio’s

Behavioral strategies and the spatial pattern formation of nesting

Nesting in dense aggregations is common in central place foragers, such as group-living birds and insects. Both environmental heterogeneity and behavioral interactions are known to induce clustering of nests, but their relative importance remains unclear. We developed an individual-based model that simulated the spatial organization of nest building in a gregarious digger wasp, Bembix rostrata. This process-based model integrates environmental suitability, as derived from a microhabitat model, and relevant behavioral mechanisms related to local site fidelity and conspecific attraction. The drivers behind the nesting were determined by means of inverse modeling in which the emerging spatial and network patterns from simulations were compared with those observed in the field. Models with individual differences in behavior that include the simultaneous effect of a weak environmental cue and strong behavioral mechanisms yielded the best fit to the field data. The nest pattern formation of a central place foraging insect cannot be considered as the sum of environmental and behavioral mechanisms. We demonstrate the use of inverse modeling to understand complex processes that underlie nest aggregation in nature

Rapid conservation evidence for the impact of sheep grazing on a threatened digger wasp

Insect populations show strong temporal fluctuations in abundance. This renders classical monitoring studies extremely difficult to provide insights into specific management actions. For rare species of conservation concern, it is not an option to develop large scale experiments to assess and steer landscape-level actions such as grazing management. Bembix rostrata (Linnaeus, 1758) is a threatened digger wasp from coastal dunes and inland sandy regions occurring in a limited number of populations in NW Europe. Since coastal dunes are rapidly being encroached by bushes, grazing management (cattle, sheep, and horses) has been implemented to keep this biotope open. In order to provide insights for local evidence based conservation, a BACI (before/after and control/impact) experiment was set up to assess the impact of sheep grazing on B. rostrata. We quantified the number of nests during 3 years at two grazed sites and a control-site excluded from grazing. We additionally assessed grazing pressure. The BACI design allowed us to directly adjust the current grazing management. The implemented sheep grazing reduced densities of B. rostrata, but did not lead to its local extinction. We discuss these findings in relation to the biology of the species. Our efficient and effective experimental design allowed a fast assessment of the current grazing management and showed that spatially heterogeneous sheep grazing could be used as a management tool to ensure the conservation of the emblematic digger wasp B. rostrata

De moeilijke balans tussen duinbeheer en bescherming van de Harkwesp : valt begrazing in de duinen te verzoenen met het behoud van ongewervelden?

Bij gebrek aan of in afwachting van grootschalige zandverstuivingsdynamiek in de duinen focust duinbeheer in natuurgebieden vaak op het herstel van habitattypen en maatregelen voor bescherming van specifieke soorten. Begrazing is hierbij een cruciaal beheerinstrument om een dynamisch duinlandschap te behouden of te creëren. Insecten en andere ongewervelden die aangepast zijn aan het dynamische karakter van de duinen zijn niet noodzakelijk ongevoelig voor begrazing in het actuele duinenlandschap. De verstoring door grazers is dus niet zomaar een surrogaat voor natuurlijke winddynamiek. In dit artikel bespreken we of en hoe het gebruik van grazers te verzoenen valt met de bescherming van de bedreigde Harkwesp Bembix rostrata en andere ongewervelden in de duinen.Large-scale sand dynamics are generally lacking in North-Western European dunes. Dune management in nature areas is therefore focused on restoration of typical habitat types and conservation of dune-specific species. Grazing with large herbivores is a crucial tool to protect and create dynamic open dune landscapes. In an altered landscape (urbanisation, fragmentation, fixated and shrub-dominated dunes, dikes, water extraction, etc.) the impact of grazers is expected to be altered compared to the historical agro-pastoral use. Especially dune-specific arthropods are vulnerable to grazing impacts, an often neglected species group in nature management, but an important one for typical biodiversity of dynamic dunes. As such disturbance by grazers cannot be used as an alternative for natural wind dynamics and needs to be reconciled with arthropod conservation in the current landscape context. We use the digger wasp Bembix rostrata, a progressive provisioner with a high level of site fidelity, as an example to illustrate this contradiction and conceive possible solutions. Grey dunes are the ideal habitat of this species. We propose the framework of a landscape mosaic to rotate grazers, preferably sheep, in time and in space to ensure open sand areas are proactively created and source populations and expansion areas are sustained

The neglected impact of tracking devices on terrestrial arthropods

Tracking devices have become small enough to be widely applied to arthropods to study their movement. However, possible side effects of these devices on arthropod performance and behaviour are rarely considered. We performed a systematic review of 173 papers about research in which tracking devices-radio frequency identification (RFID), harmonic radar and radio telemetry tags-were attached to terrestrial arthropods. The impact of such tags was quantified in only 12% of the papers, while in 40% the potential impact was completely disregarded. Often-cited rules of thumb for determining appropriate tag weight had either no empirical basis or were misconstrued. Several properties of a tracking device (e.g. weight, balance, size, drag) can affect different aspects of an arthropod's life history (e.g. energy, movement, foraging, mating). The impact can differ among species and environments. Taken together, these tag effects can influence the reliability of obtained movement data and conclusions drawn from them. We argue that the impact of tracking devices on arthropods should be quantified for each (a) study species, (b) tag type, and (c) environmental context. As an example, we include a low-effort impact study of the effect of an RFID tag on a digger wasp. Technological advancements enable studying the movement of arthropods in unprecedented detail. However, we should adopt a more critical attitude towards the use of tracking devices on terrestrial arthropods. The benefits of tracking devices should be balanced against their potential side effects on arthropods and on the reliability of the resulting data