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Hover flies (Diptera: Syrphidae) are a group of insects containing many migratory species that provide critical ecosystem services including pollination, decomposition and biological control. Their migratory behaviour remains largely overlooked and unacknowledged, but an influx of contemporary research is beginning to shift this.The goal of this review is to summarise and synthesise the past 150+ years of global hover fly migration research from over 50 papers in multiple languages. Here, we provide comprehensive evidence for hover fly migration through the lens of the methodologies used for studying these phenomena, the biological mechanisms for migration and the associated ecological and economic impacts. We also include an inventory of all recognised migratory species and discuss taxonomic patterns.In total, we compiled accounts of 46 species that are considered migratory, most of which were sourced from Europe. Recent reports, however, have also described hover fly migration in North America, Asia, the Middle East and Australia. Approximately 70% of these species are from the subfamily Syrphinae, which are important biological control agents.The migratory behaviour of hover flies has substantial impacts on ecosystem services and may be linked to long‐distance gene flow for many angiosperms via pollen transportation. These insects are also likely redistributing biological control services at a continental scale on an annual basis, which has major repercussions for the management of crop pests such as aphids. The sensitivity of hover fly migration to anthropogenic impacts is not well known, but shifting climatic conditions, pollution and increased habitat fragmentation are likely impactful and should be further explored.Despite recent advances and increased interest in the subject, hover fly migration remains understudied and many major knowledge gaps continue to persist. [ABSTRACT FROM AUTHOR]

Introduced syrphids are increasing their distribution in the New World, and Chile is one of the most impacted countries. Here, we report new localities in Chile for Eristalinus (Eristalodes) taeniops (Wiedeman, 1818), Toxomerus politus (Say, 1823), and Pseudoscaeva meridionalis (Fluke, 1951) and provide updated distributions and new records of these species in other New World countries. We discuss the potential negative impacts of these exotic syrphids on native species in Chile and highlight the power of opportunistic recording in detecting exotic species.

Information on the world distribution of E. taeniops and a distributional map of the species in the New World is presented based on available literature, specimens collected in the present study, and citizen science reports. A morphological diagnosis and background on the biology of the species are provided based on photographs and published literature. We briefly discuss how E. taeniops may be spreading in South America via airports and seaports.

Pesticides and the lack of floral resources are key drivers of insect decline in agricultural areas. Both land‐use stressors can have a variety of synergistic and sublethal effects on pollinators, affecting their health and foraging behaviour. Pollinating insects include species with vastly different life histories, giving them potentially different vulnerability and resilience to stressors. However, most research has generally focused on bees. Here, we contrast synergistic effects of nutritional stress and pesticide use on social bumblebees and solitary hoverflies.We experimentally tested the effects of the neonicotinoid acetamiprid and low‐quality food on health traits of Bombus terrestris workers and Episyrphus balteatus adults (ovarian development, body size and colony development or survival). The foraging behaviour of treated pollinators was recorded in a semi‐field setup and, for B. terrestris, we measured the pollen amount on the body surface and the pollen deposited on stigmata after a single floral visit.Both stressors affected bumblebee health. Additionally, insecticide‐treated workers showed increased flower handling times and flight durations, while low‐quality food reduced the amount of pollen on the surface of bumblebees and the pollen deposited on stigmata. Syrphids were mostly affected by low‐quality food, which decreased their survival probability and changed their foraging behaviour. Furthermore, we found an interactive effect between the two stressors, reducing E. balteatus ovary development.Synthesis and applications. Insecticide and food stress affected fitness traits of both bumblebees and syrphid flies, possibly reducing pollinator populations under natural conditions. Especially for bumblebees, long‐term exposure led to a reduction in the provision of pollination services, both by changing their behaviour and reducing pollen transfer. We found differences between the two pollinator groups, showing that results gained from single groups like bees should not be extrapolated to all pollinators. Interactive effects indicate potential buffering effects of high‐quality food against other stressors and highlight the importance of considering synergies between multiple stressors in risk assessments. This further emphasizes the relevance of floral resources such as wild flower strips in agricultural areas to conserve pollinators and pollination services. [ABSTRACT FROM AUTHOR]

Simple Summary: Hoverflies are a diverse group of dipterans (6800+ species worldwide) of high relevance to pollination and the regulation of insect pest populations. With nearly 500 described species worldwide, Cheilosia represents the largest hoverfly genus in the Palaearctic, with larvae of most species feeding on flowering plants or fungal tissues. The complexity of this genus is eased by the definition of various species groups, including the group of Cheilosia melanura, which is assessed in this paper in the context of the Iberian Peninsula. The aim of the present work is to improve the knowledge of this species group by following an integrative approach, i.e., a combined use of different data sources (e.g., morphology and genetics) to solve a taxonomic problem or evaluate a taxonomic scenario. With this approach, we found and described a species new to science from Spain and provided the first identification key for all Iberian species of the group, including most of the European species. The largest genus of Palaearctic Syrphidae, Cheilosia Meigen, 1822 (Syrphidae: Rhingiini), is currently under revision in the Ibero-Balearic region (Iberian Peninsula + Balearic Islands). Prior to this study, various species groups with putative phylogenetic support were defined for this genus of complex taxonomy. The group of Cheilosia melanura Becker, 1894 includes species distributed all over Europe, with some of these species being similar each other in both morphology and genetics. After recent fieldwork in different Iberian localities and consultation of entomological collections, a new species from Sierra Nevada (Granada, Spain) was uncovered, described, and illustrated. Data on diagnostic characters, intraspecific variability, and adult biology were also provided. Maximum likelihood analyses of the fragment "C" of the 5′ end of the cytochrome c oxydase subunit I (COI-5′) and complete COI-5′ were performed to explore and support morphological species concepts within the group. The Spanish-endemic Cheilosia andalusiaca Torp Pedersen, 1971 is recognised here to be part of the C. melanura group based both on morphological and molecular evidence. Cheilosia carbonaria Egger, 1860 and Cheilosia cynocephala Loew, 1840 from the Iberian Peninsula are reported for the first time based on specimens originating in the Spanish Pyrenees. An identification key for the Iberian species of the C. melanura group is provided. [ABSTRACT FROM AUTHOR]

Despite Batesian mimicry often eliciting predator avoidance, many Batesian mimics, such as some species of hoverfly (Syrphidae), are considered to have an "imperfect" resemblance to their model. One possible explanation for the persistence of apparently imperfect mimicry is that human perceptions of mimicry are different from those of natural predators. Natural predators of hoverflies have different visual and cognitive systems from humans, and they may encounter mimics in a different way. For example, whilst humans often encounter hoverflies at rest on vegetation, or in photographs or textbooks, where they are typically viewed from above, natural predators may approach hoverflies from the side or below. To test how viewing angle affects the perception of mimicry, images of mimetic hoverflies and their models (wasps and bees) were shown from different angles in an online survey. Participants were asked to distinguish between the images of models and mimics. The results show that the viewing angle does affect perceived mimicry in some species, although it does not provide a complete explanation for the persistence of imperfect mimicry in nature. The effect is also highly species-specific. This suggests that to understand better how selection has shaped mimetic accuracy in hoverflies and other taxa, further study is required of the viewing angles that predators utilize most commonly in nature. [ABSTRACT FROM AUTHOR]

Drone flies, Eristalis tenax (Diptera: Syrphidae), are important generalist pollinators and visit flowers globally that range widely in color. The flies' photoreceptors allow them to sense light wavelengths between 300-600 nm and E. tenax exhibit a positive phototactic response. To understand the effects of light on E. tenax movement, we conducted two-choice behavioral tests to determine their phototactic response to different wavelengths of light across the spectrum (ultraviolet to red light, plus full spectrum white light). The drone flies moved most and quickest toward sunlight, with almost twice the percentage of flies moving toward sunlight than toward black and purple light (short wavelength sources), which elicited the second strongest phototactic responses. Eristalis tenax moved minimally toward green and red light sources. When increasing air temperature by 6°C, the percent of E. tenax moving toward fluorescent white light increased by a factor of four. They also moved toward a food source in light but not dark conditions. Our findings may be useful for managing E. tenax populations in the lab or for increasing crop pollination. [ABSTRACT FROM AUTHOR]

Fruit and vegetable crops are affected by numerous arthropods, including aphids and thrips. Hoverfly adults are important pollinators, and their larvae are mainly aphid predators. Molecular studies on the stomach contents of larvae allowed to associate hoverflies with the consumption of other soft‐bodied arthropods, including thrips, with few records found in Neotropical hoverfly species. Allograpta exotica (Wiedemann) (Diptera: Syrphidae), a species widely distributed in the Americas, from the USA to Argentinian Patagonia, has been associated with numerous crops mainly affected by aphids, and to a lesser extent with whiteflies. The objective of this work was to assess the consumption and preference rates of various instars of A. exotica as biocontrol agents for two major insect pests, Myzus persicae (Sulzer) (Hemiptera: Aphididae) and Frankliniella gemina (Bagnall) (Thysanoptera: Thripidae), under controlled laboratory conditions. Additionally, we morphologically characterized the three larval stages of A. exotica. We determined that all three instars of A. exotica consume both M. persicae and F. gemina, and that they kill more thrips than aphids. Still, A. exotica preferred M. persicae over F. gemina, even when the relative aphid availability decreased compared to F. gemina, although consumption of both prey types remained high. Interestingly, A. exotica second instars consumed four times more thrips than aphids. This study explored the potential use of one of the most common hoverfly species in fruit and vegetable crops as a biocontrol agent of aphids and thrips. Further laboratory and field studies should explore more deeply the potential of this Neotropical beneficial dipteran. [ABSTRACT FROM AUTHOR]

The main study objective was to build knowledge on the genus Eumerus in the Afrotropical region. The new species Eumerus rufotibialis Radenkovic et Vujic sp. nov. of the E. obliquus group is thus reported. Also presented are the preimaginal stages of the mentioned species and Eumerus compactus van Doesburg 1966 as well as Eumerus astropilops Hull 1964. The descriptions were elaborated using scanning electron microscopy and optical microscopy imaging; supporting images, diagnostical features and comparisons with available descriptions have been included, both for imago and preimaginal descriptions. The known host plant of the three species is indicated together with some biological notes that support their saprophagous feeding habits. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual male Cheilosia grossa (a hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence has a total length of 362.40 megabases. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 17.81 kilobases in length. Gene annotation of this assembly on Ensembl identified 20,196 protein-coding genes.

The Afrotropical hoverflies belonging to the genus Mallota Meigen, 1822 (Diptera: Syrphidae) are revised. Ten species are recognized, of which four are new to science: Mallota glabra sp. nov., M. hircus sp. nov., M. wyatti sp. nov. and M. stipulata sp. nov. Merodon edentulus Macquart, 1855 is considered a junior synonym of Eristalis dasyops Wiedemann, 1819. Lectotypes are designated for Eristalis dasyops, Merodon edentulus, Mallota pachymera Bezzi, 1915 and Helophilus extremus Loew, 1858. The taxonomic history of the placement and identity of the different species of Mallota is presented. Their relationships, as well as affiliations with Afrotropical representatives of the genera Eristalis Latreille, 1804 and Myathropa Rondani, 1845, is briefly discussed based on morphological and DNA barcode data.

Simple Summary: The scarce genus of Pelecocera Meigen, 1822 (Diptera: Syrphidae) from the Holarctic Region has 14 species described. The taxonomic diagnosis of the immature stages of Pelecocera has not been performed; however, Pelecocera (Chamaesyrphus) japonica (Shiraki, 1956) larvae were found feeding on Rhizopogon roseolus in Japan. Following the findings in Japan, larvae of Pelecocera were collected in Denmark. We here report the first morphological description of the immature stages of Pelecocera (Chamaesyrphus) lugubris and Pelecocera (Pelecocera) tricincta, as well as specific data on their breeding sites. Larvae of both species were collected feeding on Rhizopogon luteolus in Denmark. The morphology of immature stages of P. lugubris and P. tricincta was studied by using both a scanning electron microscope and a stereomicroscope. A taxonomic diagnosis of the immature stages of Pelecocera and a taxonomic key are provided to separate them from the larvae of other genera. With 14 species, Pelecocera Meigen, 1822 is a scarce and small genus of hoverflies (Diptera: Syrphidae: Rhingiini) from the Holarctic Region. Apart from the finding of larvae of Pelecocera (Chamaesyrphus) japonica (Shiraki, 1956) in fungi in Japan, the larval biology of these hoverflies is virtually unknown. The early stages of all Pelecocera species are undescribed. The adults of Pelecocera (Pelecocera) tricincta Meigen, 1822 and Pelecocera (Chamaesyrphus) lugubris Perris, 1839 are found in Palearctic conifer forests with sand dunes. We here report the first morphological evidence of the immature stages of Pelecocera (P. lugubris and P. tricincta), as well as specific data on their breeding sites. Larvae of both species were collected feeding on the hypogean basidiomycete Rhizopogon luteolus Fr. & Nordholm, 1817 in Denmark in 2021. The first larval stage and second larval stage of P. tricincta, the third larval stage of P. lugubris, the anterior respiratory process, and the posterior respiratory process of the puparia of these two species were analyzed and studied using stereomicroscope and scanning electron microscope techniques. The chaetotaxy of the puparium of each species is also described and illustrated. A taxonomic diagnosis of the larvae of the genus Pelecocera is proposed to separate them from the larvae of other genera of the tribe. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual female Eristalinus aeneus (a hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 495.4 megabases in span. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.97 kilobases in length.

An updated checklist of Iranian Syrphidae (Diptera: Syrphoidea) is presented based on literature records with the latest taxonomic and nomenclatural changes. A total of 269 valid species in 70 genera among four subfamilies have been known from Iran, which is approximately 4.27 percent of the world’s total known Syrphidae. Among these, 145 species and 31 genera were added to the previous list. Of the 70 genera Eumerus Meigen (35 species, 13.01%) and Merodon Meigen (26 species, 9.67%), are the most specious, whereas 30 genera are represented in Iran by only one recorded species. The majority of Iranian hoverfly species are exclusively distributed in the Palaearctic region, while 21 species are known only from Iran and possibly endemic to the country.

We present a genome assembly from an individual female Merodon equestris (hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 873.0 megabases in span. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.95 kilobases in length.

We present a genome assembly from an individual male Cheilosia impressa (hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 395.0 megabases in span. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 16.87 kilobases in length.

Floral traits are assumed to be the main determinants of plant's pollinator spectrum, yet a majority of temperate plant species possess traits allowing to a certain degree of generalisation of their pollinator spectrum. The actual level of pollinator spectrum generalisation is likely to be the result of both plant floral traits and the diversity and abundance of plant species a plant co‐occurs with. We expect that plant species co‐occurring in highly diverse plant communities should host more generalised pollinator spectra.In the present study, we explore the degree to which the composition and generalisation of plant–pollinator spectra depend on the plant's niche width (measured as co‐occurrence with other plant species) and its local dominance (as measured by mean cover in the community). For this purpose, we compiled a database of >250 plant species pollinator spectra from the literature and coupled it with data on plant niche width and local dominance based on the Czech National Phytosociological Database.Species with wider niches had on average more generalised pollinator spectra, ranging from bumblebee‐dominated spectra to diptera‐ and/or nitidulid beetle‐dominated spectra, which was strongly related to plant phylogeny. Plants with bumblebee‐dominated spectra had neither wide niches nor niche specialists.The majority of plants had either muscid‐, hoverfly‐ or nitidulid‐dominated or completely generalised pollinator spectra. Among such plants, higher local dominance increased the proportion of opportune muscids in pollinator spectrum, while hoverflies showed the opposite pattern. Honeybees although rather infrequent in pollinator spectra also showed a strong preference for locally dominant plant species.Synthesis: The composition of a plant's pollinator spectrum is not independent of other aspects of the plant's life history, namely niche width and the ability to dominate the community. Wider plant species niches result in more generalised pollinator spectra, supporting our hypothesis that habitat generalists are less prone to specialisation on particular pollinator groups. Conversely, the ability to dominate local plant communities influenced pollinator spectra mainly through specific responses of individual pollinator groups. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Hairs often form on the flowers of Commelinaceae plants; however, their role in pollination ecology remains unclear. I examined the hypothesis that the dense hairs on the floral filaments of Tradescantia fluminensis (Commelinaceae) induce prolonged walking of pollinators on the petals, thus promoting effective pollination. This was done by comparing the behavior of flower‐visiting hoverflies on hair‐trimmed and control flowers. Hoverflies, the main pollinators of T. fluminensis, exhibited proboscis extension behavior towards hairs on floral filaments. Structural equation modeling analysis showed that the floral hairs increased the number of times the hoverflies touched the stamens, owing to the longer time that the hoverflies walked on the petals. These results suggest that the floral hairs of T. fluminensis mimic stamens, thereby enhancing pollination efficiency. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual male Pocota personata (a hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 845.2 megabases in span. Most of the assembly is scaffolded into 5 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 16.04 kilobases in length.

Simple Summary: Hoverflies are a diverse group (6200+ species) of two-winged flies that provide important ecosystem services (e.g., plant pollination and regulation of populations of pest insects). The hoverfly genus Eumerus has caught the attention of scientists and entomology amateurs due to its high number of species worldwide (250+) and its wide range of body sizes and shapes. Nevertheless, some species show a similar overall appearance making both their separation from each other and the study of their classification/biology difficult. Thus, the aim of the present work is to update the knowledge of the Eumerus hoverflies in the Iberian Peninsula by assessing the diversity of the Eumerus tricolor group under an integrative approach (i.e., combining different techniques and data sources). We found and described two new species from Spain and provided the most comprehensive identification key for all known European species of this Eumerus group. Eumerus Meigen, 1822 is one of the largest Syrphidae genera in the Palaearctic Region, with the highest levels of taxonomic diversity found in the Eumerus tricolor species group. Despite its high diversity, the interspecific levels of morphological variability can be low. Additionally, some species may show certain levels of intraspecific variability. Hence, species delimitation may become challenging. In this work, we assessed the diversity of the E. tricolor group in the Iberian Peninsula through an integrative analysis of nomenclature, morphology and the 5′ (COI-5′) and 3′ (COI-3′) end regions of the Cytochrome c oxidase subunit I gene. Two new species, Eumerus ancylostylus Aguado-Aranda & Ricarte sp. n. and Eumerus petrarum Aguado-Aranda, Nedeljković & Ricarte sp. n., were described, and their intra- and interspecific variations discussed. In addition, the first barcodes of Iberian members of the E. tricolor group were obtained, and the distribution ranges of all species were mapped within the study area. The systematic position of the new species is discussed based on the resulting COI-based trees. The male genitalia of Eumerus hispanicus van der Goot, 1966 and Eumerus bayardi Séguy, 1961 were studied and illustrated. A lectotype was designated for Eumerus lateralis (Zetterstedt, 1819). An updated dichotomous key for all known European species of the E. tricolor group is provided. The egg of E. petrarum sp. n. is also described. [ABSTRACT FROM AUTHOR]

The first data on the interaction between a phytophagous hoverfly and holoparasitic broomrape plants in Europe is reported. Description of the new species Eumerus larvatus sp. nov. Aracil, Grković et Pérez-Bañón is presented from specimens feeding within the fleshy hypogeal stems of Cistanche phelypaea in different localities of Southeast of Iberian Peninsula. Both, adult and preimaginal morphology are studied, including also a molecular analysis based on COI gene sequences. The molecular data, together with the diagnostic morphological characteristics of the adult, indicate that the species belongs to the Eumerus tricolor species-group. This paper presents the first in-depth and detailed description of the preimaginal morphology of a representative of this species group, based on scanning electron microscopy (SEM) images. [ABSTRACT FROM AUTHOR]

Invasive alien plant species are usually disliked due to their high pressure on native communities. However, their ecological effects on pollinators are complex: some species provide abundant floral resources, boosting the number of pollinators, while they often disrupt plant-pollinator interactions by outcompeting native plants. Our direct knowledge is mainly based on single-species studies, while understanding the mechanism of these complex ecological interactions needs multi-species field-based approaches. It is also imperative to clarify the pros and cons of invasive plants and drivers of invasion from the perspective of pollinators. We conducted a standard protocol-driven regional study in Central and Eastern Europe, comparing 6-7 invaded and non-invaded sites of 12 herbaceous invasive plant species. We sampled floral resources, bees, and hoverflies before and during the flowering of the invasive plants. We analysed the effects of plant invasion at the invasive plant species level and in combined analyses, and tested whether the life span (perennial vs. annual) and flowering time (early-, middle-, and late-flowering) of invasive plants affect the abundance, species richness, diversity and species composition of native plants and pollinators. The combined analyses showed lower abundance and species richness of flowering plants and pollinators before, and higher abundance of both during the flowering of invasive plants in invaded sites. However, invasive plants had significant species-specific effects. Perennial invasive plants had a stronger negative impact on floral resources and pollinators already before their flowering compared to annuals. Flowering time of invasive plants affected the pollinator guilds differently. We suggest that in certain critical time periods of the year, invasive plants might provide the dominant foraging resources for pollinators in an invaded ecosystem. But, they also often cause significant losses in native floral resources over the year. Instead of simple eradication, careful preparation and consideration might be needed during removal of invasive plants.

We present a genome assembly from an individual male Epistrophella euchroma (hoverfly, Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 523.3 megabases in span. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 17.24 kilobases in length.

An updated checklist of Iranian Syrphidae (Diptera: Syrphoidea) is presented based on literature records with the latest taxonomic and nomenclatural changes. A total of 269 valid species in 70 genera among four subfamilies have been known from Iran, which is approximately 4.27 percent of the world's total known Syrphidae. Among these, 145 species and 31 genera were added to the previous list. Of the 70 genera Eumerus Meigen (35 species, 13.01%) and Merodon Meigen (26 species, 9.67%), are the most specious, whereas 30 genera are represented in Iran by only one recorded species. The majority of Iranian hoverfly species are exclusively distributed in the Palaearctic region, while 21 species are known only from Iran and possibly endemic to the country. [ABSTRACT FROM AUTHOR]

Abstract Background Hoverflies (Diptera: Syrphidae) including Eupeodes corollae are important insects worldwide that provide dual ecosystem services including pest control and pollination. The larvae are dominant predators of aphids and can be used as biological control agents, and the adults are efficient pollinators. The different feeding habits of larvae and adults make hoverflies a valuable genetic resource for understanding the mechanisms underlying the evolution and adaptation to predation and pollination in insects. Results Here, we present a 595-Mb high-quality reference genome of the hoverfly E. corollae, which is typical of an aphid predator and a pollinator. Comparative genomic analyses of E. corollae and Coccinellidae (ladybugs, aphid predators) shed light on takeout genes (3), which are involved in circadian rhythms and feeding behavior and might regulate the feeding behavior of E. corollae in a circadian manner. Genes for sugar symporter (12) and lipid transport (7) related to energy production in E. corollae had homologs in pollinator honeybees and were absent in predatory ladybugs. A number of classical cytochrome P450 detoxification genes, mainly CYP6 subfamily members, were greatly expanded in E. corollae. Notably, comparative genomic analyses of E. corollae and other aphidophagous hoverflies highlighted three homologous trypsins (Ecor12299, Ecor12301, Ecor2966). Transcriptome analysis showed that nine trypsins, including Ecor12299, Ecor12301, and Ecor2966, are strongly expressed at the larval stage, and 10 opsin genes, which are involved in visual perception, are significantly upregulated at the adult stage of E. corollae. Conclusions The high-quality genome assembly provided new insights into the genetic basis of predation and pollination by E. corollae and is a valuable resource for advancing studies on genetic adaptations and evolution of hoverflies and other natural enemies.

Compared to monocultures, intercropping systems offer many agronomic benefits, including higher yield stability. In this study, we assessed whether cropping systems that are beneficial for yield stability are also beneficial for pollinator communities and whether the effect is modulated by the landscape type. Using a replicated block design in one heterogeneous and one homogeneous agricultural landscape, we studied the pollinator communities in eight populations (i.e., genotypes) of white clover (Trifolium repens) grown as a monoculture or as a two-species mixture (together with perennial ryegrass, Lolium perenne) or three-species mixture (together with perennial ryegrass and chicory, Cichorium intybus). We recorded 1486 honey bees and 1254 wild pollinators belonging to 46 species. Bumble bees were the most abundant wild pollinators (49.6 %), followed by hover flies (23.4 %), and non- Bombus wild bees (21.5 %). Lepidoptera accounted for only 5.4 % of the wild pollinators. We found a higher species richness and abundance of wild pollinators in monocultures than in two-species mixtures, but white clover population did not influence pollinators. Moreover, species richness and abundance were also higher in the homogeneous landscape than in the heterogenous one. Most species were foraging on white clover. However, 18 species (39.1 %, n = 18/46) were recorded foraging on chicory and/or weeds, and ten of these wild pollinator species were never recorded on white clover. Our study highlights that diverse pollinator communities require both abundant floral resources and diverse plant communities, that their needs are not in conflict with the goal of achieving yield stability, and that the landscape type can modulate the effect of the cropping system. Moreover, the lack of pollinator preference for different white clover populations suggests that farmers can select mixtures that enhance yield stability without negatively affecting pollinator communities. Overall, these results highlight that intercropping systems comprising several plant species and plant genotypes can guarantee yield stability without compromising the pollinator community, showing that win-win situations for farmers and biodiversity are possible. • Ryegrass-white clover intercropping can support diverse pollinator communities. • However, several pollinator species require species other than white clover. • Landscape heterogeneity can modulate the effect of the cropping system. [ABSTRACT FROM AUTHOR]

Abstract Background Sphaerophoria rueppellii, a European species of hoverfly, is a highly effective beneficial predator of hemipteran crop pests including aphids, thrips and coleopteran/lepidopteran larvae in integrated pest management (IPM) programmes. It is also a key pollinator of a wide variety of important agricultural crops. No genomic information is currently available for S. rueppellii. Without genomic information for such beneficial predator species, we are unable to perform comparative analyses of insecticide target-sites and genes encoding metabolic enzymes potentially responsible for insecticide resistance, between crop pests and their predators. These metabolic mechanisms include several gene families - cytochrome P450 monooxygenases (P450s), ATP binding cassette transporters (ABCs), glutathione-S-transferases (GSTs), UDP-glycosyltransferases (UGTs) and carboxyl/choline esterases (CCEs). Methods and findings In this study, a high-quality near-chromosome level de novo genome assembly (as well as a mitochondrial genome assembly) for S. rueppellii has been generated using a hybrid approach with PacBio long-read and Illumina short-read data, followed by super scaffolding using Hi-C data. The final assembly achieved a scaffold N50 of 87Mb, a total genome size of 537.6Mb and a level of completeness of 96% using a set of 1,658 core insect genes present as full-length genes. The assembly was annotated with 14,249 protein-coding genes. Comparative analysis revealed gene expansions of CYP6Zx P450s, epsilon-class GSTs, dietary CCEs and multiple UGT families (UGT37/302/308/430/431). Conversely, ABCs, delta-class GSTs and non-CYP6Zx P450s showed limited expansion. Differences were seen in the distributions of resistance-associated gene families across subfamilies between S. rueppellii and some hemipteran crop pests. Additionally, S. rueppellii had larger numbers of detoxification genes than other pollinator species. Conclusion and significance This assembly is the first published genome for a predatory member of the Syrphidae family and will serve as a useful resource for further research into selectivity and potential tolerance of insecticides by beneficial predators. Furthermore, the expansion of some gene families often linked to insecticide resistance and selectivity may be an indicator of the capacity of this predator to detoxify IPM selective insecticides. These findings could be exploited by targeted insecticide screens and functional studies to increase effectiveness of IPM strategies, which aim to increase crop yields by sustainably and effectively controlling pests without impacting beneficial predator populations.

Wildflower strips are increasingly promoted in pollinator conservation schemes to maintain the stability of ecosystem services and increase crop yield. Yet, the increased area of avocado Persea americana Mill. cultivation in sub-Saharan Africa is not accompanied by measures of biodiversity conservation or the promotion of ecosystem services. We investigated the effects of flower strips on flower visitors and avocado fruit set in Kenya. A strip mixture of sunflower Helianthus annuus L., coriander Coriandrum sativum L., and alfalfa Medicago sativa L. was established at the border of four avocado plots, while four other plots with an unmanaged border served as control. The abundance of insect flower visitors and fruit set at 10 m, 55 m, and 100 m from the border of each plot were assessed during the early, peak, and late avocado flowering periods. The honeybee Apis mellifera L. and hoverflies Syrphidae spp. accounted for 22% and 71% of flower visitors, respectively. We found interactions between the treatment, distance to the border, and the avocado flowering intensity on the abundance of honeybees but not on hoverflies. Irrespective of the distance to the border and the avocado's flowering intensity, flower strips acted as a sink for honeybees and hoverflies. Overall, the flower strip mixture of sunflower, coriander, and alfalfa did not increase pollinator abundance and avocado productivity, and it may be necessary to identify plant species for optimal benefits and study the long-term effects of floral strips on pollinators and crop production. [ABSTRACT FROM AUTHOR]

Field margins have an important ecological role in agroecosystems including hosting beneficial insect such as syrphids. However, little is known of syrphid preferences for different types of field margins. Syrphids were sampled in field margins in an organic agroecosystem to test the hypothesis that syrphid abundance in field margins depends not only on the floral resource abundance but also on field margin component type, field margin complexity, and adjacent land-use type. Floral resource abundance had the greatest influence on the number of syrphids surveyed. Field margin characteristics were deemed to effect syrphid abundance both independently of their effect on floral resources and by altering floral resource abundance. Syrphids were more abundant in field margins adjacent to cropped fields than those adjacent to grazed fields or roads. More syrphids were found in ditch components than in tree or grass strip components. The influence of floral resources on syrphid abundance varied depending on their botanical families, although no significant differences were observed for the effect of botanical family floral resource index on syrphid abundance. These findings demonstrate that field margin characteristics play an important role in facilitating plant–syrphid interactions and offer an insight in agroecosystem management for the promotion of beneficial insects. The influence of field margin characteristics on other beneficial insect groups should also be investigated. [ABSTRACT FROM AUTHOR]

There is increasing evidence that farmers in many areas are achieving below maximum yields due to insufficient pollination. Practical and effective approaches are needed to maintain wild pollinator populations within agroecosystems so they can deliver critical pollination services that underpin crop production. We established nesting and wildflower habitat interventions in 24 UK apple orchards and measured effects on flower‐visiting insects and the pollination they provide, exploring how this was affected by landscape context. We quantified the extent of pollination deficits and assessed whether the management of wild pollinators can reduce deficits and deliver improved outcomes for growers over 3 years. Wildflower interventions increased solitary bee numbers visiting apple flowers by over 20%, but there was no effect of nesting interventions. Other pollinator groups were influenced by both local and landscape‐scale factors, with bumblebees and hoverflies responding to the relative proportion of semi‐natural habitat at larger spatial scales (1000 m), while honeybees and other flies responded at 500 m or less. By improving fruit number and quality, pollinators contributed more than £16 k per hectare. However, deficits (where maximum potential was not being reached due to a lack of pollination) were recorded and the extent of these varied across orchards, and from year to year, with a 22% deficit in output in the worst (equivalent to ~£14 k/ha) compared to less than 3% (equivalent to ~£2 k/ha) in the best year. Although no direct effect of our habitat interventions on deficits in gross output was observed, initial fruit set and seed set deficits were reduced by abundant bumblebees, and orchards with a greater abundance of solitary bees saw lower deficits in fruit size. The abundance of pollinators in apple orchards is influenced by different local and landscape factors that interact and vary between years. Consequently, pollination, and the extent of economic output deficits, also vary between orchards and years. We highlight how approaches, including establishing wildflower areas and optimizing the ratio of cropped and non‐cropped habitats can increase the abundance of key apple pollinators and improve outcomes for growers. [ABSTRACT FROM AUTHOR]

Staminate flowers of triploid cultivars lack viable pollen grains [[4]], so it is always necessary to introduce a diploid variety as a pollen donor and a proper transportation of pollen from the staminate flowers of diploid cultivars to the pistillate flowers to set fruits. 2003; 13: 58-61. 10.21273/HORTTECH.13.1.0058 47 Freeman J.H., Miller G.A., Olson S.M., Stall W.M. Diploid watermelon pollenizer cultivars differ with respect to triploid watermelon yield. Although the honey bee stands out as the primary crop pollinator for watermelon worldwide, many other species contribute to watermelon pollination in the open field [[24], [27], [30], [32], [34]]. Keywords: hoverfly; pollination; watermelon; Eristalinus aeneus; plant-pollinator interactions; alternative pollinators; myophily EN hoverfly pollination watermelon Eristalinus aeneus plant-pollinator interactions alternative pollinators myophily 1021 14 11/17/22 20221101 NES 221101 1. [Extracted from the article]

• Invasive plants reduce species richness of native floral resources over the year • Invasive plants can boost foraging resources of pollinators, but only for a short term • Hoverflies and honey bees can gain more from plant invasion than wild bees • Perennial invasive plants have more negative effect over the year than annuals Invasive alien plant species are usually disliked due to their high pressure on native communities. However, their ecological effects on pollinators are complex: some species provide abundant floral resources, boosting the number of pollinators, while they often disrupt plant-pollinator interactions by outcompeting native plants. Our direct knowledge is mainly based on single-species studies, while understanding the mechanism of these complex ecological interactions needs multi-species field-based approaches. It is also imperative to clarify the pros and cons of invasive plants and drivers of invasion from the perspective of pollinators. We conducted a standard protocol-driven regional study in Central and Eastern Europe, comparing 6-7 invaded and non-invaded sites of 12 herbaceous invasive plant species. We sampled floral resources, bees, and hoverflies before and during the flowering of the invasive plants. We analysed the effects of plant invasion at the invasive plant species level and in combined analyses, and tested whether the life span (perennial vs. annual) and flowering time (early-, middle-, and late-flowering) of invasive plants affect the abundance, species richness, diversity and species composition of native plants and pollinators. The combined analyses showed lower abundance and species richness of flowering plants and pollinators before, and higher abundance of both during the flowering of invasive plants in invaded sites. However, invasive plants had significant species-specific effects. Perennial invasive plants had a stronger negative impact on floral resources and pollinators already before their flowering compared to annuals. Flowering time of invasive plants affected the pollinator guilds differently. We suggest that in certain critical time periods of the year, invasive plants might provide the dominant foraging resources for pollinators in an invaded ecosystem. But, they also often cause significant losses in native floral resources over the year. Instead of simple eradication, careful preparation and consideration might be needed during removal of invasive plants. [ABSTRACT FROM AUTHOR]

Syrphid larvae are well-known predators of aphids; however, we sometimes observed them on onion plants with thrips and without any aphids, which intercropped with barley in our previous study. Therefore, we hypothesized that syrphid larvae fed on thrips in the onion field in the absence of aphids, their main prey. This hypothesis was tested by analyzing the prey DNA from syrphid larvae collected from onion plants intercropped with barley. We found that they preyed on three thrips species: Thrips tabaci (Lindeman), Frankliniella occidentalis (Pergande), and Anaphothrips obscurus (Müller). Moreover, we observed that syrphid larvae collected from onion plants fed on larval T. tabaci in a laboratory setting. According to COI sequencing of their genomes, the syrphid species occurred from the onion plants were Sphaerophoria macrogaster (Thomson), Melanostoma scalare (Fabricius), Melanostoma mellinum (L.), and Platycheirus pennipes (Ohara); all of them were found to prey on thrips in the prey DNA analyses. These results and observations supported the hypothesis and suggested that intercropping barley as a living mulch may become an option for enhancing the potential of native syrphid species as generalist predators in the onion fields. [ABSTRACT FROM AUTHOR]

The hoverfly Eristalinus arvorum (Fabricius, 1787) (Diptera: Syrphidae), which belongs to the tribe Eristalini, is well known as a pollinating agent for crops and flowering plants in agricultural and natural ecosystems. Large quantity, wide distribution and their ecological function of the hoverfly E. arvorum make them an appropriate candidate for use as pollinators and environmental indicator species. However, little information has been known on the morphology and the biological cycle of the hoverfly. In this study, feeding experiments under artificial climate chamber and morphological qualitative and quantitative observations were carried out to study the morphology and the biological cycle of the hoverfly E. arvorum. The morphology of eggs, larvae, pupae, and adults of E. arvorum were described in detail for the first time. A complete generation of E. arvorum lasts about 30.12 ± 0.14 days, and there is no significant difference in body length between males (10.27 ± 0.29 mm) and females (11.16 ± 0.45 mm). The most noteworthy morphological features of E. arvorum are the stripes on the compound eyes, the mesonotum, and the abdomen of adults, the chorionic structure consisting of fusiform units on the egg's surface, and the anterior spiracles and pupal spiracles of the pupae. Thus, the detailed description based on morphology and life history will provide the basis for the identification, biodiversity conservation and artificial breeding of the hoverfly E. arvorum.

Aphidophagous hoverflies (Diptera, Syrphidae, Syrphinae) are common flower visitors and aphid predators in a range of flowering plants, including fruit crops. Here, we investigate whether aphid prey DNA can be detected in the gut contents of hoverfly larvae from a commercial strawberry field as a proof of concept that a molecular approach can be used to measure agricultural biocontrol. We used high-throughput sequencing (HTS) to target insect DNA and compared the resulting data to reference databases containing aphid and hoverfly DNA sequences. We explored what impact incorporating wildflowers within polythene-clad tunnels may have on aphid DNA detection rates in hoverfly larvae. In a randomized block experiment, coriander (Coriandrum sativum), field forget-me-not (Myosotis arvensis) and corn mint (Mentha arvensis) plants were inserted in rows of strawberries. Their effect on aphid DNA detection rates was assessed. Aphid DNA was found in 55 of 149 specimens (37%) validating the method in principle for measuring agricultural services provided by hoverflies. Interestingly, detection rates were higher near plots with forget-me-not than plots with coriander, though detection rates in control plots did not differ significantly from either wildflower species. These findings confirm that hoverflies predate aphids in UK strawberry fields, and that HTS is a viable method of identifying aphid DNA in predatory hoverflies. We comment on the need for further method development to narrow down identifications of both predator and prey. We furthermore provide some evidence that there is an effect of intercropping strawberry crops with wildflowers which may affect aphid consumption in hoverfly larvae. [ABSTRACT FROM AUTHOR]

Background: Hoverflies (Diptera: Syrphidae) including Eupeodes corollae are important insects worldwide that provide dual ecosystem services including pest control and pollination. The larvae are dominant predators of aphids and can be used as biological control agents, and the adults are efficient pollinators. The different feeding habits of larvae and adults make hoverflies a valuable genetic resource for understanding the mechanisms underlying the evolution and adaptation to predation and pollination in insects. Results: Here, we present a 595-Mb high-quality reference genome of the hoverfly E. corollae, which is typical of an aphid predator and a pollinator. Comparative genomic analyses of E. corollae and Coccinellidae (ladybugs, aphid predators) shed light on takeout genes (3), which are involved in circadian rhythms and feeding behavior and might regulate the feeding behavior of E. corollae in a circadian manner. Genes for sugar symporter (12) and lipid transport (7) related to energy production in E. corollae had homologs in pollinator honeybees and were absent in predatory ladybugs. A number of classical cytochrome P450 detoxification genes, mainly CYP6 subfamily members, were greatly expanded in E. corollae. Notably, comparative genomic analyses of E. corollae and other aphidophagous hoverflies highlighted three homologous trypsins (Ecor12299, Ecor12301, Ecor2966). Transcriptome analysis showed that nine trypsins, including Ecor12299, Ecor12301, and Ecor2966, are strongly expressed at the larval stage, and 10 opsin genes, which are involved in visual perception, are significantly upregulated at the adult stage of E. corollae. Conclusions: The high-quality genome assembly provided new insights into the genetic basis of predation and pollination by E. corollae and is a valuable resource for advancing studies on genetic adaptations and evolution of hoverflies and other natural enemies. [ABSTRACT FROM AUTHOR]

Hybrid seed production often relies on managed pollinators whose use in isolation cages can pose challenges. Here, we evaluated the pollination ability of the novel managed pollinator Eristalinus aeneus (Diptera: Syrphidae) in hybrid celery and fennel seed crops. During trials performed in 2019–2020 in Cordoba, Spain, we compared seed production with hoverflies released at high and low densities (40–20 ind./m2), and without released pollinators. In celery, we included a treatment with Lucilia sericata (Diptera: Calliphoridae), a blowfly used for seed production (375 ind./m2). The production of celery seeds when E. aeneus were released at high density was significantly higher (+49%) than without released pollinators, for both sterile and fertile plant genotypes; no significant differences were found between the two hoverfly densities and the blowfly treatments. In fennel, seed yield of fertile plants with high density of hoverflies was higher than with low density (+149%), or without released pollinators (+168%); whereas for sterile plants no differences were found between treatments. In both crops and plant genotypes, the highest pollen adhesion to stigmas (number of pollen grains and proportion of flowers with pollen adhered in two stigmas) was obtained with hoverflies at high density. In celery, pollen adhesion was higher with high density of hoverflies than with blowflies for both plant genotypes, despite the considerably lower numbers of released hoverflies. Our results suggest that E. aeneus is a more efficient pollinator of celery than L. sericata, and that it has the potential to effectively pollinate other hybrid Apiaceae seed crops like fennel. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome (mitogenome) of Syritta pipiens (Linnaeus, 1758) was sequenced with 15,745 bp in length including 37 genes and a non-coding region. The overall nucleotide composition showed a strong AT bias. Most protein-coding genes (PCGs) used ATN as the start codon while ATP6 and ND1 used TTG, and stopped by TAA or TAG but ND5 ended with an incomplete T. Phylogenetic trees were reconstructed based on the 24 complete mitochondrial sequences from Syrphidae using the methods of maximum-likelihood (ML) and Bayesian inference (BI), resulted in S. pipiens clustered into the clade of Eristalinae, which conformed to the traditional classification, but the trees did not support the monophyly of Eristalinae. More molecular data is needed for further study.

We examined the phylogeny and intrageneric classification of eristaline hoverfly genera from the Afrotropical Region using mitochondrial genomes. Genome skimming was used to obtain (nearly) full mtDNA and nuclear rDNA (18S, 28S) genomes of 120 museum vouchers from eight genera and 98 species. Phylogenetic reconstructions of mitogenomes and mitogenomes + nuclear rDNA yielded comparable phylogenies while that of rDNA only resulted in poorly resolved phylogenies. Phylogenetic analyses focused on six genera and supported the monophyly of the genera Chasmomma Bezzi, Eristalinus Rondani, Mesembrius Rondani and Syritta Le Peletier & Serville, whereas Simoides Loew was not monophyletic and rendered PhytomiaGuérin‐Méneville paraphyletic. We therefore synonymize Simoides with Phytomia. Within Chasmomma, two species‐groups that differ in the colour and the shape of the hind femora (Chasmomma femoratum and Chasmomma nigrum species‐groups) were supported. Within Eristalinus, the monophyly of the subgenera Merodonoides Curran and Eristalodes Mik was supported, but not of the subgenus Eristalinus Rondani. Within Syritta, the monophyly of three out of the five species‐groups tested was rejected. This approach illustrates the importance of integrative and iterative approaches in taxonomy and shows that genomic data may not only clarify the systematic relationships among hoverfly genera and species, but also offer perspectives into the evolution of morphological and ecological variation within the family. [ABSTRACT FROM AUTHOR]

Botanical gardens could serve as pollinator-friendly gardens and are suitable locations for investigating plant–pollinator interactions. Pollination in botanical gardens is a challenging topic of research, and its ecological function remains unclear in terms of pollination management for both pollinators and plants. Objective monitoring methods—including the selection of insect taxa and analytical methods—are required to elucidate plant–pollinator interactions in botanical gardens. In this study, we evaluated pollen transport networks using generalist hoverflies, as they are important pollinator insects, generalist flower visitors, and heterospecific pollen vectors that carry pollen over large distances. Hoverflies can form generalized pollen transport networks with an adequate abundance and wide distribution, and are easily collectable using sticky traps. Pollen grains on hoverfly bodies were identified based on pollen DNA barcoding using the ITS, rbcL, and trn regions. Bipartite pollen transport networks in the study period in 2018 and 2019 consisted of 116 plant taxa that were significantly generalized and showed similar structures in both years. The dominant plant taxa were two invasive species—Solidago canadensis and Bidens sp.—which had a significantly high eigenvector centrality in unipartite pollen transport networks. Hoverfly-mediated pollen transfer distances were 116–131 m on average and were significantly shorter in heterogeneous open environments. These findings suggest that hoverflies are non-negligible actors in pollen transport networks in the studied botanical garden. [ABSTRACT FROM AUTHOR]

Background: Sphaerophoria rueppellii, a European species of hoverfly, is a highly effective beneficial predator of hemipteran crop pests including aphids, thrips and coleopteran/lepidopteran larvae in integrated pest management (IPM) programmes. It is also a key pollinator of a wide variety of important agricultural crops. No genomic information is currently available for S. rueppellii. Without genomic information for such beneficial predator species, we are unable to perform comparative analyses of insecticide target-sites and genes encoding metabolic enzymes potentially responsible for insecticide resistance, between crop pests and their predators. These metabolic mechanisms include several gene families - cytochrome P450 monooxygenases (P450s), ATP binding cassette transporters (ABCs), glutathione-S-transferases (GSTs), UDP-glycosyltransferases (UGTs) and carboxyl/choline esterases (CCEs). Methods and findings: In this study, a high-quality near-chromosome level de novo genome assembly (as well as a mitochondrial genome assembly) for S. rueppellii has been generated using a hybrid approach with PacBio long-read and Illumina short-read data, followed by super scaffolding using Hi-C data. The final assembly achieved a scaffold N50 of 87Mb, a total genome size of 537.6Mb and a level of completeness of 96% using a set of 1,658 core insect genes present as full-length genes. The assembly was annotated with 14,249 protein-coding genes. Comparative analysis revealed gene expansions of CYP6Zx P450s, epsilon-class GSTs, dietary CCEs and multiple UGT families (UGT37/302/308/430/431). Conversely, ABCs, delta-class GSTs and non-CYP6Zx P450s showed limited expansion. Differences were seen in the distributions of resistance-associated gene families across subfamilies between S. rueppellii and some hemipteran crop pests. Additionally, S. rueppellii had larger numbers of detoxification genes than other pollinator species. Conclusion and significance: This assembly is the first published genome for a predatory member of the Syrphidae family and will serve as a useful resource for further research into selectivity and potential tolerance of insecticides by beneficial predators. Furthermore, the expansion of some gene families often linked to insecticide resistance and selectivity may be an indicator of the capacity of this predator to detoxify IPM selective insecticides. These findings could be exploited by targeted insecticide screens and functional studies to increase effectiveness of IPM strategies, which aim to increase crop yields by sustainably and effectively controlling pests without impacting beneficial predator populations. [ABSTRACT FROM AUTHOR]

Merlino Wood is a typical oak–hornbeam forest in the Po Plain hydrographic region. It is one of the few remaining lowland forests in Northern Italy and is a Regional Natural Reserve and a Site of Community Interest (code IT1160010). This is the first survey on hoverflies in the study area and they act as bioindicators to assess habitat conservation. Sampling was performed with three Malaise traps and an entomological net. A total of 61 species of Syrphidae were recorded between March and October 2019. Three of the species observed are considered to be under threat in Europe, three species have been recorded for the first time in Piedmont and Heringia latitarsis (Egger, 1865) has been recorded for the first time in Northern Italy. The Syrph the Net analysis has been used to assess habitat conservation. It shows good preservation of xylosaprophagous species, while the conservation conditions of other larval trophic categories are poor.

One species of genus Dasysyrphus, Enderlein 1938, namely Dasysyrphus albostriatus (Fallen, 1817) is recorded for the first time from India.

Eristalinus aeneus (Scopoli, 1763) is a suitable candidate for artificial rearing due to its pollination efficiency and subcosmopolitan distribution. However, the high mortality found at the larval stage of this species needs to be overcome. In this research, two different larval media were used to study the life cycle of E. aeneus: brewery spent grain (BSG) from a local craft-beer factory and soaked oat grains (SOG). The age-stage, two-sex life table method was used to analyze the results, which were compared using the paired bootstrap test. The greatest mortality was found at the larval stage with both media. Individuals fed on SOG presented a shorter preadult developmental time (22.05 days) than those reared with BSG (26.97 days). This fact had a direct impact on the total preoviposition period, it being shorter with SOG (34.36 days) than BSG (38.29 days), although the second provided a larger total number of eggs (19,242 eggs) and a faster adult maturation (10.67 days). The population parameters indicated that both populations will display a positive growth under the studied conditions, being the mean generation time (T) significantly shorter when using SOG (38.71 days) than BSG (45.95 days). Despite the preadult results pointing to SOG being a more efficient medium, the promising fecundity values provided by BSG, as well as it's lower cost and ecological benefits, suggest that this second medium could be improved and used as an alternative to SOG in the near future. [ABSTRACT FROM AUTHOR]

Identifying which behavioural strategies maximize individual fitness is a key objective in ecology. Organisms are known to adapt their foraging behaviour to their environment in response to abiotic and biotic constraints, such as the distribution of resources or the presence of competitors. For instance, bees are known to avoid recently visited flowers and thus focus their foraging on more rewarding patches. Whether other flower‐visiting insects adapt their foraging behaviour in response to exploitative competition for floral resources remains unknown. Here, we asked if a predatory hoverfly Episyrphus balteatus and a parasitoid Aphidius colemani 1) are physiologically impacted by flower resource limitation following exploitation of flowers by a competitor (either the bumblebee Bombus terrestris or E. balteatus); 2) have the ability to discriminate flowers that were previously exploited by a competitor; and 3) modify their foraging behaviour accordingly. Episyrphus balteatus and A. colemani individuals foraging on previously exploited flowers were found to be less concentrated in sugar compounds, especially in fructose and glucose, suggesting that previously exploited flowers contained less available sugars. Nevertheless, individuals did not avoid previously exploited patches in the choice experiment. On the contrary, E. balteatus females preferentially landed on inflorescences that had previously been exploited by conspecifics (but not by B. terrestris), while A. colemani did not show preferences between inflorescences. However, female hoverflies spent more time feeding on unexploited patches, suggesting that exploited patches were resource limited. To our knowledge, this study provides the first evidence of the use of social cues among E. balteatus individuals in food foraging strategies. It also shows that even insects with tiny nectar requirements, such as parasitoids, can suffer from heavy exploitative competition. Such results may have applied consequences for the understanding of natural enemy conservation, in particular in agroecosystems where competition with honeybees may be important. [ABSTRACT FROM AUTHOR]

The genus Romaleosyrphus Bigot is reviewed, including the description of seven new species (R. argosi Moran, sp. nov., R. bigoti Moran, sp. nov., R. drysus Moran, sp. nov., R. nephelaeus Moran & Thompson, sp. nov., R. soletluna Moran & Thompson, sp. nov., R. vockerothi Moran & Thompson, sp. nov. and R. woodi Moran, sp. nov.). Romaleosyrphus arctophiloides (Giglio-Tos), comb. nov. is transferred to Romaleosyrphus. Romaleosyrphus stat. rev. is redefined to represent the monophyletic unit of species within Criorhinina which possess holoptic males, a proximal ventral half of vein C with setae, a broad intersection of vein R1 with vein C, the distal part of R4+5 beyond M1 longer than cross-vein h and appressed pile on the abdomen. Descriptions, habitus and genitalia photographs, distributions, and an illustrated key for all nine Romaleosyrphus are presented. DNA barcode data are provided for eight of the species with a cytochrome c oxidase subunit I gene tree presented and discussed. [ABSTRACT FROM AUTHOR]