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Long-distance insect migration is poorly understood despite its tremendous ecological and economic importance. As a group, Nearctic hover flies (Diptera: Syrphidae: Syrphinae), which are crucial pollinators as adults and biological control agents as larvae, are almost entirely unrecognized as migratory despite examples of highly migratory behavior among several Palearctic species. Here, we examined evidence and mechanisms of migration for four hover fly species (Allograpta obliqua, Eupeodes americanus, Syrphus rectus, and Syrphus ribesii) common throughout eastern North America using stable hydrogen isotope (δ²H) measurements of chitinous tissue, morphological assessments, abundance estimations, and cold-tolerance assays. Although further studies are needed, nonlocal isotopic values obtained from hover fly specimens collected in central Illinois support the existence of long-distance fall migratory behavior in Eu. americanus, and to a lesser extent S. ribesii and S. rectus. Elevated abundance of Eu. americanus during the expected autumn migratory period further supports the existence of such behavior. Moreover, high phenotypic plasticity of morphology associated with dispersal coupled with significant differences between local and nonlocal specimens suggest that Eu. americanus exhibits a unique suite of morphological traits that decrease costs associated with long-distance flight. Finally, compared with the ostensibly nonmigratory A. obliqua, Eu. americanus was less cold tolerant, a factor that may be associated with migratory behavior. Collectively, our findings imply that fall migration occurs in Nearctic hover flies, but we consider the methodological limitations of our study in addition to potential ecological and economic consequences of these novel findings.

Abstract Soil fertilization with dehydrated sewage sludge accelerates the recovery process of degraded areas, improving nutrient concentration, and favors the development of webs with pioneer plants such as Acacia auriculiformis and insects. This study aimed to evaluate the sap-sucking hemipteran insects, tending ants, and Sternorrhyncha predators in A. auriculiformis saplings fertilized with or without dehydrated sewage sludge, over two years in a degraded area. Acacia auriculiformis saplings fertilized showed higher numbers of sap-sucking Hemiptera Aleyrodidae, Aethalion reticulatum, and Erythrogonia sexguttata, the tending ant Brachymyrmex sp., and the Sternorrhyncha predators Cycloneda sanguinea and Syrphus sp.. Acacia auriculiformis saplings with higher numbers of branches/sapling showed a positive effect on the sap-sucking Hemiptera Achillidae and A. reticulatum and the tending ant Brachymyrmex sp.. The highest numbers of Cephalotes sp., Brachymyrmex sp., and Pheidole sp. were positively associated with those of Aleyrodidae, A. reticulatum, and Membracidae, respectively, in A. auriculiformis saplings. Saplings with high numbers of Cephalotes sp. had low numbers of C. sanguinea. The use of A. auriculiformis, fertilized with dehydrated sewage sludge, is promising in recovering degraded areas due to the increase in sap-sucking Hemiptera, tending ants, and Sternorrhyncha predators. In addition, these ants associated with sap-sucking Hemiptera reduce Sternorrhyncha predators. Resumo A fertilização do solo com lodo de esgoto desidratado acelera o processo de recuperação de áreas degradadas, melhorando a concentração de nutrientes e favorecendo o desenvolvimento de teias com plantas pioneiras como Acacia auriculiformis e insetos. Este estudo teve como objetivo avaliar os insetos hemípteros sugadores de seiva, formigas cuidadoras e predadores de Sternorrhyncha em mudas de A. auriculiformis fertilizadas ou não com lodo de esgoto desidratado, ao longo de dois anos, em uma área degradada. As mudas de A. auriculiformis fertilizadas apresentaram maior número de hemípteros sugadores de seiva Aleyrodidae, Aethalion reticulatum e Erythrogonia sexguttata, e da formiga cuidadora Brachymyrmex sp., e os predadores de Sternorrhyncha Cycloneda sanguinea e Syrphus sp.. Mudas de A. auriculiformis com maior número de galhos/muda apresentaram efeito positivo sobre os hemípteros sugadores de seiva Achillidae e A. reticulatum, e sobre a formiga cuidadora Brachymyrmex sp.. Os maiores números de Cephalotes sp., Brachymyrmex sp. e Pheidole sp. foram positivamente associados aos de Aleyrodidae, A. reticulatum e Membracidae, respectivamente, em mudas de A. auriculiformis. Mudas com alto número de Cephalotes sp. apresentaram baixo número de C. sanguinea. O uso de A. auriculiformis, fertilizada com lodo de esgoto desidratado, é promissor na recuperação de áreas degradadas devido ao aumento de hemípteros sugadores de seiva, formigas cuidadoras e predadores do de Sternorrhyncha. Além disso, essas formigas associadas aos hemípteros sugadores de seiva reduzem a população de predadores de Sternorrhyncha.

Abstract Anthropogenic activities have intensified soil degradation and disrupted essential ecological processes, underscoring the need for effective ecological restoration strategies. Terminalia argentea, a pioneer species of the Cerrado, has demonstrated potential for recovering degraded areas and facilitating arthropod recolonization. Arthropods are sensitive to environmental changes and are thus recognized as bioindicators. This study aimed to assess the recovery of a degraded area by evaluating insect and spider ecological indices, their interactions, and the plant biomass of T. argentea saplings over a two-year field establishment period. Saplings with greater biomass (e.g., more leaves/branch) supported a higher abundance and richness of tending ants. During the first year after planting, the leaves of T. argentea saplings exhibited higher numbers of chewing insects (e.g., Cerotoma sp.) and their ecological indices (e.g., diversity), spiders (e.g., Oxyopidae) and their species richness, bees (e.g., Trigona spinipes) and their abundance, and tending ants (e.g., Brachymyrmex sp.) and their diversity and richness of species. In contrast, saplings in the second year after planting hosted higher numbers of sap-sucking insects (e.g., Aphis spiraecola), their tending ant Camponotus sp., and their Dolichopodidae predators. Saplings with more sap-sucking insects (e.g., Phenacoccus sp.) also had more tending ants (e.g., Camponotus sp.). However, an increase in tending ants (e.g., Ectatomma sp.) was associated with a reduction in predators (e.g., Photinus sp.) and chewing insects (e.g., Lamprosoma sp.). The presence of spiders (e.g., Araneidae) was correlated with higher numbers of chewing insects (e.g., Cephalocoema sp.), while Mantis religiosa and Polybia sp. were more common on saplings with higher defoliation percentages, and Syrphus sp. was associated with Bemisia sp.. These results indicate that trophic interactions, mediated by both bottom-up and top-down mechanisms, structure the arthropod community on T. argentea, promoting the coexistence of functional groups and enhancing ecological indices. Future studies involving predator exclusion and leaf chemical analyses will be essential to deepen this understanding. Resumo As atividades antropogênicas intensificaram a degradação do solo e interromperam processos ecológicos essenciais, ressaltando a necessidade de estratégias eficazes de restauração ecológica. Terminalia argentea, uma espécie pioneira do Cerrado, tem demonstrado potencial para a recuperação de áreas degradadas e para facilitar a recolonização por artrópodes. Os artrópodes são sensíveis às mudanças ambientais e, portanto, são reconhecidos como bioindicadores. Este estudo teve como objetivo avaliar a recuperação de uma área degradada por meio da análise de índices ecológicos de insetos e aranhas, suas interações e a biomassa de mudas de T. argentea durante um período de dois anos de cultivo em campo. Mudas com maior biomassa (ex.: mais folhas/galho) apresentaram maior abundância e riqueza de formigas cuidadoras. Durante o primeiro ano após o plantio, as folhas das mudas de T. argentea apresentaram maior número de insetos mastigadores (ex.: Cerotoma sp.) e seus índices ecológicos (ex.: diversidade), aranhas (ex.: Oxyopidae) e sua riqueza de espécies, abelhas (ex.: Trigona spinipes) e sua abundância, e formigas cuidadoras (ex.: Brachymyrmex sp.) e sua diversidade e riqueza de espécies. Em contraste, as mudas no segundo ano após o plantio apresentaram maior número de insetos sugadores de seiva (ex.: Aphis spiraecola), sua formiga cuidadora Camponotus sp. e seus predadores da família Dolichopodidae. Mudas com maior número de insetos sugadores de seiva (ex.: Phenacocus sp.) também apresentaram maior número de formigas cuidadoras (ex.: Camponotus sp.). Contudo, o aumento de formigas cuidadoras (ex.: Ectatomma sp.) foi associado à redução de predadores (ex.: Photinus sp.) e insetos mastigadores (ex.: Lamprosoma sp.). A presença de aranhas (ex.: Araneidae) correlacionou-se com um maior número de insetos mastigadores (ex.: Cephalocoema sp.), enquanto Mantis religiosa e Polybia sp. foram mais comuns em mudas com maiores percentuais de desfolha, e Syrphus sp. foi associado a Bemisia sp.. Esses resultados indicam que as interações tróficas, mediadas por mecanismos ascendentes e descendentes, estruturam a comunidade de artrópodes em T. argentea, promovendo a coexistência de grupos funcionais e aprimorando os índices ecológicos. Estudos futuros envolvendo a exclusão de predadores e análises químicas foliares serão essenciais para aprofundar esse entendimento.

This study focuses on the avidus–nigritarsis lineage within the genus Merodon , exploring morphological, genetic, and distributional aspects of two related assemblies within this lineage: the clavipes and pruni species groups. An integrative taxonomic approach was followed to ensure comprehensive species identification and validation, using adult morphology, wing geometric morphometrics, and genetic analysis of the mtDNA COI gene. In the clavipes group, seven species were identified, including three new species: M. aenigmaticus Vujić, Radenković & Likov, sp. nov. , M. latens Vujić, Radenković & Likov, sp. nov. , and M. rufofemoris Vujić, Radenković & Likov, sp. nov. In the pruni group, our revision revealed a new species, M. aequalis Vujić, Radenković & Likov, sp. nov. , and the revalidation of Merodon obscurus Gil Collado, 1929, stat. rev. Merodon pallidus Macquart, 1842 is redescribed. Diagnoses, identification keys to species, and distribution maps are provided, and neotypes for Syrphus clavipes Fabricius, 1781 and Merodon quadrinotatus (Sack, 1931) are designated. Additionally, the following new synonyms are proposed: M. clavipes albus syn. nov. , M. clavipes ater syn. nov. , M. clavipes niger syn. nov. , and M. splendens syn. nov. are junior synonyms of M. clavipes ; and M. velox armeniacus syn. nov. and M. velox anathema syn. nov. are junior synonyms of M. velox .

The complete mitochondrial genome of Syrphus ribesii was determined in this study. The double-stranded circular DNA molecule was 16,530 bp in length, containing 37 typical genes: 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and an A + T-rich region. Thirteen PCGs were 11,196 bp in size, encoding 3720 amino acids in total. All the PCGs started with ATN, except the COI used TTG as its initiation codon. Most PCGs terminated with standard codon TAA, while the COI ended with T and the ND5 ended with TA. The lrRNA and srRNA genes were 1341 bp and 793 bp in length, respectively. The A + T-rich region harbored some typical structures characteristic of the dipterans. The phylogenetic tree showed that Syrphus ribesii was closely related to Eupeodes corollae, and the Syrphidae and Pipunculidae constituted a monophyletic group within the Syrphoidea.

During two seasons of observations, 244 specimens of hoverflies belonging to 16 species and four trophic groups were collected from herb flowers. Predatory species constituted about 50% of all the registered species and from 55% (2010) to 64% (2011) of all the specimens found. The most numerous flower-visiting species within this group were small, poor flyers, typical of communities with low plants - Sphaerophoria scripta (Linnaeus 1758) (19.6% in 2010 and 23.5% in 2011) and Eupeodes corollae (Fabricius 1794) (13.4% and 12.1%, respectively). Both species were classified to the eudominant group. Syrphus vitripennis (Meigen 1822) and Melanostoma mellinum (Linnaeus 1758) were classed as dominants. Non-predatory saprophagous species from the subfamily Eristalinae constituted about 25% of all collected species; the phytophagous group was scarce represented by Eumerus funeralis (Meigen 1822), E. strigatus (Fallen 1817) and Merodon rufus (Meigen 1838). Of the coprophagous species, only Syritta pipiens (Linnaeus 1758) was collected (6.8-8.0%). There were clear differences between flowers in terms of feeding visits by adult hoverflies. Matricaria chamomilla L. and Thymus vulgaris L. were the most attractive flowers, whereas Origanum vulgare L., Carum carvi L., Lavandula angustifolia L. and Hyssopus officinalis L. were of an intermediate visit status and Ocimum basilicum L. was relatively under-visited.

The complete mitochondrial genome of Syrphus vitripennis was sequenced and reported here. The circle genome of S. vitripennis is 16,185 bp in length. There are 38 sequence elements including 13 protein coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. The order of all elements was the same with that of Eristalia cerealis. With two species from Muscidae and Drosophilidae as outgroups, phylogenetic relationships of eight Syrphidae species based on mitogenomes were in complete agreement with their taxonomic relationships based on morphological characteristics. Our result will provide more fundamental data to the development of the molecular systematics of Syrphidae.

Ecosystem services (ESs) are the benefits and functions that ecosystems provide to people. They make human life possible by provisioning, regulating, supporting and cultural services. Quantifying the services of agroecosystems is one of the most important strategies to increase attention to these services and provide appropriate solutions to maintain and sustain these services. In this study, some services of canola agroecosystems were evaluated and quantified based on Common International Classification of Ecosystem Services (CICES) framework under nine plots from an agricultural landscape located in Mazandaran Province, north of Iran, during 2019–2020. We investigated the ecological indicators, such as biodiversity (plant and insect), grain yield, grain oil content, soil microbial respiration, carbon sequestration, oxygen production, organic matter content, earthworm population density and soil conservation through the stability of aggregates indices. To measure the microbial respiration and organic matters, soil samples were taken from a depth of 0–30 cm before September 2019 and after harvest in June 2020. Oxygen production amount was estimated based on net primary productivity. In addition, insects community was studied in three groups: pollinator, beneficial and pest. The results showed that canola agroecosystems provide a variety of services. For example, the highest oxygen production and carbon sequestration as regulating services were obtained as 18.24 t.ha −1 and 2.49 t.ha −1 , respectively. In addition, the highest amount of microbial respiration was observed about 100.41 and 49.83 mg CO 2 per kg of soil per day, before sowing and after harvesting, respectively. From the perspective of supporting services, the maximum amounts of the Shannon–Weiner index were obtained 2.79 for plants community and 2.87 for insect community. We were recorded four beneficial insects ( Syrphus ribesii , Chrysoperla carnea, Apis ellifera mellifica , and Tromatobia oculatoria ) in studied plots. In general, carbon sequestration, organic matter, microbial respiration, earthworm’s abundance, and aggregate stability include average weight diameter index (MWD) and geometric mean diameter index (GMD), were better in plots with sustainable management . The results of this study showed that crop management and implementation of intensive agricultural system were effective in providing many ESs of canola fields.

The northern European taxa of genus Melanostoma Schiner, 1860 (Syrphidae, Diptera) are revised. A longstanding question concerning the number of Melanostoma taxa occurring in northern Europe prompted us to contrast and compare their morphological and molecular variability. Particular uncertainty concerned the putative existence of a sibling species of Melanostoma mellinum, and the identity of the taxon Melanostoma dubium in northern Europe due to existence of morphologically similar dark forms of M. mellinum in the northern parts of its distributional range. Partial sequences of two DNA markers, the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI-3') and the nuclear second internal transcribed spacer (ITS2) were analysed separately under parsimony. The obtained COI-3'gene fragment showed taxon-specific haplotypes and haplotypes that were shared among the taxa. The ITS2 sequences presented genotypes unique to each species, and congruence with our independently established taxonomic entities. Based on congruent signal of the ITS2 sequences and study of morphological characters we establish the presence of four taxa in northern Europe: Melanostoma mellium (= M. dubium nec auctt., syn. n.), M. certum sp. n. (= M. dubium auctt.), M. mellarium stat. n. (= M. mellinum auctt. partim) and M. scalare. Lectotype designations were made for Musca mellina, Syrphus mellarius and Melanostoma mellinum var. melanatus. Melanostoma mellarium = Melanostoma melanatum syn. n.; Melanostoma mellinum = Scaeva dubia syn. n., Melanostoma tschernovi syn. n., and Melanostoma clausseni syn. n. Morphological circumscriptions of the taxa and an identification key are presented.

Food searching strategies of animals are key to their success in heterogeneous environments. The optimal search strategy may include specialized random walks such as Levy walks with heavy power-law tail distributions, or persistent walks with preferred movement in a similar direction. We have investigated the movement of the soil amoebae Dictyostelium searching for food. Dictyostelium cells move by extending pseudopodia, either in the direction of the previous pseudopod (persistent step) or in a different direction (turn). The analysis of approximately 4000 pseudopodia reveals that step and turn pseudopodia are drawn from a probability distribution that is determined by cGMP/PLA2 signaling pathways. Starvation activates these pathways thereby suppressing turns and inducing steps. As a consequence, starved cells make very long nearly straight runs and disperse over approximately 30-fold larger areas, without extending more or larger pseudopodia than vegetative cells. This 'win-stay/lose-shift' strategy for food searching is called Starvation Induced Run-length Extension. The SIRE walk explains very well the observed differences in search behavior between fed and starving organisms such as bumble-bees, flower bug, hoverfly and zooplankton.