Micromorphology of egg and larva of Eristalis fratercula, with an updated key of Eristalis species with known third instar larvae (Diptera: Syrphidae)

The flower- or hoverflies (Syrphidae) and particularly the subfamily Eristalinae, are known by their importance as pollinators in both natural and agro-ecosystems. Similar to other saprophagous eristalines, the larvae of Eristalis Latreille, 1804 are characterized by an elongated anal segment and a telescopic breathing tube. These features have given them the common name of rat-tailed maggots and allow them to develop in liquid or semi-liquid media loaded with decaying organic material. This paper presents the first description of the egg and the third-instar larva of the boreal species Eristalis fratercula (Zetterstedt, 1838). Morphological studies are presented based on cryo-scanning electron microscopy (cryo-SEM). After comparison with all other known species of the genus Eristalis with described preimaginal morphology, we conclude that main diagnostic character of E. fratercula is the presence of long branched spicules located in the upper margin on the lateral lips. Finally, we provide an updated key that includes the 15 Eristalis species whose third larval stages have already been described

Preimaginal morphology and notes on the natural history of some Afrotropical flower flies of genus Eumerus Meigen 1822 (Diptera Syrphidae) including description of a new species

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.The present study was funded by the European Union project Horizon 2020, Marie Skłodowska-Curie action, Research and Innovation Staff Exchange (RISE) Programme: FlyHigh - “Insect-plant relationships: insights into biodiversity and new applications” and the H2020 European-funded Integrated Infrastructure Initiative grant SYNTHESYS Plus (www.synthesys.info) (we wish to thank the Royal Museum for Central Africa, Ter-vuren, Belgium, for our visit). The study was partly supported by the Ministry of Education, Science and Technological Development, Republic of Serbia: Grant No. 451-03-68/2022e14/200125 and Grant No. 451-03-68/2022e14/200358. Moreover, partial financial support was received from the research department of the University of Alicante within the framework of a predoctoral grant (UAFPU2019-03)

Deux nouvelles espèces du genre Merodon Meigen 1803 (Diptera : Syrphidae) de l’île de Lesbos (Grèce), dans la Méditerranée Orientale

Descriptions are given of two new species of Merodon Meigen (Diptera: Syrphidae) from the island of Lesvos (Greece): Merodon papillus Vujić, Radenkovic & Pérez-Bañón n. sp. from the ruficornis group species and Merodon sapphous Vujic, Pérez-Bañón & Radenkovic n. sp. from the aureus group. In addition to classical morphological characters, partial sequences of the mitochondrial COI gene are generated for each taxon as DNA ‘barcodes’. Main characteristics of the species habitats are reported. The zoogeographical significance of these endemic taxa to the biodiversity of the island is discussed.European Commission Framework 6 Integrated project ALARM (Assessing LArge scale environmental Risks for biodiversity with tested Methods) (GOCE-CT-2003-506675) & Ministry of Science, Technology and Development of Republic Serbia (project number 143037)

Where Is My Food? Brazilian Flower Fly Steals Prey from Carnivorous Sundews in a Newly Discovered Plant-Animal Interaction

A new interaction between insects and carnivorous plants is reported from Brazil. Larvae of the predatory flower fly Toxomerus basalis (Diptera: Syrphidae: Syrphinae) have been found scavenging on the sticky leaves of several carnivorous sundew species (Drosera, Droseraceae) in Minas Gerais and São Paulo states, SE Brazil. This syrphid apparently spends its whole larval stage feeding on prey trapped by Drosera leaves. The nature of this plant-animal relationship is discussed, as well as the Drosera species involved, and locations where T. basalis was observed. 180 years after the discovery of this flower fly species, its biology now has been revealed. This is (1) the first record of kleptoparasitism in the Syrphidae, (2) a new larval feeding mode for this family, and (3) the first report of a dipteran that shows a kleptoparasitic relationship with a carnivorous plant with adhesive flypaper traps. The first descriptions of the third instar larva and puparium of T. basalis based on Scanning Electron Microscope analysis are provided

Biological aspects of Pseudodoros clavatus (Fabricius) (Diptera: Syrphidae) fed with the black legume aphid Aphis craccivora Koch (Hemiptera: Aphididae)

Se estudió en condiciones de laboratorio el ciclo de vida, la proporción sexual y la longevidad del sírfido depredador Pseudodoros clavatus (Fabricius). El áfido de las leguminosas Aphis craccivora Koch fue utilizado como presa. P. clavatus y A. craccivora fueron recolectados en las parcelas experimentales Miguel Luna Lugo, ubicadas en Tarabana (10º 01’10,52” N; 69º 16’59,48”O, 515 m), estado Lara, Venezuela. Ambos, el depredador y la presa, fueron mantenidos en salas de cría a 25 ± 1ºC, 68 ± 10% HR y 12:12 (D:N) h de fotoperiodo. Los resultados mostraron que el ciclo de vida de P. clavatus tuvo una duración promedio de 13,6 ± 0,1 días, con un ámbito de variación de entre 12 y 16 días (huevo 2,0 ± 0,0 días; larvas 6,0 ± 0,1 y pupa de 5,6 ± 0,1 días). La relación de sexo de la progenie (macho: hembra) fue 1:1. Este índice reproductivo se considera importante para obtener un alto rendimiento en la cría del depredador. La longevidad promedio de los machos y hembras de P. clavatus fue 12,8 ± 1,1 días y 14,0 ± 0,6 días, respectivamente. Esta información puede ser útil en el desarrollo de programas de control biológico del áfido de las leguminosas.The life cycle, sex ratio and longevity of the predatory syrphid fly Pseudodoros clavatus (Fabricius) were studied under laboratory conditions. The black legume aphid, Aphis craccivora Koch, was used as prey. P. clavatus and A. craccivora were collected in the experimental plots “Miguel Luna Lugo”, located in Tarabana (10º 01’10.52”N; 69º 16’59.48”W, 515 m), Lara State, Venezuela. Both the predator and the prey were kept in breeding rooms at 25 ± 1 ° C, 68 ± 10% RH and 12:12 (D:N) h of photoperiod. The results showed that the life cycle of P. clavatus had an average duration of 13.6 ± 0.1 days, with a range of variation between 12 and 16 days (egg 2.0 ± 0.0 days; larvae 6.0 ± 0.1 and pupa of 5.6 ± 0.1 days). The average longevity of males and females of P. clavatus was 12.8 ± 1.1 days and 14.0 ± 0.6 days, respectively. The sex ratio of the progeny (male:female) was 1:1. This reproductive index is considered important in order to obtain a high performance in the breeding of the predator. This information may be useful in the development of biological control programs for legume aphids.Consejo de Desarrollo Científico, Humanístico y Tecnológico (CDCHT-UCLA), proyecto 003-DAG-2007

DNA barcoding applied: identifying the larva of Merodon avidus (Diptera: Syrphidae)

The immature stages of phytophagous hoverflies and their plant hosts are mostly unknown. This paper describes the larva of Merodon avidus Rossi, 1790 (Diptera: Syrphidae), based on material collected from Đerdap National Park in Serbia. Larvae were found in the bulbs of Ornithogalum L. (Hyacinthaceae) and in the surrounding soil. DNA barcoding was used to identify the species and scanning electron microscopy was used to describe the morphological characteristics of Merodon avidus. Reared material previously identified as Merodon constans (Rossi, 1794) is shown to belong to M. hurkmansi Marcos-García, Vujić & Mengual, 2007.This study was supported by the Ministry of Education, Science and Technological Development, Republic of Serbia, Grant No. 173002 and Grant No. 43002, the Provincial Secretariat for Science and Technological Development, Grant No. 114-457-2173/2011-01 and by the project Status and Trends of European Pollinators, FP7-ENV-2009-1-244090 (STEP)

Life table and predation rates of the syrphid fly Allograpta exotica, a control agent of the cowpea aphid Aphis craccivora

Larvae of Allograpta exotica (Wiedemann, 1830) (Diptera: Syrphidae) are important natural enemies of common agricultural pests such as aphids (Hemiptera: Aphididae). Life history, life table and functional response of A. exotica were determined using the cowpea aphid Aphis craccivora Koch, 1854 as prey under controlled conditions of temperature, humidity and light. The average recorded duration of A. exotica development was 2.0, 7.4 and 5.7 days for eggs, larvae and pupae respectively, and 15.04 days from egg to adult emergence. The adult longevity was not significantly sex dependent, but imagoes lived longer than in previous studies. The offspring sex ratio was favorable to males. The mortality and survival rate were recorded on a daily basis for all immature stages and adults. The age specific survival rate was determined and the highest mortality occurred in eggs followed by mortality in 1st and 2nd instar larva. Moreover, in the present study different levels of aphid densities 10, 30, 40, 50, 60, 70, 80 and 100 were used to calculate the functional response. Based on logistic regression analyses the three instar larvae and the whole larval stage (first to third instar) exhibited a type II functional response. Handling time was shortest for the third larval instar followed by second and first instars. Potential use of A. exotica in augmentative biological control is discussed.Consejo de Desarrollo Científico, Humanístico y Tecnológico (CDCHT-UCLA, Venezuela) for funding support for the PhD thesis project 003-DAG-2007 granted to E. Arcaya

Phylogeographic patterns of Merodon hoverflies in the Eastern Mediterranean region: revealing connections and barriers

We investigated the phylogeographic patterns of Merodon species (Diptera, Syrphidae) in the Eastern Mediterranean. Ten species were sampled on five different islands and mainland sites as a minimum. All samples were screened for their mtDNA COI barcode haplotype diversity, and for some samples, we additionally generated genomic fingerprints. The recently established zoogeographic distribution categories classify these species as having (1) Balkan distribution; (2) Anatolian distribution; (3) continental areas and large islands distribution; and (4) with wide distribution. The ancestral haplotypes and their geographical localities were estimated with statistical parsimony (TCS). TCS networks identified as the ancestral haplotype samples that originated from localities situated within the distributional category of the species in question. Strong geographical haplotype structuring was detected for many Merodon species. We were particularly interested to test the relative importance of current (Aegean Sea) and past Mid-Aegean Trench) barriers to dispersal for Merodon flies in the Aegean. We employed phylogenetic β-diversity (Pβ total) and its partition in replacement (Pβ repl) and richness difference (Pβ rich) to test the importance of each explanatory variable (interisland distance, MAT, and island area) in interisland differences using partial Mantel tests and hierarchical partitioning of variation. β-Analyses confirmed the importance of both current and past barriers to dispersal on the evolution of group. Current interisland distance was particularly important to explain the replacement of haplotypes, while the MAT was driving differences in richness of haplotypes, revealing the MAT as a strong past barrier whose effects are still visible today in the phylogenetic history of the clade in the Aegean. These results support the hypothesis of a highly restricted dispersal and gene flow among Merodon populations between islands since late Pleistocene. Additionally, patterns of phylogeographic structure deduced from haplotype connections and ISSR genome fingerprinting data revealed a few putative cases of human-mediated transfers of Merodon spp

Insights from the preimaginal morphology of the constans species‑group, to reveal novel morphological patterns of the Merodon albifrons‑evolutionary lineage (Diptera, Syrphidae)

Merodon triangulum Vujić, Radenković & Hurkmans, 2020 is a European endemic hoverfly species belonging to Merodon constans species-group, inside albifrons-lineage. The distribution of this species is known to be mostly central Europe and Balkan peninsula and it has been categorized as Near Threatened in the European IUCN red list of hoverflies; this paper cites the species for the first time in Ukraine (western Ukraine, specifically). In the present study, the preimaginal stages of this species are described and figured using Scanning Electron Microscopy. The material used for the descriptions were larvae collected in Ukraine and Serbia feeding inside underground storage organs of the spring snowflake Leucojum vernum L., 1753. This morphological description constitutes the first one inside the constans species-group, and the sixth description of the albifrons-lineage, in which there is only one species-group left to have at least one species of the preimaginal stages described (i.e., ruficornis species-group). The descriptions were compared with the rest available of the genus, stating the diagnostical characters of the present species and the shared characters inside the lineage. The novel information provided on the trophic interaction between M. triangulum larvae and Leucojum bulbs is stated for the first time and further supports the association of the constans species-group with the underground storage organs of snowflakes and snowdrops (Galantheae) in their role as host plants.Partial financial support was received from the research department of the University of Alicante in the frame work of a predoctoral grant (UAFPU2019-03). In addition, the study has been partially supported by the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (Grant No. 451-03-47/2023-01/200125 and Grant No. 451-03-47/2023-01/200358)

Characterization of preimaginal developmental stages of two cryptic South African species of the Merodon planifacies complex (Diptera: Syrphidae: Eristalinae: Merodontini), with differentiation through morphometry analysis

Merodon capi Vujić et Radenković, 2020 and Merodon roni Radenković et Vujić, 2020 are two cryptic species belonging to the Merodon planifacies Bezzi, 1915 species complex that have recently been described, with the differences between them being revealed by molecular and geometric morphometry studies of adult specimens. In the present study, the preimaginal morphology of both species is described and displayed, with the material used corresponding to samples taken from bulbs of Merwilla plumbea (Lindl.) Speta plants at two locations in KwaZulu-Natal province (South Africa). The preimaginal stages were compared, looking for morphological evidence supporting species divergence. Linear and geometric morphometric analyses of the larval posterior respiratory process were conducted for the first time and the results of these analyses support the separation of the two taxa. Information about the life cycle and the relation with the host plant is also provided. In addition, we carried out a preliminary study of the adult feeding requirements of the species, based on the description of the mouthparts and an analysis of the pollen present in the gut and on the integument of adults. The results of the study supports a close relationship between the preimaginal stages and plant species of the Hyacinthaceae family.The study was mainly funded by the European Union project: Horizon 2020, Marie Skłodowska-Curie Actions, Research and Innovation Staff Exchange (RISE) Programme: FlyHigh – “Insect–plant relationships: insights into biodiversity and new applications” (project 645636). The study was partly supported by the Ministry of Education, Science and Technological Development, Republic of Serbia, Grant No. 451-03-68/2022–14/200125 and Grant No. 451-03-68/2022–14/200358. It was also supported by the research department of the University of Alicante in the framework of a predoctoral grant (UAFPU2019-03). This manuscript was written as a part of a PhD project conducted by Andrea Aracil at the University of Alicante (Spain)