Global population genetic structure and demographic trajectories of the black soldier fly, Hermetia illucens.

BACKGROUND: The black soldier fly (Hermetia illucens) is the most promising insect candidate for nutrient-recycling through bioconversion of organic waste into biomass, thereby improving sustainability of protein supplies for animal feed and facilitating transition to a circular economy. Contrary to conventional livestock, genetic resources of farmed insects remain poorly characterised. We present the first comprehensive population genetic characterisation of H. illucens. Based on 15 novel microsatellite markers, we genotyped and analysed 2862 individuals from 150 wild and captive populations originating from 57 countries on seven subcontinents. RESULTS: We identified 16 well-distinguished genetic clusters indicating substantial global population structure. The data revealed genetic hotspots in central South America and successive northwards range expansions within the indigenous ranges of the Americas. Colonisations and naturalisations of largely unique genetic profiles occurred on all non-native continents, either preceded by demographically independent founder events from various single sources or involving admixture scenarios. A decisive primarily admixed Polynesian bridgehead population serially colonised the entire Australasian region and its secondarily admixed descendants successively mediated invasions into Africa and Europe. Conversely, captive populations from several continents traced back to a single North American origin and exhibit considerably reduced genetic diversity, although some farmed strains carry distinct genetic signatures. We highlight genetic footprints characteristic of progressing domestication due to increasing socio-economic importance of H. illucens, and ongoing introgression between domesticated strains globally traded for large-scale farming and wild populations in some regions. CONCLUSIONS: We document the dynamic population genetic history of a cosmopolitan dipteran of South American origin shaped by striking geographic patterns. These reflect both ancient dispersal routes, and stochastic and heterogeneous anthropogenic introductions during the last century leading to pronounced diversification of worldwide structure of H. illucens. Upon the recent advent of its agronomic commercialisation, however, current human-mediated translocations of the black soldier fly largely involve genetically highly uniform domesticated strains, which meanwhile threaten the genetic integrity of differentiated unique local resources through introgression. Our in-depth reconstruction of the contemporary and historical demographic trajectories of H. illucens emphasises benchmarking potential for applied future research on this emerging model of the prospering insect-livestock sector.

The puzzling mitochondrial phylogeography of the black soldier fly (Hermetia illucens), the commercially most important insect protein species.

BACKGROUND: The black soldier fly (Diptera: Stratiomyidae, Hermetia illucens) is renowned for its bioconversion ability of organic matter, and is the worldwide most widely used source of insect protein. Despite varying extensively in morphology, it is widely assumed that all black soldier flies belong to the same species, Hermetia illucens. We here screened about 600 field-collected and cultured flies from 39 countries and six biogeographic regions to test this assumption based on data for three genes (mitochondrial COI, nuclear ITS2 & 28S rDNA) and in order to gain insights into the phylogeography of the species. RESULTS: Our study reveals a surprisingly high level of intraspecific genetic diversity for the mitochondrial barcoding gene COI (divergences up to 4.9%). This level of variability is often associated with the presence of multiple species, but tested nuclear markers (ITS2 and 28S rDNA) were invariant and fly strain hybridization experiments under laboratory conditions revealed reproductive compatibility. COI haplotype diversity is not only very high in all biogeographic regions (56 distinct haplotypes in total), but also in breeding facilities and research centers from six continents (10 haplotypes: divergences up to 4.3%). The high genetic diversity in fly-breeding facilities is mostly likely due to many independent acquisitions of cultures via sharing and/or establishing new colonies from field-collected flies. However, explaining some of the observed diversity in several biogeographic regions is difficult given that the origin of the species is considered to be New World (32 distinct haplotypes) and one would expect severely reduced genetic diversity in the putatively non-native populations in the remaining biogeographic regions. However, distinct, private haplotypes are known from the Australasian (N = 1), Oriental (N = 4), and the Eastern Palearctic (N = 4) populations. We reviewed museum specimen records and conclude that the evidence for introductions is strong for the Western Palearctic and Afrotropical regions which lack distinct, private haplotypes. CONCLUSIONS: Based on the results of this paper, we urge the black soldier fly community to apply molecular characterization (genotyping) of the fly strains used in artificial fly-breeding and share these data in research publications as well as when sharing cultures. In addition, fast-evolving nuclear markers should be used to reconstruct the recent invasion history of the species.

Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae).

BACKGROUND: Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization. RESULTS: We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family. CONCLUSIONS: Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.

Organizing for the 'second curve': combining health plans and provider systems.

Provider systems should ask four questions as they seek to incorporate health plans. Is the health plan on track to build critical mass quickly enough? Does the plan balance provider and health plan business priorities? Is the provider system willing to let its health plan compete freely in the market? Is the provider system's overall vision understood and backed internally?

Genetic Diversity of Bactrocera dorsalis (Diptera: Tephritidae) on the Hawaiian Islands: Implications for an Introduction Pathway Into California.

Population genetic diversity of the oriental fruit fly, Bactrocera dorsalis (Hendel), on the Hawaiian islands of Oahu, Maui, Kauai, and Hawaii (the Big Island) was estimated using DNA sequences of the mitochondrial cytochrome c oxidase subunit I gene. In total, 932 flies representing 36 sampled sites across the four islands were sequenced for a 1,500-bp fragment of the gene named the C1500 marker. Genetic variation was low on the Hawaiian Islands with >96% of flies having just two haplotypes: C1500-Haplotype 1 (63.2%) or C1500-Haplotype 2 (33.3%). The other 33 flies (3.5%) had haplotypes similar to the two dominant haplotypes. No population structure was detected among the islands or within islands. The two haplotypes were present at similar frequencies at each sample site, suggesting that flies on the various islands can be considered one population. Comparison of the Hawaiian data set to DNA sequences of 165 flies from outbreaks in California between 2006 and 2012 indicates that a single-source introduction pathway of Hawaiian origin cannot explain many of the flies in California. Hawaii, however, could not be excluded as a maternal source for 69 flies. There was no clear geographic association for Hawaiian or non-Hawaiian haplotypes in the Bay Area or Los Angeles Basin over time. This suggests that California experienced multiple, independent introductions from different sources.

On the immature stages of some Merodontini hoverflies (Diptera: Syrphidae) from Europe and Africa.

The genera Eumerus and Merodon (Syrphidae: Merodontini) form together the most speciose grouping of hoverflies in the Palaearctic Region. However, little is known about the morphology and biology of their larvae. The few larvae of Eumerus and Merodon that have been uncovered are phytophagous in underground organs of plants (some Eumerus and all Merodon) or saprophagous in a variety of plants' parts (the reminder of Eumerus). In this study, the second larval stage (L2) of Eumerus lyneborgi Ricarte & Hauser, 2020 and both the larva (L2) and puparium of Merodon constans (Rossi, 1794) are described for the first time. Larvae of E. lyneborgi were found in a decaying stem of Cyphostemma juttae (Dinter & Gilg) Desc., 1960 (Vitaceae) in Namibia (Africa), while larvae of M. constans were collected in bulbs of Leucojum vernum Linnaeus, 1753, (Amaryllidaceae) in France (Europe). Morphology of the immature forms was studied by observation and imaging with stereomicroscopy and scanning electron microscopy. The head skeleton of E. lyneborgi larvae was found to be of the filter feeding type, i.e., in accordance with a saprophagous trophic regime, while that of M. constans was typically phytophagous. Variability in certain characters of the M. constans early stages is described and discussed in relation to the adult form and molecular information published in literature. An updated identification key to all known third larval stages/puparia of Merodon is provided.

Unveiling the Mainland vs. Insular Variability of the Eumerus barbarus Species Group (Diptera: Syrphidae) in the Western Mediterranean Basin.

Comprising nearly 300 described species, Eumerus Meigen, 1822, is one of the most speciose syrphid genera worldwide, and its taxonomic diversity is remarkable in the Mediterranean basin. The Eumerus barbarus (Coquebert, 1804) group consists of four species in the western Mediterranean. Although the phenotypic variability of this species group has been commented on in previous studies, it has never been contrasted with molecular data. In the present work, the morphological variation found in 300+ specimens of this species group from the western Mediterranean is explored and tested against the COI mitochondrial DNA (mtDNA). The highest phenotypic disparity was found in E. barbarus and Eumerus sulcitibius Rondani 1868. The integrative approach has not revealed cryptic diversity within the species E. barbarus but in E. sulcitibius. As a result, a new species close to E. sulcitibius was discovered, Eumerus sardus Aguado-Aranda, Ricarte & Hauser sp. n., from Sardinia, Italy. The new insular species is here described, illustrated, and discussed. A total of twenty-three haplotypes of COI mtDNA were identified amongst the analyzed Mediterranean specimens of E. barbarus, whereas two and five haplotypes were distinguished in the Iberian specimens of E. sulcitibius and Eumerus gibbosus van Steenis, Hauser & van Zuijen, 2017, respectively. Moreover, the first known barcodes of E. gibbosus and Eumerus schmideggeri van Steenis, Hauser & van Zuijen, 2017 were obtained, and the distribution ranges of all species are mapped. An updated dichotomous key to the males of the E. barbarus group from the western Mediterranean is provided.

The Oriental genus Nasimyia (Diptera: Stratiomyidae): Geographical distribution, key to species and descriptions of three new species.

In this paper, three new species of Nasimyia Yang & Yang, 2010, N. eurytarsa sp. nov., N. rozkosnyi sp. nov. and N. elongoverpa sp. nov. from the Oriental region are described and illustrated; N. nigripennis Yang & Yang, 2010 is found to be a junior synonym of N. megacephala Yang & Yang, 2010 (syn. nov.). Chelonomima signata de Meijere 1924 is combined as Pseudomeristomerinx signata (de Meijere, 1924) comb. nov.. Keys to the Oriental genera of Pachygasterinae with elongate abdomens and the species of Nasimyia are provided, as well as distribution maps of the four species of Nasimyia.

An annotated catalogue of the New World Therevidae (Insecta: Diptera: Asiloidea).

The genera and species of New World stiletto flies (Diptera: Therevidae) are listed, with annotated references to nomenclature, synonymies and generic combinations, type localities, the primary type depositories, distribution, and citations for the most recent revisions. The genus Cyclotelus Walker, 1850 (along with its synonyms Furcifera Kröber, 1911, and Epomyia Cole, 1923a) is synonymized under Cerocatus Rondani, 1848. Ectinorhynchus fascipennis Kröber, 1911 is given the new name Cerocatus rondanii Gaimari, and Phycus rufiventris Kröber, 1911 is given the new name Cerocatus raspii Hauser. Phycus analis Kröber, 1911 and Phycus bicolor Kröber, 1911, are placed as new combinations in Cerocatus Rondani, as are the following species that were previously in combination with Cyclotelus: Furcifera achaeta Malloch, 1932, Cyclotelus badicrusus Irwin and Webb, 1992, Phycus beckeri Kröber, 1911, Epomyia bella Cole, 1923a, Furcifera braziliana Cole, 1960a, Cyclotelus colei Irwin and Lyneborg, 1981a, Thereva diversipes Kröber, 1911, Thereva fascipennis Macquart, 1846a, Psilocephala femorata Kröber, 1911, Furcifera flavipes Kröber, 1928b, Furcifera hardyi Cole, 1960a, Furcifera kroeberi Cole, 1960a, Cyclotelus laetus Walker, 1850, Furcifera longicornis Kröber, 1911, Cyclotelus nigroflammus Walker, 1850, Psilocephala nigrifrons Kröber, 1914a, Thereva pictipennis Wiedemann, 1821, Furcifera polita Kröber, 1911, Cyclotelus pruinosus Walker, 1850, Thereva ruficornis Macquart, 1841a, Psilocephala rufiventris Loew, 1869, Thereva scutellaris Walker, 1857, Cyclotelus silacrusus Irwin and Webb, 1992, Cyclotelus socius Walker, 1850 and Psilocephala sumichrasti Bellardi, 1861. Dialineura pallidiventris Malloch, 1932, Melanothereva blackmani Oldroyd, 1968, Thereva maculicornis Jaennicke, 1867 and Thereva notabilis Macquart, 1841a are placed as new combinations in Entesia Oldroyd. Henicomyia amazonica Irwin and Webb, 1992 is a new synonym of Henicomyia flava Lyneborg, 1972. Henicomyia varipes Kröber, 1912a is given revised species status from former synonymy with
Henicomyia hubbardii Coquillett, 1898.

Large Flies Overlooked: the Genus Hermetia Latreille, 1804 (Diptera: Stratiomyidae) in the Neotropics, with 11 Synonyms and a New Species to Brazil.

Hermetia Latreille, 1804 is currently globally distributed, with ~ 80 species, but is especially diverse in tropical regions. Hitherto, 52 species occur in the Neotropics. However, apart from H. illucens (Linnaeus, 1758) and a few other common species, the group is still poorly studied. One of the main persistent problems is the limited knowledge about the identity of most species, resulting in difficulties regarding species determination and discovery of new taxa. In our efforts to revise this genus, we address several of these issues and propose the following 11 synonyms after examination of 17 type specimens: H. ampulla James, 1938 syn. nov. and H. panamensis Greene, 1940 syn. nov. of H. aurinotata Lindner, 1935; H. burmeisteri Lindner, 1949 syn. nov. of H. cornithorax (Lindner, 1928); H. fimbriata (Lindner, 1931) syn. nov. of H. crabro Osten Sacken, 1886; H. geniculata Macquart, 1855 syn. nov. of H. illucens; H. coarctata Macquart, 1846 syn. nov. and H. scutellata Macquart, 1855 syn. nov. of H. pulchra Wiedemann, 1830; H. reinhardi James, 1935 syn. nov. of H. relicta Osten Sacken, 1886; H. tincta (Walker, 1851) syn. nov. of H. rufitarsis Macquart, 1846; and H. mitis Curran, 1934 syn. nov. and H. nana Lindner, 1935 syn. nov. of H. teevani Curran, 1934. Moreover, a new striking species with a pattern of abdominal coloration resembling social wasps of Brachygastra Perty, 1833 is described from Brazil-H. brachygastropsis sp. nov.-and two species are removed from the Brazilian fauna: H. aeneipennis Giglio-Tos, 1893 and H. sexmaculata Macquart, 1834.

Catalogue of the Diptera (Insecta) of Morocco- an annotated checklist, with distributions and a bibliography.

The faunistic knowledge of the Diptera of Morocco recorded from 1787 to 2021 is summarized and updated in this first catalogue of Moroccan Diptera species. A total of 3057 species, classified into 948 genera and 93 families (21 Nematocera and 72 Brachycera), are listed. Taxa (superfamily, family, genus and species) have been updated according to current interpretations, based on reviews in the literature, the expertise of authors and contributors, and recently conducted fieldwork. Data to compile this catalogue were primarily gathered from the literature. In total, 1225 references were consulted and some information was also obtained from online databases. Each family was reviewed and the checklist updated by the respective taxon expert(s), including the number of species that can be expected for that family in Morocco. For each valid species, synonyms known to have been used for published records from Morocco are listed under the currently accepted name. Where available, distribution within Morocco is also included. One new combination is proposed: Assuaniamelanoleuca (Séguy, 1941), comb. nov. (Chloropidae).

Vertical stratification of insect abundance and species richness in an Amazonian tropical forest.

Tropical forests are among the most biodiverse biomes on the planet. Nevertheless, quantifying the abundance and species richness within megadiverse groups is a significant challenge. We designed a study to address this challenge by documenting the variability of the insect fauna across a vertical canopy gradient in a Central Amazonian tropical forest. Insects were sampled over two weeks using 6-m Gressitt-style Malaise traps set at five heights (0 m-32 m-8 m intervals) on a metal tower in a tropical forest north of Manaus, Brazil. The traps contained 37,778 specimens of 18 orders of insects. Using simulation approaches and nonparametric analyses, we interpreted the abundance and richness of insects along this gradient. Diptera, Hymenoptera, and Coleoptera had their greatest abundance at the ground level, whereas Lepidoptera and Hemiptera were more abundant in the upper levels of the canopy. We identified species of 38 of the 56 families of Diptera, finding that 527 out of 856 species (61.6%) were not sampled at the ground level. Mycetophilidae, Tipulidae, and Phoridae were significantly more diverse and/or abundant at the ground level, while Tachinidae, Dolichopodidae, and Lauxaniidae were more diverse or abundant at upper levels. Our study suggests the need for a careful discussion of strategies of tropical forest conservation based on a much more complete understanding of the three-dimensional distribution of its insect diversity.

A new species of Oryttus Spinola, 1836 from the United Arab Emirates and Tunisia, with identification key to Palaearctic species (Hymenoptera, Crabronidae).

The Palaearctic species of the genus Oryttus Spinola, 1836, are reviewed and a key to these species is given. Oryttus konradschmidti sp. nov. is described from the United Arab Emirates and Tunisia.

A catalog of Stratiomyidae (Diptera: Brachycera) from Chile, with a new synonym and notes on the species.

A list of all 24 genera and 73 species of Stratiomyidae from Chile is provided, along with all their synonyms and photos of the type specimens of 20 species (including 12 primary types). Only one species is assigned to morphospecies level. All references known to us from the taxonomic and biological literature, including information about name, author, year of publication, page number, type specimens, type locality, and references are given. The geographic distribution of each species is given based on bibliographic and collection data. Three species are removed from the Chilean fauna: Nemotelus tenuivena James, 1974 is only known from the type locality in Argentina; Promeranisa nasuta (Macquart, 1850), which has its type locality corrected to Bolivia, Chiquitos Province; and Ptecticus pomaceus Loew, 1855, referred to Chile due to a locality information error, is a junior synonym of P. trivittatus Say, 1829, syn. nov.

The family Stratiomyidae in Egypt and Saudi Arabia (Diptera: Stratiomyoidea).

BACKGROUND: This study systematically catalogues all known taxa of the family Stratiomyidae in Egypt and Saudi Arabia. It is one in a series of planned studies aiming to catalogue the whole order in both countries. NEW INFORMATION: Twenty species, belonging to seven genera and three subfamilies (Pachygastrinae, Stratiomyinae and Nemotelinae), are treated. One of these genera, Oplodontha and two species, Oplodontha pulchriceps Loew and Oxycera turcica Üstüner & Hasbenli, are recorded herein for the first time from Saudi Arabia. A lectotype for Nemotelus matrouhensis Mohammad et al., 2009 is designated. An updated classification, synonymies, type localities, world and local distributions, dates of collection and some coloured photographs are provided.

A new species of the genus Themarictera Hendel (Diptera: Tephritidae: Phytalmiinae: Acanthonevrini) from Madagascar.

Themarictera rinhai sp. n. is described from Madagascar. Previously Themarictera was a monotypic genus with only the species, T. flaveolata (Fabricius, 1805) having several synonyms, from continental Africa. A key for identification of both species is provided.

A new Eumerus hoverfly (Diptera: Syrphidae) from Namibia and South Africa, with notes on similar species.

Within the pollinator family Syrphidae, Eumerus Meigen, 1822 is a diverse genus with over 70 species recorded in the Afrotropical Region. A new species is described here from Namibia and South Africa. Adults are small to medium size flies, with spur-like expansions in the metatarsomeres 2 and 3. DNA sequences of the Cytochrome c oxidase subunit I (COI) gene were obtained from Namibian specimens. This is only the second Eumerus species documented from Namibia, where it was recorded from The National Botanic Garden, Windhoek. The new species is compared with similar species such as Eumerus vestitus Bezzi, 1912, for which a lectotype is designated. In addition, a new and preliminary morphological concept of the Eumerus obliquus group is proposed and a key to its African species is provided.

Hermetia illucens and Hermetia fenestrata (Diptera: Stratiomyidae) Colonization of "Spoiled" Stingless Bee Geniotrigona thoracica (Hymenoptera: Apidae) Hives in Malaysia.

Meliponiculture, the keeping of domesticated stingless bees such as Geniotrigona thoracica (Smith, 1857) (Hymenoptera: Apidae), is an increasingly popular agricultural industry in Malaysia. This study reports the soldier fly (Diptera: Stratiomyidae) species of the genus Hermetia colonizing stingless bee colonies in Malaysia. The larvae were reared in the laboratory to the adult stage and identified through molecular and morphological approaches. Hermetia illucens (Linnaeus, 1758) and Hermetia fenestrata de Meijere, 1904 (Diptera: Stratiomyidae) were identified from the sample provided. Earlier records of stratiomyids in stingless bee nests were misidentified as H. illucens. This paper represents the first identified record of H. fenestrata colonizing a "spoiled" stingless bee colony. In addition, adult and larval morphological differences between both species and the roles of both species in bee nest decomposition are discussed.

The visual system of male scale insects.

Animal eyes generally fall into two categories: (1) their photoreceptive array is convex, as is typical for camera eyes, including the human eye, or (2) their photoreceptive array is concave, as is typical for the compound eye of insects. There are a few rare examples of the latter eye type having secondarily evolved into the former one. When viewed in a phylogenetic framework, the head morphology of a variety of male scale insects suggests that this group could be one such example. In the Margarodidae (Hemiptera, Coccoidea), males have been described as having compound eyes, while males of some more derived groups only have two single-chamber eyes on each side of the head. Those eyes are situated in the place occupied by the compound eye of other insects. Since male scale insects tend to be rare, little is known about how their visual systems are organized, and what anatomical traits are associated with this evolutionary transition. In adult male Margarodidae, one single-chamber eye (stemmateran ocellus) is present in addition to a compound eye-like region. Our histological investigation reveals that the stemmateran ocellus has an extended retina which is formed by concrete clusters of receptor cells that connect to its own first-order neuropil. In addition, we find that the ommatidia of the compound eyes also share several anatomical characteristics with simple camera eyes. These include shallow units with extended retinas, each of which is connected by its own small nerve to the lamina. These anatomical changes suggest that the margarodid compound eye represents a transitional form to the giant unicornal eyes that have been described in more derived species.

Diptera of Canada.

The Canadian Diptera fauna is updated. Numbers of species currently known from Canada, total Barcode Index Numbers (BINs), and estimated numbers of undescribed or unrecorded species are provided for each family. An overview of recent changes in the systematics and Canadian faunistics of major groups is provided as well as some general information on biology and life history. A total of 116 families and 9620 described species of Canadian Diptera are reported, representing more than a 36% increase in species numbers since the last comparable assessment by JF McAlpine et al. (1979). Almost 30,000 BINs have so far been obtained from flies in Canada. Estimates of additional number of species remaining to be documented in the country range from 5200 to 20,400.