Black Fly Species Research Articles

Discovery of the Larvae and Pupae of the Black Fly Simulium (Gomphostilbia) khelangense and Breeding Habitats of Potential Pest Species of the S. (G.) chumpornense Subgroup (Simuliidae).

Two species of black flies (Simuliidae) in Thailand, Simulium chumpornense Takaoka and Kuvangkadilok, 2000, and S. khelangense Takaoka, Srisuka & Saeung, 2022, are potent vectors of avian blood protozoa of the genera Leucocytozoon and Trypanosoma and are pests of domestic avian species. Although the adults are abundant throughout Thailand, information on their breeding habitats is limited, and the immature stages of S. khelangense are unknown. We collected the larvae and pupae of S. khelangense from the Mekong River, the first-ever record of Simuliidae from this large continental river. Mitochondrial cytochrome c oxidase I and internal transcribed spacer 2 were used to associate the larvae and pupae with known adults. Both genetic markers strongly supported their identity as S. khelangense. The larvae and pupa of S. khelangense are described. The pupal gill filaments, larval abdominal protuberances, and setae distinguish this species from other members of the S. varicorne species group. The immature stages of S. chumpornense inhabit a wide variety of flowing waters, from small streams (3 m wide) to enormous continental rivers (400 m wide); thus, S. chumpornense is a habitat generalist. In contrast, S. khelangense was found only in the large Mekong River and is, therefore, a habitat specialist. Both species can exploit their principal habitats and produce abundant adult populations.

Current report of Silba adipata (Diptera: Lonchaeidae) attacking local fig (Ficus variegata) fruits in Bali: Molecular identification, invasion, and preference

Silba adipata is a new pest attacking white cayenne pepper (Capsicum frutescens L.) whose attack symptoms are similar to those of Bactrocera dorsalis. The S. adipata was also reported to attack local fig (Ficus variegata). This study aimed to ascertain the type of black fruit fly on F. variegata, the invasion time of S. adipata attack on F. variegata fruit, and the potential of F. variegata fruit extract as an attractant for the black fruit fly. The methods used for objectives (1), (2), and (3) were CO1 analysis, a survey method, and a preference test, respectively. The results showed that the species of black fruit fly that attacked local figs (F. variegata) in Bali was S. adipata. S. adipata invades fruit at the age of 10 weeks after the formation (WAF) of the ovary; the highest attack occurs on fruit 13 days after the formation of the ovary. Local fig fruit extract effectively attracts black fruit flies. Local fig extract was effective in attracting S. adipata to chili plants. Concentrations of 20%-100% were significantly effective in attracting adult S. adipata compared to the control. The extract concentration of 60% was highly effective in attracting S. adipata adults.

Pseudoendemism in Mediterranean black flies (Diptera: Simuliidae): a new record for Africa

The first record of a European black fly, Simulium ichnusae Rivosecchi & Contini, is documented for Africa, where it was found at elevations above 1000 m in the Djurdjura Mountains of Algeria. Considered an endemic species of Sardinia for 60 years, S. ichnusae must now be regarded as pseudoendemic. Larvae, pupae, females, and males from the Djurdjura Mountains compare well with those in the original description of the species. Chromosomally, S. ichnusae differs from the standard banding sequence of the S. vernum group by a transposed nucleolar organizer—the only known member of the group with this condition—and three fixed inversions, all of which are shared by other members of this species group. The addition of S. ichnusae to the Algerian fauna increases the number of nominal species of black flies known from the country to 34. The discovery of S. ichnusae suggests that additional trans-Mediterranean species await discovery in the coastal Mediterranean mountains and emphasizes that claims of endemism depend on thorough surveys and taxonomic accuracy.

The Biodiversity of Blackflies (Diptera: Simuliidae) in Brazil: New Distribution Records and Updated Checklist.

Currently, according to the most recent Simuliidae World Inventory, there are 97 valid species of blackflies recorded in Brazil, some of which act as vectors for zoonoses such as human onchocerciasis and mansonellosis in the northern and central-western regions of the country. Meanwhile, other species can cause serious socioeconomic problems due to the nuisance of female bites. Therefore, accurate knowledge of their distribution is crucial for the development and implementation of successful preventive strategies. With this aim, this study reviewed and updated the geographical distribution of the blackfly fauna throughout the Brazilian states. The data were compiled from three main sources: geographic information of material deposited at the Simuliidae Collection of the Instituto Oswaldo Cruz (CSIOC-IOC), a comprehensive review of scientific literature, and online biodiversity databases. We present a total of 71 new distribution records of 38 different Simuliidae species for 24 Brazilian states. Neither of these sets of records has been included in the Simuliidae World Inventory. Consequently, an updated Brazilian Simuliidae checklist, comprising a total of 98 valid species, is presented, highlighting these new distribution records. We also discuss six dubious records for the country and the implications of this updated data for the Simuliidae species richness of Brazil, its states, and biomes. This information is essential for future studies in the taxonomy, systematics, and biogeography of this family in Brazil.

Community composition of black flies during and after the 2020 vesicular stomatitis virus outbreak in Southern New Mexico, USA

BackgroundVesicular stomatitis virus (VSV), a vector-borne pathogen of livestock, emerges periodically in the western US. In New Mexico (NM), US, most cases occur close to the Rio Grande River, implicating black flies (Simulium spp.) as a possible vector. In 2020, VS cases were reported in NM from April to May, although total black fly abundance remained high until September. We investigated the hypothesis that transience of local VSV transmission results from transient abundance of key, competent black fly species. Additionally, we investigated whether irrigation canals in southern NM support a different community of black flies than the main river. Lastly, to gain insight into the source of local black flies, in 2023 we collected black fly larvae prior to the release of water into the Rio Grande River channel.MethodsWe randomly sub-sampled adult black flies collected along the Rio Grande during and after the 2020 VSV outbreak. We also collected black fly adults along the river in 2021 and 2022 and at southern NM farms and irrigation canals in 2022. Black fly larvae were collected from dams in the area in 2023. All collections were counted, and individual specimens were subjected to molecular barcoding for species identification.ResultsDNA barcoding of adult black flies detected four species in 2020: Simulium meridionale (N = 158), S. mediovittatum (N = 83), S. robynae (N = 26) and S. griseum/notatum (N = 1). Simulium robynae was only detected during the VSV outbreak period, S. meridionale showed higher relative abundance, but lower absolute abundance, during the outbreak than post-outbreak period, and S. mediovittatum was rare during the outbreak period but predominated later in the summer. In 2022, relative abundance of black fly species did not differ significantly between the Rio Grande sites and farm and irrigation canals. Intriguingly, 63 larval black flies comprised 56% Simulium vittatum, 43% S. argus and 1% S. encisoi species that were either extremely rare or not detected in previous adult collections.ConclusionsOur results suggest that S. robynae and S. meridionale could be shaping patterns of VSV transmission in southern NM. Thus, field studies of the source of these species as well as vector competence studies are warranted.Graphical

North African Endemism: A New Species of Black Fly (Diptera: Simuliidae) from the Djurdjura Mountains of Algeria.

Discoveries of endemic species highlight areas of biogeographic and conservation interest. Endemic species, however, are often morphologically disguised as more common and widespread species. The larval polytene chromosomes revealed a new species of black fly, Prosimulium fungiforme, from the Djurdjura Mountains of northern Algeria, and its female, male, pupa, and larva are described. The species is chromosomally unique; none of its 11 chromosomal rearrangements are shared with other species. Although the new species structurally resembles Prosimulium rufipes (Meigen) with which it previously has been confused, it can be distinguished from all other known species of Prosimulium in the Western Palearctic based on at least one character in each described life stage. Symbiotic organisms included two species of microsporidia, at least one of which is probably undescribed, one unknown protozoan pathogen novel in simuliids, and the trichomycete fungus Harpella melusinae Léger and Duboscq. Associated simuliid species included at least one new species of the genus Helodon. The new species of Prosimulium is tentatively considered endemic to the mountains of northern Algeria but might be expected in the mountains of eastern Morocco and northern Tunisia and perhaps in Sicily. If its endemic status holds, it would be the only nominal species of black fly unique to Algeria.

Comparative Study of Potential Habitats for Simulium qinghaiense (Diptera: Simuliidae) in the Huangshui River Basin, Qinghai-Tibet Plateau: An Analysis Using Four Ecological Niche Models and Optimized Approaches.

The Huangshui River, a vital tributary in the upper reaches of the Yellow River within the eastern Qinghai-Tibet Plateau, is home to the endemic black fly species S. qinghaiense. In this study, we conducted a systematic survey of the distribution of the species in the Huangshui River basin, revealing its predominant presence along the river's main stem. Based on four ecological niche models-MaxEnt with parameter optimization; GARP; BIOCLIM; and DOMAIN-we conduct a comparative analysis; evaluating the accuracy of AUC and Kappa values. Our findings indicate that optimizing parameters significantly improves the MaxEnt model's predictive accuracy by reducing complexity and overfitting. Furthermore, all four models exhibit higher accuracy compared to a random model, with MaxEnt demonstrating the highest AUC and Kappa values (0.9756 and 0.8118, respectively), showcasing significant superiority over the other models (p < 0.05). Evaluation of predictions from the four models elucidates that potential areas of S. qinghaiense in the Huangshui River basin are primarily concentrated in the central and southern areas, with precipitation exerting a predominant influence. Building upon these results, we utilized the MaxEnt model to forecast changes in suitable areas and distribution centers during the Last Interglacial (LIG), Mid-Holocene (MH), and future periods under three climate scenarios. The results indicate significantly smaller suitable areas during LIG and MH compared to the present, with the center of distribution shifting southeastward from the Qilian Mountains to the central part of the basin. In the future, suitable areas under different climate scenarios are expected to contract, with the center of distribution shifting southeastward. These findings provide important theoretical references for monitoring, early warning, and control measures for S. qinghaiense in the region, contributing to ecological health assessment.

Diversity, Distribution and Host Blood Meal Analysis of Adult Black Flies (Diptera: Simuliidae) from Thailand.

Understanding the factors associated with the species diversity and distribution of insect vectors is critically important for disease epidemiology. Black flies (Diptera: Simuliidae) are significant hematophagous insects, as many species are pests and vectors that transmit pathogens to humans and other animals. Ecological factors associated with black fly species distribution have been extensively examined for the immature stages but are far less well explored for the adult stage. In this study, we collected a total of 7706 adult black fly specimens from various locations in forests, villages and animal shelters in Thailand. The integration of morphology and DNA barcoding revealed 16 black fly taxa, including Simulium yvonneae, a species first found in Vietnam, which is a new record for Thailand. The most abundant species was the Simulium asakoae complex (n = 5739, 74%), followed by S. chumpornense Takaoka and Kuvangkadilok (n = 1232, 16%). The Simulium asakoae complex was dominant in forest (3786 of 4456; 85%) and village (1774 of 2077; 85%) habitats, while S. chumpornense predominated (857 of 1175; 73%) in animal shelter areas. The Simulium asakoae complex and S. nigrogilvum Summers, which are significant pests and vectors in Thailand, occurred at a wide range of elevations, although the latter species was found mainly in high (>1000 m) mountain areas. Simulium chumpornense, S. nodosum Puri and the S. siamense Takaoka and Suzuki complex occurred predominately in low (<800 m)-elevation areas. Simulium furvum Takaoka and Srisuka; S. phurueaense Tangkawanit, Wongpakam and Pramual; and S. nr. phurueaense were only found in high (>1000 m) mountain areas. A host blood meal analysis revealed that the S. asakoae; S. chamlongi Takaoka and Suzuki; S. nigrogilvum; S. chumpornense; and the S. striatum species group were biting humans. This is the first report of the latter two species biting humans. We also found that S. chumpornense was biting turkeys, and S. chamlongi was biting chickens, which are new host blood sources recorded for these species. In addition, we found that the S. feuerborni Edwards complex was biting water buffalo, which is the first report on the biting habits of this species.

First Record of Simulium (Chirostilbia) (Diptera: Simuliidae) in the province of Buenos Aires, Argentina

Blackflies are dipterans that belong to the family Simuliidae, common inhabitants of lotic ecosystems. The present study reports the first record of Simulium (Chirostilbia) subpallidum Lutz for Buenos Aires, rising to eight registered species of blackflies in the province. This report represents, to date, the southernmost distribution detected for the species and subgenus in South America.

From bites to barcodes: uncovering the hidden diversity of black flies (Diptera: Simuliidae) in Vietnam

BackgroundPrompt and precise identification of black flies (Simuliidae) is crucial, given their biting behaviour and significant impact on human and animal health. To address the challenges presented by morphology and chromosomes in black fly taxonomy, along with the limited availability of molecular data pertaining to the black fly fauna in Vietnam, this study employed DNA-based approaches. Specifically, we used mitochondrial and nuclear-encoded genes to distinguish nominal species of black flies in Vietnam.MethodsIn this study, 135 mitochondrial cytochrome c oxidase subunit I (COI) sequences were established for 45 species in the genus Simulium in Vietnam, encompassing three subgenera (Gomphostilbia, Nevermannia, and Simulium), with 64 paratypes of 27 species and 16 topotypes of six species. Of these COI sequences, 71, representing 27 species, are reported for the first time.ResultsCombined with GenBank sequences of specimens from Malaysia, Myanmar, Thailand, and Vietnam, a total of 234 DNA barcodes of 53 nominal species resulted in a 71% success rate for species identification. Species from the non-monophyletic Simulium asakoae, S. feuerborni, S. multistriatum, S. striatum, S. tuberosum, and S. variegatum species groups were associated with ambiguous or incorrect identifications. Pairwise distances, phylogenetics, and species delimitation analyses revealed a high level of cryptic diversity, with discovery of 15 cryptic taxa. The current study also revealed the limited utility of a fast-evolving nuclear gene, big zinc finger (BZF), in discriminating closely related, morphologically similar nominal species of the S. asakoae species group.ConclusionThis study represents the first comprehensive molecular genetic analysis of the black fly fauna in Vietnam to our knowledge, providing a foundation for future research. DNA barcoding exhibits varying levels of differentiating efficiency across species groups but is valuable in the discovery of cryptic diversity.Graphical abstract

DNA barcoding of black flies (Diptera: Simuliidae) in Indonesia

BackgroundDNA barcoding is a valuable taxonomic tool for rapid and accurate species identification and cryptic species discovery in black flies. Indonesia has 143 nominal species of black flies, but information on their biological aspects, including vectorial capacity and biting habits, remains underreported, in part because of identification problems. The current study represents the first comprehensive DNA barcoding of Indonesian black flies using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences.MethodsGenomic DNA of Indonesian black fly samples were extracted and sequenced, producing 86 COI sequences in total. Two hundred four COI sequences, including 118 GenBank sequences, were analysed. Maximum likelihood (ML) and Bayesian inference (BI) trees were constructed and species delimitation analyses, including ASAP, GMYC and single PTP, were performed to determine whether the species of Indonesian black flies could be delineated. Intra- and interspecific genetic distances were also calculated and the efficacy of COI sequences for species identification was tested.ResultsThe DNA barcodes successfully distinguished most morphologically distinct species (> 80% of sampled taxa). Nonetheless, high maximum intraspecific distances (3.32–13.94%) in 11 species suggested cryptic diversity. Notably, populations of the common taxa Simulium (Gomphostilbia) cheongi, S. (Gomphostilbia) sheilae, S. (Nevermannia) feuerborni and S. (Simulium) tani in the islands of Indonesia were genetically distinct from those on the Southeast Asian mainland (Malaysia and Thailand). Integrated morphological, cytogenetic and nuclear DNA studies are warranted to clarify the taxonomic status of these more complex taxa.ConclusionsThe findings showed that COI barcoding is a promising taxonomic tool for Indonesian black flies. The DNA barcodes will aid in correct identification and genetic study of Indonesian black flies, which will be helpful in the control and management of potential vector species.Graphical abstract

Black fly species and their association with Brazilian biomes

The family Simuliidae occurs widely around the globe, except in the Antarctic region, deserts, and islands that lack water streams. Because fresh stream water environments are breeding grounds for their immature forms. This study sought to relate and compare Brazilian biomes based on their simuliid faunas. After gathering information on the distribution patterns of Simuliid species included in the most recent global taxonomic review, a table on their presence in the Brazilian territory was prepared, indicating the regions in which the different species were present in each biome. Subsequently, correspondence and cluster analyses were performed to determine the biomes with which the species were most associated and the similarities of the simuliid faunas among those biomes, respectively. The correspondence analysis showed that most species were predominantly associated with three biomes: The Amazon, Cerrado, and Atlantic Forest, while the cluster analysis showed that the simuliid faunas of the Cerrado and Atlantic Forest are similar and that when taken together, these two biomes are similar to the Amazon biome.

Simulium (Gomphostilbia) wijiti, a new species of black fly (Diptera: Simuliidae) from northern Thailand and its genetic position with related species in the Simulium ceylonicum species-group

A new black fly species, Simulium (Gomphostilbia) wijiti, is described based on adult females, males, pupal exuviae and mature larvae from Mae Hong Son Province, Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from four Thai members of the S. ceylonicum species-group [S. (G.) curtatum Jitklang et al., S. (G.) pangsidaense Takaoka, Srisuka & Saeung, S. (G.) sheilae Takaoka & Davies, and S. (G.) trangense Jitklang et al.], in the female by the short to medium long sensory vesicle; in the male by the large number of upper-eye (large) facets in 15 vertical columns and 15 or 16 horizontal rows; in the pupa by the dorsum of abdominal segments darkened; and in the larva by the antenna as long as or slightly shorter than the stem of the labral fan (longer than the stem of the labral fan in four other species). Phylogenetic analysis based on the COI gene sequences revealed that this new species is genetically closely related to S. leparense of the S. ceylonicum species-group, but is clearly separated from the latter species, and also from the three Thai related species (S. curtatum, S. sheilae and S. trangense) of the same species-group with interspecific genetic distances ranging from 9.65% to 12.67%. This is the fifth member of the S. ceylonicum species-group recorded from Thailand.

DNA Barcoding of Black Flies (Diptera: Simuliidae) in Slovakia and Its Utility for Species Identification

DNA barcoding based on the cytochrome oxidase I gene is increasingly used in black flies (Diptera: Simuliidae), but extensive data for larger areas are still rare. Slovakia, with well-explored black fly fauna, was chosen to verify the reliability of DNA barcoding for species identification. The DNA barcoding region of the COI gene of 235 individuals of 25 black fly species from Slovakia was sequenced. Among them, 30 sequence clusters with assigned Barcode Index Numbers (BINs) were identified, and 5 of them were recorded for the first time. The average intraspecific genetic divergence was 0–3.24%, whereas the average interspecific divergence was 12.3–17.8%. Based on the barcode sequence, 14 species could be identified unambiguously, and 3 of them (Prosimulium latimucro, Simulium costatum, S. degrangei) are split into two or more barcode clusters. In eleven species, some degree of barcode sharing occurred, often combined with barcode splitting. The results showed hidden diversity as well as cases of shared barcode sequences among the studied species. Further investigation using other molecular markers is necessary due to the overlap of intraspecific and interspecific variability.

North–South Differentiation of Black Flies in the Western Cordillera of North America: A New Species of Prosimulium (Diptera: Simuliidae)

Glaciation has been a powerful determiner of species distributions and the genetic structure of populations. Contemporary distributions of many organisms in North America’s Western Cordillera reflect the influence of Pleistocene glaciation. We identified a pattern of north–south differentiation in the genus Prosimulium of western North America, which reflects the separation of northern and southern populations by the North American Ice Sheet during the Pleistocene Epoch. The taxonomic implication is that new species exist within nominal species, requiring formal description or revalidation of names currently in synonymy. We morphologically and cytogenetically examined populations of one nominal species of black fly, Prosimulium esselbaughi Sommerman, over its known range from Alaska south to California and Colorado. Chromosomal and morphological evidence supports the presence of two species, P. esselbaughi sensu stricto from Alaska to at least southern British Columbia, and a new species, Prosimulium supernum in the central Rocky Mountains and high Sierra Nevada range of the United States. The new species is described in all life stages above the egg, along with its polytene chromosomes. The existence of differentiated populations of other nominal species of black flies in northern and southern North America provides a system for investigating possible co-differentiation of vectors and parasites.

An approach to telmophagous Nematocera (Ceratopogonidae, Psychodidae, and Simuliidae) of Spain, with emphasis on its medical and veterinary importance

Nematocera are a suborder of Diptera which historically influenced human history more than any other arthropod group. Four families show a hematophagous behaviour, one being solenophagous (Culicidae), feeding directly on blood vessels, and three being telmophagous (Ceratopogonidae, Psychodidae, and Simuliidae), feeding on blood which pools at the site where their mouthparts have formed a laceration. Although mosquitoes rank first in importance, the telmophagous are also of great interest. Objectives: to update the status of these nematocerans through a transdisciplinary approach, reviewing the main characteristics of each family, the situation of the main vector-borne diseases transmitted by them in the country, especially during the 21st century, and the most relevant species or species groups from a medical and veterinary perspective. Methods: a literature search of databases was conducted and supplemented by browsing specialized journals and citation searching. Results were reviewed and filtered. Results: to date, 84 species of biting midges (Ceratopogonidae), 13 species of sand flies (Psychodidae), and 53 species of black flies (Simuliidae) have been reported in Spain. Culicoides imicola and the Obsoletus complex stand out as the most important biting midges, as they are incriminated in the transmission of bluetongue and Schmallemberg virus; Phlebotomus perniciosus and Phlebotomus ariasi are the vectors of Leishmania infantum; and Simulium erythrocephalum and the Ornatum complex cause the greater part of nuisance and bites to humans in Spain. Conclusions: there is a need to increase research capacity in Spain in order to address several health challenges arising from the presence of telmophagous Nematocera in particular, and of blood-sucking atropods in general.

Recurring Late December Outbreaks of Adult Simulium jenningsi Group Black Flies (Diptera: Simuliidae) in Seminary, Mississippi, USA

Abstract Black flies (Diptera: Simuliidae) are reemerging as biting and nuisance pests in many southern states, presumably from improving water quality in creeks and rivers. Since 2009, entomologists at Mississippi State University and the Mississippi Department of Health have conducted surveys to ascertain what black fly species are present in the state as well as their geographic distribution and seasonality. These surveys revealed what appears to be a recurring, significant emergence of black flies every year around 25 December at one site in southern Mississippi. In this study, adult black flies were collected from 1 January 2018 to 31 December 2021 by hand netting in the exact same way each time at Okatoma Creek, Seminary, MS. Forty-eight collecting trips to the site over the 4-yr period yielded a total of 176 black flies, all morphologically identified as Simulium jenningsi Group Malloch. Molecular identification was successfully performed on 17 specimens collected during the December outbreaks. Of the 17 specimens analyzed, 10 and 7 specimens grouped with 100% bootstrap confidence inside clades comprising S. jenningsi or S. podostemi, respectively.

КРОВОСОСУЩИЕ ЧЛЕНИСТОНОГИЕ (АCARI: IXODIDAE; DIPTERA: CULICIDAE, SIMULIIDAE) В НАСЕЛЕННЫХ ПУНКТАХ РАЗЛИЧНОЙ КАТЕГОРИИ НА ТЕРРИТОРИИ МОГИЛЕВСКОЙ ОБЛАСТИ БЕЛАРУСИ

The article presents data on the species diversity of blood-sucking arthropods in settlements of various types of the Mogilev region of Belarus. A total of 2 species of Ixodidae − Ixodes ricinus and Dermacentor reticulatus has been found; 18 species of mosquitoes from 3 genera (Aedes, Anopheles, Coquillettidia) and 5 black fly species from 3 subgenera of genera Simulium have been found. The abundance of Ixodidae ticks averaged 12.3±2.9 per flag/km, adult mosquitoes – 31.8±9.5 ind. per sampling, larvae – 26.0±9.4 ind. per square meter, immature black flies – 47.7±13.6 ind. per square decimeter.

Parasite-host relationships of water mites (Acari: Hydrachnidia) and black flies (Diptera: Simuliidae) in southeastern Spain

BackgroundDocumentation on water mites in Spain is scarce, as is information on the parasite-host relationship between certain water mite species and representatives of the dipteran family Simuliidae. The discomfort caused to humans and animals by black flies seems to be increasing in recent years. In this context, an investigation of parasitic water mites is of great importance, not only from the point of view of biodiversity, but also in terms of their potential to control black fly populations.MethodsRivers across a wide region of eastern Spain were sampled to determine the specific richness of simuliid dipterans and to investigate their possible parasites, such as water mites, mermithid nematodes and microsporidia (fungal microbes). Data on environmental variables, abundance, prevalence and intensity of parasitism on the collected specimens were analyzed.ResultsIn 10 streams, 15,396 simuliid pupae were collected and checked for the presence of water mite larvae; 426 pupae in seven streams were found to be associated with water mite larvae. Of the 21 simuliid species identified based on morphological characters, eight were found to be associated with water mite larvae. Water mite infection was not equally distributed among black fly species. Also, the prevalence of parasitism was low and differed among simuliid species, ranging from one to 13 water mites per black fly pupa. Variation at the intra- and interspecific levels was detected in terms of the number of water mites inside the black fly cocoons. Free-living deutonymphal and adult water mites representing 15 different species of six genera and five families were morphologically identified. The taxonomic identity of the parasitic mite larvae is unclear at present. Morphologically, they fit descriptions of larval Sperchon (Hispidosperchon) algeriensis Lundblad, 1942, but the possibility cannot be excluded that they represent Sperchon algeriensis, the most abundant species at the adult stage in this study and unknown at the larval stage, or even another species of the genus. A molecular analysis produced for the first time cytochrome oxidase I gene sequences for S. algeriensis.ConclusionsOur results contribute to current knowledge on Spanish Hydrachnidia and their relationships with simuliids as hosts. However, further research is needed to evaluate the diversity, distribution, bioecology and prevalence of this parasitism.Graphical

Discovery of a new black fly species in the Simulium (Simulium) striatum species-group (Diptera: Simuliidae) from northeastern Thailand and its phylogenetic relationships with seven Thai related species

The female, male, pupa and mature larva of Simulium (Simulium) poolpholi sp. nov. collected from a large and seasonal stream in northeastern Thailand are described. This new species is placed in the S. striatum species-group by the female sternite 8 concave posteromedially in form of the inverted-U shape, ovipositor valve with a ventrally produced process along its inner margin, male ventral plate saddle-shaped, style with a basal protuberance, and pupal gill with 10 filaments. It is morphologically similar to S. (S.) phraense Takaoka, Srisuka & Saeung from northern Thailand by lacking annular ridges on the surface of pupal gill filaments but it is distinguished from the latter species by the arrangement of pupal gill filaments. Molecular analysis using the fast-evolving nuclear big zinc finger (BZF) gene shows that S. (S.) poolpholi sp. nov. formed a distinct clade, being separated from the seven other Thai species of this species-group by a genetic distance of 1.84–4.55%. Our discovery increases the number of species in the S. striatum species-group in Thailand to nine.