Tabanidae Research Articles

Brighteness-dependent visual attractiveness of the human body for horse flies (Diptera: Tabanidae): a field experiment.

The landing patterns of blood-sucking females (Diptera: Tabanidae) are largely influenced by their visual perceptions. When attacking humans, the shape of different body parts and overall brightness of the body could be the factors determining the place of blood-sucking. The visual attractiveness of the human body for tabanids was investigated through a black and a white mannequin in the Danube floodplain, Slovakia. The mannequins were covered by glue once a week. On both of the mannequins, 332 horse flies were stuck. The trapped horse flies on the mannequins belong to the genera Tabanus Linnaeus, 1758, Hybomitra Enderlein, 1922, Chrysops Meigen, 1803, Haematopota Linnaeus, 1758 and Atylotus (Linnaeus, 1767). Based on the trapped tabanids, the black mannequin is 6.06 times more attractive than the white one. The most tabanid carcasses were found on the lower limbs (56.32%) and the least occurred on the head (2.1%), the difference in their occurrence between the lower limbs and head of both mannequins was significant (P < 0.001). A similar significant difference was observed on certain parts of both mannequins on the taxonomical level of the genera Tabanus, Hybomitra, and Atylotus, the carcasses of which aggregated mostly on the lower limbs, rather than on the upper limbs and head.

Molecular evidence of pathogens and endosymbionts in the black horse fly Osca lata (Diptera: Tabanidae) in Southern Chile.

Little is known about the role of horse flies in potential pathogen transmission in Chile. This study provides evidence of the molecular detection of microorganisms in southern Chile. In the present study, adult Osca lata horse flies were trapped from Punucapa (39°45'06"S/73°16'08"W, Región de Los Ríos) and Puyehue (40°39'10"S/72°10'57"W, Región de Los Lagos), Chile. Among the 95 samples analyzed by PCR using specific primers, microorganisms were detected in 23.2% (n = 22) of the samples. Rickettsia spp. DNA was detected in 15.8% (n = 15) of the samples, Trypanosomatidae DNA in 5.3% (n = 5) of the samples, and filarial DNA in 2.1% (n = 2) of the samples. This study found that horse flies in the region are capable of carrying a variety of both parasites and endosymbionts. Further research is needed to understand the specific impact of horse flies as mechanical or biological vectors and develop effective control measures to prevent the spread of any microorganisms associated with disease.

Microbiota profile in organs of the horseflies (Diptera: Tabanidae) in Northeastern China.

Tabanids, commonly known as horseflies and belonging to the family Tabanidae, are blood-feeding arthropods (BFA) found worldwide. They are known for their ability to mechanically and biologically transmit various animal pathogens. Tabanids are potential vectors for diseases such as Francisella tularensis, Anaplasma marginale, Theileria spp., and contributors to lumpy skin diseases. Despite their involvement in common BFA studies, tabanids have not been extensively explored in microbiome research. In this study, the microbiota structure and composition in various organs of four distinct genera of tabanids: Atylotus, Haematopota, Tabanus, and Hybomitra were examined. High-throughput sequencing of the bacterial 16S rRNA gene was performed to gain insights into the microbial communities associated with the different tabanid species. Result display that microbiota composition and diversity, including Firmicutes, Proteobacteria, and Bacteroidetes, varied significantly among the different organs, with the ovaries exhibiting significantly higher diversity. Apart from the Haematopota genus, Tenericutes were enriched in the midgut of other tabanid species, whereas the Malpighian tubules exhibited a higher abundance of Bacteroides. Notably, the ovarian microbiota structure was conserved among the four tabanid species, indicating its potential association with reproductive development. Evaluation of the potential pathogen risk revealed putative pathogens in over 100 genera associated with these tabanid commensal organisms. Twenty genera were annotated as zoonotic agents with a high abundance of Citrobacter and Brucella, highlighting the presence of this important group of zoonotic pathogens. Functional predictions of vector-microbiota interactions indicate that microbiota significantly affects vector biological traits and can influence pathogen transmission via direct interactions or by regulating host immunity and nutrition. For the first time, the distribution characteristics and functions of four genera of horsefly microbiota were analyzed, revealing the presence of multiple potential pathogenic microorganisms. These findings provide valuable insights for future research and the development of symbiotic-based strategies to control insect-borne diseases among tabanids.

Direct Observation of Feeding Behavior of Adult Tabanidae (Diptera) on Beef Cattle from Khon Kaen Province in Thailand.

Tabanidae (horse flies and deer flies) are hematophagous insects that cause direct and indirect damage to animal production. The aims of this study were to determine the preferred site, time of day, and duration of tabanid feeding on beef cattle and identify factors related to infestation by tabanids. The population of tabanids was surveyed on certain body parts of the beef cattle (fore udder, tail, navel, leg, dewlap, body, and under) during the morning hours (9.00-10.30 a.m.), midday (12.00-13.30 a.m.), and afternoon (15.30-17.00 p.m.) every day for 10 days. The findings showed that two genera, Tabanus Linnaeus, 1758, and Chrysops Meigen, 1803, landed on the cows. The leg was statistically significantly the most frequent landing site for tabanids (15.067 ± 7.54) compared with other parts. The average feeding duration for each insect was 2.76 ± 1.77 min. The results showed that a significant number of tabanids were present during midday, as compared with the morning and afternoon. Temperature was found to be positively associated with fly abundance. A regression model was derived in this study (y = 4.23x - 116.09). This information is important for tabanid control and prevention in beef cattle.

Diversity and seasonality of horse flies (Diptera: Tabanidae) in Amazon Forest fragments of Monte Negro, Rondônia, Western Amazon.

Tabanidae are considered a nuisance to humans, wild animals, and livestock due to their painful, annoying, and insistent biting. Tabanids transmit some pathogens and parasites biologically and mechanically. In humans, there are relatively few pathogens transmitted regularly. Still, tabanids serve as vectors of a number of disease agents of animals, including viruses, bacteria, protozoans, and nematodes. They are more abundant in tropical and humid regions, and their seasonal patterns are affected by habitat changes such as deforestation and fragmentation. Here, we analyze the tabanid fauna in Monte Negro, a central municipality of Rondônia, Brazil, comparing abundance, richness, and diversity in forest and pasture habitats. Traps were set for 5days a month for 12 consecutive months. We also examined how abiotic factors (humidity, temperature, and rainfall) affected the abundance, diversity, and richness and the effectiveness of Malaise and Nzi traps as sample methods. The influence of climatic variables on the richness and abundance of the species was tested using generalized linear models, and we used non-parametric dimensional scaling (nMDS) for analysis of species composition and diversity in different traps and environments. We collect 1032 specimens of 25 species. The most abundant species were Tabanus antarcticus, Dichelacera tetradelta, Tabanus mucronatus, and Leucotabanus albovarius. Forest habitats had the highest number of tabanids, followed by pasture and the anthropized area, and there was no significant difference regarding the effectiveness of the Malaise and Nzi traps. The study provides new information on the distribution and ecology of tabanids in Brazil.

An illustrated list for the Tabanidae (Diptera: Brachycera) from thirteen localities of the São Paulo state and redescription of Catachlorops (Amphichlorops) flavus (Wiedemann)

ABSTRACT The family Tabanidae (Diptera: Brachycera) is composed of flies commonly known as horse flies and deer flies. The family is cosmopolitan and possesses both economic and conservation interests. The females are hematophagous attacking a variety of animals, including cattle, but both females and males from several genera are flower visitors. Despite the fauna of São Paulo being largely explored due to historical factors, several species of Tabanidae in the state are still poorly known. Several are known only from the type series, and information from the literature is limited to old, sometimes inadequate descriptions and drawings. Herein we provide an illustrated list, based on the literature and specimens collected in thirteen localities from São Paulo state. For all the identified specimens we provide high-definition images from different views. Important diagnostic features for each species are supplied to facilitate the identification of the species in the region. We report five new records for São Paulo state: Catachlorops (Amphichlorops) flavus (Wiedemann), Dichelacera rubricosa (Wulp), Leucotabanus sebastianus Fairchild, Phaeotabanus aphanopterus (Wiedemann), Tabanus schadei Fairchild and one for Brazil: D. rubricosa. Also, C. flavus is redescribed along with the description of the male.

Tabanus chrysurus is a potential biological vector of Trypanosoma (Megatrypanum) theileri in Japan.

Several species of horse flies (Diptera: Tabanidae) are known as vectors of Trypanosoma (Megatrypanum) theileri and T. theileri-like trypanosomes; these host-parasite relationships were established based on the developmental stages of these parasites discovered in the hindgut of horse flies. T. theileri and T. theileri-like trypanosomes have been detected in cattle and wild deer in Japan; however, the vector horse fly species remains unidentified. Therefore, in this study, we aimed to identify the potential horse fly species serving as vectors of T. theileri in Japan. A total of 176 horse flies were collected between June to September 2020 and 2021 in Tokachi, Hokkaido, Japan. The T. theileri infection in the captured horse flies was determined by PCR and microscopic analyses of their midgut and hindgut. Additionally, the trypanosome, microscopically detected in a horse fly, was molecularly characterized and phylogenetically analyzed using 18S rRNA and partial cathepsin L-like protein gene (CATL) sequence of the trypanosome. The microscopy and PCR analyses revealed 0.57% and 35.8% prevalence of T. theileri in horse flies, respectively. Epimastigote stages of T. theileri, adhered to the hindgut epithelial cells of Tabanus chrysurus via flagella or actively moving in the lumen of the gut, were detected. Phylogenetic analysis revealed the connection of isolated trypanosomes with T. theileri in the TthI clade. These results suggest that Ta. chrysurus is a potential vector of T. theileri.

Two new species of Dasybasis Macquart from the Peruvian Andes of Cusco (Diptera: Tabanidae: Diachlorini).

Two new horse fly species, Dasybasis mancoi sp. nov. and D. huaynai sp. nov. (Diptera: Tabanidae: Diachlorini), are described from the Peruvian Andes near Cusco on the basis of morphological features, including those of the female genitalia. Digital photographs of both species and of the terminalia of both females and of one male are provided. The two new species are related to D. bulbula Coscarn & Philip, as evidenced by their similar morphological characteristics.

Effects of heavy metal pollution on population dynamics of another important pollinator insect group: Horseflies (Diptera: Tabanidae)

Horseflies represent important agents of pollination as well as other pollinator insects, like butterflies, bees and wasps. Horseflies belong to the genera Atylotus, Dasyramphis, Glaucops, Pangonius, Philoliche, Chrysops, Hybomitra, and Tabanus species are exclusive nectar feeders. Glucose, fructose and sucrose are major components of plant nectars which are used nourishing for developing eggs. Because of these features horseflies have a significant role in pollination of phanerogams. This study was conducted to investigate the effects of toxic heavy metals on the population dynamics of horsefly species. Monthly changes on the accumulation of heavy metals in the larval habitats of horsefly species were determined with Perkin Elmer Optical Spectrophotometer and also correlations between concentrations of heavy metals and population fluctuations of horse fly species were observed. The results demonstrated that lead, iron and cadmium have statistically important negative effects on the population dynamics of horsefly species.

Tabanidae Fauna (Order: Diptera) of the Arab Countries in the Middle East

Family Tabanidae (Diptera) has cosmopolitan distribution with about 4455 described species. A comprehensive review of literature was conducted to list the recorded species from Arab countries of the Middle East (Bahrain, Iraq, Jordan, Oman, Palestine, Qatar, Syria, Saudi Arabia, the United Arab Emirates, and Yemen). The study reveals the presence of 110 species in four subfamilies and 13 genera. To the moment, the Tabanidae of the Arab countries of the Middle East is poorly studied. Syria and Lebanon do not have a valid checklist, while Iraq, Palestine and the United Arab Emirates are fragmentarily studied. Jordan and Saudi Arabia were well studied. However, this study did not list any species from Bahrain and Qatar.

Tabanidae (Diptera) collected on horses in a Cerrado biome in the state of Tocantins, Brazil.

Tabanidae (Diptera), popularly known as horse flies, is an important vector group. This is the first study to ascertain the abundance and diversity of horse flies in horses at the cerrado biome of the state of Tocantins, Brazil. Collecting took place in typical Cerrado, and sampling occurred in the dry and rainy seasons. The horseflies were collected from horses using an entomological net. A total of 249 individuals were collected and spread over 25 species. The prevalent species were Stypommisa aripuana (25.8%) and Catachlorops rufescens (6.4%), in the dry period, and Fidena lissorhina (22.5%), Tabanus occidentalis var. dorsovittatus (10%) and Poeciloderas quadripunctatus (6.4%), in the rainy season. The results suggest that tabanids attack horses throughout the dry and rainy seasons, posing a constant threat to their health in the Cerrado of Tocantins.

Discrimination of cryptic species: Tabanus triangulum and Tabanus occidentalis (Diptera: Tabanidae) differ in size and shape.

Horse fly females (Diptera, Tabanidae) are hematophagous and can vector pathogens that affect livestock. Complexes of cryptic species are common in Tabanidae, as exemplified by some species of Tabanus, including Tabanus triangulum and Tabanus occidentalis, both prevalent in the Southern region of Brazil. In this study, geometric morphometrics were employed to ascertain the wing venation in species identification. It was demonstrated that this tool effectively differentiates T. triangulum from T. occidentalis in the coastal plain of Rio Grande do Sul state, situated within the Pampa biome. The results indicate that T. triangulum and T. occidentalis occupy distinct regions of the morphological space, allowing their precise identification through geometric morphometrics, which is fast, affordable, and easy to implement.

Characterization of complete mitochondrial genome of three Horse flies of the genus Tabanus (Diptera: Tabanidae): comparative analysis.

Tabanidae (Horse-Flies or Deer-Flies) are one of the most economically important as well as medically significant haematophagous insect family within the order Diptera. Members of this group are also responsible for the mortality of substantial number of live-stock every year. Due to their pathogen transmission potential and vector competencies makes them an important insect group to study. Till now, mitochondrial genome of 18 species of tabanids were available. The complete mitogenome of three species T. diversifrons (15,809bp), T. rubidus (15,878bp) and T. tenens (15,872bp) were generated by Next generation sequencing method. They consist 37 genes, with a positive AT skew and a negative GC skew. The gene order of these three species is similar to the typical gene arrangement of infra-order Tabanomorpha. Most of the tRNAs showed typical clover-leaf secondary structure except trnS1, which lacks the DHU arm. The sliding window analysis showed that thenad4L is the most conserved while atp8, and nad6 are the most variable genes. Moreover, the ratios of non-synonymous to synonymous substitution rates indicated that all PCGs under the purifying selection. Phylogeny revealed Chrysops and Haematopota are monophyletic while species of Hybomitra are nested within the polyphyletic clade of Tabanus. T. diversifrons exhibits sister relationship with Atylotus miser. Two morphologically divergent species T. rubidus and T. tenens are found to be genetically similar and indistinguishable by mitochondrial genome. The hypervariable genes like atp8 and nad6 can be used as molecular markers for the identification of recently diverged lineages of family Tabanidae. Further, to address uncertainties arising from the two morphological divergent species, it is imperative to obtain data from nuclear gene markers.

Biogeographic regionalization of the Amazon using highly diverse horse flies (Diptera: Tabanidae): insights from three decades of data

ABSTRACT Delimiting biogeographic regions based on occurrence data is an interesting approach to investigating processes behind biodiversity distribution patterns. Comparing spatial scales and identifying predictor variables of biogeographic regions have wide application for biodiversity conservation. In this study we used a comprehensive database containing more than thirty years of horse fly records to estimate species richness, endemism, and species composition, and regionalize the Amazon biogeographically. We compared five spatial scales defined by grid size (1–5º), and test five hypotheses (elevation, climate, vegetation cover, and two regionalizations from the literature) to identify predictors of the biogeographic regions. Endemism, species richness and composition were predicted by different sets of predictor variables, although the models were highly dependent on spatial scale. We identified three well-defined biogeographic regions, which have been formed by a combination of geographic distance, climate and historical factors converging with some theories proposed for mammals. Our models indicated dispersal as a key factor for regionalization, as it can be constrained by a combination of climate and historical processes changing habitats over time, although this finding was highly dependent on spatial scale. We showed that horse flies are interesting models for biogeography although they have been historically neglected.

Horse fly and deer fly (Diptera: Tabanidae) species and abundance following logging in northwestern Ontario

Horse flies and deer flies are important components of habitat for many species, but how logging may alter the communities of biting flies in the boreal forest is largely unexplored. Such knowledge is important to conservation, because biting flies can shape the behaviour and sometimes even the demography of vertebrates in the boreal forest. We compared the abundance and distribution of Tabanidae species in managed boreal forest stands in northwestern Ontario with three harvest histories. Using sweep nets during 2 summers, we collected specimens from forest stands that were young (harvested 20–35 years ago), intermediate (harvested 36–69 years ago), and old (unharvested or harvested ≥ 70 years ago). We tested the hypothesis that greater harassment potential in young stands was due not only to more abundant tabanids, but more abundant obligate blood-feeding (anautogenous) tabanids, which are more persistent in host seeking. We caught 8,895 specimens from 44 species. The oldest stands had the highest species richness, but the lowest abundance of individuals, whereas young stands had the highest relative abundance and the most anautogenous specimens, potentially causing more stress to hosts in young stands. These results demonstrate that forest harvesting may reduce habitat suitability for many large mammals due to an altered tabanid community.

Allergy to stings and bites from rare or locally important arthropods: Worldwide distribution, available diagnostics and treatment.

Insect venom allergy is the most frequent cause of anaphylaxis in Europe and possibly worldwide. The majority of systemic allergic reactions after insect stings are caused by Hymenoptera, and among these, vespid genera induce most of the systemic sting reactions (SSR). Honey bees are the second leading cause of SSR. Depending on the global region, other Hymenoptera such as different ant genera are responsible for SSR. Widely distributed hornets and bumblebees or local vespid or bee genera rarely induce SSR. Hematophagous insects such as mosquitoes and horse flies usually cause (large) local reactions while SSR occasionally occur. This position paper aimed to identify either rare or locally important insects causing SSR as well as rarely occurring SSR after stings or bites of widely distributed insects. We summarized relevant venom or saliva allergens and intended to identify possible cross-reactivities between the insect allergens. Moreover, we aimed to locate diagnostic tests for research and routine diagnosis, which are sometimes only regionally available. Finally, we gathered information on available immunotherapies. Major allergens of most insects were identified, and cross-reactivity between insects was frequently observed. While some diagnostics and immunotherapies are locally available, standardized skin tests and immunotherapies are generally lacking in rare insect allergy.

New records, descriptions, and redescriptions of male horse flies (Diptera: Tabanidae) in Brazil

Tabanidae Latreille are hematophagous and act as mechanical and biological vectors of several pathogens, and therefore they have been widely studied in both ecology and public health, as well as in taxonomy works. Males are nectarivorous and rarely captured, so for most species they remain unknown. Thus, we aimed to describe/redescribe the males of five species: Esenbeckia osornoi Fairchild, 1942, Acanthocera marginalis Walker, 1854, Dicladocera mutata Fairchild, 1958, Stypommisa aripuana Fairchild &amp; Wilkerson, 1986, and Tabanus mucronatus Fairchild, 1961. Three males are described for the first time and two others are redescribed, we also provide a complete description of the species, including photographs of habitus, head and genitalia.

Distribution of Biting Flies Associated with Swine Production Facilities in the Southeastern United States

High populations of pest flies on swine facilities can be detrimental to the animals and producers. The purpose of this study was to identify the distribution pattern and the influence of habitats on distribution of adult biting flies surrounding commercial swine production barns in North Carolina. In this study, fly surveillance was conducted on four swine facilities in Bladen County, North Carolina, U.S.A., from January to October 2019. Biting flies typically associated with livestock were passively collected weekly on sticky traps, which were placed in three concentric circles surrounding swine barns, and then counted and identified. Stable flies [Stomoxys calcitrans (L.); Diptera: Muscidae] were most abundant on swine facilities that were mixed-use with pastured beef cattle. However, swine producers with no pastured cattle should be aware of the potential for stable flies to disperse from off-property larval development sites. Therefore, adult fly management may be necessary if populations reach nuisance levels. Horse and deer fly (Diptera: Tabanidae) captures were not related to trap proximity to water. Differences in horse and deer fly trap captures was likely less of a reflection of differences in potential fly development habitat quality (e.g., water) and more related to adult fly habitat selection.

Developmental dynamics and survival characteristics of the common horse bot flies (Diptera, Gasterophilidae, Gasterophilus) in desert steppe

The genus Gasterophilus (Diptera, Gastrophilidae) is an obligate parasite of the equine family that causes widespread myiasis in desert steppe. Based on four common naturally excreted Gasterophilus larvae collected systematically in the Karamaili Ungulate Nature Reserve from March to September 2021, this paper studies the population dynamics and ontogenetic laws of horse flies, and discuss the coexistence pattern and population dynamics prediction of horse flies. The results showed that the Gasterophilus larvae had obvious concentrated development period, and the time of population peaks was different, the earliest was G. nigricornis (late March), followed by G. pecorum-Ⅰ (mid-April), G. nasalis (late April), G. intestinalis (early May), G. pecorum-Ⅱ (mid-August). The order of development threshold temperature “Cnigricornis < Cpecorum-Ⅰ ≤ Cpecorum-Ⅱ < Cnasalis < Cintestinalis” is consistent with the peak order of different larval populations. The life history survival rate (L) was as follows: Lnigricornis (83.97%) ≥ Lintestinalis (81.25%) > Lnasalis (72.42%) ≥ Lpecorum-Ⅱ (71.65%) > Lpecorum-Ⅰ (39.23%). This study combined indoor experiments and field surveys revealed the development of horse fly populations with different life strategies in desert grasslands. Based on the different development threshold temperatures of several horse flies, the staggered population dynamics of Gasterophilus form continuous infection stress on the host. In addition, G. pecorum exhibited a univoltine bimodal population distribution in this area and led to two high-intensity host infections, which is one of the important reasons why it has become the dominant species of myiasis in desert steppe.

Detection of genetic material of causative agents of animal viral diseases in blood-sucking dipterans from the Tyumen Region

The purpose of the research is to test blood-sucking dipterans collected in the Tyumen Region for genetic material of viruses that cause dangerous diseases in live-stock animals.Materials and methods. From May to October 2021, blood-sucking insects of the Diptera order whose species membership was established by tabular keys were collected on pastures and farms in ten Tyumen Region districts. In 60 samples formed from the captured insects according to the taxonomic affiliation and the period and place of collection, the presence of genetic material of the leukemia provirus and the dermatitis nodularis virus of cattle (bovine) and the African swine fever virus was evaluated by polymerase chain reaction (PCR) in real time.Results and discussion. Adult insects collected for the PCR analysis were blood-sucking flies (family Muscidae, genus Stomoxys), mosquitoes (family Culicidae, genus Aedes), midges (family Simuliidae, genera Byssodon and Schoenbaueria), horseflies (family Tabanidae, genera Hybomitra, Tabanus and Haematopota), and biting midges (family Ceratopogonidae, genus Culicoides). As a result of the PCR testing of the samples for the bovine leukemia provirus DNA, 1 out of 13 samples of Stomoxys spp. (7.7%) and 1 of 13 samples of Hybomitra spp. (7.7%) were positive. The bovine leukemia provirus DNA detected in blood-sucking insects indicates the presence of this pathogen in the insect collection area as well as their possible involvement in its spread. Further research is needed on the Stomoxys spp. and Hybomitra spp. vector competence in vivo, considering natural and climatic features of the Tyumen Region.