Species Of Tabanus Research Articles

Exploring the biological diversity and source species of medicinal horseflies through metabarcoding

Horseflies from the Tabanidae family play a significant role in traditional Chinese medicine to treat various health conditions, including coronary heart disease, stroke, headaches, liver cirrhosis, psoriasis, and hepatic carcinoma. There are 27 species of Tabaninae (Tabanidae) used as medicine, and they showed high morphological similarities with those for which medicinal properties have not been reported. Nonetheless, there have been reports suggesting that medicinal crude drugs sometimes contain irrelevant or false species, impacting the drug's efficacy. In this current study, we collected 14 batches, totaling 13,528 individuals, from various provinces in China. Instead of “classic” DNA barcoding strategy, we employed a high-throughput metabarcoding approach to assess the biological composition of crude drug mixtures derived from horseflies. Our analysis identified 40 Amplicon Sequence Variants (ASVs) with similarity percentages ranging from 92% to 100% with 12 previously reported species. Species delimitation methods revealed the presence of 11 Molecular Operational Taxonomic Units (MOTUs), with ten belonging to the Tabanus genus and one to Hybomitra. Tabanus sp6 displayed the highest relative abundance, and its ASVs showed close resemblance to Tabanus pleski. Our investigations revealed that the medicinal batches were biologically composed of 6 to 12 species. Some batches contained ASVs that closely resembled species previously associated with false Tabanus species. In conclusion, our findings offer valuable insights into the biological composition of crude drugs derived from horseflies and have the potential to enhance the quality of these traditional medicines.

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.

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.

First insights into using outline-based geometric morphometrics of wing cell contours to distinguish three morphologically similar species of Tabanus (Diptera: Tabanidae)

Accurate species identification of horse flies (Diptera: Tabanidae) is crucial due to their role as vectors for various pathogens, which is essential for understanding their biology, devising strategies to control their populations, and enhancing disease surveillance. This study assessed the efficacy of outline-based geometric morphometrics (GM) by analyzing the wing cell contours of discal, first submarginal, and second submarginal cells to distinguish three morphologically similar Tabanus species commonly found in Thailand, T. megalops, T. rubidus, and T. striatus. Statistical analysis demonstrated significant size differences between T. rubidus and the two other species (P < 0.05), with T. rubidus exhibiting larger wing cells. Tabanus megalops and T. striatus had similar sizes; their size differences were not statistically significant. The accuracy of size analysis based on validated classification tests was relatively low, ranging from 64.67% to 68.67%. Nonetheless, all wing cell contours showed significant shape differences between the three species, as confirmed by Mahalanobis distance comparisons using 1000 permutation tests (P < 0.05). The shape of the first submarginal cell contour showed the highest classification accuracy (86.67%). Outline-based GM offers a significant advantage for analyzing fly specimens with incomplete wings that have intact cells. For damaged specimens, analyzing the contour of the first submarginal cell through this technique can be a viable alternative.

Revisiting the Tabanid Fauna (Diptera: Tabanidae) of Uruguay: Notes on the Species of the Genus Tabanus Linnaeus, with the Description of a New Species.

We describe a new species of Tabanus (for Uruguay, the first in more than 90years) based on females from the Department of Tacuarembó, Uruguay. Tabanus tacuaremboensis sp. n. is the 15th species of the genus Tabanus recorded from Uruguay. The species description is accompanied by illustrations of the diagnostic external and internal characters. In addition, for comparison with the new species, we provide photographs of the regional species of Tabanus whose distributions are still poorly known. In view of the lengthy hiatus since the last new tabanid species was described from Uruguay, we offer a brief discussion of the importance of new and further sampling in areas where the tabanofauna is still poorly known.

Characterization of the complete mitochondrial genomes of six horseflies (Diptera: Tabanidae).

The family Tabanidae (Insecta: Diptera) is one of the economically most important group of haematophagous insects, causing millions of livestock deaths per year. However, current knowledge on the mitochondrial genomes (mitogenomes) from this family is limited. Additional tabanid mitogenomes characterization is of utmost importance for their identification, epidemiologic and phylogenetic studies. We sequenced the mt genomes of six horseflies with an Illumina platform and their phylogenetic relationship was conducted with other infraorder Tabanomorpha members with available mt genome datasets. All six newly sequenced mitogenomes were typical 37-gene circular structures retaining the gene order of Tabanomorpha. The trnQ, trnM and trnA were highly conserved among the six mitogenomes (identity=100%). The TΨC arm and variable loop regions were relatively more variable compared to the amino acid receptor arm, anticodon arm and DHU arm of the tRNAs. Among 13 protein-coding genes (PCGs) of tabanids mitogenomes, the highest nucleotide diversity was detected in atp8, cox1, cox3, nad6 and cytb (0.1 for each). In addition, atp8 genes exhibited the highest evolutionary rate (ω=0.24) among 13 PCGs. The interspecies K2P genetic distances among some Tabanus spp. across the mitogenome was greater (0.08) than intergeneric genetic distance between T. amaenus and Atylotus miser (0.07). Phylogenetic analyses revealed non-monophyletic relationships among horseflies of the genus Tabanus. The present study showed mt gene order is highly conserved within Tabanus species. Our mito-phylogenomic analysis supports the paraphyly of the genus Tabanus. The new data provide novel genetic markers for studies of population genetics and systematics of horseflies.

Landmark Data to Distinguish and Identify Morphologically Close Tabanus spp. (Diptera: Tabanidae).

Simple SummaryTabanus spp. (Diptera: Tabanidae) are blood-sucking parasites of animals and humans. The accurate identification of these flies is very important for determining the vector species involved in disease transmission and for planning effective vector control and management strategies. We explored the effectiveness of landmark-based geometrics at distinguishing and identifying morphologically similar species of Tabanus (T. megalops, T. rubidus, and T. striatus) in Thailand. Our study reveals that geometric morphometrics is effective at distinguishing between the three species of Tabanus. Furthermore, our study material can be used as reference material for species identification.Tabanus spp., also known as horse flies (Diptera: Tabanidae), are important vectors of several animal pathogens. Adult females of Tabanus megalops and Tabanus striatus, which are members of the T. striatus complex, are morphologically similar and hence difficult to distinguish using morphological characteristics. In addition, molecular identification by DNA barcoding is also unable to distinguish these species. These two species can occur sympatrically with Tabanus rubidus, which is morphologically similar to T. megalops and T. striatus. Wing geometric morphometrics has been widely used in various insects to distinguish morphologically similar species. This study explored the effectiveness of landmark-based geometrics at distinguishing and identifying T. megalops, T. rubidus, and T. striatus in Thailand. Specimens were collected from different geographical regions of Thailand, and only unambiguously identified specimens were used for geometric morphometric analyses. Left wings of females of T. megalops (n = 160), T. rubidus (n = 165), and T. striatus (n = 85) were photographed, and 22 wing landmarks were used for the analysis. Wing shape was able to distinguish among species with high accuracy scores, ranging from 94.38% to 99.39%. We showed that morphologically very close species of Tabanus can be reliably distinguished by the geometry of their wing venation, and we showed how our experimental material could be used as a reference to tentatively identify new field collected specimens.

Distribution of Fly Pests in a Farm in Plateau State, Nigeria

An evaluation of fly pests of cattle was conducted in Federal College of Animal Health and Production Technology (FCAH&amp;PT) Farm, Chaha Village, Jos South Local Government Area, Plateau State, Nigeria between August and October, 2020. Samples were collected from the farm weekly for three months. A total of nine hundred and nineteen (919) adult dipterous flies comprising fifteen species in eight genera across the three sub-orders were caught and identified using aerial sweeping hand net, light trapping and aerial insecticide spray. Phlebotomus papaltasi (44.18%) was the most prevalent while Simulium damnosum (0.22%) was the least. Others were Musca domestica (17.73%), Stomoxys calcitrans (11.43%), Culicoides species (10.99%), Musca autumnalis (10.23%), mosquitoes – Anopheles gambiae/Culex quequinfasciatus (4.89%) and Tabanus species (0.33%). The haematophagous flies (72.04%) out-numbered the non-haematophagous flies (27.96%) and the number of females collected/caught 780 (84.87%) were higher than the males 139 (15.13%). The highest collections were made in October (353 representing 38.41%) while September had the lowest (263 /28.62%). The study established the presence of fly pests in the farm and recommends that appropriate control measures should be put in place to forestall any disease outbreak.

Alighting and Feeding Behavior of Trypanosome-Transmitting Vectors on Cattle in Nigeria.

Vector control is important to effectively prevent trypanosomiasis. Therefore, alighting and feeding responses of trypanosome-transmitting vectors were conducted in Nigeria. The aim of this study was to assess the landing preference, level of fly annoyance on cattle, and feeding behavior by direct observation of cows, bulls, and calves. The percentage of Glossina species, Tabanus species, and stomoxyine that fed on cattle blood after landing varied according to the age and sex of the cattle host. Although most flies left the cattle host before completing their meal because of host defensive behaviors, an average of 78, 19.6, and 10.2% of Glossina, Tabanus, and stomoxyines, respectively, were fully engorged. The longest mean feeding time was observed in Glossina. Over more than 90% of Glossina spp. landed on the belly and legs. Most Tabanus spp. (85%) also landed on the belly and legs while Tabanus par Walker (Diptera: Tabanidae) often landed on the back (45%). Half of Stomoxys species landed on the head and neck. Vector flies' feeding success varied according to cattle host age and was negatively correlated with defensive host behaviors and apparent fly density. Hence, fly defensive behaviors contribute to trypanosomiasis dynamics in a cattle herd, and expended energy from defensive behaviors could adversely affect productivity.

TRYPANOSOMA EVANSI INFECTION IN CAMELS (CAMELUS DROMEDARIUS) OF ARABIAN GULF REGION, AN OVERVIEW (A REVIEW ARTICLE)

Trypanosomiasis (Surra) is the most important and serious infectious disease of camels (racing and breeding) and is widespread throughout camel-rearing areas, caused by Trypanosoma Evansi which is widespread throughout tropical and sub-tropical regions. In UAE and Saudi Arabia, camel trypanosomiasis is responsible for causing heavy economic losses which may be in terms of reduced productivity, emaciation, decrease in milk and meat production, premature births and abortions, mortality, decrease in the physiological vitality of the racing camel and cost of treatment. The disease is transmitted mechanically from camel to camel by biting flies, notably Tabanus species, Haematopota and Pangonia. The disease can attack camel at any stage of its life and repeat infections are common. Trypanosomosis in camels usually occurs in chronic form but may be acute when the animal is under stress, particularly in racing camels and during lactation and pregnancy. The disease is CHARacterized by intermittent fever, progressive anemia, edema of dependent parts of the body, dullness, listlessness, loss of body condition, despite a good appetite, abortion, nasal and ocular discharges, nervous signs and death. The suppressive effects on the immune system of infected camels also become susceptible to other diseases, especially Clostridium perfringens type C infection. Anaemia and edema appears to be a major component of the pathology of surra. The hematological and blood biochemistry parameters of infected camels are decrease in erythrocytes, an increase in lymphocyte, neutrophils, esonophils and monocytes, hyperproteinemia, hyperglobulinemia, hypoglycemia, serum urea increased, serum iron Abdulwahhab Al-Juboori .et.al., 430 decreased and increase in the levels of serum enzymes (AST, ALT, GOT and LDH). Card agglutination test, antigen enzyme linked immunosorbent assay and polymerase chain reaction have been found most sensitive and specific for the diagnosis of trypanosomiasis. For treatment, quinapyramine salts and melarsenoxyde (Cymelarsan) are very effective and widely used for curative and prophylactic purposes, respectively. Preventive measures before the onset of the disease (Chemoprophylaxis) and curative measures after the disease is clinically evident (Chemotherapy) have shown varying success in controlling and combating the disease.

A review of the genus Tabanus Linnaeus, 1758 (Diptera: Tabanidae) from Egypt.

The Egyptian fauna of the genus Tabanus Linnaeus is reviewed. Only seventeen species are recognized instead of the previous 21. This is because six species have been removed as doubtful records, and an additional two species have been added (T. leucostonus Loew, 1858 (new record) and T. arenivagus Austen, 1920). A key to Egyptian species of Tabanus is included together with illustrations. Specimens examined and distributions are given for each species. The status of the six species doubtful to occur in Egypt is discussed.

Synergism between ammonia and phenols for Hybomitra tabanids in northern and temperate Canada

Baits for tabanids (Diptera: Tabanidae) were tested in the Northwest Territories (60 °N) and Ontario (45 °N) using Nzi traps. Tests targeted ammonia, phenols/cow urine and octenol. About 200 000 tabanids were captured in 15 experiments with a maximum capture of 4182 in one trap in 1 day. In the Northwest Territories, phenols, urine and octenol were effective single baits for only some species. At both locations, adding ammonia to an unbaited or an octenol-baited trap had no effect on catches. By contrast, catches were increased for several species when ammonia was combined with phenols or urine. In Ontario, including ammonia in various baits increased catches by 1.5- to 3.4-fold relative to octenol alone for three Hybomitra and one Tabanus species. Synergism between ammonia and phenols was clearly demonstrated for the dominant Hybomitra species in Ontario (Hybomitra lasiophthalma), but not for the dominant species in the Northwest Territories (Hybomitra epistates). In five other northern Hybomitra species, baits of ammonia and/or octenol in combination with phenols resulted in a 1.7- to 4.1-fold increase in catch relative to an unbaited trap. Further tests of ammonia as a synergist for biting flies may prove useful in, for example, tsetse, which respond strongly to phenols.

Molecular identification of Anaplasma marginale and rickettsial endosymbionts in blood-sucking flies (Diptera: Tabanidae, Muscidae) and hard ticks (Acari: Ixodidae)

In an attempt to identify the main vector and possible transmission routes of Anaplasma spp. in a region of Hungary with high prevalence of ovine and bovine anaplasmosis, DNA was extracted from 316 haematophagous arthropods (individually or in pools), including 4 species of ixodid ticks, 6 species of tabanid flies and hornflies. Midichloria-like organisms were identified with PCR (amplifying a portion of the 16S rRNA gene) and sequencing from Dermacentor marginatus and Ixodes ricinus. Significantly higher 16S positive D. marginatus individuals were collected in March than in April, suggesting earlier questing of ticks that contain rickettsial agents (thus endosymbionts). Midichloria- and Wolbachia-like organisms were also found in randomly caught horse flies ( Tabanus bovinus and T. tergestinus) as well as hornflies ( Haematobia irritans), respectively, with 97–99% similarity to sequences deposited in the GenBank. Although all ticks were negative in the Anaplasma spp.-specific msp4 PCR, four individuals of T. bovinus collected near to grazing cattle were positive for Anaplasma marginale. The results of the present study provide the first molecular evidence for the potential mechanical vector role of T. bovinus in the transmission of A. marginale, and broaden the range of haematophagous arthropods harbouring Midichloria-like bacteria, for the first time in any Dermacentor or Tabanus species.

Notes on Tabanidae (Diptera) that are Surra vectors or pestiferous with description of a new species of Tabanus from India

A new species of Tabanid fly, Tabanus hisarensis, sp. nov., collected from Hisar (Haryana) is described and illustrated. This is related to Tabanus sufis Jaennicke and Tabanus kurahashii Inaoka and Burger and is characterised by having a broad frons and transverse basal callosity. Notes on morphology, distribution and biology of Atylotus agrestis (Wiedemann), Atylotus virgo (Wiedemann), Haematopota roralis Fabricius, Tabanus dorsilinea Wiedemann, Tabanus rubidus Wiedemann, Tabanus striatus Fabricius and Tabanus triceps Thunberg are also given. These species are common blood feeding pests of horses, mules, cattles, camels and other livestock and some of them (A. agrestis, T. dorsilinea, T. rubidus, T. striatus) are proven vectors of Surra disease of livestock in India.

Evaluation of Pyrethroid Ear Tag and Spray Treatment of Cattle Against Horse Flies (Diptera: Tabanidae)

Permethrin and fenvalerate ear tags, and fenvalerate sprays (0.01 and 0.02%) were evaluated against tabanids under field conditions in Louisiana. Residual concentration of insecticide in the hair from the head, side, back, abdomen, front and back legs of steers was measured after each fly collection period by gas chromatography. Mortality rates were reported relative to the feeding pattern of species of tabanids studied and insecticide concentration of different body regions. A total of 2,922 females belonging to three Tabanus species were collected. Mortality rates were 3% in controls, 9% in permethrin tag, 15% in fenvalerate tag, 67% in 0.01% fenvalerate spray and 79% in 0.02% fenvalerate spray treatments.

TOXICITY OF FENVALERATE TO FIVE UNFED SPECIES OF TABANIDS AND ENGORGED TABANUS FUSCICOSTATUS HINE (DIPTERA: TABANIDAE)

The toxicity of topically applied fenvalerate for five Tabanus species was determined on a per fly and per weight basis. The LD50's ranged from 0.0086 to 0.0816 μg/fly for Tabanus fuscicostatus and T. americanus, respectively. The LD50's in μg/g fly weight ranged from 0.156 for T. americanus to 0.404 for T. pallidescens. Blood-engorged T. fuscicostatus were less susceptible to topical application of fenvalerate than unfed individuals.

Review of Tabanus Species (Diptera: Tabanidae) with Pilose and Patterned Eyes in Mexico and Western North America, and Descriptions of Two New Species from Mexico

Those Tabanus species from Mexico and western North America with pilose eyes bearing a colored pattern in life, and distinguished from species of Hybomitra are reviewed. Two new species of Tabanus, Tabanus selvaticus Burger, Bermudez & Bermudez, n. sp. from Hidalgo and Tabanus sierrensis Burger, Bermudez & Bermudez, n. sp. from Durango, are described. Four species are transferred to Tabanus from Hybomitra: burgeri (Philip), n. comb.; howdeni (Philip), n. comb.; mimus (Philip), n. comb.; and zancla (Philip), n. comb. T. mimus is found to be a senior synonym of Hybomitra aitkeni Philip, n. syn. One species, laticornis Hine, is reassigned to Tabanus from Hybomitra , pending additional study. Species treated in this study are placed into four groups based on shared external features of adults, and of larvae and pupae when known. A key to adult females is provided for the species discussed.

Mud Cylinders of Tabanidae (Diptera) from Texas

Last instars of four Afrotropical Tabanus species construct mud cylinders in which pupation occurs. This behavior is believed to ensure adult survival where mud in which these species develop becomes dry and cracked during dry seasons. Evidence of construction of mud cylinders by Tabanus atratus F. and possibly other species that construct similar mud cylinders is described from Texas. Differences between, and possible explanations for, the construction of Afrotropical and Texas mud cylinders are discussed.

Sugar Feeding by Female Tabanids (Diptera: Tabanidae) and its Relation to Gonotrophic Activity

Developmental stages of terminal follicles and parity were determined for 1311 blood-seeking females of 17 Chrysops , 7 Hybomitra , and 7 Tabanus species in Connecticut during 1978 and 1979. Nulliparous individuals with stages I, I–II, or 11 follicles were observed in 29 species; nulliparity (n ≥ 50 dissections) ranged from 28.7% of 181 Hybomitra lasiophthalma to 90% of 160 Chrysops vittatus . Anautogeny prevails in inland populations of tabanids at this locality. Cold anthrone reagent detected fructose and/or sucrose in 71% of 799 nulliparous and in 72.3% of 512 parous specimens. Prevalence of sugar-positive females (n ≥ 24 tested) ranged from 58% in H. sodalis to 92% in C. cincticornis . In an additional 366 tabanids analyzed by thin-layer chromatography, 55.9% of 345 positives had glucose, fructose, and sucrose, 38.3% contained glucose and fructose, and 5.8% showed glucose alone. Of the 1677 females tested by either method, 72.9% contained fructose and/or sucrose. Results indicate extensive feedings on sugars and suggest that these carbohydrates are essential dietary nutrients.

FURTHER LARVAE AND PUPAE OF EASTERN NORTH AMERICAN TABANIDAE (DIPTERA)

AbstractLarvae and pupae of eight species of Tabanidae are described: Chrysops sequax Williston, Hybomitra cincta (Fabricius), H. longiglossa (Philip), H. microcephala (Osten Sacken), H. daeckei (Hine), Tabanus novaescotiae Macquart, T. colon Thunberg, and T. wiedemanni Osten Sacken. A key is provided for identification of nine of the 10 species of Tabanus currently known to possess a stigmatal spine.