Horse Fly Species Research Articles

Long‐proboscid horseflies (Philoliche: Tabanidae) as pollinators of co‐adapted plants in Africa and Asia

AbstractElongated nectar‐feeding mouthparts have evolved in several fly families, most notably Nemestrinidae, Bombylidae and Tabanidae. Plants pollinated by these “long‐proboscid flies” tend to have relatively specialized pollination systems. In this review, I focus on the blood‐ and nectar‐feeding horsefly genus Philoliche (Tabanidae: Pangoniinae) which includes species that are important pollinators of plants in Africa and, to a lesser extent, in Asia. The nectar‐feeding mouthparts of flower‐visiting Philoliche species range from 5 to 65 mm in length, with considerable intraspecific variation evident in some taxa. Plants pollinated by Philoliche species tend to have corolla tubes (or highly exerted reproductive structures) that match the proboscis dimensions of their pollinators. Some Philoliche species and their nectar host plants show population‐level covariation in proboscis lengths and flower depths that is indicative of co‐adaptation. I summarize existing information on the distribution and morphology of Philoliche species known to pollinate flowers as well as the identity, morphology and nectar properties of plants pollinated by these insects. This survey identifies some Philoliche species as keystone pollinators. Distinct guilds of plants are adapted to different horsefly species in different geographical regions and are generally ecologically reliant on these insects, although some plant species share tabanid and nemestrinid pollinators that are functionally similar on account of convergent evolution of their proboscis dimensions. Lack of information about the larval biology, nectar host plants, fire ecology and dispersal distances of Philoliche species is the biggest challenge for the conservation of these specialized pollinators and the plants that depend on them.

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.

Diversity of horsefly fauna (Diptera: Tabanidae) of Bansko Hill

From 2018 to 2022, at 10 localities on Bansko Hill, 3,639 horseflies were sampled. Most specimens (3,404) were sampled in 2022 in the period from mid-May to mid-September. The horseflies sampled are classified into two subfamilies, six genera and 19 species. The species Hybomitra ukrainica (Olsufjev, 1952), Tabanus miki Brauer in Brauer and Bergenstamm, 1880, Haematopota grandis Meigen, 1820 and Haematopota pandazisi (Kröber, 1936) are new finds of horsefly species for the studied area. The species Tabanus tergestinus Egger, 1859 is the most abundant species and makes up 71.11% of the horseflies sampled. The species Tabanus bromius L., 1758 followed with 10.16% of the abundance, Tabanus sudeticus Zeller, 1842 with 8.82% and Atylotus loewianus (Villeneuve, 1920) with 5.74% of the horseflies sampled, while 15 other species of horseflies were represented by the remaining 4.17%. In the collected sample, male horseflies accounted for 51.71% of the sample; all of them were sampled with an oil liquid trap. The largest number of horseflies (84.14%) were sampled in localities on the northeastern side of Bansko Hill, covered with forest vegetation of secondary origin. Three species, T. bromius, T. tergestinus and Heptatoma pellucens, (Fabricius, 1776) have the longest flight period, from mid-May to mid-September. The highest peaks of abundance for T. tergestinus, T. bromius, and T. sudeticus were recorded in July, for H. pellucens in June and for A. loewianus in August. The greatest similarity in horsefly fauna (85.71%) was recorded in the localities Popovac and Karanac. 90.98% of horseflies were collected by liquid oil traps, followed by sticky traps (5.22%) and canopy traps (3.79%). Data from earlier studies from 2011 and data from the current studies in the area of Bansko Hill have yielded records of 22 species of horsefly.

The Tabanidae (Diptera) of the Greek islands and Cyprus: An annotated checklist with remarks on ecology, zoogeography, and new records on the East Mediterranean fauna

The horse-fly fauna of the East Mediterranean is poorly known and, in some geographical areas, has not been studied for decades. The present study summarizes the results of tabanid collections performed over 30 years in the Greek islands (the Cyclades, Dodecanese, North Aegean and Crete) and Cyprus. In total, 18 species were known from the study territory. The present study reports an additional 10 species. Previously, only 1 horsefly species was known from the Dodecanese islands, 1 from the North Aegean islands, and 2 from the Cyclades. This study has raised the number of species to 6, 7, and 9, respectively. The combined taxa for the three island groups have increased from 4 to 17 species. Specifically, the number of species has increased from 3 to 7 in Crete and from 11 to 19 in Cyprus. Additionally, we report 1 new record from the Greek mainland, 1 from the Levantine region, 2 from Lebanon, and 2 from Israel. Four Afrotropical–Palearctic vector species: Atylotus agrestis (Wiedemann, 1828); Tabanus gratus Löw, 1858b; Tabanus sufis Jaennicke, 1867; and Tabanus taeniola Palisot de Beauvois, 1806; are recorded for the first time from Cyprus, and A. agrestis from southern Italy. Their status as invasive species in Europe is discussed, the four species are illustrated.

The impact of climate changes on the ranges of invertebrates (Diptera, Molluska) in Tavush province of Armenia

Aim. The work’s aim is to study the species composition of invertebrates (Insecta, Molluska) of the Tavush province of Armenia and changes of their ranges due to climatic conditions.Material and Methods. Our own collections of 2021–2022 from different areas of the Tavush province and the collections of invertebrates of the Scientific Centre of Zoology and Hydroecology served as study material. The collection and identification of dipterous insects and mollusks was carried out according to generally accepted methods. The work was performed at the Scientific Centre of Zoology and Hydroecology The scientific material is stored in the collection fund of the Scientific Centre.Results. As a result of our studies of invertebrate species composition, 28 species of horseflies (Tabanidae) are currently listed for the Tavush region: 27 species of phytophagous gall midges (Cecidomyiidae) and 10 species of mollusks. As a result of warming climate change new changes of locality have been registered for: 6 horsefly species S. (N.) caucasicus, Ch. (H.) f. flavipes, Ch. ludens, T. unifasciatus, T. indrae vappa, T. miki; 4 phytophagous gall midge species A. verbasci, D. tortrix, S. euphorbiae, R. terminalis; For one species of mollusk, H. buchi, there are new localities. All these species have expanded their habitat: in horseflies, changes in the range along vertical zonality are observed.Conclusions. As a result of this research, it was revealed that as a consequences of climate change, the ranges of some species of invertebrates – horseflies, gall midges‐phytophages and mollusks – have expanded compared to the data of previous years. All species in which there is a direct dependence of range change on climatic conditions can be further considered as bioindicators of climate change.

The horseflies fauna diversity (Diptera: Tabanidae) in the habitats along the Mura river in Međimurje, Croatia

From May to September 2022, in the habitats along the Mura River, 1295 horseflies were sampled, classified into two subfamilies, six genera, and 21 species. Seven new records of horseflies were recorded for the first time in the researched area. Newly recorded species are: Tabanus bovinus, Tabanus cordiger, Tabanus sudeticus, Heptatoma pellucens, Haematopota italica, Haematopota scutellata, Haematopota subcylindrica. The species Haematopota pluvialis is the most abundant species, accounting for 60.07% of all sampled horseflies. Tabanus bromius followed with 21.23%, while the other 19 horseflies account for 18.7%. 18 species of horseflies belonged to the boreal-Eurasian type of fauna, two belonged to the Mediterranean type of fauna, i.e. the southern European subtype, while one species belonged to the Afro-Eurasian-arid type of fauna. In the collected sample of horseflies, 33 males classified into 10 species were recorded, while all other collected horseflies were females (1262 specimens) classified into 20 species. The greatest similarity of the horseflies fauna was recorded between the localities Križovec and Goričan, 81.81%. 17 species of horseflies were sampled with a modified Manitoba trap (the so-called canopy trap), and 14 species were sampled with an oil or liquid trap. The largest number of horsefly specimens (59.07%) was sampled in the month of July, while the least horseflies were sampled in September (0.15%). The most abundant species, Tabanus bromius and Haematopota pluvialis, recorded their highest peaks of abundance in July. The longest flight period lasting five months (from May to September) was recorded only for Haematopota pluvialis. Tabanus bromius was represented in all 11 localities, while the species Haematopota pluvialis was represented in 10 localities, as well as the species Chrysops viduatus. Based on the earlier research conducted in 2011 and current research of the horseflies fauna along the Mura river in Međimurje, 22 taxa of horseflies (21 species and 1 subspecies) classified into six genera were identified.

Molecular of Anaplasma marginale Theiler (Rickettsiales: Anaplasmataceae) in horseflies (Diptera: Tabanidae) in Uruguay

Anaplasma marginale is transmitted biologically by infected ticks or mechanically by biting flies and contaminated fomites. In tick-free areas, such as southern Uruguay, horseflies could be the principal vectors of this pathogen for bovines, causing anaplasmosis. The objective of this work was to detect the presence of A. marginale by MSP-5 PCR and Sanger sequencing in the most prevalent species of horseflies obtained using different collection methods in Colonia, Tacuarembó and Paysandú, Uruguay. Eight horsefly species were tested (Dasybasis missionum, Poeciloderas lindneri, Tabanus campestris, T. claripennis, T. fuscofasciatus, T. platensis, T. tacuaremboensis and T. triangulum); four species were found to be positive for A. marginale, with D. missionum and P. lindneri having the most frequent infections, while only one individual each of T. fuscofasciatus and T. tacuaremboensis was positive. Both D. missionum and P. lindneri were positive for A. marginale in tick-free areas, and the implications are discussed in this report.

Tabanidae (Diptera) captured on horses in Amazon Forest fragments of the state of Rondônia, Brazil

Tabanidae is one of the most diverse families of hematophagous dipterans. Tabanids, in general, are mechanical vectors of some pathogens. Given the vector importance and the lack of knowledge of the tabanid fauna in horses in Amazon Forest fragments of the state of Rondônia, this work aimed to determine the season that the different species of horse flies prefer to carryout hematophagy on horses and verify whether the horse fly community remains the same throughout the year. The sampling areas for tabanid captures were in the municipality of Monte Negro, Western Amazon, Brazil. Four new occurrences were recorded for the state of Rondônia: Stenotabanus albilinearis, Tabanus fuscofasciatus, T. macquarti and T. restrepoensis, which increases the number of species for the state to 109. The horse flies were most frequently collected on the hind leg (43.15%) and front leg (31.11%), followed by the belly (7.41%) and the ear (5.18%). In the other anatomical regions, the collection frequency was 13.15% of the remaining individuals.

DNA barcoding of the horsefly fauna (Diptera, Tabanidae) of Croatia with notes on the morphology and taxonomy of selected species from Chrysopsinae and Tabaninae

In the Croatian fauna, horseflies (Tabanidae) are represented by 78 species belonging to two subfamilies, five tribes, and 10 genera. Identification of these species is based on morphological characteristics. In this study, 43 species of horseflies were analyzed. The highest number of species (19) belongs to the genus Tabanus, followed by the genera Hybomitra with seven species, Haematopota with six species, Chrysops with four species, Atylotus and Philipomyia with two species each, and the genera Silvius, Dasyrhamphis, and Heptatoma with one species each. The standard DNA barcoding region of the mitochondrial cytochrome c oxidase gene, subunit I (COI), was sequenced and compared to the Barcode of Life Database (BOLD). Our analyses confirmed our morphological identifications and added 16 new Barcode Index Numbers (BINs) for Tabanidae to BOLD. Potential problems in the systematics and taxonomy of this family are highlighted.

Forest fragments, primary and secondary forests harbour similar arthropod assemblages after 40 years of landscape regeneration in the Central Amazon

Abstract Large‐scale deforestation leads to habitat loss and fragmentation with major consequences for biodiversity. However, the impacts of these environmental disturbances can be mitigated by forest regeneration. We evaluated the effects of forest fragmentation and vegetation recovery on arthropod assemblages in human‐modified landscapes in the Amazon. Arthropods were sampled in 10‐ha forest fragments, continuous primary forests, and secondary forests using Malaise traps. We identified arthropods in multiple taxonomic resolutions from order to species. We collected 25,230 arthropods belonging to 17 orders. Coleoptera and Hemiptera were more abundant in secondary forests compared to other habitats. A dipteran family (Clusiidae) and a horse fly species (Dichelacera cervicornis—Tabanidae) were identified as indicators of forest fragments and continuous forests, respectively. Similar levels of taxonomic diversity between habitats were documented. The taxonomic composition also was similar between studied habitats in all taxonomic resolutions. Although the studied landscapes suffered strong environmental disturbances four decades ago, the vegetation has been in continuous regeneration since then, favouring the dispersal of arthropods throughout habitats. Forest fragments and old secondary forests contribute to the maintenance of a rich and diverse arthropod assemblage in landscapes composed of large tracts of continuous primary forests.

The Effectiveness of Malaise Traps, H-Traps, and Sticky Traps for Collecting Horseflies (Diptera: Tabanidae)

The Effectiveness of Malaise Traps, H-Traps, and Sticky Traps for Collecting Horseflies (Diptera: Tabanidae)

Molecular Detection of Trypanosoma kaiowa in Tabanus triangulum (Diptera: Tabanidae) from the Coastal Plain of Rio Grande do Sul, Southern Brazil

The species of the genus Trypanosoma are carried and transmitted by horseflies parasitizing a high diversity of vertebrates. In the Coastal Plain of Rio Grande do Sul, southern Brazil, Tabanus triangulum is the most abundant species and, similarly to the other species of horseflies, there is little knowledge about its vector competence. Therefore, this study aimed to screen the field-collected T. triangulum for the presence of Trypanosoma, to estimate infectivity. Horseflies were sampled by the Malaise trap in the forest fragments at the coastal plain and DNA was extracted from whole body flies. The Polymerase Chain Reaction was performed. Horseflies presented amplification of 18S ribosomal gene-specific of Trypanosoma species. DNA sequencing and phylogenetic analysis positioned the strains in the Kaiowa clade with Trypanosoma kaiowa, associated with the crocodilian clade of Trypanosoma. This study represents the first report of the presence of the Tr. kaiowa in T. triangulum and the expansion of the parasite's range further south in South America.

FAUNAL REVIEW OF HORSEFLIES OF THE AKMOLA REGION

Data on the species composition and ecology of horseflies in the study area are presented. The habitation of horseflies belong to five genera has been established. 25 species of horseflies were identified in the study area. Under favorable climatic conditions, there is an increase in the number of horseflies. The terms of activity and number of horseflies on pastures of cattle and horses were studied.

Seasonal Dynamics of Activity of Horseflies (Diptera, Tabanidae) in Pskov Province

We studied the seasonal dynamics of flight activity in horseflies (Diptera, Tabanidae) belonging to 30 species from 6 genera. The results show that the abundance of horseflies is largely controlled by abiotic factors, such as temperature and relative humidity. Horseflies start their flight activity at an air temperature not lower than +15°C and relative humidity not lower than 57%. There are species-specific differences in the seasonal pattern of activity. Depending on the season when activity commences, the horseflies studied can be divided into spring species (end of May), early summer species (beginning of June), and summer species (beginning of July). We attribute this variation in the timing of adult emergence to different temperature and humidity optima for larval and pupal development in different horsefly species. A routine is proposed for estimating the long-term seasonal dynamics of flight activity of horseflies with the use of weekly and monthly mean temperatures, relative air humidity, and the sum of degree-days. In a similar manner, the flight activity pattern can be projected into the future.

Incompletely observed: niche estimation for six frequent European horsefly species (Diptera, Tabanoidea, Tabanidae)

BackgroundMore than 170 species of tabanids are known in Europe, with many occurring only in limited areas or having become very rare in the last decades. They continue to spread various diseases in animals and are responsible for livestock losses in developing countries. The current monitoring and recording of horseflies is mainly conducted throughout central Europe, with varying degrees of frequency depending on the country. To the detriment of tabanid research, little cooperation exists between western European and Eurasian countries.MethodsFor these reasons, we have compiled available sources in order to generate as complete a dataset as possible of six horsefly species common in Europe. We chose Haematopota pluvialis, Chrysops relictus, C. caecutiens, Tabanus bromius, T. bovinus and T. sudeticus as ubiquitous and abundant species within Europe. The aim of this study is to estimate the distribution, land cover usage and niches of these species. We used a surface-range envelope (SRE) model in accordance with our hypothesis of an underestimated distribution based on Eurocentric monitoring regimes.ResultsOur results show that all six species have a wide range in Eurasia, have a broad climatic niche and can therefore be considered as widespread generalists. Areas with modelled habitat suitability cover the observed distribution and go far beyond these. This supports our assumption that the current state of tabanid monitoring and the recorded distribution significantly underestimates the actual distribution. Our results show that the species can withstand extreme weather and climatic conditions and can be found in areas with only a few frost-free months per year. Additionally, our results reveal that species prefer certain land-cover environments and avoid other land-cover types.ConclusionsThe SRE model is an effective tool to calculate the distribution of species that are well monitored in some areas but poorly in others. Our results support the hypothesis that the available distribution data underestimate the actual distribution of the surveyed species.

Diversity and seasonality of horse flies (Diptera: Tabanidae) in Uruguay

Horse flies (Diptera: Tabanidae) cause direct and indirect losses in livestock production and are important vectors of pathogens. The aim of this study was to determine the diversity and seasonality of horse fly species at an experimental farm in Tacuarembó and the diversity of species in different departments of Uruguay. For 20 months, systematic collections were performed in two different environments at the experimental farm using Nzi and Malaise traps. In addition, nonsystematic collections were performed at farms located in the departments of Paysandú, Tacuarembó and Colonia. A total of 3,666 horse flies were collected, and 16 species were identified. These species included three species that had not been previously recorded in Uruguay, namely, Dasybasis ornatissima (Brèthes), Dasybasis missionum (Macquart), and Tabanus aff. platensis Brèthes, and a species that had not been previously taxonomically described (Tabanus sp.1). Among the systematically captured samples, the most abundant species were Tabanus campestris Brèthes, T. aff. platensis and D. missionum, representing 77.6% of the collected specimens. The horse fly season in Tacuarembó started in September and ended in May. No horse flies were caught during winter. Variations in the prevalences of species in the different departments were observed, which indicates the need for new sampling efforts.

Horse flies (Diptera: Tabanidae) collected in Central African Republic, Gabon and Liberia with comments on their updated distribution

Abstract A zoogeographical review summarized the current distribution of 28 morphologically determined horse fly species recently collected in three Western Africa countries. In Malaise trap collections, the family Tabanidae was represented by three subfamilies, Pangoniinae, Chrysopsinae and Tabaninae (tribes Philolichini, Chrysopsini, Tabanini and Haematopotini), and six genera: Philoliche Wiedemann, 1828 (1 species), Chrysops Meigen, 1803 (3 specis), Ancala Enderlein, 1922 (2 species), Euancala Enderlein, 1922 (1 species), Tabanus Linnaeus, 1758 (13 species) and Haematopota Meigen, 1803 (8 species). Information contained in the principal publication The Catalogue of the Diptera of the Afrotropical Region 1980 is complemented by newly published studies on horse flies in Sub-Saharan Africa.

Current fauna of parasitic flies of Yamalo-Nenets Autonomous Region

The fauna of blood-sicking two-winged insects of the Yamalo-Nenets Autonomous District is represented by 116 species. Hybomitra aequetincta, H. arpadi, H. lundbecki, H. nitidifrons nitidifrons, H. nitidifrons confiformis, Hybomitra astur. Thus, the fauna of gadflies of the district is represented by 26 species and 2 subspecies, and 16 species and 1 subspecies are known as potential carriers of dangerous diseases of humans and animals. The faunal list of mosquitoes of the region is represented by 29 species, incl. Replenished with 2 species -O. nigrinus and O. behningi, 24 species of midges, incl. 1-Simulium paramorsitans, biting midges with 33 species, incl. 1 species -Culicoides punctatus. This species was first indicated both for the tundra zone and for the region. The dominant species of horseflies were H. aequetincta and H. arpadi with an EID of 27.3%. Among the 12 registered species of mosquitoes, O. communis (ID 29%) prevailed in the Yamal District (ID 29%), and O. hexodontus in the Tazovsky District. (EID 29.4%). Among the identified species of midges, Simulium paramorsitans dominated in numbers, in the Yamal region with an ID of 80.7%, and in the Tazovsky region -90.5%. In the tundra in the south of the Yamal region, during the mass flight, up to 500 individuals of mosquitoes were simultaneously attacked by an average of 4598 individuals by the maximum data recorded. In the more northern point of the region, Bovanenkovo, the number of mosquitoes during this period was 270 individuals according to the average registration data, at a wind speed of 10 m/s. In the Tazovsky district, 46 female mosquitoes simultaneously attacked a man at a time, and 26 deer at a time. In the more northern part of the region - in Bovanenkovo, the number of midges according to the average data was 70 individuals, while the wind speed at the time of the survey reached 10 m / s, and for the midges this wind is a serious obstacle for active summer. In the Tazovsky district during this period, the number of midges was significantly lower and amounted to 131 individuals, according to the maximum data for recording per person and 56 individuals - per deer. The maximum number of biting midges (C. punctatus, up to 130 individuals registered for 5 minutes) was observed over the Arctic Circle in Yar-Sale in late August. The main component of the midges, the most disturbing reindeer in the tundra zone, are mosquitoes, and in some periods - midges. When studying the distribution of dedemagena tarandi under the conditions of the subarctic tundra of the Tazovsky region in 2018, the reindeer extensinvasiveness averaged 66.7 ± 1.6% with an invasion intensity of 9.4 ± 1.2 larvae. In the Priuralsky and Yamalsky districts, on average, the deer incidence of pathogens of edema nausea is slightly lower -34.6 and 28.8% by extension, with an invasion intensity of 9.4 ± 1.6 and 8.6 ± 1.2 larvae, respectively, in our opinion, due to the massive conduct of early chemotherapy. However, the invasion of deer that did not undergo therapeutic measures remains high - up to 100%, with AI - 18.5 ± 1.7 larvae. The release of larvae to pupation in 2018 was observed in August, which was not recorded in the literature. Thus, the first insects appeared near deer from 6.30-7 hours, and the last at 21 hours. From the second half of August, insect activity was noted from 9.30-11 am (the peak of activity was at 13-14 o'clock and at 16-18 h, respectively). The highest activity and the number of gadflies is observed at illumination of 45-90 thousand lux and a temperature of 18-28 C. In the days of high activity and abundance, more than 10 female gadflies attacked the control deer in a 30-minute count. Early education (III decade of November - I decade of December) on the skins of fistulas and a significant amount of larvae of II age attract attention, which, in our opinion, can also be associated with a change in climatic conditions.