Tabanid Flies (Diptera: Tabanidae) of the Northern Part of Gyeonggi Province, Republic of Korea

Tabanid flies were surveyed using New Jersey light traps and Mosquito Magnet® traps at US Army installations and training sites in the northern part of Gyeonggi Province, Republic of Korea. A total of 344 tabanid flies, comprising 14 species and 5 genera, were collected from June to August during 2003‐2004. Dominant species were Chrysops vanderwulpi (57.3%), Haematopota sinensis (29.1%), Haematopota koryoensis (4.4%) and Tabanus mandarinus (2.3%). Mosquito Magnet traps that generated CO₂through the combustion of propane gas were nearly 6 times more effective in collecting tabanid flies than New Jersey light traps. Based on Mosquito Magnet trap collections, peak populations occurred from mid‐June to early July.;     

Meteorological effects on the daily activity patterns of tabanid biting flies in northern Queensland,Australia

Information on the daily activity patterns of tabanid flies is important in the development of strategies that decrease the risk of pathogens transmitted by them. In addition, this information is useful to maximize numbers of tabanids trapped during short‐term studies and to target feeding behavior studies of certain tabanid species to their times of peak activity. The current study examined the effects of various meteorological factors on the daily activity patterns of common tropical species of tabanids in north Queensland. Each species studied responded differently to weather factors. Tabanus townsvilli Ricardo (Diptera: Tabanidae) was most active during late morning and early afternoon, whereas Pseudotabanus silvester (Bergroth) and Tabanus pallipennis Macquart were most active in the late afternoon. Tabanus dorsobimaculatus Macquart was most active in the morning and early afternoon. Data on daily activity patterns of tabanid flies indicates that in an area such as Townsville, North Queensland, where several species of tabanid are present concurrently in high numbers, the overlapping periods of high activity for these species indicate a high risk of pathogen transmission for most of the day (10.00–19.00 hours). Similarly, because each species responds differently to weather variables, only extreme weather conditions are likely to inhibit activity of all species. These data also indicate that for maximal results, trapping and feeding behavior studies should be tailored to the preferred activity period of the species under investigation.     

A comparison of trapping methods for Tabanidae (Diptera) in North Queensland, Australia

The ability to monitor the abundance and diversity of tabanid flies over wide areas requires effective and low-cost surveillance methods. Such monitoring activities help to quantify the risk of transmission of pathogens by tabanids. Here we examine the effectiveness and practicality of two types of trap (canopy traps and Nzi traps) and two types of attractant (octenol and carbon dioxide) for monitoring tabanid flies in tropical Australia. The Nzi trap consistently caught more tabanids and more species of tabanids than the canopy trap. It was also more robust and therefore required less maintenance in remote locations. The use of attractants substantially increased capture rates, both of individuals and species, and traps using both attractants were consistently the most effective. However, in remote locations, where it is not possible to check traps frequently, the use of attractants may not be feasible. When attractants were not used, the canopy trap caught very few tabanids, but the Nzi trap remained effective enough to be useful as a monitoring device. In addition, the number of tabanid species caught by the Nzi traps remained high, and included those that were most abundant. We therefore conclude that, in this region, Nzi traps are preferable for tabanid monitoring and that attractants greatly improve their effectiveness. However, for longterm monitoring, especially in remote locations, Nzi traps without attractants are a satisfactory option.     

Use of odour-baited sticky boards to trap tabanid flies and investigate repellents

Tabanid flies were captured in a sheep pasture in Hungary using black plastic boards (30 × 30 cm), coated with an adhesive sheet, which were either unbaited or baited with ethane-ethiol or Swormlure-4. Five species of tabanid were caught, of which Tabanus tergestinus was caught in the greatest number (87% of 192). The sex ratio of T. tergestinus on unbaited boards was not statistically significantly different to equality. However, on baited boards, males were significantly more numerous, probably due to a repellent effect of the odours on female tabanids. Because of the importance of repellents in tabanid control, this result encourages the exploration of a wider range of compounds as tabanid repellents than are used at present. Sticky boards offer a simple technique for trapping both sexes of tabanids, especially males, which are poorly represented in many tabanid traps.     

Seasonal succession of tabanid species in equine infectious anaemia endemic areas of Italy

Equine infectious anaemia (EIA) is a disease with an almost worldwide distribution, with several outbreaks having been reported recently in European countries. In Italy, two regions, Lazio and Abruzzo, are considered as endemic areas for this disease. In nature, the EIA virus is mechanically transmitted by biting flies such as tabanids (Diptera: Tabanidae), although few studies have investigated the epidemiological implications. In the present study, several sites characterized by different levels of EIA prevalence were sampled. In sites with high tabanid populations, a seasonal succession of tabanid species with a dual‐peak corresponding to early active species (i.e. in June to July) and late active species (i.e. in August to September) was clearly observed. Moreover, a positive correlation was found between EIA prevalence and tabanid abundance and species richness, suggesting that tabanid diversity might extend the duration of the seasonal transmission period of EIA. Further observations are required to better assess how vector diversity influence EIA transmission.     

Comparative epidemiology of Dipofilaria roemeri infection in two regions of Queensland

The occurrence of Dirofilaria roemeri in definitive and intermediate hosts in two separate areas in southeast Queensland, is compared. The presence of D. roemeri in a macropod species in a defined region is determined by both the geographic distribution and the biting behaviour of those species of tabanid fly which are capable of acting as intermediate host. The seasonal succession and seasonal abundance of 4 tabanid species at Durakai and 8 tabanid species at Allan are responsible for a seasonal pattern of transmission of this filarioid. Moderate to low levels of transmission occur from November through March. Maximum transmission occurs in April associated with the peak in population of Dasybasis hebes, the most important tabanid involved in transmission of D. roemeri in both areas. Findings indicate that the wallaroo is the source of infection for tabanid flies and acts as the reservoir of infection for grey kangaroos and red-necked wallabies, in southeast Queensland. Transmission of D. roemeri is discussed in the light of behavioural interactions between definitive and intermediate hosts.     

Simplified media for spiroplasmas associated with tabanid flies

Traditionally, isolation, maintenance, and testing of Spiroplasma species (Mollicutes: Entomoplasmatales) from horse flies (Tabanus spp.) and deer flies (Chrysops spp.) (Diptera: Tabanidae) have been accomplished in the complex M1D medium. A relatively inexpensive, simplified medium for tabanid spiroplasmas could expedite procedures that require large quantities of growth medium. Nine strains of spiroplasmas, eight from tabanids and one from mosquitoes, were cultured in three simplified broth media, R2, R8-1, and C-3G, and in M1D. There was no significant difference in the rate of spiroplasma growth in M1D and the three simplified media. R2 medium supported the growth of tabanid spiroplasmas more consistently and with better morphology through 10 subcultures than did the other simplified media. Primary isolations were made in R2 medium from tabanids collected (i) in Georgia, U.S.A., with 10 isolations from 10 flies and (ii) in coastal Costa Rica, with isolation rates of 70% (28/40) and 73% (27/37), respectively, for R2 and M1D. Of the seven group VIII field isolates from Costa Rica, four were capable of sustained growth in R2, and three were triply cloned in this simplified medium. These results suggest that the simplified medium R2 is suitable for many procedures with tabanid spiroplasmas.     

Seasonal abundance of horse flies (Diptera: Tabanidae) from two locations in eastern Croatia.

A total of 10,539 tabanid horse flies from 22 species and five genera was collected in the Tikves forest within the Kopacki rit Nature Park in eastern Croatia. Seasonal abundance was analyzed for the six most abundant species. Tabanus maculicornis, Tabanus tergestinus, and Haematopota pluvialis reached their highest peak abundance in the fourth week of June. Atylotus loewianus and Tabanus bromius reached their highest peak of abundance in the first week of August, whereas Tabanus sudeticus reached its maximum abundance in the third week of July. Horse flies also were collected once a week on the pasture at Petrijevci from mid-May to mid-September during 1993. Paired collections were made from a Malaise trap and from a horse by using a sweep net. A total of 2,867 tabanids belonging to 26 species was collected. The number of tabanids collected on horses was much higher than the total captured with Malaise traps. On their natural host (horse), 2.6 times more tabanids were collected than in the traps. Seasonal abundance was analyzed only for the eight most abundant species. Chrysops paralellogrammus, Tabanus autumnalis, Tabanus bromius, Tabanus tergestinus, Haematopota pluvialis, and Haematopota subcylindrica all reached their highest peak of abundance in the second week of July, whereas Tabanus maculicornis reached the maximal peak of abundance in the third week of June. Seasonal meteorological variability that occurs periodically from one year to another has a significant influence on the maximal peaks of tabanid abundance.     

Differences in Morphometry and Activity among Tabanid Fly Assemblages in an Andean Tropical Montane Cloud Forest: Indication of Altitudinal Migration?

Evidence suggests that variations along ecological gradients shape organism traits such as behavior or morphometry. We studied the effect of altitude on the flight activity of tropical tabanid fly assemblages of one species of Stypommisa Enderlein along a 1 km altitudinal gradient on the northwestern slopes of the Ecuadorian Andes. Our objectives were as follows: (1) to test the hypothesis that highland individuals present larger flight body structures; and (2) to compare the flight activity patterns of flies’ assemblages among altitudes and correlate it with weather factors. We sampled specimens in Malaise traps at 1180, 1680 and 2180 m of altitude from 0600 to 1830 h for 20 d at each site. Seven weather variables were measured every hour and flight activity was inferred from relative tabanid fly abundances/hour in traps. We measured morphometrical parameters that included tabanid fly body size, thorax volume, wing area and wing loading. Flight activity patterns revealed a bimodal distribution at 1680 m, and two asynchronous unimodal distributions, one at 1180 and one at 2180 m. GLM analyses revealed that temperature, mist and rainfall were the best predictors of fly activity differences among altitudes. Morphometrical analyses showed that body size and thorax volume increased with increasing altitude. Synchronous groups of flies at different altitudes (those between 1180–1680_(pm) m, and 1680_(am)–2180 m) were morphologically similar, suggesting that flies could be capable of migrating from highlands to lowlands at defined hours of the day depending on forest weather conditions.     

广州从化无规定马属动物疫病区和缓冲区病媒生物本底调查

为掌握广州从化无规定马属动物疫病区和缓冲区病媒生物的种类和分布,确保广州亚运马术比赛的顺利进行及从化无规定马属动物疫病区作为国内唯一获国际认可的"无疫区"在今后的正常运作和可持续发展,作者对该区域病媒生物进行了本底调查。本次调查共采集到吸血蚊类2698头,隶属1科4属5种;蝇类12788头,隶属4科17属28种;虻类161头,隶属1科3属6种;蠓类71头,隶属1科1属3种;蜱类743头,隶属1科1属1种。为控制这些病媒生物传播疾病的发生,应根据广州从化无规定马属动物疫病区和缓冲区病媒生物的分布特点和消长规律,定期开展病媒生物监测,及时掌握各种病媒生物的种群变化情况,并适时开展防虫除虫和控制检疫传染病的工作。     

Novel spirochetes isolated from mosquitoes and black flies in the Czech Republic

During the years 1999–2002, a total of 4,898 individuals of 26 species of hematophagous insects (4,149 mosquitoes, 583 black flies, and 166 tabanid flies) was examined for the presence of spirochetes using dark‐field microscopy. There was an overall recovery of spirochetes from the midguts of Culicidae and Simuliidae of 23.5% and 11.4%, respectively. Spirochetes were not detected in Tabanidae. Seven spirochetal strains have been successfully recovered from mosquitoes and black flies: BR149 (Culex pipiens), BR151 (Cx. pipiens), BR173 (Cx. pipiens), BR177 (Cx. pipiens), BR193 (Aedes cinereus), BR208 (Cx. pipiens), and BR231 (Simulium noelleri). The strains have been adapted to laboratory conditions (BSK‐H Complete medium). Their preliminary determination based on 16S rRNA gene sequencing has shown that they differ from the Lyme disease spirochete Borrelia burgdorferi sensu lato as well as other members of the Order Spirochaetales indicating novel bacterial species in the Family Spirochaetaceae.     

Performance of painted plywood and cloth Nzi traps relative to Manitoba and greenhead traps for tabanids and stable flies

Experiments were conducted to adapt the cloth Nzi trap to a format suitable for fixed applications in biting fly sampling or control. Catches of tabanids [Tabanus L., Chrysops (Meigen), and Hybomitra Enderlein], and stable flies [Stomoxys calcitrans (L.)] in painted plywood traps were compared with those in standard phthalogen blue cloth traps, and in similarly painted cloth traps. The Manitoba horse fly trap and the Tabanus nigrovittatus Macquart "greenhead" box trap were used as additional standards during one tabanid season. Shiny features of traps reduced catches, e.g., paint on cloth instead of wood, or use of aluminum screening instead of netting. Nevertheless, appropriately painted plywood Nzi traps caught as many biting flies as did standard cloth Nzi traps, if paint finishes were matte, and with the use of phthalogen blue colorants. Nzi traps collected about the same tabanid fauna as the Manitoba and T. nigrovittatus traps, but with improved catches of Chrysops and Tabanus. Recommendations are provided on appropriate color matching, and selection of readily-available materials for trap construction.     

Effectiveness and outlook for using attractants in controlling horseflies in pastures

The paper concerns the possibility of decreasing the number of tabanid flies on pastures by means of ball- and funnel-shaped traps (of the Manitoba type) with insecticides and expediency of using the above method for the cattle protection that prevents the milk productivity loss by 6.7 to 8.3%. In addition to the traps, a regular cattle dip with insecticides, which are most attracting for the whole complex of bloodsucking Diptera and zoophilous flies, offers promise in the control of tabanids.     

Anticoagulant activities in salivary glands of tabanid flies

Tabanid flies are telmophages (pool feeders), taking frequent and rapid bloodmeals from many different individual hosts. To investigate how they accomplish this intermittent feeding strategy, we examined the anticoagulant activities in salivary gland extracts (SGE) from 19 species representing six genera: Atylotus, Chrysops, Haematopota, Heptatoma, Hybomitra and Tabanus (Diptera: Tabanidae). Standard coagulation screen assays were used to determine thrombin time, prothrombin time and activated partial thromboplastin time. Chromogenic substrate assays were performed for thrombin and factor Xa activity. SGE of most species (except Chrysops spp.) considerably prolonged human plasma clotting time in a dose-dependent manner, and showed potent and specific antithrombin activity in the chromogenic substrate assay. Heptatoma pellucens displayed the strongest anticoagulant activity. Specific anti-factor Xa activity in tabanid SGE was not detected. Electrophoretic profiles of SGE proteins differed between genera and species. Overall, the results suggest that tabanids have evolved at least two antihaemostatic strategies.     

Molecular phylogeny of the horse flies: a framework for renewing tabanid taxonomy

Horse flies, family Tabanidae, are the most diverse family‐level clade of bloodsucking insects, but their phylogeny has never been thoroughly explored using molecular data. Most adult female Tabanidae feed on nectar and on the blood of various mammals. Traditional horse fly classification tends towards large heterogeneous taxa, which impede much‐needed taxonomic work. To guide renewed efforts in the systematics of horse flies and their relatives, we assembled a dataset of 110 exemplar species using nucleotide data from four genes—mitochondrial CO1, and nuclear 28S, CAD and AATS. All commonly recognized tribes in Tabanidae are represented, along with outgroups in Tabanomorpha. The phylogeny is reconstructed using Bayesian inference, and divergence times are estimated using Bayesian relaxed clock methods with time constraints from tabanid fossils. Our results show Athericidae strongly supported as the lineage most closely related to Tabanidae, and Pangoniinae and Tabaninae as monophyletic lineages. However, Chrysopsinae is nonmonophyletic, with strong support for both a nonmonophyletic Bouvieromyiini and for Rhinomyzini as sister to Tabaninae. Only the tribes Philolichini, Chrysopsini, Rhinomyzini and Haematopotini are recovered as monophyletic, although Scionini is monophyletic with exclusion of the peculiar genus Goniops Aldrich. Mycteromyia Philippi and Adersia Austen, two enigmatic genera sometimes placed in separate family‐level groups, are recovered inside Pangoniini and Chrysopsini, respectively. Several species‐rich genera are not recovered as monophyletic, including Esenbeckia Rondani, Silvius Meigen, Dasybasis Macquart and Tabanus L. Tabanidae likely originated in the Cretaceous, and all major extant groups were present by the early Palaeogene. This newly revised phylogenetic framework for Tabanidae forms the basis for a new assessment of tabanid diversification and provides context for understanding the evolution of trophic specialization in horse flies.     

Hyaluronidase activity in the salivary glands of tabanid flies

Tabanids are haematophagous insects that act as biological and mechanical vectors of various diseases, including viruses, bacteria and parasites. The saliva of these insects contains strong anticoagulant and vasodilatory activities as well as immunoregulatory peptides. Here we demonstrate pronounced hyaluronidase (hyase) activity in ten tabanid species of the genera Chrysops, Haematopota, Hybomitra and Tabanus. Compared to other haematophagous insects, the ability of tabanid hyases to hydrolyze hyaluronic acid (HA) is extremely high, for example the enzyme activity of Hybomitra muehlfeldi was found to be 32-fold higher than the salivary hyase activity of the sand fly Phlebotomus papatasi. Hyases of all ten tabanid species tested also cleaved chondroitin sulfate A, another glycosaminoglycan present in the extracellular matrix of vertebrates. The pH optimum of the enzyme activity was measured in eight tabanid species; the hyase of Haemopota pluvialis was the only one with optimum at pH 4.0, while in the other seven species the activity optimum was at 5.0. SDS PAGE zymography showed the monomeric character of the enzymes in all tabanid species tested. Under non-reducing conditions the activities were visible as single bands with estimated MW between 35 and 52 kDa. The very high hyaluronidase activity in tabanid saliva might be related to their aggressive biting behavior as well as to their high efficiency as mechanical vectors. As they are supposedly involved in the enlargement of feeding hematomas, hyases might contribute to the mechanical transmission of pathogens. Pathogens present in vector mouthparts are co-inoculated into the vertebrate host together with saliva and may benefit from increased tissue permeability and the immunomodulatory activity of the salivary hyase.     

Pollination of sevenPlectranthus spp. (Lamiaceae) in southern Natal, South Africa

The genusPlectranthus (Lamiaceae) shows remarkable radiation on the sandstones of southern Natal and northern Transkei in South Africa, where six endemic species occur. Two of these endemic species,P. hilliardiae andP. oribiensis, are included in this study, as well asP. reflexus, for which only limited data are available. The other species that were studied areP. ambiguus, P. ciliatus, P. ecklonii, P. madagascariensis andP. zuluensis. Four of these taxa,P. ambiguus, P. hilliardiae, P. reflexus andP. saccatus var.longitubus, have uniquely long corolla-tubes (20–30mm) and this is related to pollination by nemestrinid flies of the genusStenobasipteron that have proboscides of similar length. Other nemestrinid species of the genusProsoeca have shorter proboscides and pollinate two species ofPlectranthus with shorter corolla-tube lengths (6–15mm). Acrocerid flies, tabanid flies and anthophorid bees are also important visitors to these species. This study on the pollination of seven species of varying corolla-tube lengths shows a correlation between floral tube length and proboscis length of insect visitors, many of which are recorded for the first time as pollinators ofPlectranthus.     

Colour in the eyes of insects

Many insect species have darkly coloured eyes, but distinct colours or patterns are frequently featured. A number of exemplary cases of flies and butterflies are discussed to illustrate our present knowledge of the physical basis of eye colours, their functional background, and the implications for insect colour vision. The screening pigments in the pigment cells commonly determine the eye colour. The red screening pigments of fly eyes and the dorsal eye regions of dragonflies allow stray light to photochemically restore photoconverted visual pigments. A similar role is played by yellow pigment granules inside the photoreceptor cells which function as a light-controlling pupil. Most insect eyes contain black screening pigments which prevent stray light to produce background noise in the photoreceptors. The eyes of tabanid flies are marked by strong metallic colours, due to multilayers in the corneal facet lenses. The corneal multilayers in the gold-green eyes of the deer fly Chrysops relictus reduce the lens transmission in the orange-green, thus narrowing the sensitivity spectrum of photoreceptors having a green absorbing rhodopsin. The tapetum in the eyes of butterflies probably enhances the spectral sensitivity of proximal long-wavelength photoreceptors. Pigment granules lining the rhabdom fine-tune the sensitivity spectra.     

Effect of cattle color, age, size and behavior on the intensity of the attack and sucking attachment by gadflies

Mechanisms of effect of some morphophysiological parameters of cattle (age, colour, weight, skin area, intensity of defensive movements) on the attacking and attaching activity of tabanid flies were studied. Investigations were carried out in the south of Pskov Province in small herds by the method of simultaneous recording of attacking and attaching tabanids on all animals of the herd. It was established that differences in the attaching activity of Haematopota, Tabanus and Hybomitra flies depend mainly on the parameters affecting the efficiency of their attacks and connected with the age of animals, intensity of defensive movements and the host's skin area. The former correlates with the age of cows negatively while the latter positively. Therefore, more tabanids attach themselves to old animals than to young ones. For Chysops flies the main factor determining their intensity of attachment is the intensity of attacking. When attacking the Chrysops flies show preference to animals of dark colour independent of their age. It is shown that the increase in the attacking intensity results in the decrease of its efficiency and therefore reduces the probability of attachment for each individual.     

Phorcotabanus cinereus (Wiedemann, 1821) (Diptera,Tabanidae), an ornithophilic species of Tabanid in Central Amazon,Brazil

In Central Amazon, Brazil, the tabanid Phorcotabanus cinereus (Wiedemann) was recorded attacking the native duck Cairina moschata (Linnaeus) (Anseriformes, Anatidae). The flight and behavior of the tabanid during the attacks and the host's defenses were videotaped and analyzed in slow motion. The tabanid was recorded flying rapidly around the heads of the ducks before landing. Landing always took place on the beak, and then the tabanid walked to the fleshy caruncle on the basal part of the beak to bite and feed. Firstly the duck defends itself through lateral harsh head movements, and then, when it is being bitten, it defends itself by rubbing its head on the body, or dipping the head into water, when swimming. If disturbed, the fly resumed the same pattern of flight as before and would generally try to land again on the same host and bite in the same place. This feeding activity was observed predominantly between 9:30 am and 4:30 pm and always in open areas, near aquatic environments, from June 1996 to January 1997, the dry season in Central Amazon. To test the attractiveness of other animals to P. cinereus, mammals, caimans and domestic and wild birds were placed in suitable habitat and the response of P. cinereus observed. P. cinereus did not attack these animals, suggesting that this species has a preference for ducks, which are plentiful in the region.