Blood-sucking Flies Research Articles

Isolation and Characterization of a Coagulation Factor Xa Inhibitor from Black Fly Salivary Glands

We have discovered and characterized a novel coagulation factor Xa inhibitor from the salivary gland of the black fly, Simulium vittatum. Salivary glands were surgically dissected from the flies and a crude salivary gland extract was tested for inhibition of a number of coagulation assays. The gland extract inhibited both thrombin and factor Xa. To purify further the factor Xa inhibitor, a factor Xa affinity column was utilized. Final purification of the black fly factor Xa inhibitor was achieved by reverse-phase C8 microbore high pressure liquid chromatography. Inhibition of factor Xa was nearly stoichiometric by the purified inhibitor with no inhibitor of thrombin detected. SDS-polyacrylamide gel electrophoresis indicated the inhibitor had a molecular weight of 18,000 and sequence analysis of the inhibitor revealed a blocked amino terminus. These data indicate that the blood-sucking black fly has evolved a highly potent inhibitor of mammalian coagulation factor Xa to disrupt its host normal hemostatic clotting mechanisms.

Advances in Cow Dung Ecology: International Aspects of the Australian Bush Fly Research Programme

Intensive research carried out over the last 20 years on the biology and control of the Australian bush fly, Musca vetustisima, a widespread and irritating pest of man in that region, has provided a wealth of information about the community relationships of fauna in the cow dung pats which provide the breeding habitat of the fly. The extension of this project to South Africa and to Southern Spain in the search for exotic dung beetles or allied controlling agents to deal with both the bush fly and the blood-sucking buffalo fly, Haematobia, has given this programme a wider significance.

New approaches to the chemical control of arthropod pests of livestock

Chemicals are important tools in our effort to control livestock ectoparasites, and they are likely to remain so in the foreseeable future. Chemical control is the most widely used and in most cases the only method available to the producer. Therefore, it is imperative that we continue to seek new chemicals as well as new systems for delivery of those chemicals in an effective, efficient, and safe manner. New approaches to chemical control involve both new chemicals and new delivery systems in a complementary and often a synergistic relationship. Three relatively new classes of chemicals, pyrethroids, insect growth regulators, and avermectins, have provided special opportunities for development of new delivery systems. The development of the insecticidal ear tag has been perhaps the most significant new approach to chemical control of livestock ectoparasites in recent years. Although originally developed for control of ear ticks, the tag has had its greatest impact on control of the horn fly, a major pest of cattle in the U.S. The pyrethroid tags provided season-long control of horn flies in most climates and at the same time dramatically reduced the use of pesticide. Unfortunately, the problem of resistance to pyrethroids in the tags has been encountered. Unless effective techniques for resistance management can be developed, the producer may lose this valuable new tool. Sustained-release boluses provide a means of delivering IGR's, such as methoprene and diflubenzuron, for control of immature stages of the horn fly and face fly in manure of cattle. These devices are designed to lodge in the reticulum of cattle and release the chemical to the digestive tract over an extended period. Bolus formulations may in fact provide a tool for management of horn fly resistance to pyrethroids. Ivermectin, a potent new chemical from a new class of agricultural pesticides, provides an important opportunity for developing innovative delivery systems for control of livestock pests. Its systemic activity against ticks and blood-sucking flies at extremely low dosages provides potential for development of long-lasting subcutaneous implants. Its ability to control immature stages of dung-breeding flies, such as the horn fly and face fly, offers the potential for development of sustained-release boluses for larvicidal treatments. These three selected examples of new approaches to chemical control of livestock ectoparasites point to two obvious trends: 1) reduction in quantity of a chemical to be applied without sacrifice of efficacy and 2) use of controlled-release technology to prolong effectiveness of the chemical. Although the examples presented are focused on applications to cattle, similar approaches have application for other livestock. New approaches such as these have important implications in implementation of either area-wide or IPM control programs. Such programs will need convenient and effective chemical delivery systems to be successful if in fact chemicals are to be a part of the programs.

Ectoparasites of horses in south-western Nigeria

Arthropods feeding on horses in the stables situated in three towns in south-western Nigeria were investigated. Flies were caught on horses with trap-net while ticks and lice were picked from them with forceps. Stomoxys, Tabanus, Glossina and Hippobosca species were the main blood-sucking flies caught, while myiasis flies and Musca species were also found. Furthermore, three genera of ticks, Boophilus, Hyalomma and Rhipicephalus and two species of lice, Haematopinus equi and Damalina equi, were recorded. The veterinary importance of the association of these arthropods with horses is discussed.

The role of taxonomy in the control of flies pestering grazing cattle and sheep in Hungary

A reliable and stable taxonomic basis is necessary for improvements in the control of secretophagous and blood-sucking flies visiting pastured cattle because (a) the number of these dipterous species is very high; (b) the community differs from area to area; and (c) a better knowledge of the biology of the species can aid the development of more effective control measures. The actual size and density of populations cannot be estimated accurately on the basis of individual flies caught from or counted on cattle or in their environs. The true densities can only be determined by rearing the flies. It would appear that no single control method can be effective against all species because of the major differences in biology between them. In this taxonomy can help. Thirty-one species of Diptera, several of veterinary importance, have been reared from sheep droppings. Sheep droppings have no autochthonous community and all species reared also occur in cattle droppings, although in different proportions.

Evidence on horizontal transmission of bovine leukemia virus due to blood-sucking tabanid flies.

Evidence on horizontal transmission of bovine leukemia virus due to blood-sucking tabanid flies.

Behavior and reproductive physiology of blood-sucking snipe flies (Diptera: Rhagionidae:Symphoromyia) attacking deer in Northern California

At the University of California Hopland Field Station in Mendocino County, six species of hematophagous Symphoromyia attacked the Columbian black-tailed deer, Odocoileus bemionus columbianus, during the months of transition (April through June) from the rainy season to the drought season. Between 1964 and 1966, S. pachyceras, S. cervivora, S. inconspicua, S. nana, S. trun-cata, and S. sackeni had similar seasonal patterns of abundance, with each present 6 to 10 weeks. Minimum temperature thresholds at which Symphoromyia attacked were determined for five species. The upper temperature threshold for attack by S. sackeni was between 34.4 and 37.2°C. Diverse wind and light conditions had little effect on the host-seeking behavior of the species studied. Symphoromyia attacking deer were seldom attracted to hosts other than deer, and only S. sackeni and S. pachyceras fed on other hosts. The seasonal occurrence of snipe flies coincided with the annual spring shedding of winter pelage by the deer and, in bucks, with the growth of antlers. All Symphoromyia attacked only the face, ears, or antlers of deer after relatively direct approach, and most species engorged within 1 to 3 minutes. There was a direct relationship between snipe flies feeding on the ears and face and the more rapid loss of the woolly underhairs at these sites. The tilted posture of feeding snipe flies that angled the body upward between and above raised guard hairs permitted feeding on the outer ear surface, a site where most other blood-sucking flies are repulsed by the sensory guard hairs. The number of Symphoromyia attracted to an individual deer and to the face or ears of an animal varied greatly. The tolerance to flies and the anti-biting fly behavior of individual deer (ear flicking, brushing flies from the face, and reducing the silhouette by lying down, lowering the head, flattening the ears, and extending the legs) contributed to variations in numbers of snipe flies on and around the hosts.

Blood-sucking flies and primate polyspecific associations

PRIMATE polyspecific associations are likely to be an effective means of reducing the number of fly bites individual monkeys receive1. The probability of acquiring a vector-borne disease, and the severity of that disease increases with the number of fly bites an animal receives2–4. Bait animals placed in groups are known to attract fewer individual mosquitoes per bait individual than are bait animals placed singly3,5. Mean group size of the mangabey, Cercocebus albigena is about 13 in Kibale Forest, Uganda, and the mean group size of Colobus badius and Cercopithecus ascanius are 50 and 35 respectively6. Associations of groups of these species are likely to reduce significantly the number of dipteran bites individual monkeys receive1,7. Other explanations proposed for primate polyspecific associations include increased food location abilities, and increased predator detection and avoidance8,9. I report here the correlation of the temporal occurrence of C. albigena polyspecific associations with the activity of biting and sucking flies, C. albigena feeding and other activities, and the temporal occurrence of attacks by the crowned eagle-hawk (Stephanoaetus coronatus) (eagles are the only known predator of these monkeys). The study was carried out in the Kibale Forest, Ngogo Reserve.

Blood-Sucking Flies Feeding on Sheep in Eastern Australia.

An investigation was undertaken to determine the species of blood-sucking flies which feed on sheep. Engorged insects were collected by a number of methods and their blood meals were identified by precipitin and haemagglutination inhibition tests. Sixteen species of mosquitoes attacked sheep, and of these Anopheles annulipes and Culex annulirostris dominated. Twelve species of biting midges in the genera Culicoides, Leptoconops and Lasiohelea were shown to bite sheep; the dominant species were C. marksi and C. breuitarsis. The simuliid Austrosimulium pestilens and the muscid Stomoxys calcitrans also fed on sheep. Some of these species also fed on other hosts-eight on ox, five on marsupials and one on horse. Four of the most widespread Culicoides species, C. brevitarsis, C. dycei, C. marksi and C. victoriae, fed on both sheep and ox, a factor of epidemiological significance in their potential role as vectors of arbovirus diseases of livestock.

Seasonal prevalence of flies feeding on cattle in northern Nigeria.

A survey over a year of flies feeding on a tethered bull was carried out on a ranch in the north of Nigeria. Flies were netted on one day in each month for two hours in both morning and afternoon. Flies caught included surface feeders, blood suckers and those causing myiasis. The commonest genus caught wasMusca which was present in relatively large numbers throughout the year.Stomoxys calcitrans was by far the most abundant of the blood-sucking fly species caught.

Methods for assessing the density and survival of blood-sucking Diptera.

In a review of the principles involved in sampling insect populations Morris (I 17) has described the process as a mixture of art, science, and drudgery. The drudgery is known to us all, the science lies in understanding the responses of insects to trapping devices and their movements into the sampling area, while the art comes from an appreciation of the variables inherent in every field situation. The sampling methods adopted for blood-sucking flies may also reflect the background and objec­ tives of the operators. Those concerned with pest species, for instance, often employ standard techniques on a large scale with the immediate aim of monitoring the efficiency of control measures. They are dependent on funds from local authorities and may be answerable to the community in which they live. On the other hand. those concerned with assessing a disease hazard usually have more long-term objec­ tives, and their funds may come from a central authority. They often work in considerable isolation and individual whims and preferences lead to a lack of stan­ dardization in the techniques employed. Muirhead-Thomson (119) has recently reappraised the diverse methods used for sampling vectors and emphasized the need for greater uniformity. His lead is to be welcomed but much remains to be done. In some branches of entomology the use of specific chemical attractants for trapping pest species is becoming increasingly common, and the list of available lures is growing rapidly (8). This trend is much less noticeable in the case of biting flies probably because warm-blooded animals themselves are such potent sources of attraction. Thus, regardless of whether the active components have been identified or not, the use of animals as baits has long been the basis of many sampling methods used in the assessment of populations. At the same time medical and veterinary entomologists have been looking more critically at the interaction of trapping de­ vices and host attractants and have been considering how such traps could be

Simuliidae, Ceratopogonidae, and Chloropidae as Prey of Oxybelus emarginatum1

Excellent accounts of the nesting behavior of solitary wasps have been recorded (Evans 1960, 1966; Krombein 1964), but few studies have been made on the actual capture and removal of blood-sucking flies from animals by these Hymenoptera. References to Hymenoptera as predators of Simuliidae are rare (Vargas 1945), and little is known of the effectiveness of these natural control agents.

The Mode of Action of Repellent Chemicals Against Blood-sucking Flies

AbstractRecent conflicting theories regarding host finding by blood-sucking flies and the mode of action of repellents are examined and discussed. The claim that repellents owe their activity to infra-red absorption in a narrow waveband (449–467 cm.−1) was examined by measurement of published curves for infra-red absorption by repellent, non-repellent, and doubtful chemicals. Peaks of absorption at this waveband in comparison with adjacent Wave numbers are three times as common in repellent as in non-repellent materials, but in comparison with absorption over the entire spectrum studied all groups of materials show a trough of absorption at this narrow waveband. No supporting evidence could be found for the claim that mosquito repellents masquerade as water vapour by virtue of their infra-red absorption spectra, nor for the suggestion arising out of this, that such repellents should be attractive at low humidities. Repellency of indalone was found to increase as humidity decreased.Regardless of the role molecular vibration may play in olfactory perception, the usefulness of infra-red radiation to blood-sucking flies seeking their hosts and to man seeking repellents for the flies remains to be demonstrated.

A Carbon Dioxide Trap for Simuliidae (Diptera)1

The need of a uniform method of collecting black flies has long been apparent to students of the Simuliidae. The literatue reveals that at least 3 types of daylight traps have been used to collect them, but each has certain limitations. A trap designed by Monchadski and Radzivilovskaja (1948) required the constant presence of an observer to act as bait, and a trap used by Davies and James (1957) depended upon ground beef and tallow as an attractant. Fredeen (1961) designed and tested 3 silhouette traps for studying the attacking behavior of Simulium articum Malloch. Certain species of Simuliidae were reported by Williams and Davies (1957) to be attracted to light traps. Carbon dioxide has been used to attract mosquitoes to collecting stations according to Reeves (1951, 1953) and Brown (1951). Callahan2 (1965) stated that the total body radiation of the host also may playa significant role in attracting bloodsucking flies.

Nocturnal Activity of Black Flies (Simuliidae)

IN 1957, in conjunction with Dr. Lewis Davies, I published a communication on the occurrence of large numbers of blood-sucking flies of the family Simuliidae in a light trap in Inverness-shire1. Trapping was continued for just over four years and a total of 17,500 flies belonging to ten species were captured. Some of the results of the work have since been discussed2,3.

Blood-sucking flies (Diptera) and Myxomatosis transmission in a mountain environment in NSW. 2. Comparison of the use of man and rabbit as bait in evaluating vectors of Myxomatosis.

Human baiting and the use of rabbit-baited cone-drop traps were compared as techniques for gathering information on the host relationships of biting flies in a mountain environment of south-eastern Australia. Bait-trapping was carried out at four stations during the period of dusk activity for biting flies on 21 days covering all seasons. Neither technique proved entirely satisfactory by itself, and it was shown that the precipitin testing of blood-fed specimens taken at bait is an essential ancillary to both. When used in conjunction with the precipitin method both techniques provided useful data on the feeding behaviour of mosquitoes, but neither was satisfactory for the Ceratopogonidae, and (although still inadequate) the rabbit-baited cone-drop trap provided data on the local Simuliidae not yet obtained by any other method. Human baiting was unquestionably the simpler technique, and yielded a far greater amount of pertinent data, particularly for mosquitoes, the predominant myxomatosis vector group of the region. An analysis is made of the vectors of myxomatosis and their relative importance in the transmission of that disease in the study region.

Studies in the effect of weather conditions on the activity and abundance of insect populations

This paper is a statistical analysis of captures of insects every night for over 4 years in traps in a locality in the Scottish Highlands. It should be considered in relation to a similar account of work in south-east England (Williams 1951 a ). From the trap catches (on a logarithmic scale), and meteorological records taken alongside the traps, statistical analyses, chiefly by multiple regressions, were made to show (1) the relation between day to day changes in log catch and corresponding changes in temperature and wind, and (2) the relation between changes in mean log catch in the same month in different years and changes in rainfall and temperature in the three previous months. The former is an activity effect, and the latter a population effect. Details are given for total Diptera, for the bloodsucking flies of the family Simuliidae, and for total Lepidoptera in a light trap, and for total Diptera in a suction trap, this latter for activity only. The results show quantitatively the very high dependance, more so in some groups and at certain seasons, of the activity of insects on the current weather conditions, and of the population level on the previous weather. A fuller summary is included in the paper, pp. 367 to 369.

Blood-sucking flies (Diptera) and Myxomatosis Transmission in a mountain environment in NSW

The possible vectors of myxomatosis amongst rabbits in a typical mountain environment in eastern New South Wales have been investigated. The disease was established in an isolated population of rabbits and the course of its fluctuations followed through a period of two and a half years, involving two large-scale reductions in rabbit density. Of over 60 species of blood-sucking flies encountered, 9 species of Culicidae, 2 of Simuliidae, 3 of Ceratopogonidae, and 1 of Tabanidae have been shown to feed on rabbits. Two recoveries of myxomatosis virus have been made from mixed collections of Aedes queenslandis and A. alboannulatus. The relative importance of the species known to attack rabbits is discussed in relation to the transmission and maintenance of the disease. Information on host preferences and the feeding, resting, and movement of adults is given. Possible factors influencing the autumn incidence of the disease on the eastern coast and tablelands area of New South Wales are discussed, and further means of exploiting myxomatosis towards the control of rabbits in specific environments are suggested.

Game and Tsetse Fly in Southern Rhodesia

Until nearly the end of the nineteenth century about two-thirds of Southern Rhodesia was uninhabitable by domestic cattle, and thus, to a great extent, unusable by mankind whether European or native, because of the disease trypanosomiasis. In man this is called sleeping sickness, in cattle nagana. It is caused by trypanosomes, minute organisms which live in the blood of the victims of the disease. These trypanosomes are sucked up, with the blood of the infected man or beast, by blood-sucking tsetse flies, develop in the fly and may be transmitted to the next creature on which the fly feeds.

The Extermination of Animal Populations by Artificial Predation and the Estimation of Populations

This paper falls into two parts, as the itle indicates. They are linked together by the circumstance that-both are referred to the same body of data (Table 1). The term 'Artificial Predation' is he e adopted to include all cases where a population of animals is directly attacked by man, by shooting, trapping, hand collection or other similar methods. The term implies that man is the predator. Cases in which man affects an animal population indirectly by altering the animals' environment, for example destruction of a forest leading to the extermination of monkeys, are not artificial predation. Cases in which poison is spread in an essential part of the animals' environment as in mosquito control by insecticides, are also not artificial predation. Nevertheless ideas parallel to those developed in this paper have been usefully applied to a case in which a population of blood-sucking flies (Tsetse) was attacked by introducing into their environment a number of cattle externally treated with an insecticidal preparation (Whiteside 1949). The distinction is sometimes fine, but it is proposed to define the term as including cases in which the animal finds and eats a poison, but excluding cases where the poison is made to seek the animal (mosquito control, gas warfare, fumigation). The justification for this distinction is that most animals are available to a predator only when they are themselves seeking for food. It is not generally agreed whether artificial predation is or is not a feasible method of exterminating a population of animals. On the one hand, artificial predation nearly exterminated the American bison (Peattie 1943; Calahane 1944), and is said to have completely exterminated the passenger pigeon (Abbot 1944). It exterminated the quagga (Lydekker 1926, p. 41). It exterminated the tsetse-fly, Glossinapalpalis, on the island of Principe (Austen & Hegh 1922), but failed to exterminate the same fly on the island of Mugasiro (Koch 1914), although it did exterminate this fly in an isolated patch of bush on a small river (Glasgow & Duffy 1947). It has been suggested (Oakley