Movement Of Flies Research Articles

The Ecology of a Natural Population of the Queensland Fruit Fly, Dacus Tryoni. V. The Dispersal of Adults.

As part of a project on the movements of D. tryoni at an orchard near Wilton, N.S.W., llnes of cuelure traps were placed out in the shape of a cross with the orchard In the centre. The nearest traps were situated 0.5 mile (0.8 km) and the most distant traps 15 miles (24 km) from this orchard. Both newly emerged and mature flies were marked and released into the orchard; the rates at which they dispersed and the distance and direction they travelled were estimated from the recapture of marked males in the traps. Both newly emerged and mature adults dispersed over an area of several hundred square miles within a few weeks of being released in the orchard. Emigrants were caught in the outer ring of traps, 14-15 miles (22.4-24 km) from the orchard, within 3 weeks of being released. Overall, the mean distances flown by emigrants, for flies released when immature and when mature, were approximately the same. It is suggested that this was because of the absence of host trees in the area surrounding the orchard. Whereas the immature flies have a post-teneral dispersive phase during which movements are largely independent of host trees, the movements of mature flies are more directly related to the availability of fruiting hosts. The absence of host trees near the orchard therefore encouraged the long-distance dispersal of the mature flies. In urban areas where fruitlng hosts are plentiful, the dispersive movements of mature flies are likely to be less than those of immature flies.

Factors Affecting the Aggregation of the Adult Cabbage Root Fly (Erioischia brassicae (Bouche)) at Hedges

Members of various groups of insects, including weak fliers such as Cecidomyiidae and stronger flying Staphylinidae, accumulate on the leeward side of artificial and natural windbreaks (e.g. Lewis 1965, 1969, 1970; Lewis & Stephenson 1966). Many factors affect this accumulation, including the height and permeability of windbreaks and the wind speed, but it has been suggested (Lewis & Dibley 1970) that insects accumulate because they are carried on the wind and are caught in the turbulent circulating air mass to the leeward of the windbreaks. Hawkes (1 972a) showed that adult Erioischia brassicae accumulated at hedges and this behaviour was associated with feeding from hedgerow flowers. There was a diurnal population movement of flies between hedges and a brassica crop and this appeared to be incompatible with accumulation at windbreaks as a result of the insects being carried on the wind. This paper describes experiments to observe whether wind causes aggregation of E. brassicae at natural hedges and at a lath barrier representing an artificial windbreak.

Distribution of cabbage root flies in brassica crops

SUMMARYChanges in the distribution of adult cabbage root flies were determined in 0–05‐0‐4 ha brassica plots during 1970 and 1971 using yellow water‐traps.The three generations of flies occurred at similar times in both years and the numbers caught generally decreased from the first to the third generation. In resident populations, the numbers of males and females declined by 70 and 40% respectively, between the second and third generations. When there was no decline, immigration presumably compensated for flies trapped or otherwise lost. The results confirmed that male cabbage root fly movement is trivial, that wind has little effect on distribution at a brassica plot and that females move into the crop independently of males. They failed to confirm that females aggregate markedly at hedgerows or fences, that they spend little time in the crop or that they regularly return to hedgerows.Differences in the dispersal behaviour of the male and female flies were reflected in the numbers caught. Some males dispersed actively during the first 2 weeks after emergence but many were displaced slowly downwind. Once at a plot, wind appeared to have little effect on distribution of young males, but older males tended to shelter just downwind of the hedge. Relatively few males were caught near hedges but they tended to aggregate along the crop‐interfaces, particularly during the first generation. Plot size did not appear to influence the pattern of fly distribution greatly. Females dispersed more actively than males and were generally more uniformly distributed through the crops even during periods of immigration. Gravid females entered an isolated plot without accompanying males, inferring that they are migratory and mate near the site of emergence. Female distribution was not related to the stage of ovarial development except during maximum oviposition when those that had laid some eggs visited the hedgerow. Aged females became progressively easier to capture and usually died in the crop.

Head Movement of Flies during Visually Guided Flight

MOST visually advanced animals are able to move their eyes relative to the body. This makes vision independent of body movements; in man it enables the eyes to keep the visual world stationary on the retinae, to scan the field of view, and to maintain fixation on moving objects1. The extent to which animals other than vertebrates are able to perform these activities is largely unknown; many, especially arthropods, make body movements tending either to stabilize the visual surroundings2,3 or to cause fixation of objects by the eyes4,5. In a very few cases, however, it has been shown that arthropod eyes may make directed movements independent of the body: examples are the fixation of prey by mantids6 and by salticid spiders7, and compensatory eye movements in a moving visual surround by crabs8 and locusts9. Here I describe the head movements (and therefore, in insects, eye movements) made by blowflies during sustained flight. I show these to be of two kinds: rapid saccadic flicks in which the head takes up a new angle with respect to the visual surroundings, and stabilization movements which keep the angular position of the head almost constant, in spite of body movements of up to 10° in either direction.

Responses of Adult Face Flies1 to Relative Humidities2

Responses of 5-day-old Musca autumnalis De Geer (Diptera: Muscidae) to alternative humidities were studied using 2-choice humidity chambers. Humidity was controlled with aqueous salt solutions. Timed tracings of movements of individual flies were made using a television camera and monitor. Both males and females spent significantly more time on the drier sides of the humidity chambers. More females than males stayed on the drier sides, and males moved faster than females. Orthokinesis and probably klinokinesis were involved in their responses.

Behavioural studies of Glossina morsitans Westw. using tantalum-182.

Investigations, using tantalum-182, into the behaviour of Glossina morsitans Westw. in large field cages are described. Individual straight-line displacements occurred on average about every three hours and were generally small and erratic in direction. The perimeters of the cages tended to ‘ trap ’ an enclosed population, but flies appeared to move to the walls more quickly when they were shaded by an outer covering of hessian. Horizontal distribution and movements of flies did not appear to be associated directly with the enclosed vegetation, artificial roosting sites or host animals. Observations on vertical displacements indicated diurnal movements to and from boles of trees and changes in roosting heights. The majority of flies rested between six and ten feet above the ground, though individuals were seen from ground level to 30 ft. Few observations were done at night, but two flies were seen on the underside of leaves.

Movement and Oviposition of Wheat Bulb Flies

SUMMARYWater traps examined weekly were used to assess the activity of adult wheat bulb flies during the oviposition period in late July, August and eariy September. Traps were placed at various distances up to 1 mile (1–6 km) from known sources of infestation at Whittlesey, Cambridgeshire and at Rothamsted. Most flies were caught down wind from possible emergence sites and few were caught more than 1/4‐1/2 mile (0.4–0.8 km) away. The distribution of flies between traps was similar in both the first and second halves of the trapping period. At Whittlesey there was a significant positive correlation between the number of flies caught in a trap and the number of eggs laid in the field containing the trap.

Selection for divergent emigration rates in laboratory populations of Musca domestica

SummaryHigh and low emigration rates through a laboratory system were selected for in populations of house flies (Musca domestica L.). Emigration consisted of movement of flies from on plastic box to another by way of a connecting tube. Selection was carried out by first dividing a wild population of flies into two lines and then selecting for movement from the box in one line and against movement from the box in the other line. The selection experiment was performed twice. In both experiments a statistically significant difference between the two strains was obtained in three to four generations of selection. In the second experiment, after 5 genrations the mean number of high emigration rate flies emigrating in 1 hour was 4.37 times the mean number of low emigration rate flies and in 24 hours was 2.81 times the number of low emigration rate flies. The second experiment was terminated after 6 generations, but the first experiment was continued for 35 generations. In this case, divergence ceased in roughly 15 generations.The possible relevance of the findings to laboratory population experiments in which spatial discontinuities are included is discussed.

Horn Fly Dispersal1

Tests were conducted at state college, Mississippi, during 1966 to establish the dispersion of horn flies, Haematobia irritans (L). Four procedures for the tests conditions were used and each was replicated 3 times. Procedures of releasing and recapturing marked flies were used to establish movement. Regression curves were computed to predict dispersion for each of the 4 test conditions by the use of a developed regression formula. Recaptured marked horn fly numbers decreased significantly as the distance from the release point increased, but a significant number of horn flies were recaptured at each collection point. Flies were found to move distances in excess of 400 yards. Tests indicted fly movement was principally nocturnal. A significantly larger number of flies moved at night than in the daytime. It is concluded that the ability of the horn fly to fly aggressively, especially during night-time hours, has been greatly underestimated. These flies are very active in seeking a suitable host.

Deposition of labeled beta-alanine in ebony and non-ebony Drosophila melanogaster with notes on other amino acids.

HE ebony mutant of Drosophila melanogaster shows a number of abnormalities in mating behavior which lead to lowered mating success. The movements of these ebony flies is slowed and apparently uncoordinated as compared with the wild type (JACOBS 1960). It was thought that this abnormal behavior as well as the correlated black body color may possibly result from aberrant amino acid metabolism. In preliminary attempts to detect differences in deposition rates of amino acids in ebony and non-ebony flies, 16 different C14 labeled amino acids were injected into the newly formed puparium stage of pupae, and radioactivity of pupa cases and body parts was determined. Of the injected amino acids, beta-alanine showed greater C' deposition in the pupa cases of non-ebony than of ebony homozygotes, while ebony showed an increased rate of elimination of C1400,, as compared with non-ebony homozygotes. The heterozygotes were intermediate in these activities (JACOBS and BRUBAKER 1963). The present study was undertaken to make quantitative comparisons with other amino acids, to inject the adult stage of various stocks, and to determine by autoradiography in which part of the flies the beta-alanine derived C is deposited.

Dispersion of insecticide-resistant populations of the house fly, Musca domestica L.

House flies, Musca domestica L., were collected by insect net from dairy barns in the area of Freehold, New Jersey, marked by suitable fluorescent dyes, and released in the same barns. Dispersion of flies to other barns was determined by night searches with a black light. Collections of flies from barns, traps, and fly ribbons also were used to determine fly movement. For some releases flies were reared on the farms. Over a 2-year period 9 experiments were conducted using 133,000 marked flies released at 6 locations. The studies showed that insecticide-resistant flies will move quite readily from one barn to another, moving at least a mile in a day and apparently in all directions. Flies were recovered up to 6.5 miles from the release point. Largest numbers of flies were recovered in barns where conditions seemed most favorable to flies. Reciprocal movement of flies between barns was shown in 3 instances. Measurement of the population at the release point at intervals after release indicated the size of the total fly population in these barns. This procedure permitted calculation of actual numbers of flies migrating to a given barn.

The Influence of Yeast Hydrolysate on the Behavior of the Melon Fly1

This study, which was conducted to determine some effects of yeast hydrolysate on the behavior of the melon fly ( Dacus cucurbitae Coq.) in the field, showed that the number of flies present or found dead was greater when yeast hydrolysate bait was applied to non-host plants favored by the adults than to favored host plants or to plyboard slabs. The application of yeast hydrolysate to non-host plants, fuzzy rattle pod ( Crotolaria incana L.) and corn, did not result in an increase of flies on the treated plants in certain tests, but in others there was an increase. In general, positive responses were found to be associated with high population density. The application of this bait to host plants, cucumber and cantaloupe, did not result in the movement of flies to these crop plants from nearby untreated corn plants.

The Pattern of Glossina morsitans Communities

Tsetse flies (Glossina morsitans Westw.) were marked and released at Daga-Iloi, in Tanganyika on four or, usually, six days weekly for over 15 months, at 75 catching points situated 100 yards apart on an “octagonal spiral” whose successive rings were separated by 250 yards. Outer “spirals” were also traversed occasionally.The country was hilly and dominated by woodland of Brachystegia tamarindoides, broken by more open grassland with Combretum on the one hand and by thicketed ravines on the other. The ungulate animals included zebra, buffalo, bushbuck, roan antelope, hartebeest, reedbuck, duiker, wart-hog and bushpig, with very occasional elephant, rhinoceros, waterbuck and klipspringer. Baboons and Cercopithecus monkeys were also present. Spoors of the ungulates were recorded on the daily rounds: bushbuck were most common about the ravines, but in general the ungulates tended to be most common in the open grassland with Combretum.G. morsitans was most numerous in tall Brachystegia woodland where the slope was moderate, and where open grasslands were not too far away. Thicketed ravines were avoided. The highest apparent densities were observed on the outer “spirals”, perhaps because of disturbance on the inner one traversed almost every day.During the rains, well-marked concentrations of flies occurred in certain parts of the Brachystegia woodland, and these re-formed in the second year. The hungriest flies were always found outside the Brachystegia, and hunger was higher in the dry season. Hunger was measured objectively by the proportion of non-teneral males alighting head-upwards on members of the catching party, which hungry flies mostly do.There was a negative correlation between numbers of flies and numbers of ungulates, and a positive correlation between the numbers of ungulates and hunger of the flies. This is in accordance with the feeding-ground theory, and is very generally observed with G. morsitans in East Africa. Certain movements of individual flies also accorded with the theory, against which, however, the suggestion has now been made that flies caught in the putative feeding grounds have not ventured out into them until attracted there by the sight of the catching party. This suggestion is to some extent countered by quotations from previous work, but it deserves further thought, and carefully planned experiments.Passage of large herds of buffalo through portions of the “spiral” were not apparently accompanied by mass movements of flies, even when the animals passed by day and many flies fed on them.

Urban fly dispersion studies with special reference to movement pattern of Musca domestica.

SummaryAt Phoenix, Arizona, approximately 147,000 radioactive Musca domestica were liberated at a primary release site. For the 2-day period following, 15 fly traps were operated at 3 secondary sites 0.5 mile from the primary release point; the flies collected at each secondary site were then dusted with a characteristic dye, after which they were again liberated.Collection stations within one mile of the primary release point indicated that, even though fly dispersion from that site followed a general random design, one sector of the recovery zone yielded a higher rate of recapture of radioactive specimens than the remaining sectors.A total of 104 radioactive and dyed M. domestica was retrieved. Fly movement from each of the 3 secondary release sites exhibited a random pattern. Reciprocal migration was manifested, certain specimens reversing their initial path of migration and returning to the general area of the primary release site.The data indicate M. domestica to be essentially an insect of migrating habits. The house fly apparently spends the greater part of its existence in moving from site to site not only in search of breeding and feeding sources but also from an inherent instinct to wander.

DDT residual Films

Exposure of house-flies to residual films of DDT, deposited on wall-board from kerosene solutions, has shown that the initial toxicity increases (1) as the deposit of DDT per unit area increases, and (2) as the concentration of DDT in the solution increases, although the amount of DDT applied is kept constant. In practice, DDT in kerosene should be applied to absorbent materials at as high a concentration as possible, consistent with reasonable coverage, in order to avoid much of the DDT being carried by the solvent into the substrate, where it is no longer available for contact with the insects.With wall-board, a critical value for the product of concentration and deposit of DDT has been shown to exist, above which any mechanical stimulus, including movement of flies on the treated surface, will cause the DDT present in supersaturated solution to crystallise, with consequent marked increase in toxicity of the film. Under some circumstances, removal of the crystal carpet is followed by its partial regeneration. If the product of the concentration and deposit falls below the critical value, the residual film is at no time very effective and soon loses its initial toxicity.The persistence of toxic films of DDT on wall-board has been shown, over an exposure period of 18 months, to be closely bound up with the crystallisation of the deposits and their powers of regeneration during intermittent exposure to flies.This work has been carried out as part of the programme of research of the Pest Infestation Laboratory, and this account is published by permission of the Department of Scientific and Industrial Research.

Further investigations on the biology and control of the carrot fly (Psila rosae F.)

Records were obtained for the emergence of the first and second generation flies at Chatteris and Cambridge. There is a correlation between the age of the carrot crop and the commencement of the emergence of the second generation from it. The first generation was successfully controlled by killing the flies with a poison bait sprayed on the dikesides of the carrot fields. This treatment reduced the popúlation of second generation flies and also their attack. Spraying the dikesides and/or the headlands of eight maincrop carrot fields in August and September greatly reduced the second generation damage. Very high kills of carrot fly were obtained on the headlands of treated fields. Poor results were given by the treatment on three very weedy fields which were incompletely treated. A marked increase in attack occurred in three untreated areas in 1942 as compared with the previous year.Application of the poison bait spray in the field is discussed. Creosote‐treated string gave promising results in small‐scale experiments for the control of the second generation. Calomel dust (4°) with and without grass cuttings caused no reduction in attack.In hot sunny weather the flies shelter in the vegetation around carrot fields from about 10 a.m. until about 5 p.m. In the cooler conditions of early morning and evening there is a movement of flies into the field. This rhythm is not maintained in dull warm weatherSeedling carrots may be attacked in the field any time after the cotyledon stage. This enables the first generation of flies to propagate on main crop carrots. Soil sections about carrot rows showed that pupae of the overwintering generation are closely congregated around the carrots. Various insecticides were tested for the destruction of pupae in the soil. A creosote‐sawdust mixture gave the best results.Storage experiments showed that clamped carrots deteriorate much less than those unlifted. The population of flies is greatly increased by allowing attacked carrots to remain unlifted throughout the winter or by ploughing in.

INVESTIGATIONS ON THE BIOLOGY AND CONTROL OF THE CARROT FLY (PSILA ROSAE F.)

Records were obtained for the emergence of the first and second generation flies at Chatteris and Cambridge. There is a correlation between the age of the carrot crop and the commencement of the emergence of the second generation from it. The first generation was successfully controlled by killing the flies with a poison bait sprayed on the dikesides of the carrot fields. This treatment reduced the population of second generation flies and also their attack. Spraying the dikesides and/or the headlands of eight maincrop carrot fields in August and September greatly reduced the second generation damage. Very high kills of carrot fly were obtained on the headlands of treated fields. Poor results were given by the treatment on three very weedy fields which were incompletely treated. A marked increase in attack occurred in three untreated areas in 1942 as compared with the previous year. Application of the poison bait spray in the field is discussed. Creosote-treated string gave promising results in small-scale experiments for the control of the second generation. Calomel dust (4°) with and without grass cuttings caused no reduction in attack. In hot sunny weather the flies shelter in the vegetation around carrot fields from about 10 a.m. until about 5 p.m. In the cooler conditions of early morning and evening there is a movement of flies into the field. This rhythm is not maintained in dull warm weather Seedling carrots may be attacked in the field any time after the cotyledon stage. This enables the first generation of flies to propagate on main crop carrots. Soil sections about carrot rows showed that pupae of the overwintering generation are closely congregated around the carrots. Various insecticides were tested for the destruction of pupae in the soil. A creosote-sawdust mixture gave the best results. Storage experiments showed that clamped carrots deteriorate much less than those unlifted. The population of flies is greatly increased by allowing attacked carrots to remain unlifted throughout the winter or by ploughing in.

The Causes and Implications of Hunger in Tsetse-flies

1. Tsetse-flies have been divided into four stages of hunger by their external appearance. These stages have been correlated with the internal appearance determined by dissection. It was found that the fat-bodies became maximally developed shortly after a meal, and thereafter diminished rapidly in bulk. Hunger of flies in samples is expressed as the Mean Hunger Stage (M.H.S.).2. Flies in different stages of hunger showed different behaviour in the field. Thus hungry flies usually attacked head-upwards, replete flies, if attacking, tending to adopt a head-down attitude. Most replete flies preferred to settle on the ground, or on objects other than the members of the catching party. Hungry flies were the most persistent followers.3. The true habitats and feeding-grounds of Glossina morsitans, G. swynnertoni, and G. palpalis are described, so far as they are known to the writer.4. Confirmation of the feeding-ground theory was obtained for G. swynnertoni by an analysis of the to-and-fro movements of marked flies.5. Considerable independent movement of flies was shown to occur in the absence of carriage on man or game. Some flies under such conditions travelled over 2 miles in 3 hours.