Musca Vetustissima Research Articles

Populations of the bush fly (Musca vetustissima Walker) in arid Australia

AbstractPopulations of the bush fly Musca vetustissima were usually low in arid south‐western Australia. Herbaceous plants that grew only after rain resulted in changes to cattle dung that increased its attractiveness to bush flies for oviposition in laboratory tests. Larvae reared in such dung consistently produced large flies of high fecundity, and larval survival was usually high. Similar responses to the dung were evident from examination of flies sampled in the field. Although greatly increased bush fly abundance was possible only after major improvement in cattle dung, it was not a general phenomenon as immature survival did not always increase. Even major population increases resulted from periods of high immature survival that were brief relative to the duration of favourable dung. Nematodes Heterotylenchus sp. appeared to be an important mortality factor of the immature stages at such times.Build‐up of high bush fly populations occurred only in cattle‐grazing areas, but base‐level abundance was similar regardless of the presence of cattle. Almost all female flies were gravid when cattle dung was unfavourable for breeding, and in areas without cattle. In arid areas, acceptable oviposition sites probably are more limiting than are sources of protein for oögensis.

BUSH FLY ABUNDANCE AND POPULATION EVENTS IN RELATION TO DUNG BEETLE CATCHES ON THE SOUTH COAST OF NEW SOUTH WALES

AbstractOver 2 seasons, 1980–81 and 1981–82, the patterns of abundance of female bush flies, Musca vetustissima (Walker), at 3 field sites on the N. S. W. south coast varied little between sites but greatly between seasons. There was no direct relationship between the patterns of bush fly abundance and of native dung beetle catches at the same sites.Analysis of the results of dissection of the 1981–82 bush fly samples suggested that, although much oviposition had occurred, the mortality of the immature stages had been high. There was also more direct evidence that the bulk of the flies caught had recently immigrated, so that their numbers were largely independent of the results of local bush fly breeding. Although obscured by migrations of adult flies and by the high levels of immature mortality caused by other factors, the role of dung beetles as one of the causes could be inferred from the data to be of the same high order as indicated by published laboratory studies.

BUSH FLY ABUNDANCE IN AN OVERWINTERING ZONE DURING 1979–82 COMPARED WITH SOME DATA COLLECTED BEFORE THE INTRODUCTION OF EXOTIC DUNG BEETLES

AbstractRecent estimates of the abundance of bush flies (Musca vetustissima Walker) overwintering in southern Queensland were compared with fragmentary data collected before exotic dung beetles were established in the region. The difference found was not significant.

An assessment of some methods for the bioassay of changes in cattle dung as insect food, using the bush fly, Musca vetustissima Walker (Diptera: Muscidae)

AbstractSeveral methods for the bioassay of changes in cattle dung as insect food were defined and simultaneously assessed using Musca vetustissima Wlk. Size of emerging adults, in particular head width, was a reliable estimator of changes in the dung, but survival was not. Freezing of dung for 24 h had no effect. Flies of similar size emerged from dung placed on moist sand (field capacity moisture) and on an impermeable membrane; on dry sand, size was greatly reduced when the dung was coarse and less nutritious. The optimal method was deemed to be use of fresh dung on sand at field capacity moisture, leaving flies to emerge and die before measuring the head widths in a sample.

Field assessments of the impact of night-flying dung beetles (Coleoptera: Scarabaeidae) on the bush fly, Musca Vetustissima Walker (Diptera: Muscidae), in south-western Australia

AbstractThe effect of excluding the night-flying dung fauna, which included one abundant species of dung beetle (Scarabaeidae) in each of two areas, on the numbers of Musca vetustissima Wlk. emerging from cattle dung pads was studied in south-western Australia. Fresh dung pads were exposed to natural, daytime oviposition by M. vetustissima and half were covered at night. A test at one site before dung beetles emerged showed no effect of other nocturnal fauna on fly survival. In three experiments where Onthophagus ferox Har. was excluded, the numbers of flies emerging increased from 679 to 1019 per dung pad. In five experiments where Onitis alexis Klug was excluded, the number of flies emerging increased from 14 to 33 per dung pad. The mortality contributed by Onthophagus ferox was estimated to be around 27% and that by Onitis alexis around 15%.

Susceptibility to drowning of eggs of the dung breeding flies Haematobia irritans exigua and Musca vetustissima (Dipt., Muscidae) in relation to dung beetle activity

AbstractThe susceptibility of the eggs of the buffalo fly Haematobia irritans exigua and of the bush fly Musca vetustissima to drowning in the fluid squeezed from fresh bovine dung was examined. The age of eggs on immersion and the duration of immersion affects survival in both species, but buffalo fly eggs can tolerate longer periods of immersion than can bush fly eggs. Buffalo fly eggs close to hatching when submerged will develop and hatch under dung fluid whereas bush fly eggs of any age at immersion are incapable of hatching under dung fluid. These results are discussed in relation to the effect of dung beetle activity on fly survival.Zusammenfassungüber die Empfindlichkeit der Eier der Dungfliegen Haematobia irritans exigua und Musca vetustissima (Dipt., Muscidae) gegen Tauchung in Dungflüssigkeit in Beziehung zur Einwirkung der Dungkäfer auf die DungfliegenDie überlebensfähigkeit der Eier von H. irritans exigua und M. vetustissima bei Tauchung in frischer Dungflüssigkeit hing bei beiden Arten vom Eialter und der Tauchdauer ab, jedoch tolerierten die Eier von Haematobia längere Tauchperioden als jene von Musca. Die Maden von Haematobia schlüpften auch in der Dungflüssigkeit, während jene von Musca dazu nicht in der Lage sind. Die Ergebnisse werden hinsichtlich der Einwirkung von Dungkäfern auf das überleben der Dungfliegen diskutiert.

The seasonal distribution and characteristics of bush fly Musca vetustissima Walker populations in south‐western Australia

Abstract In the agricultural region of south‐western Australia the bush fly Musca ventustissima Walker was found to occur permanently in the north‐eastern half but it died out during winter in the south‐west. The abundance of bush flies increased rapidly throughout the overwintering zone in early spring as a result of local breeding. Flies then dispersed south‐westwards, completely repopulating the region during October. Immigrant flies were large and therefore highly fecund, and of advanced reproductive maturity. Local breeding then rapidly increased the population. Maximum abundance occurred in mid‐spring in the north and east and in early summer in the south and west. Abundance was greatest in the north where large overwintering populations occurred, and in the far south where repopulation occurred early in the seasonal cycle of pasture growth so that the more favourable cattle dung produced flies that were more fecund than their immigrant parents. The abundance of bush flies declined throughout the region in summer, to negligible levels near the south‐west coast but, paradoxically, higher levels occurred inland where there were fewer cattle. On average, flies were smaller and reproductively younger in summer. In areas where irrigated pastures produced more favourable dung in summer, the patterns of abundance and other characteristics of flies did not differ substantially from those in comparable non‐irrigated areas. The abundance and other characteristics of a bush fly population 10 km from a cattle‐grazing breeding site were similar to those at the site, indicating that constant dispersal is the basis of the bush fly's ubiquity.

The effect of a flood irrigation cycle on breeding by the bush fly, Musca vetustissima Walker (Diptera: Muscidae)

AbstractThe effect of a single flood irrigation cycle on the number of adults of Musca vetustissima Wlk. emerging from cattle dung was examined in the field in south-western Australia. Sets of fresh dung pads were exposed to natural oviposition on the day after a flooding and then every three days until the next flooding, 21 days later. The emergence of flies was compared with that from equivalent sets of dung pads in an adjacent unflooded but otherwise similar pasture. The age-stages most susceptible to drowning were post-feeding larvae and pre-emergent puparia. Reduced fly emergence from dung placed in the irrigated pasture one day after the first irrigation was attributed to suppression of oviposition by the wet conditions. Overall, there was a reduction of 57% in the number of flies emerging in the irrigated pasture compared with the unflooded control.

ESTABLISHMENT AND DISPERSAL OF THE INTRODUCED PREDATORY MITE, MACROCHELES PEREGRINUS KRANTZ, IN AUSTRALIA

ABSTRACTA South African predatory mite, Macrocheles peregrinus, phoretic on dung beetles (Scarabaeidae), was released at 2 sites in northern Australia as part of a programme on the biological control of the buffalo fly, Haematobia irritans exigua De Meijere and the bush fly, Musca vetustissima Walker. Releases were made at Rockhampton, Queensland and at Adelaide River, Northern Territory, in December 1980 and February 1981 respectively. Establishment was achieved immediately and after 14 months the area colonised around each release site was approximately 180,000 km2.

EFFECT OF SEVERAL ADDITIVES TO CATTLE DUNG ON YIELD AND SIZE OF PUPAE OF THE BUSH FLY MUSCA VETUSTISSIMA WALKER (DIPTERA: MUSCIDAE) IN CULTURES

AbstractThe addition of 100 mL of blood and bone, a fertilizer derived from dried and crushed offal from slaughter houses, to 2L of cow dung significantly increased the yield of pupae of Musca vetustissima from laboratory cultures. The addition of up to 200 mL of blood and bone significantly increased the length of the pupae produced. The yields and lengths were significantly greater after addition of blood and bone than after addition of the same amounts of sawdust suggesting a nutritional effect from the blood and bone.

A test for repellency to non‐biting flies and a comparison of repellents using Musca domestica L.

AbstractA system for testing the effect of a repellent against nonbiting flies attracted to man was developed for Musca domestica L. and Musca vetustissima Walk., and was used to compare the repellency of a range of chemicals against the former. Both arms of one person were simultaneously exposed to large numbers of the test insect in a cage, with repellent applied to a 45 cm2 area on one arm, and the solvent to an identical area on the other arm. By varying the dose of repellent, a dose‐to‐repellency relationship was established and evaluated using probit analysis to determine 50% (RD50) and 90% (RD90) repellency. Both values were required to characterise a repellent. Greatest uniformity of results was obtained with even illumination of the cages from above and exclusion of side lighting. RD50 and RD90 values were not affected by prior exposure of the flies in a cage and did not change with time. Of the repellents tested, dipropyl isocinchomeronate was the most effective against M. domestica. The repellent effect of mixtures of the compounds was tested against M. domestica and was less than expected by summation of the components acting alone, suggesting that to minimise the total dose of chemical applied to skin, single compounds are preferable to mixtures.

Attempts to measure the influence of dung beetles (Coleoptera: Scarabaeidae) on the field mortality of the bush fly Musca vetustissima Walker (Diptera: Muscidae) in south-eastern Australia

AbstractThe immature stages of Musca vetustissima Wlk. in dung pads in south-eastern Australia suffered a high mortality through the actions of a complex array of dung organisms, including dung beetles (scarabaeids), predatory beetles (hydrophilids and histerids) and predatory mites (Macrocheles glaber (Müll.)). At times of high dung beetle numbers, it was possible to demonstrate a relationship between fly mortality and dung beetle numbers. Single-species dung beetle populations appeared to be as effective as multiple-species populations in reducing fly numbers, except that some benefit was derived from a combination of day- and night-flying species. When dung beetle numbers were low, their influence could not be measured because of the high mortalities already caused by the other dung fauna. It is suggested that in those circumstances any mortality caused by the dung beetles may simply have become substituted for an existing mortality caused by other fauna without adding to the total mortality.

Seasonal changes in characteristics of cattle dung as a resource for an insect in southwestern Australia

AbstractThe value of cattle dung as a food resource for the bush fly Musca vetustissima (Walker) in the winter rainfall agricultural region of southwestern Australia was assessed by bioassay in the laboratory. The size (headwidth) of adult females was measured from flies reared on different samples of dung. Variation in size correlated with seasonal patterns of pasture growth, larger flies being produced during the growing season from autumn to spring. Size declined with senescence of annual pastures in late spring and early summer, occurring later in southern areas where the growing season was longer. After pasture senescence, dung from shorter growing season areas usually produced larger flies, apparently a result of the inverse relationship between digestibility of feed and length of growing season. Dung from irrigated perennial pastures never produced flies as large as that from annual pastures but generally high values were sustained during summer. Grazing of cereal stubble and feeding of hay in annual pasture areas during summer usually caused some increase in fly size. A spontaneous resurgence in the size of flies often occurred several weeks after pasture senescence and was attributed to more thorough digestion as a result of reduced intake of less palatable dry pasture.

EFFECT OF POPULATION DENSITY ON REPRODUCTION AND DUNG DISPERSAL BY THE DUNG BEETLE ONTHOPHAGUS BINODIS IN THE LABORATORY

Equal numbers of newly emerged male and female Onthophagus binodis Thunberg were placed at densities from 2–100 beetles on one‐litre pads of cattle dung. After one week the number of brood balls produced was counted and the volume of dung dispersed (buried and shredded) visually assessed. The surviving beetles from each box were then placed on another pad, and the process repeated until all beetles were dead. Beetle survival was not influenced by initial beetle density and fell linearly with time (P < 0.001). Brood ball production/female/week did not appear to be influenced by beetle age and could be predicted from current beetle density Y = 15.03e−0.045X, R2 = 0.42. Dung dispersal increased with increasing density up to about 35 beetles/pad, above which the proportion dispersed plateaued at about 90%. Dung burial, estimated from the number of brood balls produced/week, was on average greatest (450 ml) with 20–30 beetles/pad. The effect of density on production of brood balls was inferred to reflect the frequency of contact between adults in the pad.RÉSUMÉEffets de la densité de la population sur la reproduction et la dispersion des bouses chez Onthophagus binodis au laboratoireL'examen au laboratoire a porté sur la relation entre le nombre d'Onthophagus binodis Thunberg et le nombre de pelotes pour l'alimentation larvaire produite par femelle dans des galettes de un litre de bouse de vache. Un nombre déterminé d'insectes a été placé sur la bouse et le nombre de pelotes dénombré chaque semaine, les adultes survivants ont été dénombrés et placés sur une nouvelle galette de bouse. Cette opération a été répétée chaque semaine jusqu'à ce que tous les insectes du lot aient été morts.La survie a diminué linéairement avec le temps sans avoir été influencée par la densité d'origine (de 2 à 100 insectes par paquet). Après une période d'une semaine précédant la reproduction, une relation non linéaire inverse entre la production de pelotes par femelle et le nombre d'insectes présents a pu être observée. Les régressions linéaires de données transformées (logarithmes de X et Y) ont été comparées pour 14 cohortes d'insectes âgés de 2 à 19 semaines. Pour des raisons pratiques, les régressions sont semblables pour les insectes de tous âges. Une fonction exponentielle négative a été utilisée pour relier la production de pelotes (Y) à la densité des insectes (X):Y = 15,03e−0.45x avec R2 = 0,42 et F = 67,53 pour 2 et 188 df (P < 0,001).La quantité de bouse travaillée à chaque densité a été calculée à partir du nombre de pelotes produites par semaine et le volume de galette utilisé pour faire chaque pelote. La quantité de bouse travaillée culmine à 450 ml quand 25 à 35 insectes sont dans la galette. Aux densités supérieures à 35 insectes, la plus grande partie de la galette est dispersée, mais l'essentiel de celle‐ci est fragmentée et non travaillée. Une courbe de Michaelis et Mantus a été employée pour décrire la relation entre le volume de bouse dispersée (axe Y) et le nombre d'insectes (axe X): Y = 89,29X/1 + 0,084X avec R2 = 0,64, F = 145,23 pour 2 et 162 df (P < 0,001).La densité d' O. binodis n'a influencé significativement, ni la production de pelotes complètes (6% étaient inachevées), ni la proportion de pelotes qui contenaient des chambres d'incubation d'oeufs (86%, n = 663). Ainsi les réactions à la diversité se produisent avant le début de la fabrication de la pelote, ce qui permet de déduire qu'elles reflètent la fréquence des contacts entre adultes dans la galette.

Arthropod-induced mortality in immature stages of the bush fly, Musca vetustissima Walker (Diptera: Muscidae)

AbstractLaboratory and field experiments were carried out in Australia to determine the effect of arthropods in cattle dung on the survival of the eggs and larvae of Musca vetustissima Wlk. They were tested in the numbers in which they came to dung pads near Canberra, during the 1978–79 and 1979–80 seasons. Laboratory tests indicated that the mite Macrocheles glaber (Müll.), the hydrophilid Cercyon sp. and the histerid Saprinus sp. were all very effective predators. The native dung beetles Onthophagus granulatus Boh. and O. australis Guér. exerted only a marginal controlling effect; and the staphylinid and aphodiine beetles were found to be largely ineffective. The control exerted by the total field fauna when brought into the laboratory was considerable when one or more of the three species of effective predators was present. In the field trials, the control of M. vetustissima was further enhanced by the adverse influence of weather.

Some effects of three species of dung beetles (Coleoptera: Scarabaeidae) in south-western Australia on the survival of the bush fly, Musca vetustissima Walker (Diptera: Muscidae), in dung pads

AbstractThe effectiveness of three species of scarabaeids in reducing the survival of Musca vetustissima Wlk. in cattle dung was compared in laboratory experiments in Australia at 27°C in which the arthropod fauna collected in dung-baited traps in different localities at different times of year was added to one-litre dung pads containing known numbers of M. vetustissima eggs. The dung was collected from each site at the time of the experiment. Onitis alexis Klug collected in October and December at Geraldton, and Onthophagus binodis (Thnb.) collected in January at Bunbury, shredded most of the dung, reducing fly survival to 4% of that in control pads. O. binodis collected in March and October at Bunbury, and O. ferox Har. collected in May and December at Busselton, mostly buried dung, reducing fly survival to 32% of that in controls. Factors other than the numbers of beetles were also important in determining the degree of suppression of the fly.

Estimating absolute densities of the bushfly, Musca vetustissima Walker (Diptera: Muscidae), using West Australian blowfly traps

AbstractCatches of Musca vetustissima Wlk. in West Australian blowfly traps containing week-old baits were consistently greater (4·5–24·1 times higher) than in traps with fresh baits. Recovery of marked flies within 26·5h of release showed mean dispersal distances of 1·5 ± 0·7 km for males and 1·6 ± 0·6 km for females under favourable weather conditions (mean air temperature 28·8°C and mean wind speed 5·5 m/s). The recovery rate of males (1·3%) and females (1·0%) over this period indicates the feasibility of using single mark-release experiments to estimate absolute fly densities. It is shown that estimates having a 95% probability of being within ± 10% of the true population density could be achieved by the release of 39 000 marked flies.

Effects of introduced dung beetles (Coleoptera: Scarabaeidae) on the breeding and abundance of the Australian bushfly, Musca vetustissimaWalker (Diptera: Muscidae)

AbstractIn laboratory experiments in Australia under standard conditions, densities of the dung beetle Euoniticellus intermedius (Reiche) exceeding 150/1-litre pad of cattle dung were shown to suppress breeding of Musca vetustissima Wlk. The experiments also suggested that it was the effect of dung disturbance on the survival of eggs of the fly that led to suppression. Natural vaiation in the quality of cattle dung obscured but did not alter the effects of high beetle densities. The mobility of M. vetustissima in particular, obscured the relationship of its abundance to dung beetle numbers in the field in 1974–75 and 1975–77 an intial high level of flies was apparently reduced and suppressed by a seasonally late but otherwise similar level of beetle attack on dung pads.

Initial Assessment of an Introduced Polyphagous Alysiine Parasitoid Which Attacks the Australian Bushfly

Aspergillus japonicus Saito is a common soil-borne fungus, and exists on the surface of some cereal crop seeds. Secalonic acid F (SAF) is the main allelochemical from the fungus. Bioassays showed that SAF significantly stimulated the seedling growth of corn (Zea mays L.) at a concentration of 0.0375 mmol.L-1. The root length, root numbers and root oxidation activities increased by 31.7%, 13.2%, and 373%, respectively. Secalonic acid F also increased the nutrient absorption of P, K, Ca, Mg, and S at the same concentration. However, SAF inhibited the seedling growth of corn at concentrations of 0.3 mmol.L-1 and 0.6 mmol.L-1. The root length, root dry weight, and shoot length were inhibited by 27.7%, 39.1% and 35.8% by 0.3 mmol.L-1 of SAF, and root activities were inhibited by 72.1% and 100% by 0.3 mmol.L-1 and 0.6 mmol.L-1 of SAF, respectively. The nutrient absorption of N, P, K, Ca, Mg and Fe was reduced when the corn seedlings were treated with 0.3 mmol.L-1 SAF. Transmission electron microscope, observations showed that the corn treated with 0.3 mmol.L-1 of SAF had a swelling and disorderly arrangement chloroplast, and the stratiform structure of chloroplast became unconspicuous.

Mathematical model of the survival rates of female bushflies (Musca vetustissima Walker) (Diptera: Muscidae) as inferred from field populations

AbstractThe survival rate of the females of Musca vetustissima Wlk., the Australian bushfly, was determined as a function of age and size from an analysis of the age-size distribution of 11 530 females caught over a period of four years at three sites in south-eastern Australia. The mean length of life of the largest female flies commonly observed in the field was about 15·5 egg-stage periods, as compared to 8·5 for the smallest flies commonly observed. Over the same range of sizes, the breeding potential of a female varied by a factor of 22 to 1. It was found that the attractiveness of a human observer as a bait to female flies varied with the flies' reproductive state; taking the attractiveness to newly emerged flies to be unity, the attractiveness of the observer to flies that had just laid eggs was 1·22, and to flies in the pre-gravid stage 0·15. The mathematical model presented in this paper is appropriate for use in an overall model of bushfly population dynamics.