Stable Fly Adults Research Articles

Spatial repellency, antifeedant activity and toxicity of three medium chain fatty acids and their methyl esters of coconut fatty acid against stable flies.

Stable flies are one of the most detrimental arthropod pests to livestock. With changing climates and agronomic practices, they expand their roles as pests and disease vectors as well. Their painful bites reduce livestock productivity, annoy companion animals, and interfere with human recreational activities. Current management technologies are unable to effectively control stable flies. The present study reports new results concerning the contact, spatial repellency, and toxicity of a bio-based product, coconut fatty acid and their methyl ester derivatives of free fatty acids of C8:0 , C10:0 and C12:0 to stable flies. Three medium chain fatty acid methyl esters (C8:0 , C10:0 and C12:0 ) showed strong antifeedant activity against stable flies and their strengths were dose-dependent. Only the C8:0 acid, C8:0 - and C10:0 methyl esters elicited significant antennal responses. Laboratory single cage olfactometer bioassays revealed that coconut fatty acid and C8:0 methyl ester displayed active spatial repellency. All three methyl esters showed strong toxicity against stable flies. Antifeedant activity is the main method through which coconut fatty acid deters stable fly blood-feeding. The C8:0 , C10:0 and C12:0 methyl esters act not only as strong antifeedants, but also possess strong toxicity against stable fly adults. Limited spatial repellency was observed from coconut fatty acid and C8:0 methyl ester. © 2019 Society of Chemical Industry.

Dispersal of Stable Flies (Diptera: Muscidae) From Larval Development Sites in a Nebraska Landscape

Seven mark-recapture studies were conducted over 3 yr to assess dispersal of newly emerging adult stable flies, Stomoxys calcitrans L., from larval development sites in a mixed agricultural environment in northeastern Nebraska. Infested hay debris piles were marked by dusting their surfaces with fluorescent pigments, adults were captured with surrounding grids of Alsynite sticky traps, and specimens were dissected to determine feeding histories and reproductive age. Distances and directions of 3,889 marked specimens indicated males and females dispersed equally and in all directions. Midguts of males and females were equally likely to contain blood-meal remnants. Percentage with blood remnants and percentage of females with yolk increased with distance from mark origin, indicating survival and spread were positively associated with host finding success. A time-integrated diffusion model fit to results from the seven studies indicated 50% of stable fly adults had dispersed beyond 1.6 km of their natal site, but only 5% had dispersed beyond 5.1 km. These results indicate that stable fly adults on cattle in a given area are most likely to have originated from larval development sites within an ≈ 5 km radius of the subject cattle.

Retention ofEscherichia coliby House Fly and Stable Fly (Diptera: Muscidae) During Pupal Metamorphosis and Eclosion

Populations of Escherichia coli obtained by feeding larval house flies, Musca domestica L. and stable flies, Stomoxys calcitrans (L.), persisted through the pupal stage. The abundance of E. coli in house fly pupae increased initially then declined before adult emergence. Abundance of E. coli in stable fly pupae increased through pupal development and remained high. Infected stable fly pupal cases typically contained more E. coli than house fly pupal cases. A greater proportion of emerging adult house flies were infected with E. coli compared with stable flies; however, the abundance of E. coli on infected flies was similar between species. Adult flies contained 0.04-0.19% of the E. coli in the pupal cases. The proportion of infected house fly adults and the amount of E. coli on the infected flies were related to the levels of E. coli in the pupal cases; however, these relationships did not occur with the stable fly. Results suggest that retention of E. coli from larval to adult house flies could play a role in the transmission and spread of E. coli, whereas stable fly adults probably play a minor role in E. coli spread. However, pupae of both species have potential to act as reservoirs for E. coli.

Influence of temperature, humidity and rainfall on field population trend of Stomoxys calcitrans (Diptera: Muscidae) in a semiarid climate in Mexico

The influence of temperature, humidity and rainfall on field population trend of stable fly, Stomoxys calcitrans, over three consecutive years in two dairy farms located in semiarid climate in Aguascalientes State, in Mexico, were determined. The dairies were visited weekly between April 1999 to March 2002, on each occasion 10% of the dairy cows were selected making direct counts of stable flies observed front the legs. The occurrence of stable fly adults from weekly counts was divided in four population phases: population increasing phase I (first peak), fluctuation phase, population increasing phase II (second peak) and population decreasing phase, for each year of study. Pearson’s correlation analysis was developed (P < 0.01) between weekly average fly number per cow and mean temperature, mean relative humidity and rainfall recorded from one to four weeks before count in each population phases. The population increasing phase I, was observed in spring-summer period, in where relative humidity had significant correlation indices (r = 0.6 to 0.8), the first peak occurred in September, June and August, of each year studied, respectively. The population-decreasing phase was observed between last weeks of summer and in the fall, showed high correlation indices with temperature (r = 0.9). No significant correlations were founded with the rainfall over the study.

Biology and control of tabanids, stable flies and horn flies.

Tabanids are among the most free-living adult flies which play a role as livestock pests. A single blood meal is used as a source of energy for egg production (100-1,000 eggs per meal), and females of certain species can oviposit before a blood meal is obtained (autogeny). Therefore, the maintenance of annual populations requires successful oviposition by only 2% of females. Wild animal blood sources are usually available to maintain annual tabanid populations. Larval habitats are also independent of domestic livestock. Thus, the use of repellents or partial repellents is the only effective chemical strategy to reduce the incidence of tabanids on livestock. Permanent traps (and possibly treated silhouette traps) can be employed to intercept flies. Selective grazing or confinement can also reduce the impact of tabanids. Stable fly adults are dependent on vertebrate blood for survival and reproduction, but the amount of time spent in contact with the host is relatively small. Stable fly larvae develop in manure, spilled feed and decaying vegetation. Management of larval habitats by sanitation is the key to stable fly control. Treatment of animals with residual insecticides can aid in control; thorough application to the lower body parts of livestock is important. Proper use of modified traps, using either treated targets or solar-powered electrocution grids, can be effective in reducing stable fly populations. Adult horn flies spend the major part of their time on the host, and the larvae are confined to bovid manure. Therefore, almost any form of topical insecticide application for livestock is effective against horn flies, in the absence of insecticide resistance. Treatments should be applied when economic benefit is possible; economic gains are associated with increased weaning weights and weight gains of yearling and growing cattle. Oral chemical treatments (insect growth regulators or insecticides) administered at appropriate rates via bolus, water, food or mineral mixtures can inhibit horn fly larval development. However, adult horn fly movement among cattle herds limits the use of larval control for horn fly population management. The augmentation of native parasites, predators and competitors has been attempted and even promoted for horn fly and stable fly control, but evidence for the success of such programmes is equivocal.

Origin of Stable Flies (Diptera: Muscidae) on West Florida Beaches: Electrophoretic Analysis of Dispersal

Stable fly adults were collected from 16 locations within the state of Florida and from locations in six other states in an attempt to determine the source of stable fly populations along Florida beaches on the Gulf of Mexico. Electrophoretic analyses were made of a minimum of 10 enzymes in each of 37 separate populations. Extremely low heterozygosity resulted in an inability to use standard genetic identity and distance procedures for determining the divergence of allopatric populations to establish the source of flies captured from beach areas where reproduction was unlikely. Comparisons of rare alleles in populations grouped geographically, computations of number of possible migrants, and analysis of conditional average frequency of alleles led to the conclusion that flies captured on Florida beaches come from a variety of sites, with locations northwest of the beaches contributing the majority of flies in outbreaks.

Reproductive performance of adult stable flies (Diptera: Muscidae) when fed fresh or reconstituted, freeze-dried bovine or porcine blood.

The reproductive performances were compared of adult stable flies, Stomoxys Calcitrans (L.), fed fresh porcine or bovine blood or reconstituted, freeze-dried porcine or bovine blood. Adult stable flies fed fresh or reconstituted, freeze-dried porcine blood oviposited significantly more eggs than adults fed fresh or freeze-dried bovine blood. No decline in fecundity was observed for adults maintained for 10 successive generations on fresh porcine blood or on reconstituted, freeze-dried porcine or bovine blood. However, fecundity of adults maintained on fresh, heparinized bovine blood declined in later generations. The data provide evidence that stable fly adults can be maintained successfully on reconstituted, freeze-dried blood, and that porcine blood is nutritionally superior to the blood of cattle.

The analytical determination of proctolin by HPLC and its pharmacological action in the stable fly

1. A method utilizing high-performance liquid chromatography as a purification technique and also for quantitative analysis of proctolin (Arg-Tyr-Leu-Pro-Thr) in whole-body extracts of the stable fly, Stomoxys calcitrans (L.), has been developed. 2. Analysis of newly eclosed stable fly adults showed proctolin present at a concentration of 12.4 ± 0.66 ng/g insect. Recovery of proctolin from spiked extract was > 90%. 3. Proctolin (4 × 10 −9 M) caused a noticeable increase in both the frequency and amplitude of spontaneous contractions in the hindgut of the stable fly.

Feeding Incidence of Stable Flies 1 on Beef Cattle, as Influenced by Temperature, Relative Humidity, and Light

Much knowledge about the stable fly, Stomoxys calcitrans (L.), remains to be gathered before successful control of this pest can be achieved. For example, we need to know some of the habits of the adults, including the way their feeding behavior is affected by various climatological conditions. Simmons (1944) stated that in tests conducted in Sarasota, FL, stable fly adults fed more readily in the early morning and late afternoon than they did at midday. However, since time is only relative, we cannot attribute this varied biting rate to time of day, but instead to the environmental conditions that were prevalent during those hours.