Location: Agroecosystem Management Research
2019 Annual Report
Objectives
Objective 1: Develop sustainable methods for the management of stable flies and other flies impacting livestock production.
Sub-objective 1.1 Identify and test larvicides for stable flies and other flies developing in livestock wastes.
Sub-objective 1.2 Develop attractants for use on traps.
Sub-objective 1.3 Develop adult fly repellents with extended residual activity.
Sub-objective 1.4 Evaluate effects of stable flies on behavior and productivity of cattle.
Sub-objective 1.5 Evaluate the effectiveness of a Push-Pull stable fly management strategy.
Objective 2: Characterize effects of biological, chemical, and physical substrate properties on stable fly larval development.
Sub-objective 2.1 Characterize functional groups of microorganisms in substrates associated with stable fly and house fly larval development.
Sub-objective 2.2 Identify endosymbionts and parasitoids associated with stable flies.
Sub-objective 2.3 Characterize nutritional factors required for stable fly larval development.
Objective 3: Develop a physiologically based demographic model (PBDM) to predict temporal and spatial patterns of stable fly population dynamics under current and potential climatic conditions.
Sub-objective 3.1 Determine physiological responses of stable fly developmental stages to environmental variables.
Sub-objective 3.2 Incorporate parameters from 3.1 into PBDM.
Sub-objective 3.3 Validate PBDM.
Approach
Stable flies are among the most serious arthropod pests of livestock in the United States, costing producers in excess of $2 billion per year in lost production. They exhibit an extraordinary ability to adapt to, and exploit, regional agricultural and animal husbandry practices. Stable fly management has proven to be a daunting task largely due to their adaptability, mobility, and gaps in our knowledge of their behavior and biology. This project will address all of these issues. Primarily, the project will develop new methods for the management of stable flies by exploiting the most vulnerable stages in their life cycles. Secondarily, we will develop a better understanding of stable fly biology and how they interact with their environment and hosts. Finally, new and existing information on stable fly biology will be incorporated into a dynamic, physiologically-based demographic model. This model will permit us to predict the dynamics of stable fly populations under real and potential environmental conditions, as well as provide insight into the validity of our understanding of their interactions with biotic and abiotic factors in the environment for development and reproduction. Successful completion of this project will result in new technologies for the management of stable fly populations, reduced impact of stable flies on livestock production systems, and a greater understanding of their biology for the continued development and evolution of stable fly management technologies.
Progress Report
This is the final report for project #3042-32000-010-00D, which expired in FY2019 and was replaced by project #3042-32000-011-00D.
New technologies for the management of stable flies were developed and evaluated. Several formulations of botanical and Insect Growth Regulator (IGR) compounds were evaluated for their larvicidal effects in laboratory and field bioassays. Two IGRs, cyromazine and novaluron, of different insecticide activity classes provide season long control of stable fly larvae developing in winter hay feeding sites with a single application. Novaluron significantly reduces the numbers of stable flies emerging from pineapple residues. An encapsulated formulation of catnip oil showed over 90% efficacy for stable fly larvae and pupae in laboratory tests. Methyl laurate, a newly identified coconut fatty acid derived compound exhibits strong toxicity against adult stable flies as well as strong repellency. A starch-based coconut fatty acid formulation developed in collaboration with ARS, University of Nebraska - Lincoln and Costa Rican colleagues deters stable flies from laying eggs and acts as a biopesticide (Subobjective 1.1).
Attractant compounds from fermenting substrates and host animals were identified including m-cresol, p-cresol, 1-octen-3-ol, 2-phenylethanol, short chain fatty acids (C3, C5, C6), and nitrogen- and sulfa compounds. Traps baited with these compounds collect 30-50% more stable flies than unbaited traps. Slow-release formulations of attractants were tested in the feedlot environment using white panel traps. Several compounds were evaluated for activity as oviposition attractants in laboratory assays. Field trials of an attractant-impregnated adhesive for an automatic trapping device were conducted as part of a cooperative research and development agreement CRADA with Nitto Denko. Visual sensitivity of stable flies was examined with a novel electroretinogram (ERG), indicating that blue, green, orange, and red may enhance trap attraction. (Subobjective 1.2).
Novel repellents were identified and evaluated. Medium chain fatty acids including lauric acid, capric acid and caprylic acid from coconut oil effectively repel biting flies (stable fly and horn fly), ticks, bed bugs and mosquitoes. A water-based amylose starch complex formulation containing 15% coconut fatty acids protects cattle from biting flies for 96 hours. Longevity and effectiveness are better than those of DEET. (Subobjective 1.3).
Push-Pull field trials were conducted in collaboration with scientists from University of Nebraska. Stable flies are effectively driven away from repellent treated cattle and visit trap animals treated with insecticide, but no repellent, where they receive a fatal dose of insecticide. An insecticide impregnated screen for stable fly control and several trap designs, including a new pre-glued card trap, were evaluated. Collaborative investigations involving scientists at Clay Center, Nebraska, Kerrville, Texas, University of Tennessee and University of Arkansas to identify genetic markers associated with host susceptibility to biting fly infestations continue (Subobjective 1.5).
Bacterial and fungal isolates from stable fly larvae and pupae were cultured. Isolates were identified with matrix assisted laser desorption ionization time-of-flight MALDI-TOF mass spectrometry. Serratia marcescens, a pathogen of stable fly larvae, was the most prevalent isolate. Additionally, substrate from a common larval developmental source (a hay, urine, and manure mixture collected from calf bedding) was submitted for 16S and 18S sequencing. Flavobacterium are the dominant bacteria in substrates supporting stable fly larval development (Subobjective 2.1).
A new species of Herpetomonas was isolated from stable flies. The 18S rRNA gene was partially sequenced and found to be most similar to Herpetomonas ztiiplika, a trypanosomatid isolated from a biting midge. Infection with the herpetomonad is ubiquitous; stable flies of all life stages are infected in field collections. (Subobjective 2.2).
Stable fly pupae were collected from field sites and processed for subsequent isolation and identification of pteromalid parasitoids. Five species of Spalangia and two species of Muscidifurax were collected parasitizing stable fly pupae (Subobjective 2.2).
Sequencing of 16S and 18S amplicons from substrates and the gut microbiota of third instar stable fly larvae revealed that the microbiota of the third-instar stable fly larvae is distinct from that of the supporting substrate. The microbiotas of larvae reared on different substrates are more similar to each other than those of their individual supporting substrates. (Subobjective 2.3).
The development of stable flies relative to temperature and diet quality was assessed. Diet quality primarily affected the size of the flies whereas temperature was primarily responsible for developmental rate. The poorest diets produced fly pupae weighing less than 4 mg while the best diets produced pupae weighting over 16 mg. The length of the distal-medial cell of adult flies was correlated with the weight of the pupa. Diet quality has no affect on the sex ratio of the flies, but female flies are about 5% larger than males. Female and male stable flies develop at the same rate (Subobjective 3.1).
Supplementing larval developmental substrates with ammonium bicarbonate increases egg to adult survival 2-fold with no effect on size. Other ammoniacal salts including ammonium chloride, ammonium hydroxide, ammonium phosphate and ammonium sulfate had either no effect or a negative effect on survival.
A thirteen-year data set of stable fly trap catches at a location in eastern Nebraska was analyzed. Temperature 0 to 3 weeks before collection date had the greatest effect upon trap catches followed by precipitation 2 to 7 weeks prior to collection. Optimal conditions for stable flies were a mean temperature of 21°C and a mean of 10 mm of precipitation per day. Life history data are being incorporated into models to describe stable fly population dynamics (Subobjective 3).
Assays characterizing stable fly larval olfaction were developed. Fifty-four compounds from ten chemical classes were evaluated. Larvae were highly attracted to ammonia and moderately attracted to several esters. In choice tests, stable fly larvae migrate into substrates with increased ammonia concentrations (Subobjective 3.1).
Accomplishments
1. Coconut free fatty acids-based repellent formulations for animal protection. Flies and other biting insects are annoying and potentially dangerous causing suffering and transmitting diseases among humans and livestock. ARS scientists in Lincoln, Nebraska, developed a novel starch-pectin water-based formulation of coconut fatty acids for use on livestock and companion animals. This formulation repels biting flies for up to 5-days in pasture settings. Formulations, including lotions, sunscreen-based and lavender oil-based, effectively repel mosquitoes.
Review Publications
Friesen, K.M., Berkebile, D.R., Zhu, J.J., Taylor, D.B. 2018. Laboratory rearing of stable flies and other muscoid diptera. Journal of Visualized Experiments. (138):e57341. https://doi.org/10.3791/57341.
Zhu, J.J., Cermak, S.C., Kenar, J.A., Brewer, G., Haynes, K., Boxler, D., Baker, P., Wang, D., Wang, C., Li, A.Y., Xue, R., Shen, Y., Wang, F., Agramonte, N.M., Bernier, U.R., Filho, J., Ligia, B., Taylor, D.B., Friesen, K.M. 2018. Better than DEET repellent compounds derived from coconut oil. Nature Scientific Reports. 8:14053. https://doi.org/10.1038/s41598-018-32373-7.
Mckay, L., Delong, K.L., Schexnayder, S., Griffith, A.P., Taylor, D.B., Olafson, P.U., Trout Fryxell, R. 2019. Cow-calf producers' willingness to pay for bulls resistant to horn flies, Haematobia irritans (L.) (Diptera: Muscidae). Journal of Economic Entomology. Vol 112(3):1476-1484. https://doi.org/10.1093/jee/toz013.
Olafson, P.U., Kaufman, P.E., Duvallet, G., Solorzano, J., Taylor, D.B., Trout Fryxell, R. 2019. Frequency of kdr and kdr-his alleles in stable fly (Diptera: Muscidae) populations from the United States, Costa Rica, France, and Thailand. Journal of Medical Entomology. Vol 56(4):1145-1149. https://doi.org/10.1093/jme/tjz012.
Florez-Cuadros, M., Berkebile, D.R., Brewer, G., Taylor, D.B. 2019. Effects of diet quality and temperature on stable fly (diptera: muscidae) development. Insects. 10(7):E207. https://doi.org/10.3390/insects10070207.
