via ARIS system
Novel methods for insect control that target developmental processes especially those triggered by juvenile hormone are needed as a number of chemical toxicants such as organophosphate insecticides have come under increased scrutiny due to environmental concerns. Before joining ARS, I have embarked on my Ph.D. research program to screen a series of non- mutagenic anti-juvenile hormone derivatives extracted from Panama woods using Y-choice olfactometer and identified them as a bio-rational insecticide. These studies demonstrated that anti-juvenile hormone analogs (JHA), benzyl-1,3-benzodioxoles (BBDs) compounds, and precocene II, influenced sex attractancy, while BBDs affected development and reproduction, in the Mediterranean fruit fly, Ceratitis capitata. Topical, oral, and contact application of these compounds caused cytological effects on spermatogenesis, vitellogenesis and juvenile hormone binding. Some of these effects can be restored by juvenile hormone (JH) therapy. This discovery has pioneered the modern research to the application of methoprene (JH analogue) to adult fruit flies such as Anastrepha spp. and Bactrocera spp. to accelerate sexual development in operational SIT programs. Since joining USDA-ARS in 1997, I have been conducting research to develop new or improved fruit fly rearing diets and methodologies to enhance fruit fly quality and to transfer these technologies to other countries to support SIT program worldwide. My major research accomplishments are presented below:
Ascorbic Acid Improves Fruit Fly Quality
Do you know why bell pepper was listed as one of the most commonly infested cultivated hosts of Solananceous fruit fly, Bactrocera latifrons? Because bell pepper possess high concentration of vitamin C (ascorbic acid) which plays an essential role in the nutrition of plant feeding insects,. Bactrocera latifrons was the 4th most economic important fruit flies in Hawaii and was massreared at the USDA-ARS rearing facility since 1983 when it was established in Manoa, Hawaii on a carrot powder diet. Pupal production was low as compared to the other three fruit flies species in Hawaii. An ascorbic acid-rich diet was developed for the Solanaceous fruit fly, Bactrocera latifrons, which significantly enhanced production. This research demonstrated, for the first time that ascorbic acid is beneficial for B. latifrons pupal development and has been implemented in the USDA-ARS mass rearing facility in Honolulu where an ascorbic acid supplement (e.g., pumpkin powder) was added to the larval diet. This addition increased overall production (15% higher) and improved fly quality such as adult emergence (13% higher). This work has been cited as exemplary of highly effective diet improvement research in "Insect diet" book by Dr. Allen Cohen.
Developed Chemically Defined Diets for Medfly
When a colony crashed in a fruit fly rearing facility, there is no easy way to findout what is the cause because most mass rearing diets have been composed of whole foods, i.e., yeast, one that were not chemically defined. For decades, diet improvement was remained in the stage of replacement or addition of ingredients despite of the nutrients the insect needs. We did not have well established nutritional information of fruit fly diet available because it was not an easy subject to be studied. Development of a completely chemically defined diet for Mediterranean fruit fly adults and a semi-chemically defined meridic diet, with only one undefined ingredient along with trace amount of nutrients for the Mediterranean fruit fly larvae has initiated this rescue. This research provided mass rearing facilities worldwide with useful nutritional information and guideline for diet development, diet improvement, or diet ingredient selection. It also demonstrated that both adults and larvae of Mediterranean fruit fly require similar nutrients for survival and the currently used adult diets need to be improved to increase egg production because the need of fatty acid in the diet. In the practical level, this work has been adopted by: (1) COLTEC-LALLEMAND, a bio-ingredient company in Guatemala, developed a vitamin/protein enriched diet for adult flies based on this adult diet recipe; (2) Dr. David Nestel (Institute of Plant Protection, The Volcani Center, Israel) for his research on lipid and protein loads in pupating larvae and emerging adults. Dr. Chang and Dr. Il Kyu Cho were further to discover the effect of niacin on fruit fly larvae and their dosage interaction with other B vitamins that affect fruit fly larval development through this meridic diets. This work also resulted in expert mission invited by the International Atomic Energy Agency (IAEA) to consult and demonstrate the meridic Mediterranean fruit fly larval diet in Seibersdorf, Austria in 2002; and by USDA-APHIS-PPQ California Cooperative Medfly Preventive Release Program to consult on improving the pre-released Mediterranean fruit fly adult diet.
Opened A New Avenue In Fruit Fly Rearing - Liquid diet
The performance of current used conventional diet using wheat products (e.g., millfeed, bagasse) as supporting substrates has been satisfactory. However, the cost spent on used diet disposal has been the single greatest costs of deploying this technology to SIT for control and eradication programs. This includes the costs of space, labor, and ingredients used to mass-rear the flies. The discovery of an inert and reusable sponge cloth as supporting substrate to replace wheat product along with to reduce the tray size; and evaluate ingredient quality, e.g. 25 available commercialized yeast products used in larval or adult diets, has pioneered the development of a liquid larval diet for mass rearing Bactrocera speciesfruit flies to ease up the used diet disposal management, space, and cost saving, and the quality assurance of liquid diet reared fruit flies. Over 12 generations fly performance tests of liquid diet reared fruit flies under laboratory and large scale field conditions has assured the fly quality of these flies, including mating competitiveness. This work opened a whole new avenue of research and practical application in tephritid fruit fly rearing. It suggested possibilities for diets and mass rearing in a more cost effective, space-saving, labor saving, and environmentally friendly manner. It can save up to $100,000 per year used diet disposal. It also presented options for other species that were conventionally considered as restricted to solid or semi solid food. Insects reared from this technology can be utilized as sample resources for advanced nutrigenomics and nutriproteomics research.
Pioneered on Fruit Fly Nutri-Proteomics Research
We now know what type of diets/nutrients can satisfy fruit fly development, butwereally did not know what these nutrients do in fruit fly system remains a puzzle for us. Therefore, a proteomics research that studies the protein interaction, transformation, functionality will be necessary to unveil fruit fly biological process. Fruit fly nutriproteomics research using liquid-diet or meridic-diet-reared insects as sample resources were initiated. Dietary nutrients such as niacin, wheat germ oil or other fatty acids, provided during the larval stage, altered larval and adult protein patterns which thereby affected optical receptor development in the larval stage or vitellogenesis in adult stages were demonstrated. Further research to understand the functional interactions between diet nutrients, protein, and performance are underway. This research is the collaboration among ARS-PBARC, ARS Columbia, Missouri, and University of Hawaii. ARS-PBARC developed the idea through her diet research, conduct 2-D analysis, and then provided the resulted samples for MS/MS analysis in cooperation with Drs. Qing X. Li, Il Kyu
Cho, of the University of Hawaii at Manoa and Dr. Thomas A. Coudron and David Stanley of USDA-ARS-BCIRL in Columbia, Missouri. ARS conducted the bioassay and protein analysis aspect of the research while Drs. Li, Cho, Coudron, Stanley were responsible for the biochemical aspect of the research. Drs. Li, Cho, Coudron, Stanley and I analyzed and reported the research results through equal contributions. The functional role of nutrition on larval, pupal and/or adult performance is for most insects non-empirical. The impact of this research is that the basic level, we produced linkages between specific diet components and regulation of specific insect genes and proteins, from which we will be able to understand the mechanisms of how diets influence performance parameters. At the practical level, we are identifying key biomarkers that can in turn be linked with specific nutrients and used to accelerate the development of optimal diets.
Liquid Diet Technology On Fruit Fly Genetic Sexing Strain
Over two billion Mediterranean fruit flies/week are mass-reared for use in sterileinsect technique (SIT) driven pest control programs worldwide. Use of the liquid diet for mass production of tephritid fruit fly has the potential to save big expenses on labor, material, and space. After the breakthrough in the development of liquid larval diet for Bactrocera species, development of a liquid diet for both bisexual and genetic sexing strains of a worldwide economically important pest, the Mediterranean fruit fly were emerged. This work attracted eleven Mediterranean fruit fly rearing groups worldwide to evaluate this diet in their countries. These eleven groups include Argentina, Austria, Guatemala, Italy, Kenya, Slovakia, United Kingdom, Western Australia, Israel, USA, and Belgium. This technology has been demonstrated successfully on a small or large scale (20 trays a stack) in the California Department of Food and Agriculture (CDFA) Mediterranean fruit fly rearing facility in Waimanalo. It has resulted in invitations by IAEA for consultation on rearing olive fruit fly and Mediterranean fruit fly (Vienna 8 strain) use this technology and by ARC/LNR, Stellenbosch, South Africa for demonstration of applicability of the liquid diet to the Mediterranean fruit fly mass rearing facility in South Africa. Currently, Stellenbosch is working to implement this technology in their rearing facility.
Transferred Liquid Diet Technology through A Starter Kit and Onsite Demonstration
A breakthrough of rearing fruit fly larvae, both Bactrocera species andMediterranean fruit fly, in a sponge cloth supported liquid diet has been successfully developed and has been proved as competitive performer as those of conventional diet both in the lab and field. In order to implement this new technology, we first have to persuade the potential user to adopt into our product. It would be more persuasive if we can offer some hands-on or demonstration experience on our products as technology transfer means. We transferred the liquid diet technology to other interested users through composing a liquid diet starter kit, and sending it to interested groups at both fruit fly and non-fruit fly rearing facilities worldwide for evaluation. Starter kit evaluation should be considered the basis of potential large scale implementation. Upon successful evaluation on starter kits, the users were requested to evaluate the diet incorporating their local materials, and then larger scale implementation will be reinforced with each user's availability. This work has greatly encouraged IAEA cooperative research program (CRP) participating countries to initiate the use of this technology in their rearing programs, has established 31 cooperative agreements with both newly emerging and already established fruit fly rearing facilities worldwide to evaluate this new technology with hands-on experience before implementing it on a mass scale, and has implemented this technology at larger scales using local materials in rearing facility in Mauritius, the Philippines, Thailand, Kenya etc. This technology has also attracted the attention of non-fruit fly rearing specialists to evaluate on house flies and spider mites etc.
Discovered Insecticidal Effect of Basil Oil on Fruit Fly
Fruit fly male attractants, i.e., methyl eugenol and cuelure, currently used in IPMprogram for annihilation to control fruit flies are solely to attract male fruit flies to the traps. To kill these attracted flies, a pesticide is needed. If we can have one formulation that possesses both attract and kill properties, it would simplify the control methods and achieve the goal. Basil oil and its constituents are highly toxic to three adult fruit flies species has been discovered and identified physiological interactions between these constituents and male sex attractants (e.g., methyl eugenol and cuelure).The idea was developed through unexpected observation of oriental fruit flies swarmed in a basil plant in a residential area in Honolulu. Oriental fruit flies were attracted to basil in the lab evaluation as well. Basil oil was purchased in Riverside, California and expected to see the similar response as in basil plant. Surprisingly, basil oil was proved that possesses insecticidal property instead. The constituents of basil oil was analyzed and identified through the cooperation with Drs. Qing Xiao Li and Il Kyo Cho of the University of Hawaii at Manoa. I conducted the bioassay aspect of the research while Drs. Li and Cho were responsible for biochemical aspect of the research. We analyzed and reported the research results through equal contributions. Dr. Li suggested and filed for provisional patent application. This research has led to a provisional patent between the USDA and the University of Hawaii on a novel formulation and a method to develop a novel formulation has potential for controlling insects such as fruit flies and house flies in a quick and efficient way is underway.
Service, Leadership and Participation in Professional Activities:
Honors, Awards, Achievements and Recognition: