2008 Annual Report
1a.Objectives (from AD-416)
To accelerate and enhance the formulation of high performance insect diets that improve the fitness of mass reared insects used in research and insects used in the biological control of insect and weed pests by: .
1)improving the formulation of artificial diets and diet-delivery systems;.
2)determining the impact of nutrient substitutions on the efficiency of diet utilization; and.
3)developing genomic biomarkers to monitor fitness traits related to nutrition.
1b.Approach (from AD-416)
Formulation changes will be made to micronutrient levels and substitutions will be made for the fibrous, temperature sensitive and antibiotic materials in artificial diets as part of an empirical-based effort to improve artificial diets. Life history measurements will be used to assess the impact those dietary changes on the health of the insect. The impact of dietary component changes on the biochemical fate of nutrients will be monitored. Enzymatic activity and metabolism of nutrients will be used to assess the impact of dietary changes on the efficiency of nutrient absorbance and nutrient utilization. The use of genomic biomarkers as indicators of fitness for insects reared on diets varying in nutritional quality will be investigated. Differentially-expressed genes will be identified using suppressive subtractive hybridization and microarray analyses.
Changes in the formulation of our insect predator diet were tested to investigate different nutrient sources for cost savings and different materials to minimize texture and contamination problems. Beneficial insects were reared on the modified diets and tested for improved growth and performance. Additionally, modifications to the formulation of the insect predator diet were also tested for rearing newly emerging pest insects. Promising leads from these preliminary studies will be pursued using life history analyses and genomic and proteomic probes. Our diet and rearing systems developed for the glassy winged sharpshooter were transferred to another ARS unit to assist in their studies of vectoring Pierce’s Disease in grapes. Consultation continues to be provided to that unit. Results from our studies investigating the effect biofortification of plants may have on biological control agents demonstrated that beneficial parasites performed well against insect pests reared on fortified diets. The intent of these studies is to forecast the influence plant biofortification will have on the physiology of insect pests and subsequently the effectiveness of beneficial agents in controlling pest insects in biofortified cropping systems. Studies continued on using proteomic probes to investigate the functional relationships between food and performance of mass reared fruit flies of agricultural importance. The intent of these studies is to discover linkages between diet components and the regulation of specific genes and proteins in fruit flies. Those linkages will lead to the development of biomarkers that can be used to optimize artificial diets and to measure fitness of the mass reared insects. Work also continued in the investigation of enzymatic steps in the synthesis pathway of lipid mediators responsible for regulating a variety of physiological processes. These studies have made use of specific enzyme inhibitors and insect cell culture techniques to delineate the function of these lipid mediators at the cellular level. Progress has been made in the purification of a critical enzyme in this pathway. The intent of these studies is to investigate the possibility of developing novel biologically-based approaches to pest insect control. These activities directly address goals of NP 304 Action Plan, Part II, Section B (Rearing of Insect Mites) and Component V (Pest Control Technologies), Goal 2 (Efficient production, delivery and utilization of beneficial organisms used in BC).
Impact of biofortification of plants on the effectiveness of biological control agents. The success of research and commercial efforts to improve the nutritional value in plants has the potential to benefit insects as well as humans and livestock and by doing so could make it more difficult to control pest insects with biological control agents. Recent studies have shown that beneficial bacteria and fungi are less effective in controlling pest insects that feed on ascorbic acid-enhanced diets which were used to mimic a nutritionally enhanced plant. Those reports demonstrate the need for more information on how nutritionally enhanced plants affect the relationship between beneficial agents and pest insects. Results from our studies showed that a beneficial insect manifested improved biological traits when reared on a pest insect fed a diet enhanced with ascorbic acid. This discovery demonstrates that the most effective biological control agent in cropping systems comprised of nutritionally enhanced plants may prove to be a beneficial insect rather than the beneficial pathogen. Both researchers and commercial groups will find this information to be of considerable importance as they test ways to enhance a wide variety of nutritional substances in plants. This accomplishment directly addresses goals of NP 304 Action Plan, Part II, Section B (Rearing of Insect Mites) and Component V (Pest Control Technologies), Goal 2 (Efficient production, delivery and utilization of beneficial organisms used in BC) and within the Research Component B (Weed Science) Part II, Section D (Combining BC Agents).
5.Significant Activities that Support Special Target Populations
Scientists on this project have mentored a visiting scientist from the Biotechnical Institute at the University of Montenegro in Podgorica, Montenegro. The visiting scientist was awarded a Norman Borlaug Fellowship and selected the insect nutrition program at BCIRL in order to advance her knowledge and skills in the areas of using parasitoids and predataors for insect pest control and mass rearing and release of beneficial insects.
Coudron, T.A., Brandt, S.L., Hunter, W.B. 2007. Molecular profiling of proteolytic and lectin transcripts in Homalodisca vitripennis (Hemiptera: Auchenorrhyncha: Cicadellidae) feeding on sunflower and cowpea. Archives of Insect Biochemistry and Physiology. 66(2):76-88.
Li, W., Li, J., Coudron, T.A., Lu, Z., Pan, W., Liu, X., Zhang, Q. 2008. The role of photoperiod and temperature in diapause induction of the endoparasitoid wasp, Microplitis mediator (Haliday) (Hymenoptera: Braconidae). Annals of the Entomological Society of America. 101(3):613-618.
Durmus, Y., Buyukguzel, E., Terzi, B., Tunaz, H., Stanley, D.W., Buyukguzel, K. 2007. Eicosanoids mediate melantoic nodulation reactions to viral infection in larvae of the parasitic wasp, Pimpla turionellae. Journal of Insect Physiology. 54:17-24.
Schmid, M.R., Brockmann, A., Perk, C.W., Stanley, D.W., Tautz, J. 2008. Adult honey bees (Apis mellifera L.) abandon hemocytic, but not phenoloxidase-based immunity. Journal of Insect Physiology. 54:215-221.
Merchant, D., Ertl, R.L., Rennard, S.I., Stanley, D.W., Miller, J.S. 2007. Eicosanoids mediate insect hemocyte migration. Journal of Insect Physiology. 54:215-221.
Coudron, T.A., Shelby, K., Ellersieck, M.R., Odoom, E.D., Lim, E.E., Popham, H.J. 2008. Developmental response of Euplectrus comstockii (Hymenoptera: Eulophidae) to ascorbic acid in the diet of the larval host, Heliothis virescens (Lepidoptera: Noctuidae). Biocontrol. 54:175-182.
Stanley, D.W., Miller, J.S. 2008. Eicosanoid actions in insect immunology. In: Beckage, N., editor. Insect Immunology. Elsevier. p. 49-67.