Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Outputs (Narrative): Chemistry and Biological functions of preen gland secretions of six species of birds - Black-capped Chickadee, Tree Swallow, American Robin, House Finch, American Goldfinch and House Sparrows were investigated. The secretions were collected several times a year from about 100 individual birds that were trapped in mist nets and by other methods. Chemistry of the secretions was investigated using several analytical methods such as Liquid and Gas Chromatography (LC and GC) and spectroscopic methods that included Mass (MS), Fourier Transformed-Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. We tested the importance of preen gland secretions to feather mites using choice bioassays. We also conducted manipulative experiments whereby, we altered mite load on birds to test the effect of presence or absence of mites on preen gland secretion compositions. To test this, we altered mites on birds and collected secretions from the birds every 7-14 days for 3.5 months. We analyzed the secretion components using both GC-MS and LC-MS techniques. We also conducted choice bioassays to test the effect of altered secretions on the mites. We in collaboration with Kent Loeffler of Plants sciences, Cornell University, using intervolometer experiments (monitoring feeding using a camera that takes pictures every few seconds), observed the real-time events in choice bioassays as to when and how mites feed on secretions. We are collaborating with Scott Robinson of University of Illinois to study how the secretions are applied and how they spread on the feathers using Environmental Scanning Electron Microscopy (ESEM) techniques. We are continuing to collect data for a few species that could not be collected due to various logistical reasons such as weather conditions and nest failures etc. in the past years. The results from the above data are being analyzed and incorporated into three manuscripts to be submitted to peer-reviewed journals in coming months. Our collaborators, Prof. Burtt and students in Ohio Wesleyan University conducted studies on the microbial organisms found on the feathers and effect of preen gland secretions on these microbes. Prof. Proctor of University of Alberta is identifying the mites involved in our studies. PARTICIPANTS: Meena Haribal, Cornell University, Ithaca, NY USA, performed all the experiments and is doing analyses of the data and writing the manuscripts. Heather Proctor, University of Alberta, Edmonton, Canada, is identifying the feather-mites that are involved in the above studies. Edward Burtt, Wesleyan University, Ohio, USA, performed the collection and identification of microbes on the feather surface of species of birds involved in the above studies. Kent Loffler, Cornell University, was involved in set up of intervolometer experiments. Scott Robinson, University of Illinois, Urbana-Champaign is collaborating on Environmental Scanning Electron Microscopy (ESEM) studies. Christian Burns, Cornell University, Ithaca NY, USA, student, volunteered in summer of 2007. Kalysta Sanders, New College, Sarasota, Florida, USA, student, volunteered in summer of 2007 TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Outcomes (Changes in knowledge). Chemistry of preen gland secretions of individual species is unique and it varies between sexes in some species and also varies seasonally. In the choice bioassays, we found that the secretions of all species of birds were attractive to mites that came from the same species of birds and mites died on the secretions in the experimental conditions. Thus, secretions may contain components that are both attractive and toxic to mites. In natural conditions, mites may be feeding on the secretions after they have been modified either by environmental conditions or by some other interactions. The experimental manipulation of amounts of mites on birds resulted in differences in secretion compositions between the birds that were with and without mites. The differences in secretion compositions were observed only after three months. This suggested that the short term monitoring of the secretions may not show any differences as it takes longer time to alter the physiology of birds. Also, single method of analyses may not be useful for testing the differences in secretion components as some analytical methods showed marked differences and others showed subtle differences, showing that different classes of components are involved in altered secretion compositions. There was no difference in the attractiveness of secretions from either group of experimental birds to mites. Expected impacts: This current study along with our previous studies and the reported literature will help us understand how the secretions have evolved in birds and their interactions with the organisms that are associated with birds at various times of their life stages. Very little is known about biology of feather mites, this study will further enhance our knowledge of ecology feather mites. The above studies show that secretions have impact on the organisms that are associated with birds and some of these organisms are harmful to birds. Thus, with our understanding of the functions and chemistry of secretions, we could use the knowledge to prepare synthetic formulations that could be applied to birds to enhance their health and could be used in veterinary medicine and poultry industry.
Publications
- Haribal M, Dhondt A A and Rodriguez E. Diversity in chemical compositions of preen gland secretions of tropical birds. Biochemical Systematics and Ecology 2009 (In press)
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