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Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
Published on: September 20, 2011
Chemosensory reception, behavioral expression, and ecological interactions at multiple trophic levels.
Ryan P Ferrer1, Richard K Zimmer
1Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095-1606, USA.
The Journal of Experimental Biology
|May 10, 2007
Summary
California newts exhibit stage-specific chemosensation. Arginine triggers predatory search in adults but suppresses cannibalism in larvae, reflecting distinct life-history adaptations.
Area of Science:
- * Zoology and Sensory Ecology: Investigating chemoreception and its role in animal behavior across different life stages.
- * Amphibian Biology: Focusing on the California newt (Taricha torosa) and its ontogenetic shifts in sensory perception.
Background:
- * Chemosensation is crucial throughout an animal's life, with selection pressures influencing physiological and behavioral changes at different stages.
- * The California newt undergoes significant chemosensory organ reorganization during metamorphosis from aquatic larva to semi-terrestrial adult.
- * Understanding these stage-specific chemosensory abilities is key to comprehending their trophic interactions and ecological roles.
Purpose of the Study:
- * To compare the chemosensory-mediated behaviors of adult California newts with those of their larval stage.
- * To identify specific amino acids that elicit behavioral responses in adult newts.
- * To investigate the role of arginine as a chemical signal with potentially opposing effects in different life-history stages.
Main Methods:
- * Bioassays conducted in natural mountain stream environments.
- * Testing the behavioral responses of free-ranging adult newts to 13 individual L-amino acids and arginine analogs.
- * Comparing adult responses to previously established larval responses to chemical stimuli, including blocking nasal cavity openings.
Main Results:
- * Adult newts exhibited predatory search behavior, actively seeking out arginine, glycine, and alanine.
- * Arginine was the most potent attractant for adults, with a low response threshold.
- * In contrast, arginine suppressed cannibal-avoidance behavior in larvae and did not elicit search reactions, with structural modifications affecting adult attraction more than larval suppression.
Conclusions:
- * Arginine acts as a chemical signal with opposing behavioral effects (predatory search in adults, suppressed cannibalism in larvae).
- * Significant differences in responses to arginine analogs suggest distinct chemosensory receptor targets between larval and adult newts.
- * An ontogenetic shift in chemoreceptive abilities reflects unique selection pressures at different life-history stages, altering behavioral expression and ecological consequences.
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