Journal of Chemical Ecology

, Volume 17, Issue 12, pp 2539–2551 | Cite as

Taxon-specific differences in responsiveness to capsaicin and several analogues: Correlates between chemical structure and behavioral aversiveness

  • J. Russell Mason
  • N. Jay Bean
  • Pankaj S. Shah
  • Larry Clark


The present set of experiments was designed to explore avian insensitivity to capsaicin. Based upon a molecular model of avian chemosensory repellency, we hypothesized that structural modifications of the basic capsaicin molecule, which is itself not aversive to birds, might produce aversive analogues. To this end, European starlings (Sturnus vulgaris) and Norway rats (Rattus norvegicus) were given varied concentrations of synthetic capsaicin and four analogues (methyl capsaicin, veratryl amine, veratryl acetamide, vanillyl acetamide) in feeding and drinking tests. The results agreed with a model that we are developing to describe the chemical nature of avian repellents. Synthetic capsaicin and vanillyl acetamide were not repellent to birds, owing to the presence of an acidic phenolic OH group. Conversely, veratryl acetamide was aversive, due to the basic nature of this compound. For rats, repellent effectiveness among compounds was reversed: synthetic capsaicin was the best repellent while veratryl acetamide was the worst. We speculate that this taxonomic reversal may reflect basic differences in trigeminal chemoreception. In any case, it is clear that chemical correlates of mammalian repellents are opposite to those that predict avian repellency.

Key words

Capsaicin chemosensory irritation rat Rattus norvegicus starling Sturnus vulgaris trigeminal 


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Copyright information

© Plenum Publishing Corporation 1991

Authors and Affiliations

  • J. Russell Mason
    • 1
  • N. Jay Bean
    • 2
  • Pankaj S. Shah
    • 3
  • Larry Clark
    • 1
  1. 1.U.S. Department of AgricultureAnimal and Plant Health Inspection Service, Science and Technology Denver Wildlife Research CenterPhiladelphia
  2. 2.Psychology DepartmentVassar CollegePoughkeepsie
  3. 3.Monell Chemical Senses CenterPhiladelphia

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