Feeding deterrence in the seed-eating sparrow ZonotrichIa capensis against common seed secondary phenols

RIOS JUAN MANUEL; MANGIONE ANTONIO

SAN LUIS

Jornada; XXVII Jornadas de la Sociedad de Biología de Cuyo; 2009

Universidad Nacional de San Luis

Some allelochemical compounds such as phenolic secondary compounds (PSC´s) include deterrent activity against seed-eating animals. Birds have the ability to recognize such compounds and can circumvent the intake avoiding the adverse or toxic effects. Zonotrichia capensis it is a highly opportunist wild bird with a great diet breath, since it feeds on different kinds of weed seeds many of them with PSC´s. We test the hypothesis that this sparrow is able to avoid different kinds of phenols in relation to the particular phenol chemical structure. We realize two-choice feeding trials in the laboratory in order to evaluate the effects of topical application with solutions at 1% of single PSC´s common in weed seeds. Only those compounds that turned out to be deterrents were re-evaluated to a minor concentration of 0.5%. The PSC´s were: tannic acid =TA; condensed tannins =CT and the phenylpropanoids: cinnamic acid =CA; cafeic acid =CfA and ferulic acid =FA. Z. capensis avoided significantly seeds topically applied with TA, CA and CfA at both concentrations and did not avoid the seeds topically applied with 1% of CT and FA. This sparrow rejects the phenols according to the particular chemical structure. During the trials, the birds were holding the chemical treated seeds through a few seconds and then it was leaving them to fall down probably due to the trigeminal stimulation provoked by the bitterness or distasteful flavor.