Dietary Alkaloid Sequestration in a Poison Frog: An Experimental Test of Alkaloid Uptake in Melanophryniscus stelzneri (Bufonidae)

Autor(es)

Hantak, Maggie M. ^[1] ; Grant, Taran ^[2] ; Reinsch, Sherri ^[3] ; Mcginnity, Dale ^[3] ; Loring, Marjorie ^[4] ; Toyooka, Naoki ^{[5, 6]} ; Saporito, Ralph A. ^[1]

Afiliação do(s) autor(es)

^[1] John Carroll Univ, Dept Biol, University Hts, OH 44118 - USA

^[2] Univ Sao Paulo, Inst Biociencias, Dept Zool, BR-05508090 Sao Paulo - Brazil

^[3] Nashville Zoo, Nashville, TN 37211 - USA

^[4] Barry Univ, Miami Shores, FL 33161 - USA

^[5] Toyama Univ, Grad Sch Sci & Technol Res, Toyama 9308555 - Japan

^[6] Toyama Univ, Grad Sch Innovat Life Sci, Toyama 9308555 - Japan

• Tipo de documento: Artigo Científico
• Fonte: Journal of Chemical Ecology; v. 39, n. 11-12, p. 1400-1406, DEC 2013.
• Citações Web of Science: 25

Resumo

Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloid-containing defensive chemicals from granular glands in the skin. These species, collectively referred to as `poison frogs,' form a polyphyletic assemblage that includes some species of Dendrobatidae, Mantellidae, Myobatrachidae, Bufonidae, and Eleutherodactylidae. The ability to sequester alkaloids from dietary arthropods has been demonstrated experimentally in most poison frog lineages but not in bufonid or eleutherodactylid poison frogs. As with other poison frogs, species of the genus Melanophryniscus (Bufonidae) consume large numbers of mites and ants, suggesting they might also sequester defensive alkaloids from dietary sources. To test this hypothesis, fruit flies dusted with alkaloid/nutritional supplement powder were fed to individual Melanophryniscus stelzneri in two experiments. In the first experiment, the alkaloids 5,8-disubstituted indolizidine 235B' and decahydroquinoline were administered to three individuals for 104 days. In the second experiment, the alkaloids 3,5-disubstituted indolizidine 239Q and decahydroquinoline were given to three frogs for 153 days. Control frogs were fed fruit flies dusted only with nutritional supplement. Gas chromatography/mass spectrometry analyses revealed that skin secretions of all experimental frogs contained alkaloids, whereas those of all control frogs lacked alkaloids. Uptake of decahydroquinoline was greater than uptake of 5,8-disubstituted indolizidine, and uptake of 3,5-disubstituted indolizidine was greater than uptake of decahydroquinoline, suggesting greater uptake efficiency of certain alkaloids. Frogs in the second experiment accumulated a greater amount of alkaloid, which corresponds to the longer duration and greater number of alkaloid-dusted fruit flies that were consumed. These findings provide the first experimental evidence that bufonid poison frogs sequester alkaloid-based defenses from dietary sources. (AU)

• Processo FAPESP: 12/10000-5 - Uma abordagem multidisciplinar para o estudo da diversificação de anfíbios
• Beneficiário: Taran Grant
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores