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Determinants of Biparental Care in the Spotted Poison Frog, Dendrobates vanzolinii (Anura: Dendrobatidae)

1999; American Society of Ichthyologists and Herpetologists; Volume: 1999; Issue: 3 Linguagem: Inglês

10.2307/1447590

1938-5110

Janalee P. Caldwell, Veronica R. L. Oliveira, Veronica R. L. Oliveira,

Animal Behavior and Reproduction

A study of the spotted poison frog, Dendrobates vanzolinii, carried out in Amazonian rain forest in Brazil, revealed that these frogs form pair-bonds, using the definition of pair bonding as a social and copulatory, or mating, relationship between two individuals that share some aspect of offspring rearing. Pairs of frogs cooperate to provide biparental care for their offspring. Observations of naturally marked pairs revealed that one to several eggs are attached above the waterline in tiny waterfilled cavities, typically in saplings or woody vines in the forest understory; after an egg develops into a tadpole, the male transports it on his back to a different cavity where the tadpole undergoes further development in a small amount of water. Tadpoles of D. vanzolinii, as well as those of other species of Dendrobates, are predatory and cannibalistic; eggs deposited above the waterline in a cavity are not allowed to drop in the water below where a larger, cannibalistic tadpole may be present. Tadpole deposition sites are chosen by the male parent, who always transports tadpoles in this species. The tiny holes in vines or saplings contain only a small amount of water and lack food resources for the tadpole. Typically, unfertilized (nutritive) eggs deposited by the female parent are the only source of food for the tadpoles. Both parents have a role in this form of biparental care: the male guides the female to the deposition site housing the tadpole where they undergo courtship behavior, which appears to be necessary to induce ovulation in the female. Males are territorial, and no males were seen entering another male's territory. Females remained in the territory of their mate and were not observed interacting with other frogs. Large treeholes and other types of potential tadpole deposition sites are scarce in this area of Amazon forest, but tiny vine and sapling holes are common. Lack of food resources in these holes and the avoidance of tadpole cannibalism are potential determinants of biparental care in this species. Additional work on biparental care of this and closely related species should focus on the significance of size of deposition cavities, the role of tadpole deposition patterns, the extent of cannibalism, and other aspects of tadpole behavior and ecology unique to these species. Um estudo de, Dendrobates vanzolinii feito na floresta amaz6nica brasileira, revelou que estas ras formam lacos de casal, usando a definicao de laco de casal como uma relacao social e copulat6ria, ou de acasalamento, entre dois individuos que partilham alguma parte do cuidar da prole. Observacoes de pares marcados naturalmente revelaram que de um a varios ovos sao postos acima da linha d'agua em cavidades minusculas contendo agua, tipicamente em arvores jovens ou cipos lenhosos no estrato arbustivo da floresta. Quando os girinos eclodem, o macho os transporta as costas ate uma outra cavidade onde os girinos se desenvolvem um pouco mais, num volume de agua pequeno. Girinos de D. vanzolinii, assim como os de outras especies de Dendrobates, sao predadores e canibais. Ovos postos acima da linha d'agua de uma cavidade sao impedidos de cair na agua, onde um girino maior e canibal poderia estar. Os sitios de deposicao de girinos sao escolhidos pela ra macho, que e quem transporta os girinos nesta especie. Os buracos minusculos nos cip6s e arvores jovens contem apenas um volume de agua pequeno e carecem de alimentos para o girino. Ovos nao-fertilizados (nutritivos) postos pela ra f6mea sao tipicamente a unica fonte de alimentacao dos girinos. Ambos os pais tem um papel nesta forma de cuidado biparontal: ambos os pais. O macho conduz a femea ate o local de postura onde efetuam a corte, que aparentemente 6 necessaria para induzir