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Ecological speciation in Darwin’s finches: Parsing the effects of magic traits.

Por:

Podos, Jeffrey

Colaborador(es):

Tipo de material:

ArtículoIdioma: Inglés Tema(s):

Clasificación CDD:

21 598.883

En: Current Zoology Vol. 59, no. 1 (2013), p. 8-19Tema: Many recent studies of ecological speciation have focused on “magic trait” scenarios, in which divergent selection on viability traits leads inextricably to corresponding divergence in mechanisms, especially mate recognition systems, that facilitate assortative mating. Speciation however may also proceed via other scenarios, such as when populations experience directly selected or random divergence in mate recognition systems. The relative contributions of magic trait versus other scenarios for speciation remain virtually unexplored. The present study aims to test the relative contribution of the magic trait scenario in the divergence of populations of the medium ground finch Geospiza fortis of Santa Cruz Island, Galapagos. First, we assess differences in G.fortis song between a northern population (Borrero Bay) and a southeastern population (El Garrapatero), differences that we propose (along with other within-island geographic song variations) have arisen via scenarios that do not involve a magic trait scenario. Pairwise comparisons of raw and composite (PC) song parameters, as well as discriminant functions analyses, reveal significant patterns of song divergence between sites. Second, we test the ability of territorial males at Borrero Bay to discriminate songs from the two sites. We find that G. fortis males can discriminate within-island song variants, responding more strongly to local tan to “foreign” songs, along 3 raw and 1 composite response measures. Third, we compare these findings to prior data sets on song divergence and discrimination in Santa Cruz G. fortis. These comparisons suggest that song divergence and discrimination are shaped less strongly by geographic sources than by morphological (beak-related) sources. We thus argue that interpopulation song divergence and discrimination, fundamental elements of assortative mating in Darwin’s finches, can be fostered in early stages of divergence under magic trait as well as alternative scenarios for speciation, but with more emphasis on the magic trait scenario, at least for this species on this island [Current Zoology 59 (1): 8–19, 2013].

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Existencias ( 2 )
Notas de título ( 2 )

Existencias
Imagen de cubierta	Tipo de ítem	Biblioteca actual	Biblioteca de origen	Colección	Ubicación en estantería	Signatura topográfica	Materiales especificados	Info Vol	URL	Copia número	Estado	Notas	Fecha de vencimiento	Código de barras	Reserva de ítems	Prioridad de la cola de reserva de ejemplar	Reservas para cursos
	Artículo	Corley Smith Library Artículos		Galápagos		598.883 POD (Navegar estantería(Abre debajo))					Disponible			2017-2139
	Documento electrónico	Corley Smith Library Colección PDF		Galápagos		598.883 POD 2013 (Navegar estantería(Abre debajo))					Disponible			2021-2029

Many recent studies of ecological speciation have focused on “magic trait” scenarios, in which divergent selection on
viability traits leads inextricably to corresponding divergence in mechanisms, especially mate recognition systems, that facilitate assortative mating. Speciation however may also proceed via other scenarios, such as when populations experience directly selected or random divergence in mate recognition systems. The relative contributions of magic trait versus other scenarios for speciation remain virtually unexplored. The present study aims to test the relative contribution of the magic trait scenario in the divergence of populations of the medium ground finch Geospiza fortis of Santa Cruz Island, Galapagos. First, we assess differences in G.fortis song between a northern population (Borrero Bay) and a southeastern population (El Garrapatero), differences that we propose (along with other within-island
geographic song variations) have arisen via scenarios that do not involve a magic trait scenario. Pairwise comparisons of raw and composite (PC) song parameters, as well as discriminant functions analyses, reveal significant patterns of song divergence between sites. Second, we test the ability of territorial males at Borrero Bay to discriminate songs from the two sites. We find that G. fortis males can discriminate within-island song variants, responding more strongly to local tan to “foreign” songs, along 3 raw and 1 composite response measures. Third, we compare these findings to prior data sets on song divergence and discrimination in Santa Cruz G. fortis. These comparisons suggest that song divergence and discrimination are shaped less strongly by geographic sources than by morphological (beak-related) sources. We thus argue that interpopulation song divergence and discrimination, fundamental elements of assortative
mating in Darwin’s finches, can be fostered in early stages of divergence under magic trait as well as alternative scenarios for speciation, but with more emphasis on the magic trait scenario, at least for this species on this island [Current Zoology 59 (1): 8–19, 2013].

English