Morphological adaptation to coastal marshes in spite of limited genetic structure in the Neotropical passerineSpartonoica maluroides(Aves: Furnariidae)

Abstract

Tidal marshes present profound adaptive challenges to terrestrial vertebrates. For example, North American sparrows have relatively longer and thinner bills and darker dorsal plumage in coastal saltmarshes than in interior marshes. Bay‐capped wren‐spinetail (Furnariidae; Spartonoica maluroides) show a strong association with South American saltmarshes. We hypothesized that bay‐capped wren‐spinetail have similar morphological adaptations to North American sparrows to the saltmarsh environment, which would be indicative of the generality of selection on these traits in the coastal saltmarsh ecosystem. We captured individuals of S. maluroides from coastal saltmarshes and interior marshes. Populations were compared based on morphology and molecular markers. We found significant phenotypic differences in bill shape and plumage coloration (melanism) between S. maluroides populations from coastal and inland marshes. The low levels of genetic variation, weak geographical structure and shallow divergences, based on mitochondrial DNA and microsatellite data, suggest that coastal populations had a recent demographic expansion. Our results are consistent with the pattern of morphological divergence found between North American Emberizids. The possibility of convergent evolutionary adaptations between saltmarsh North American Emberizids and South American Furnariids suggests that there are strong selective pressures associated with saltmarsh environments on the beak, leading to adaptations for food acquisition, and on plumage coloration for better camouflage for predator avoidance (melanism). © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 78–91.

Causes and Consequences of Nest Mass and Structure Variation in the Bay-Capped Wren-SpinetailSpartonoica maluroides

“…Recently, it has been reported that Wren-spinetail populations that breed in coastal marshes (dominated by Spartina densiflora) show phenotypic differences in bill morphology and plumage coloration (melanism) in respect to populations breeding at inland marshes (Cardoni et al 2013). This suggests that different selective forces would be acting on Wren-spinetail's traits, which may induce changes in important aspects of its life history, such as foraging (Cardoni et al 2013) or nesting strategies (this study).…”

“…Several studies have shown that some bird species have adapted to the conditions presented by the marshes, for example, increment in beak size to increase heat body loss (Greenberg et al 2012), changes in the performance of the song as mating signals (Ballentine 2006), changes in body sizes (Greenberg & Droege 1990, Grenier & Greenberg 2006, and plumage melanism (Greenberg & Droege 1990). Recently, it has been reported that Wren-spinetail populations that breed in coastal marshes (dominated by Spartina densiflora) show phenotypic differences in bill morphology and plumage coloration (melanism) in respect to populations breeding at inland marshes (Cardoni et al 2013). This suggests that different selective forces would be acting on Wren-spinetail's traits, which may induce changes in important aspects of its life history, such as foraging (Cardoni et al 2013) or nesting strategies (this study).…”

“…Limnornis curvirostris, Limnoctites rectirostris, Phleocryptes melanops, Cranioleuca sulphurifera; Narosky et al 1983, de la Peña 1988, thus indicating either phylogenetic constraints on nest architecture evolution or differences in the characteristics of nest sites. In any case, evolution seems to have favored a flexible strategy in Wren-spinetail in terms of the nest architecture, as a possible adaptation to live in a structurally variable environment, such as saltmarshes (Cardoni et al 2013, Isacch et al 2014.…”

Diversity and Habitat Distribution of Birds in Coastal Marshes and Comparisons with Surrounding Upland Habitats in Southeastern South America

“…Vegetation profile represents an averaged profile of Bahía Samborombón and Laguna Mar Chiquita Estuaries and Coasts habitats was the bay-capped wren-spinetail, a furnarid species (Cardoni et al 2012). Bay-capped wren-spinetail also use other habitats along their distribution (Cardoni et al 2013), but show a strong association with South American saltmarshes (Isacch et al 2004;Isacch and Cardoni 2011;Cardoni et al 2011). In addition, comparisons of coastal and inland marsh populations show significant phenotypic differences in bill shape and plumage coloration (melanism), a convergent pattern with North American sparrows (Cardoni et al 2013), suggesting that there are strong selective pressures associated with saltmarsh environments.…”

Neotropical bird evolution and 100 years of the enduring ideas of Frank M. Chapman

“…Mauck & Burns () further showed that bill morphology in flowerpiercers has been highly labile and argued that differences in ecomorphology, behaviour, and habitat use likely account for the local coexistence of several species in this group at tropical sites. The evolutionary lability of avian bills and its possible influence on diversification is revealed by detailed work at a microevolutionary scale on Darwin's finches (Grant, Grant & Petren, ) and in the furnariid Spartonoica maluroides (Cardoni et al ., ), which show divergence in bill morphology associated with adaptation to different food supplies and contrasting environments.…”