Limits...
Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide.

Alvarado AH, Fuller TL, Smith TB - Ecol Evol (2014)

Bottom Line: However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide.Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide.We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides.

View Article: PubMed Central - PubMed

Affiliation: Center for Tropical Research, Institute of the Environment and Sustainability, University of California La Kretz Hall, Suite 300, 619 Charles E. Young Dr. East, Los Angeles, California, 90095.

ABSTRACT
Migratory divides, the boundary between adjacent bird populations that migrate in different directions, are of considerable interest to evolutionary biologists because of their alleged role in speciation of migratory birds. However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide. Here, we integrate multiple approaches by using genetic, geolocator, and morphological data to investigate a migratory divide in hermit thrushes (Catharus guttatus). First, high genetic divergence between migratory groups indicates the divide is a region of secondary contact between historically isolated populations. Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide. Third, a diagnostic genetic marker that proved useful for tracking a key population suggests a likely intermediate nonbreeding location of birds from the hybrid zone. This finding, combined with lower return rates from this region, is consistent with comparatively lower fitness of hybrids, which is possibly due to this intermediate migration pattern. We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides.

No MeSH data available.


Related in: MedlinePlus

Hermit thrush (Catharus guttatus) on the breeding grounds in British Columbia, Canada. Photo by Robert McMorran.
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fig01: Hermit thrush (Catharus guttatus) on the breeding grounds in British Columbia, Canada. Photo by Robert McMorran.

Mentions: Hermit thrushes (Fig.1) have an extensive range, breeding throughout most of North America in coniferous, deciduous, and mixed forests (Dellinger et al. 2012). Intraspecific patterns of phenotypic variation are complex, with as many as 12 subspecies described (Dellinger et al. 2012). These subspecies are divided into major groups with geographic ranges that mirror many other avian taxa (Weir and Schluter 2004), making the hermit thrush an ideal candidate for studying the evolutionary processes which dictate biogeographic patterns of avian diversity throughout North America. Hermit thrushes overwinter throughout the southern United States and Mexico; however, little is known about the specific overwintering destinations of particular breeding populations or their migratory routes (Dellinger et al. 2012).


Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide.

Alvarado AH, Fuller TL, Smith TB - Ecol Evol (2014)

Hermit thrush (Catharus guttatus) on the breeding grounds in British Columbia, Canada. Photo by Robert McMorran.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228619&req=5

fig01: Hermit thrush (Catharus guttatus) on the breeding grounds in British Columbia, Canada. Photo by Robert McMorran.
Mentions: Hermit thrushes (Fig.1) have an extensive range, breeding throughout most of North America in coniferous, deciduous, and mixed forests (Dellinger et al. 2012). Intraspecific patterns of phenotypic variation are complex, with as many as 12 subspecies described (Dellinger et al. 2012). These subspecies are divided into major groups with geographic ranges that mirror many other avian taxa (Weir and Schluter 2004), making the hermit thrush an ideal candidate for studying the evolutionary processes which dictate biogeographic patterns of avian diversity throughout North America. Hermit thrushes overwinter throughout the southern United States and Mexico; however, little is known about the specific overwintering destinations of particular breeding populations or their migratory routes (Dellinger et al. 2012).

Bottom Line: However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide.Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide.We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides.

View Article: PubMed Central - PubMed

Affiliation: Center for Tropical Research, Institute of the Environment and Sustainability, University of California La Kretz Hall, Suite 300, 619 Charles E. Young Dr. East, Los Angeles, California, 90095.

ABSTRACT
Migratory divides, the boundary between adjacent bird populations that migrate in different directions, are of considerable interest to evolutionary biologists because of their alleged role in speciation of migratory birds. However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide. Here, we integrate multiple approaches by using genetic, geolocator, and morphological data to investigate a migratory divide in hermit thrushes (Catharus guttatus). First, high genetic divergence between migratory groups indicates the divide is a region of secondary contact between historically isolated populations. Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide. Third, a diagnostic genetic marker that proved useful for tracking a key population suggests a likely intermediate nonbreeding location of birds from the hybrid zone. This finding, combined with lower return rates from this region, is consistent with comparatively lower fitness of hybrids, which is possibly due to this intermediate migration pattern. We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides.

No MeSH data available.


Related in: MedlinePlus