Presentation Detail

SSB Symposium: Ernst Mayr Symposium

Yohe, Laurel R. [1], Reddy, Sushma [2], Lordahl, Rachel [3], Davalos, Liliana M [4].

Diversification of lineages and traits supports multiple adaptive radiations in babblers (Aves: Timaliidae).

Birds of the family Timaliidae(babblers), are a species-rich group of passerines distributed throughout the Old World characterized by distinct phenotypic differences and highly diverse morphological features, including highly variable body size, bill structure,and plumage patterns. The evolutionary relationships among babblers have puzzled biologists for decades and the family is under constant revision. Although widely distributed, closely related species often coexist, suggesting niche partitioning among close relatives. The high morphological diversity may indicate a variety of niches being exploited by this family and may be a result of ecological opportunity. Because similar species can exist together in the same geographic location, intraspecific competition may have forced these birds to occupy other niches and eventual diversification to prevent competitive exclusion.High variation in morphological traits that provide higher fitness in a niche and rapid divergence from a common ancestor are features often used to diagnose an adaptive radiation, but frequently are poorly quantified. Rather than labeling the divergence of babblers as an adaptive radiation after-the-fact, we hypothesize the diversification of several subfamilies and genera within babblers as adaptive radiations by quantitatively analyzing the evolution and persistence of morphological traits related to fitness. To test the hypotheses of adaptive radiations, we quantified the variation in traits related to the ecology of babblers that may provide a fitness advantage in feeding mechanisms and adaptations. We then used a Bayesian approach to detect whether or not the patterns of diversity of species show related patterns of morphological diversity by combining the best estimates of the phylogeny of Timaliidae (Moyle, et al., 2012) and morphological measurements. High morphological variation of fitness related traits within a species-rich clade is indicative of an adaptive radiation.Within the three major clades of babblers, we found that traits and species in the subfamilies Leiothrichinae and Timaliinae support diversifications by adaptive radiation. These subfamilies contain genera with a high number of species as well as single-species genera. Within this radiation, we also noted evidence for adaptive radiations within laughingthrushes (Garrulax) and Stachyris babblers. Both genera contain high species richness compared to their sister clades, as well an enormous variation morphological characters, body size, and plumage patterns.

1 - Stony Brook University, Ecology & Evolution, 650 Life Sciences Building, 6th Floor, Stony Brook, NY, 11794-5245, USA
2 - Loyola University Chicago, Biology, 1032 W Sheridan Rd, Life Sciences Building, Chicago, IL, 60660, USA
3 - Stony Brook University, Ecology & Evolution, 650 Life Sciences Building, 6th Floor, Stony Brook, NY, 11794-5245, United States
4 - Stony Brook University, Ecology and Evolution, 650 Life Sciences, Stony Brook, NY, 11794, USA

Keywords:
adaptive radiation
diversification
morphology
birds
babblers
Aves.

Presentation Type: Symposium Presentation
Session: 210
Location: Ballroom 2/Cliff Lodge
Date: Sunday, June 23rd, 2013
Time: 9:45 AM
Number: 210006
Abstract ID:964
Candidate for Awards:Ernst Mayr Award,W.D. Hamilton Award for Outstanding Student Presentation,Student Travel Awards from the ASN