Genetic and morphological differentiation among populations of the Rivoli’s Hummingbird (Eugenes fulgens) species complex (Aves: Trochilidae)

Abstract

Genetic variation and phylogeographic studies have been crucial for understanding mechanisms of speciation. We analyzed genetic variation and phylogeography to reconstruct the demographic history of the Rivoli’s Hummingbird (Eugenes fulgens) species complex and also evaluated their morphological differentiation. This widely distributed species inhabits the highlands of Mexico and northern Central America, with 2 subspecies separated by the Isthmus of Tehuantepec (west: E. f. fulgens, east: E. f. viridiceps). We surveyed genetic variation in 2 mitochondrial DNA markers (mtDNA, with 129 individuals) and nuclear DNA (6 microsatellites, with 85 individuals). We also inferred the demographic history, estimated divergence times, and analyzed morphological variation using 470 vouchered specimens. We modeled the current potential distribution of the species using ecological niche modeling and projected it into the past to model the effects of the Pleistocene climatic cycles. Haplotype networks, pairwise FST comparisons, AMOVA, and morphological analysis revealed differences between geographically isolated populations separated by the Isthmus of Tehuantepec (IT; corresponding to the 2 recognized subspecies: fulgens and viridiceps), and by the Motagua-Polochic-Jocotán (MPJ) system fault. Demographic scenarios revealed a contraction in distribution during the last interglacial, and expansion during the Last Glacial Maximum (LGM) with little change since the LGM. Divergence between groups separated by the Isthmus of Tehuantepec ~59,600 yr ago occurred in the presence of gene flow, suggesting that the Isthmus of Tehuantepec is a semipermeable barrier to gene flow. STRUCTURE analyses of microsatellite data detected 3 genetically differentiated groups. Several results fit a model of recent lineage divergence, including a significant signal of genetic differentiation, demographic expansion, decreased gene flow from past to present, and northward expansion during the LGM and contraction during the interglacial periods. We conclude that the genetic differentiation of E. fulgens in the Madrean Pine-Oak Woodlands resulted from recent geographical isolation of populations separated by natural barriers (IT and MPJ).

Color and morphological differentiation in the Sinaloa Wren (Thryophilus sinaloa) in the tropical dry forests of Mexico: The role of environment and geographic isolation

“…In contrast with evidence of phenotypic divergence within bird species from montane habitats, such as cloud, pine and pine-oak forests, as a result of drift in isolation by geographic barriers [ 46 , 50 , 125 ], our findings suggest that ecological barriers are important in terms of promoting phenotypic differentiation among lowland habitats with no apparent geographic barriers to dispersal. However, this is only the first evidence to contribute to our understanding of the mechanisms that promote phenotypic differentiation along the TDF.…”

Phylogenetic relationships and systematics of the bamboo‐specialistAmaurospizablue seedeaters

“…2010, Zamudio‐Beltrán & Hernández‐Baños 2015, Zamudio‐Beltrán et al . 2020, Castillo‐Chora et al . 2021).…”

Genetic and Ecological Divergence of Cinnamon HummingbirdAmazilia rutila(Aves: Trochilidae) Continental Populations Separated by Geographical and Environmental Barriers

“…However, these vicariant events seemly occurred at different times (Barber & Klicka, 2010; Ornelas et al, 2013, 2015), indicating that genetic divergence occurred variously during different temporal windows. In addition, phylogeographic studies have found low levels of genetic differentiation and gene flow between populations separated by the Isthmus, for both highland and lowland hummingbird species (Hernández-Soto et al, 2018; Rodríguez-Gómez et al, 2013, 2021, Zamudio-Beltrán et al, 2020a, 2020b) and other taxa (Arbeláez-Cortés et al, 2010; Cortés-Rodríguez et al, 2008b; Mendoza et al, 2019; Navarro-Sigüenza et al, 2008; Ornelas et al, 2010; Vázquez-Miranda et al, 2009), leading these authors to suggest that the Isthmus is a semipermeable barrier to gene flow. Divergence time estimates for the split between populations of A. rutila separated by the Isthmus (4.84–3.16 million years ago; Vázquez-López et al, 2021) support the hypothesis that the split between populations by the Isthmus pre-date the Pleistocene glacial periods.…”

“…The first pattern has been found in hummingbirds (Trochilidae), with strong geographic structuring ( i ) in species with populations separated by biogeographic barriers such as the Isthmus of Tehuantepec, the Trans-Mexican Volcanic Belt, and/or the Motagua-Polochic-Jocotán fault system (Hernández-Soto et al, 2018; Jiménez & Ornelas, 2016; Malpica & Ornelas, 2014; Rodríguez-Gómez et al, 2013, 2021, Zamudio-Beltrán et al, 2020, 2020b); ( ii ) species with disjunct distribution of populations (Arbeláez-Cortés & Navarro-Sigüenza, 2013; González et al, 2011; Licona-Vera & Ornelas, 2014); ( iii ) or in species inhabiting naturally fragmented habitats such as cloud forests (Cortés-Rodríguez et al, 2008a; Ornelas et al, 2016; Zamudio-Beltrán & Hernández-Baños, 2018). In contrast, the second pattern of weak geographic structuring and high levels of gene flow has been found in hummingbird species inhabiting lowland humid forest edges and coastal habitats, oases in tropical deciduous forests and arid montane scrub (González-Rubio et al, 2016; Licona-Vera et al, 2018a; Miller et al, 2011; Rodríguez-Gómez & Ornelas, 2015, 2018).…”