H. Lisle Gibbs

Bio: H. Lisle Gibbs is an academic researcher from Ohio State University. The author has contributed to research in topics: Population & Reproductive success. The author has an hindex of 43, co-authored 132 publications receiving 5681 citations. Previous affiliations of H. Lisle Gibbs include University of Michigan & McMaster University.

Realized reproductive success of polygynous red-winged blackbirds revealed by DNA markers.

Abstract: Hypervariable genetic markers, including a novel locus-specific marker detected by a mouse major histocompatibility complex probe, reveal that multiple paternity is common in families of polygynous red-winged blackbirds (Agelaius phoeniceus). Almost half of all nests contained at least one chick resulting from an extra-pair fertilization, usually by a neighboring male. Genetically based measures of reproductive success show that individual males realize more than 20% of their overall success from extra-pair fertilizations, on average, and that this form of mating behavior confounds traditional measures of male success. The importance of alternative reproductive tactics in a polygynous bird is quantified, and the results challenge previous explanations for the evolution of avian polygny.

Genomic signals of selection predict climate-driven population declines in a migratory bird

Abstract: The ongoing loss of biodiversity caused by rapid climatic shifts requires accurate models for predicting species’ responses. Despite evidence that evolutionary adaptation could mitigate climate change impacts, evolution is rarely integrated into predictive models. Integrating population genomics and environmental data, we identified genomic variation associated with climate across the breeding range of the migratory songbird, yellow warbler ( Setophaga petechia ). Populations requiring the greatest shifts in allele frequencies to keep pace with future climate change have experienced the largest population declines, suggesting that failure to adapt may have already negatively affected populations. Broadly, our study suggests that the integration of genomic adaptation can increase the accuracy of future species distribution models and ultimately guide more effective mitigation efforts.

Oscillating selection on Darwin's finches

Abstract: An important goal in the study of evolution is to determine the occurrence, causes and possible micro-evolutionary consequences of selection in natural populations1–3. Darwin's finches (Geospizinae) are suitable organisms for investigation because their morphological traits are highly heritable4, and they live in a climatically variable environment (Galapagos Islands)5,6. It has been suggested that selection fluctuates in direction and intensity, favouring different morphological optima in different years7, because strong annual variation in rainfall causes changes in food supply composition7,8. This suggestion has been supported in part by studies of the medium ground finch, Geospiza forth, on the island of Daphne Major, which have shown that large adult size is favoured under drought conditions, when the overall food supply is low and large hard seeds are disproportionately abundant8,9. Here we document a reversal in the direction of selection following the opposite climatic extreme, and demonstrate the connection between oscillating selection and fluctuations in food supply.

Genetic evidence for female host-specific races of the common cuckoo

Abstract: The common cuckoo Cuculus canorus is divided into host-specific races (gentes). Females of each race lay a distinctive egg type that tends to match the host's eggs, for instance, brown and spotted for meadow pipit hosts or plain blue for redstart hosts. The puzzle is how these gentes remain distinct. Here, we provide genetic evidence that gentes are restricted to female lineages, with cross mating by males maintaining the common cuckoo genetically as one species. We show that there is differentiation between gentes in maternally inherited mitochondrial DNA, but not in microsatellite loci of nuclear DNA. This supports recent behavioural evidence that female, but not male, common cuckoos specialize on a particular host, and is consistent with the possibility that genes affecting cuckoo egg type are located on the female-specific W sex chromosome. Our results also support the ideas that common cuckoos often switched hosts during evolution, and that some gentes may have multiple, independent origins, due to colonization by separate ancestral lineages.

Recurrent patterns of natural selection in a population of Darwin's finches

Abstract: The adaptive significance of morphological traits can be assessed by measuring and identifying the forces of selection acting on them Boag and Grant documented directional selection in a small population of Darwin's medium ground finches, Geospiza fortis, on I Daphne Major, Galapagos, in 1977 Large beak and body size were favoured at a time of diminishing food supply and high adult mortality We show here that in two subsequent periods of moderate to high adult mortality (1980 and 1982), the population was subject to the same selection We have used a recently developed technique to ascertain the targets of direct selection Beak depth and body weight were commonly under direct selection to increase but, surprisingly, beak width was directly selected to decrease, over all three periods of mortality The results have implications for our understanding of evolutionary change in morphological traits of Darwin's finches

Phylogenies and Community Ecology

Abstract: ▪ Abstract As better phylogenetic hypotheses become available for many groups of organisms, studies in community ecology can be informed by knowledge of the evolutionary relationships among coexisting species. We note three primary approaches to integrating phylogenetic information into studies of community organization: 1. examining the phylogenetic structure of community assemblages, 2. exploring the phylogenetic basis of community niche structure, and 3. adding a community context to studies of trait evolution and biogeography. We recognize a common pattern of phylogenetic conservatism in ecological character and highlight the challenges of using phylogenies of partial lineages. We also review phylogenetic approaches to three emergent properties of communities: species diversity, relative abundance distributions, and range sizes. Methodological advances in phylogenetic supertree construction, character reconstruction, null models for community assembly and character evolution, and metrics of community ...

Inbreeding effects in wild populations.

Abstract: Whether inbreeding affects the demography and persistence of natural populations has been questioned. However, new pedigree data from field populations and molecular and analytical tools for tracing patterns of relationship and inbreeding have now enhanced our ability to detect inbreeding depression within and among wild populations. This work reveals that levels of inbreeding depression vary across taxa, populations and environments, but are usually substantial enough to affect both individual and population performance. Data from bird and mammal populations suggest that inbreeding depression often significantly affects birth weight, survival, reproduction and resistance to disease, predation and environmental stress. Plant studies, based mostly on comparing populations that differ in size or levels of genetic variation, also reveal significant inbreeding effects on seed set, germination, survival and resistance to stress. Data from butterflies, birds and plants demonstrate that populations with reduced genetic diversity often experience reduced growth and increased extinction rates. Crosses between such populations often result in heterosis. Such a genetic rescue effect might reflect the masking of fixed deleterious mutations. Thus, it might be necessary to retain gene flow among increasingly fragmented habitat patches to sustain populations that are sensitive to inbreeding.

The global diversity of birds in space and time

Abstract: Current global patterns of biodiversity result from processes that operate over both space and time and thus require an integrated macroecological and macroevolutionary perspective. Molecular time trees have advanced our understanding of the tempo and mode of diversification and have identified remarkable adaptive radiations across the tree of life. However, incomplete joint phylogenetic and geographic sampling has limited broad-scale inference. Thus, the relative prevalence of rapid radiations and the importance of their geographic settings in shaping global biodiversity patterns remain unclear. Here we present, analyse and map the first complete dated phylogeny of all 9,993 extant species of birds, a widely studied group showing many unique adaptations. We find that birds have undergone a strong increase in diversification rate from about 50 million years ago to the near present. This acceleration is due to a number of significant rate increases, both within songbirds and within other young and mostly temperate radiations including the waterfowl, gulls and woodpeckers. Importantly, species characterized with very high past diversification rates are interspersed throughout the avian tree and across geographic space. Geographically, the major differences in diversification rates are hemispheric rather than latitudinal, with bird assemblages in Asia, North America and southern South America containing a disproportionate number of species from recent rapid radiations. The contribution of rapidly radiating lineages to both temporal diversification dynamics and spatial distributions of species diversity illustrates the benefits of an inclusive geographical and taxonomical perspective. Overall, whereas constituent clades may exhibit slowdowns, the adaptive zone into which modern birds have diversified since the Cretaceous may still offer opportunities for diversification.