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Biology Faculty Research

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Articles 61 - 90 of 396

Full-Text Articles in Biology

Proteasome Storage Granules Protect Proteasomes From Autophagic Degradation Upon Carbon Starvation, Richard S. Marshall, Richard D. Vierstra Apr 2018

Proteasome Storage Granules Protect Proteasomes From Autophagic Degradation Upon Carbon Starvation, Richard S. Marshall, Richard D. Vierstra

Biology Faculty Research

26S proteasome abundance is tightly regulated at multiple levels, including the elimination of excess or inactive particles by autophagy. In yeast, this proteaphagy occurs upon nitrogen starvation but not carbon starvation, which instead stimulates the rapid sequestration of proteasomes into cytoplasmic puncta termed proteasome storage granules (PSGs). Here, we show that PSGs help protect proteasomes from autophagic degradation. Both the core protease and regulatory particle sub-complexes are sequestered separately into PSGs via pathways dependent on the accessory proteins Blm10 and Spg5, respectively. Modulating PSG formation, either by perturbing cellular energy status or pH, or by genetically eliminating factors required for …


Kelch F-Box Protein Positively Influences Arabidopsis Seed Germination By Targeting Phytochrome-Interacting Factor1, Manoj Majee, Santosh Kumar, Praveen Kumar Kathare, Shuiqin Wu, Derek Gingerich, Nihar R. Nayak, Louai Salaita, Randy Dinkins, Kathleen Martin, Michael Goodin, Lynnette M A Dirk, Taylor D. Lloyd, Ling Zhu, Joseph Chappell, Arthur G. Hunt, Richard D. Vierstra, Enamul Huq, A Bruce Downie Apr 2018

Kelch F-Box Protein Positively Influences Arabidopsis Seed Germination By Targeting Phytochrome-Interacting Factor1, Manoj Majee, Santosh Kumar, Praveen Kumar Kathare, Shuiqin Wu, Derek Gingerich, Nihar R. Nayak, Louai Salaita, Randy Dinkins, Kathleen Martin, Michael Goodin, Lynnette M A Dirk, Taylor D. Lloyd, Ling Zhu, Joseph Chappell, Arthur G. Hunt, Richard D. Vierstra, Enamul Huq, A Bruce Downie

Biology Faculty Research

Seeds employ sensory systems that assess various environmental cues over time to maximize the successful transition from embryo to seedling. Here we show that the Arabidopsis F-BOX protein COLD TEMPERATURE-GERMINATING (CTG)-10, identified by activation tagging, is a positive regulator of this process. When overexpressed (OE), CTG10 hastens aspects of seed germination. CTG10 is expressed predominantly in the hypocotyl, and the protein is localized to the nucleus. CTG10 interacts with PHYTOCHROME-INTERACTING FACTOR 1 (PIF1) and helps regulate its abundance in planta. CTG10-OE accelerates the loss of PIF1 in light, increasing germination efficiency, while PIF1-OE lines fail to complete germination in …


The Life Of A Microtubule, Ram Dixit, Sabine Petry Mar 2018

The Life Of A Microtubule, Ram Dixit, Sabine Petry

Biology Faculty Research

The Minisymposium “The Life of a Microtubule: Birth, Dynamics and Function” highlighted new findings on how microtubules (MTs) are made, how their length and spatial organization is regulated, and finally how they contribute to cellular functions.


Ecomorphological Variation In Three Species Of Cybotoid Anoles, A. F. Kahrl, Brittney M. Ivanov, K. C. Wollenberg Valero, Michele A. Johnson Mar 2018

Ecomorphological Variation In Three Species Of Cybotoid Anoles, A. F. Kahrl, Brittney M. Ivanov, K. C. Wollenberg Valero, Michele A. Johnson

Biology Faculty Research

Caribbean Anolis lizards exhibit a complex suite of ecological, morphological, and behavioral traits that allow their specialization to particular microhabitats. These microhabitat specialists, called ecomorphs, have independently evolved on the four islands of the Greater Antilles, and diversification among anole ecomorphs has been the focus of many studies. Yet, habitat specialization has also occurred among species within the same ecomorph group. Here, we examined ecological, morphological, and behavioral divergence in three Hispaniolan trunk-ground species, the cybotoid anoles: Anolis cybotes, A. marcanoi, and A. longitibialis. We found differences in limb morphology, locomotor behavior, and perch use among the three cybotoid species …


Overdispersed Spatial Patterning Of Dominant Bunchgrasses In Southeastern Pine Savannas, Katherines A. Hovanes, Kyle E. Harms, Paul R. Gagnon, Jonathan A. Myers, Bret D. Elderd Feb 2018

Overdispersed Spatial Patterning Of Dominant Bunchgrasses In Southeastern Pine Savannas, Katherines A. Hovanes, Kyle E. Harms, Paul R. Gagnon, Jonathan A. Myers, Bret D. Elderd

Biology Faculty Research

Spatial patterning is a key natural history attribute of sessile organisms that frequently emerges from and dictates potential for interactions among organisms. We tested whether bunchgrasses, the dominant plant functional group in longleaf pine savanna groundcover communities, are nonrandomly patterned by characterizing the spatial dispersion of three bunchgrass species across six sites in Louisiana and Florida. We mapped bunchgrass tussocks of >5.0 cm basal diameter in three [Formula: see text] plots at each site. We modeled tussocks as two-dimensional objects to analyze their spatial relationships while preserving sizes and shapes of individual tussocks. Tussocks were overdispersed (more regularly spaced than …


New Classification Of The Dictyostelids, Sanea Sheikh, Mats Thulin, James C. Cavender, Ricardo Escalante, Shin-Ichi Kawakami, Carlos Lado, John C. Landolt, Vidyanand Nanjundiah, David C. Queller, Joan E. Strassmann, Frederick W. Spiegel, Steven L. Stephenson, Eduardo M. Vadell, Sandra L. Baldauf Feb 2018

New Classification Of The Dictyostelids, Sanea Sheikh, Mats Thulin, James C. Cavender, Ricardo Escalante, Shin-Ichi Kawakami, Carlos Lado, John C. Landolt, Vidyanand Nanjundiah, David C. Queller, Joan E. Strassmann, Frederick W. Spiegel, Steven L. Stephenson, Eduardo M. Vadell, Sandra L. Baldauf

Biology Faculty Research

Traditional morphology-based taxonomy of dictyostelids is rejected by molecular phylogeny. A new classification is presented based on monophyletic entities with consistent and strong molecular phylogenetic support and that are, as far as possible, morphologically recognizable. All newly named clades are diagnosed with small subunit ribosomal RNA (18S rRNA) sequence signatures plus morphological synapomorphies where possible. The two major molecular clades are given the rank of order, as Acytosteliales ord. nov. and Dictyosteliales. The two major clades within each of these orders are recognized and given the rank of family as, respectively, Acytosteliaceae and Cavenderiaceae fam. nov. in Acytosteliales, and Dictyosteliaceae …


Iucn Conservation Status Does Not Predict Glucocortoid Concentrations In Reptiles And Birds, L. B. Martin, Maren N. Vitousek, Jeremy W. Donald, T. Flock, M. J. Fuxjager, W. Goymann, M. Hau, Jerry F. Husak, Michele A. Johnson, Bonnie K. Kircher, R. Knapp, E. T. Miller, L. A. Schoenle, T. D. Williams, C. D. Francis Jan 2018

Iucn Conservation Status Does Not Predict Glucocortoid Concentrations In Reptiles And Birds, L. B. Martin, Maren N. Vitousek, Jeremy W. Donald, T. Flock, M. J. Fuxjager, W. Goymann, M. Hau, Jerry F. Husak, Michele A. Johnson, Bonnie K. Kircher, R. Knapp, E. T. Miller, L. A. Schoenle, T. D. Williams, C. D. Francis

Biology Faculty Research

Circulating glucocorticoids (GCs) are the most commonly used biomarkers of stress in wildlife. However, their utility as a tool for identifying and/or managing at-risk species has varied. Here, we took a very broad approach to conservation physiology, asking whether International Union for the Conservation of Nature (IUCN) listing status (concern versus no obvious concern) and/or location within a geographic range (edge versus non-edge) predicted baseline and post-restraint concentrations of corticosterone (CORT) among many species of birds and reptiles. Even though such an approach can be viewed as coarse, we asked in this analysis whether CORT concentrations might be useful to …


Detecting Bias In Large-Scale Comparative Analyses: Methods For Expanding The Scope Of Hypothesis-Testing With Hormonebase, Michele A. Johnson, C. D. Francis, E. T. Miller, C. J. Downs, Maren N. Vitousek Jan 2018

Detecting Bias In Large-Scale Comparative Analyses: Methods For Expanding The Scope Of Hypothesis-Testing With Hormonebase, Michele A. Johnson, C. D. Francis, E. T. Miller, C. J. Downs, Maren N. Vitousek

Biology Faculty Research

To address large-scale questions in evolutionary biology, the compilation of data from a variety of sources is often required. This is a major challenge in the development of databases in organismal biology. Here, we describe the procedure we used to reconstruct the phylogeny of the 474 species represented in HormoneBase, including fish, amphibians, mammals, birds, and reptiles. We also provide the methodology used to compile vertebrate environmental, life history, and metabolic rate data for use in conjunction with the HormoneBase database to test hypotheses of the evolution of steroid hormone traits. We then report a series of analyses using these …


The Evolution Of Androgen Receptor Expression And Behavior In Anolis Lizard Forelimb Muscles, Michele A. Johnson, Bonnie K. Kircher, Diego J. Castro Jan 2018

The Evolution Of Androgen Receptor Expression And Behavior In Anolis Lizard Forelimb Muscles, Michele A. Johnson, Bonnie K. Kircher, Diego J. Castro

Biology Faculty Research

The motor systems that produce behavioral movements are among the primary targets for the action of steroid hormones, including androgens. Androgens such as testosterone bind to androgen receptors (AR) to induce physiological changes in the size, strength, and energetic capacity of skeletal muscles, which can directly influence the performance of behaviors in which those muscles are used. Because tissues differentially express AR, resulting in tissue-specific sensitivity to androgens, AR expression may be a major target of selection for the evolution of behavior. Anolis lizards (i.e., anoles) provide a robust system for the study of androgen-regulated traits, including the behavioral traits …


Cocaine Selectively Reorganizes Excitatory Inputs To Substantia Nigra Pars Compacta Dopamine Neurons, Gerard M.J. Beaudoin Iii, J. A. Gomez, J. M. Perkins, J. L. Bland, A. K. Petko, C. A. Paladini Jan 2018

Cocaine Selectively Reorganizes Excitatory Inputs To Substantia Nigra Pars Compacta Dopamine Neurons, Gerard M.J. Beaudoin Iii, J. A. Gomez, J. M. Perkins, J. L. Bland, A. K. Petko, C. A. Paladini

Biology Faculty Research

Substantia nigra pars compacta (SNc) dopamine neurons and their targets are involved in addiction and cue-induced relapse. However, afferents onto SNc dopamine neurons themselves appear insensitive to drugs of abuse, such as cocaine, when afferents are collectively stimulated electrically. This contrasts with ventral tegmental area (VTA) dopamine neurons, whose glutamate afferents react robustly to cocaine. We used an optogenetic strategy to isolate identified SNc inputs and determine whether cocaine sensitivity in the mouse SNc circuit is conferred at the level of three glutamate afferents: dorsal raphé nucleus (DR), pedunculopontine nucleus (PPN), and subthalamic nucleus (STN). We found that excitatory afferents …


Draft Genome Sequence Of Streptomyces Sp. Strain Jv178, A Producer Of Clifednamide-Type Polycyclic Tetramate Macrolactams, Yunci Qi, John M. D’Alessandro, Joshua A.V Blodgett Jan 2018

Draft Genome Sequence Of Streptomyces Sp. Strain Jv178, A Producer Of Clifednamide-Type Polycyclic Tetramate Macrolactams, Yunci Qi, John M. D’Alessandro, Joshua A.V Blodgett

Biology Faculty Research

Here, we report the draft genome sequence of Streptomyces sp. JV178, a strain originating from Connecticut (USA) garden soil. This strain produces the polycyclic tetramate macrolactam compounds clifednamides A and B. The draft genome contains 10.65 Mb, 9,045 predicted protein coding sequences, and several natural product biosynthetic loci.


Phyllotactic Regularity Requires The Paf1 Complex In Arabidopsis, Kateryna Fal, Mengying Liu, Assem Duisembekova, Yassin Refahi, Elizabeth S. Haswell, Olivier Hamant Nov 2017

Phyllotactic Regularity Requires The Paf1 Complex In Arabidopsis, Kateryna Fal, Mengying Liu, Assem Duisembekova, Yassin Refahi, Elizabeth S. Haswell, Olivier Hamant

Biology Faculty Research

In plants, aerial organs are initiated at stereotyped intervals, both spatially (every 137° in a pattern called phyllotaxis) and temporally (at prescribed time intervals called plastochrons). To investigate the molecular basis of such regularity, mutants with altered architecture have been isolated. However, most of them only exhibit plastochron defects and/or produce a new, albeit equally reproducible, phyllotactic pattern. This leaves open the question of a molecular control of phyllotaxis regularity. Here, we show that phyllotaxis regularity depends on the function of VIP proteins, components of the RNA polymerase II-associated factor 1 complex (Paf1c). Divergence angles between successive organs along the …


Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose Oct 2017

Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose

Biology Faculty Research

The deep ocean and its sediments are a continuous source of non-methane short-chain alkanes (SCAs) including ethane, propane, and butane. Their high global warming potential, and contribution to local carbon and sulfur budgets has drawn significant scientific attention. Importantly, microbes can use gaseous alkanes and oxidize them to CO2, thus acting as effective biofilters. A relative decrease of these gases with a concomitant 13C enrichment of propane and n-butane in interstitial waters vs. the source suggests microbial anaerobic oxidation. The reported uncoupling of sulfate-reduction (SR) from anaerobic methane oxidation supports their microbial consumption. To date, strain …


Seasonal Variation In The Utility Of A Status Signaling System: Plumage Ornament Predicts Foraging Success Only During Periods Of High Competition, Philip Queller, Troy G. Murphy Oct 2017

Seasonal Variation In The Utility Of A Status Signaling System: Plumage Ornament Predicts Foraging Success Only During Periods Of High Competition, Philip Queller, Troy G. Murphy

Biology Faculty Research

Status signals allow competitors to assess each other’s resource holding potential and reduce the occurrence of physical fights. Because status signals function to mediate competition over resources, a change in the strength of competition may affect the utility of a status signaling system. Status signals alter competitor behavior during periods of high competition, and thus determine access to resources; however, when competition is reduced, we expect these signals to become disassociated from access to resources. We investigated seasonal changes in status signaling of the male black-crested titmouse (Baeolophus atricristatus), a species that experiences substantial changes in population density …


Prey Availability Affects Territory Size, But Not Territorial Display Behavior, In Green Anole Lizards, Chelsea M. Stehle, Andrew C. Battles, Michelle N. Sparks, Michele A. Johnson Oct 2017

Prey Availability Affects Territory Size, But Not Territorial Display Behavior, In Green Anole Lizards, Chelsea M. Stehle, Andrew C. Battles, Michelle N. Sparks, Michele A. Johnson

Biology Faculty Research

The availability of food resources can affect the size and shape of territories, as well as the behaviors used to defend territories, in a variety of animal taxa. However, individuals within a population may respond differently to variation in food availability if the benefits of territoriality vary among those individuals. For example, benefits to territoriality may differ for animals of differing sizes, because larger individuals may require greater territory size to acquire required resources, or territorial behavior may differ between the sexes if males and females defend different resources in their territories. In this study, we tested whether arthropod abundance …


Photosensing And Thermosensing By Phytochrome B Require Both Proximal And Distal Allosteric Features Within The Dimeric Photoreceptor, E Sethe Burgie, Adam N. Bussell, Shu-Hui Lye, Tong Wang, Weiming Hu, Katrice E. Mcloughlin, Erin L. Weber, Huilin Li, Richard D. Vierstra Oct 2017

Photosensing And Thermosensing By Phytochrome B Require Both Proximal And Distal Allosteric Features Within The Dimeric Photoreceptor, E Sethe Burgie, Adam N. Bussell, Shu-Hui Lye, Tong Wang, Weiming Hu, Katrice E. Mcloughlin, Erin L. Weber, Huilin Li, Richard D. Vierstra

Biology Faculty Research

Phytochromes (Phys) encompass a diverse collection of bilin-containing photoreceptors that help plants and microorganisms perceive light through photointerconversion between red light (Pr) and far-red light (Pfr)-absorbing states. In addition, Pfr reverts thermally back to Pr via a highly enthalpic process that enables temperature sensation in plants and possibly other organisms. Through domain analysis of the Arabidopsis PhyB isoform assembled recombinantly, coupled with measurements of solution size, photoconversion, and thermal reversion, we identified both proximal and distal features that influence all three metrics. Included are the downstream C-terminal histidine kinase-related domain known to promote dimerization and a conserved patch just upstream …


Big Brains Stabilize Populations And Facilitate Colonization Of Variable Habitats In Birds, Trevor S. Fristoe, Andrew N. Iwaniuk, Carlos A. Botero Sep 2017

Big Brains Stabilize Populations And Facilitate Colonization Of Variable Habitats In Birds, Trevor S. Fristoe, Andrew N. Iwaniuk, Carlos A. Botero

Biology Faculty Research

The cognitive buffer hypothesis posits that environmental variability can be a major driver of the evolution of cognition because an enhanced ability to produce flexible behavioural responses facilitates coping with the unexpected. Although comparative evidence supports different aspects of this hypothesis, a direct connection between cognition and the ability to survive a variable and unpredictable environment has yet to be demonstrated. Here, we use complementary demographic and evolutionary analyses to show that among birds, the mechanistic premise of this hypothesis is well supported but the implied direction of causality is not. Specifically, we show that although population dynamics are more …


Plant Mechanosensitive Ion Channels: An Ocean Of Possibilities, Debarati Basu, Elizabeth S. Haswell Sep 2017

Plant Mechanosensitive Ion Channels: An Ocean Of Possibilities, Debarati Basu, Elizabeth S. Haswell

Biology Faculty Research

Mechanosensitive ion channels, transmembrane proteins that directly couple mechanical stimuli to ion flux, serve to sense and respond to changes in membrane tension in all branches of life. In plants, mechanosensitive channels have been implicated in the perception of important mechanical stimuli such as osmotic pressure, touch, gravity, and pathogenic invasion. Indeed, three established families of plant mechanosensitive ion channels play roles in cell and organelle osmoregulation and root mechanosensing - and it is likely that many other channels and functions await discovery. Inspired by recent discoveries in bacterial and animal systems, we are beginning to establish the conserved and …


Point Of View: The Sustainable Professor, Elizabeth S. Haswell Aug 2017

Point Of View: The Sustainable Professor, Elizabeth S. Haswell

Biology Faculty Research

Responsible agricultural practices provide a useful lens through which to consider the lives and careers of researchers.


Life Behind The Wall: Sensing Mechanical Cues In Plants, Olivier Hamant, Elizabeth S. Haswell Jul 2017

Life Behind The Wall: Sensing Mechanical Cues In Plants, Olivier Hamant, Elizabeth S. Haswell

Biology Faculty Research

There is increasing evidence that all cells sense mechanical forces in order to perform their functions. In animals, mechanotransduction has been studied during the establishment of cell polarity, fate, and division in single cells, and increasingly is studied in the context of a multicellular tissue. What about plant systems? Our goal in this review is to summarize what is known about the perception of mechanical cues in plants, and to provide a brief comparison with animals.


Negative Density Dependence Mediates Biodiversity–Productivity Relationships Across Scales, Joseph A. Lamanna, R Travis Belote, Laura A. Burkle, Christopher P. Catano, Jonathan A. Myers Jul 2017

Negative Density Dependence Mediates Biodiversity–Productivity Relationships Across Scales, Joseph A. Lamanna, R Travis Belote, Laura A. Burkle, Christopher P. Catano, Jonathan A. Myers

Biology Faculty Research

Regional species diversity generally increases with primary productivity whereas local diversity–productivity relationships are highly variable. This scale-dependence of the biodiversity–productivity relationship highlights the importance of understanding the mechanisms that govern variation in species composition among local communities, which is known as β-diversity. Hypotheses to explain changes in β-diversity with productivity invoke multiple mechanisms operating at local and regional scales, but the relative importance of these mechanisms is unknown. Here we show that changes in the strength of local density-dependent interactions within and among tree species explain changes in β-diversity across a subcontinental-productivity gradient. Stronger conspecific relative to …


Sexual Selection And Sex Ratios In Anolis Lizards, Pavitra Muralidhar, Michele A. Johnson Jul 2017

Sexual Selection And Sex Ratios In Anolis Lizards, Pavitra Muralidhar, Michele A. Johnson

Biology Faculty Research

Biased sex ratios, or unequal numbers of males and females in a population, can alter the intensity of sexual selection by enhancing competition for mates, and thus may affect the evolution of reproductive strategies. Studies of sex ratio variation across a clade provide an opportunity to examine the morphological or behavioral consequences of different levels of sexual selection. We examined sex ratio variation, using phylogenetic comparative methods, across a diverse clade of terrestrial vertebrates, the Anolis lizards. Across a sample of 14 species in 21 localities, we found remarkable bidirectional variation in sex ratios across the Anolis clade: males are …


A Genomics Education Alliance, Sarah C.R. Elgin, Gita Bangera, Vincent Buonaccorsi, Douglas L. Chalker, Elizabeth Dinsdale, Erin L. Dolan, Linnea Fletcher, Arthur G. Hunt, Carolyn Lawrence-Dill, Wilson Leung, Laura Reed, Anne Rosenwald, Sandesh Subramanya, Emily Wiley, Jason Williams Jul 2017

A Genomics Education Alliance, Sarah C.R. Elgin, Gita Bangera, Vincent Buonaccorsi, Douglas L. Chalker, Elizabeth Dinsdale, Erin L. Dolan, Linnea Fletcher, Arthur G. Hunt, Carolyn Lawrence-Dill, Wilson Leung, Laura Reed, Anne Rosenwald, Sandesh Subramanya, Emily Wiley, Jason Williams

Biology Faculty Research

Scientists are sequencing new genomes at an increasing rate with the goal of associating genome contents with phenotypic traits. After a new genome is sequenced and assembled, structural gene annotation is often the first step in analysis. Despite advances in computational gene prediction algorithms, most eukaryotic genomes still benefit from manual gene annotation. Undergraduates can become skilled annotators, and in the process learn both about genes/genomes and about how to utilize large datasets. Data visualizations provided by a genome browser are essential for manual gene annotation, enabling annotators to quickly evaluate multiple lines of evidence (e.g., sequence similarity, RNA-Seq, gene …


The Tension-Sensitive Ion Transport Activity Of Msl8 Is Critical For Its Function In Pollen Hydration And Germination, Eric S. Hamilton Jul 2017

The Tension-Sensitive Ion Transport Activity Of Msl8 Is Critical For Its Function In Pollen Hydration And Germination, Eric S. Hamilton

Biology Faculty Research

All cells respond to osmotic challenges, including those imposed during normal growth and development. Mechanosensitive (MS) ion channels provide a conserved mechanism for regulating osmotic forces by conducting ions in response to increased membrane tension. We previously demonstrated that the MS ion channel MscS-Like 8 (MSL8) is required for pollen to survive multiple osmotic challenges that occur during the normal process of fertilization, and that it can inhibit pollen germination. However, it remained unclear whether these physiological functions required ion flux through a mechanically gated channel provided by MSL8. We introduced two point mutations into the predicted pore-lining domain of …


Family Living Sets The Stage For Cooperative Breeding And Ecological Resilience In Birds, Michael Griesser, Szymon M. Drobniak, Shinichi Nakagawa, Carlos A. Botero Jun 2017

Family Living Sets The Stage For Cooperative Breeding And Ecological Resilience In Birds, Michael Griesser, Szymon M. Drobniak, Shinichi Nakagawa, Carlos A. Botero

Biology Faculty Research

Cooperative breeding is an extreme form of cooperation that evolved in a range of lineages, including arthropods, fish, birds, and mammals. Although cooperative breeding in birds is widespread and well-studied, the conditions that favored its evolution are still unclear. Based on phylogenetic comparative analyses on 3,005 bird species, we demonstrate here that family living acted as an essential stepping stone in the evolution of cooperative breeding in the vast majority of species. First, families formed by prolonging parent–offspring associations beyond nutritional independency, and second, retained offspring began helping at the nest. These findings suggest that assessment of the conditions that …


Sexual Selection, Speciation And Constraints On Geographical Range Overlap In Birds, Christopher Cooney, Joseph A. Tobias, Jason T. Weir, Carlos A. Botero, Nathalie Seddon May 2017

Sexual Selection, Speciation And Constraints On Geographical Range Overlap In Birds, Christopher Cooney, Joseph A. Tobias, Jason T. Weir, Carlos A. Botero, Nathalie Seddon

Biology Faculty Research

The role of sexual selection as a driver of speciation remains unresolved, not least because we lack a clear empirical understanding of its influence on different phases of the speciation process. Here, using data from 1306 recent avian speciation events, we show that plumage dichromatism (a proxy for sexual selection) does not predict diversification rates, but instead explains the rate at which young lineages achieve geographical range overlap. Importantly, this effect is only significant when range overlap is narrow (< 20%). These findings are consistent with a ‘differential fusion’ model wherein sexual selection reduces rates of fusion among lineages undergoing secondary contact, facilitating parapatry or limited co-existence, whereas more extensive sympatry is contingent on additional factors such as ecological differentiation. Our results provide a more mechanistic explanation for why sexual selection appears to drive early stages of speciation while playing a seemingly limited role in determining broad-scale patterns of diversification.


Spatial Structure Of The Mormon Cricket Gut Microbiome And Its Predicted Contribution To Nutrition And Immune Function, Chad C. Smith, Robert Srygley, Frank G. Healy, Karthikeyan Swaminath, Ulrich G. Mueller May 2017

Spatial Structure Of The Mormon Cricket Gut Microbiome And Its Predicted Contribution To Nutrition And Immune Function, Chad C. Smith, Robert Srygley, Frank G. Healy, Karthikeyan Swaminath, Ulrich G. Mueller

Biology Faculty Research

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the niches available for microbes to colonize. We present a high-resolution analysis of the structure of the gut microbiome in the Mormon cricket Anabrus simplex, an insect known for its periodic outbreaks in the western United States and nutrition-dependent mating system. The Mormon cricket microbiome was dominated by eleven taxa from the Lactobacillaceae, Enterobacteriaceae, and Streptococcaeae. While most of …


Ancient Bacteria–Amoeba Relationships And Pathogenic Animal Bacteria, Joan E. Strassmann, Longfei Shu May 2017

Ancient Bacteria–Amoeba Relationships And Pathogenic Animal Bacteria, Joan E. Strassmann, Longfei Shu

Biology Faculty Research

Long before bacteria infected humans, they infected amoebas, which remain a potentially important reservoir for human disease. Diverse soil amoebas including Dictyostelium and Acanthamoeba can host intracellular bacteria. Though the internal environment of free-living amoebas is similar in many ways to that of mammalian macrophages, they differ in a number of important ways, including temperature. A new study in PLOS Biology by Taylor-Mulneix et al. demonstrates that Bordetella bronchiseptica has two different gene suites that are activated depending on whether the bacterium finds itself in a hot mammalian or cool amoeba host environment. This study specifically shows that B. …


Why Do Curly Tail Lizards (Genus Leiocephalus) Curl Their Tails? An Assessment Of Displays Toward Conspecifics And Predators, Bonnie K. Kircher, Michele A. Johnson May 2017

Why Do Curly Tail Lizards (Genus Leiocephalus) Curl Their Tails? An Assessment Of Displays Toward Conspecifics And Predators, Bonnie K. Kircher, Michele A. Johnson

Biology Faculty Research

Animal display behaviors are used to convey specific messages to other animals, including potential mates, rivals, and predators. However, because these different types of interactions can be mediated by a single behavioral display, or conversely, multiple signals can be used to convey one specific message, interpretation of any particular behavioral display can be difficult. Leiocephalus lizards (i.e., curly tails) provide an excellent opportunity to study the use of display behaviors across multiple contexts. Previous research has demonstrated that the use of tail curling in these lizards is associated with predation risk, but less is known regarding the use of this …


Does High Relatedness Promote Cheater-Free Multicellularity In Synthetic Lifecycles?, R F. Inglis, E Ryu, O Asikhia, Joan E. Strassmann, David C. Queller Apr 2017

Does High Relatedness Promote Cheater-Free Multicellularity In Synthetic Lifecycles?, R F. Inglis, E Ryu, O Asikhia, Joan E. Strassmann, David C. Queller

Biology Faculty Research

The evolution of multicellularity is one of the key transitions in evolution and requires extreme levels of cooperation between cells. However, even when cells are genetically identical, noncooperative cheating mutants can arise that cause a breakdown in cooperation. How then, do multicellular organisms maintain cooperation between cells? A number of mechanisms that increase relatedness amongst cooperative cells have been implicated in the maintenance of cooperative multicellularity including single-cell bottlenecks and kin recognition. In this study, we explore how relatively simple biological processes such as growth and dispersal can act to increase relatedness and promote multicellular cooperation. Using experimental populations of …