scholarly journals Are Feeding Modes Concealing Morphofunctional Diversity? The Case of the New World Parrotfishes

2021 ◽  
Vol 8 ◽  
Author(s):  
Lucía Pombo-Ayora ◽  
Jose Tavera
Keyword(s):  
Feeding Ecology ◽  
Functional Ecology ◽  
Ancestral Reconstruction ◽  
Functional Diversification ◽  
Feeding Mode ◽  
Selective Pressures ◽  
Feeding Modes ◽  
Feeding Morphology ◽  
Novel Structures ◽  
Ecological Differences

In functional ecology, morphology is expected to reflect function; however, occasional decoupling of these two can be found. In the case of feeding ecology, the diversity of the diet or diversity of the feeding modes within a clade is expected to be positively related to the diversity of the morphological traits involved in the feeding performance. Parrotfishes are separated into two main groups, the “reef” clade and the “seagrass” clade. Both groups have important differences in their evolutionary history. Still, more interestingly, they have important morphological and ecological differences. The genera Scarus and Sparisoma are the most specious genera of parrotfishes. They belong to each of those main groups, respectively. All Scarus species have the same feeding mode, while in Sparisoma, there are three different feeding modes. We want to test if the morphological jaw diversity of these genera corresponds with the diversity in their feeding modes. Using a disparity analysis of feeding traits within a phylogenetical framework, we did not find a relationship between functional feeding morphology and feeding modes of the American parrotfishes of the genera Scarus and Sparisoma. Interestingly we found that some muscular traits are the source of the high disparity in the genus Scarus. We explore some possible morpho-functional reasons for this phenomenon and reappraise the parrotfishes’ scraper feeding mode’s functional diversity. We also consider that there could be more ecological differentiation between Scarus species that we are aware of. Using an ancestral reconstruction of feeding modes of 52 species of parrotfishes, we found that the scraping feeding mode exhibited by all Scarus species is an evolutionary convergence with the scraping feeding modes performed by some Sparisoma species. Different selective pressures or ecological conditions may have shaped the differences in the feeding ecology and the feeding morphology of these two genera. Probably, key novel structures and muscular properties found in the Scarus species’ jaw played an essential role in this genus’s morpho-functional diversification. Finally, we propose that feeding modes may not fully capture the complexity of feeding ecology in parrotfishes.

scholarly journals Genomic Adaptations to Salinity Resist Gene Flow in the Evolution of Floridian Watersnakes

2020 ◽  
Author(s):  
Rhett M Rautsaw ◽  
Tristan D Schramer ◽  
Rachel Acuña ◽  
Lindsay N Arick ◽  
Mark DiMeo ◽  
...  
Keyword(s):  
Gene Flow ◽  
Isolation By Distance ◽  
Species Boundaries ◽  
Selective Pressures ◽  
Nerodia Fasciata ◽  
Isolation By Environment ◽  
Significant Gene ◽  
Candidate Loci ◽  
Osmoregulatory Function ◽  
Ecological Differences

Abstract The migration-selection balance often governs the evolution of lineages, and speciation with gene flow is now considered common across the tree of life. Ecological speciation is a process that can facilitate divergence despite gene flow due to strong selective pressures caused by ecological differences; however, the exact traits under selection are often unknown. The transition from freshwater to saltwater habitats provides strong selection targeting traits with osmoregulatory function. Several lineages of North American watersnakes (Nerodia spp.) are known to occur in saltwater habitat and represent a useful system for studying speciation by providing an opportunity to investigate gene flow and evaluate how species boundaries are maintained or degraded. We use double digest restriction-site associated DNA sequencing to characterize the migration-selection balance and test for evidence of ecological divergence within the Nerodia fasciata-clarkii complex in Florida. We find evidence of high intraspecific gene flow with a pattern of isolation-by-distance underlying subspecific lineages. However, we identify genetic structure indicative of reduced gene flow between inland and coastal lineages suggesting divergence due to isolation-by-environment. This pattern is consistent with observed environmental differences where the amount of admixture decreases with increased salinity. Furthermore, we identify significantly enriched terms related to osmoregulatory function among a set of candidate loci, including several genes that have been previously implicated in adaptation to salinity stress. Collectively, our results demonstrate that ecological differences, likely driven by salinity, cause strong divergent selection which promotes divergence in the N. fasciata-clarkii complex despite significant gene flow.

scholarly journals Functional diversity of small-mammal postcrania is linked to both substrate preference and body size

2020 ◽  
Vol 66 (5) ◽  
pp. 539-553
Author(s):  
Lucas N Weaver ◽  
David M Grossnickle
Keyword(s):  
Body Size ◽  
Phenotypic Diversity ◽  
Small Body ◽  
Ecological Factors ◽  
Morphological Divergence ◽  
Functional Diversification ◽  
Evolutionary Patterns ◽  
Selective Pressures ◽  
Trade Offs ◽  
Body Sizes

Abstract Selective pressures favor morphologies that are adapted to distinct ecologies, resulting in trait partitioning among ecomorphotypes. However, the effects of these selective pressures vary across taxa, especially because morphology is also influenced by factors such as phylogeny, body size, and functional trade-offs. In this study, we examine how these factors impact functional diversification in mammals. It has been proposed that trait partitioning among mammalian ecomorphotypes is less pronounced at small body sizes due to biomechanical, energetic, and environmental factors that favor a “generalist” body plan, whereas larger taxa exhibit more substantial functional adaptations. We title this the Divergence Hypothesis (DH) because it predicts greater morphological divergence among ecomorphotypes at larger body sizes. We test DH by using phylogenetic comparative methods to examine the postcranial skeletons of 129 species of taxonomically diverse, small-to-medium-sized (<15 kg) mammals, which we categorize as either “tree-dwellers” or “ground-dwellers.” In some analyses, the morphologies of ground-dwellers and tree-dwellers suggest greater between-group differentiation at larger sizes, providing some evidence for DH. However, this trend is neither particularly strong nor supported by all analyses. Instead, a more pronounced pattern emerges that is distinct from the predictions of DH: within-group phenotypic disparity increases with body size in both ground-dwellers and tree-dwellers, driven by morphological outliers among “medium”-sized mammals. Thus, evolutionary increases in body size are more closely linked to increases in within-locomotor-group disparity than to increases in between-group disparity. We discuss biomechanical and ecological factors that may drive these evolutionary patterns, and we emphasize the significant evolutionary influences of ecology and body size on phenotypic diversity.

scholarly journals RNA Structure Duplication in the Dengue Virus 3′ UTR: Redundancy or Host Specificity?

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Luana de Borba ◽  
Sergio M. Villordo ◽  
Franco L. Marsico ◽  
Juan M. Carballeda ◽  
Claudia V. Filomatori ◽  
...  
Keyword(s):  
Viral Replication ◽  
Viral Genome ◽  
Untranslated Region ◽  
Rna Synthesis ◽  
Rna Structures ◽  
Functional Diversification ◽  
Selective Pressures ◽  
Selective Forces ◽  
Rna Elements ◽  
Selection Of

ABSTRACTFlaviviruses include a diverse group of medically important viruses that cycle between mosquitoes and humans. During this natural process of switching hosts, each species imposes different selective forces on the viral population. Using dengue virus (DENV) as model, we found that paralogous RNA structures originating from duplications in the viral 3′ untranslated region (UTR) are under different selective pressures in the two hosts. These RNA structures, known as dumbbells (DB1 and DB2), were originally proposed to be enhancers of viral replication. Analysis of viruses obtained from infected mosquitoes showed selection of mutations that mapped in DB2. Recombinant viruses carrying the identified variations confirmed that these mutations greatly increase viral replication in mosquito cells, with low or no impact in human cells. Use of viruses lacking each of the DB structures revealed opposite viral phenotypes. While deletion of DB1 reduced viral replication about 10-fold, viruses lacking DB2 displayed a great increase of fitness in mosquitoes, confirming a functional diversification of these similar RNA elements. Mechanistic analysis indicated that DB1 and DB2 differentially modulate viral genome cyclization and RNA replication. We found that a pseudoknot formed within DB2 competes with long-range RNA-RNA interactions that are necessary for minus-strand RNA synthesis. Our results support a model in which a functional diversification of duplicated RNA elements in the viral 3′ UTR is driven by host-specific requirements. This study provides new ideas for understanding molecular aspects of the evolution of RNA viruses that naturally jump between different species.IMPORTANCEFlaviviruses constitute the most relevant group of arthropod-transmitted viruses, including important human pathogens such as the dengue, Zika, yellow fever, and West Nile viruses. The natural alternation of these viruses between vertebrate and invertebrate hosts shapes the viral genome population, which leads to selection of different viral variants with potential implications for epidemiological fitness and pathogenesis. However, the selective forces and mechanisms acting on the viral RNA during host adaptation are still largely unknown. Here, we found that two almost identical tandem RNA structures present at the viral 3′ untranslated region are under different selective pressures in the two hosts. Mechanistic studies indicated that the two RNA elements, known as dumbbells, contain sequences that overlap essential RNA cyclization elements involved in viral RNA synthesis. The data support a model in which the duplicated RNA structures differentially evolved to accommodate distinct functions for viral replication in the two hosts.

scholarly journals Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction

2013 ◽  
Vol 280 (1770) ◽  
pp. 20131940 ◽  
Author(s):  
Thomas L. Stubbs ◽  
Stephanie E. Pierce ◽  
Emily J. Rayfield ◽  
Philip S. L. Anderson
Keyword(s):  
Late Cretaceous ◽  
Morphological Variation ◽  
Late Triassic ◽  
Complex Relationship ◽  
Ecological Diversity ◽  
Unique Combination ◽  
Morphological Disparity ◽  
Selective Pressures ◽  
Feeding Modes ◽  
Jaw Biomechanics

Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles.

scholarly journals Reduce the Degradation of Polyhydroxyalkanoates: Feeding in the Oxygen-limiting Section Increases the Accumulation of PHAs

2021 ◽  
Author(s):  
Yanyu Xiao ◽  
Qian Fang ◽  
Yihan Xie ◽  
Kequan Zhang ◽  
Qiqi Ping ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Microbial Community ◽  
Sequence Analyses ◽  
Feeding Mode ◽  
Feeding Modes ◽  
Aerobic Process ◽  
Increasing Trend ◽  
Limiting Stage ◽  
The One ◽  
Maximum Content

Abstract To solve the problem that the content of polyhydroxyalkanoates (PHAs) in the aerobic section of the traditional anaerobic-aerobic process continues to decrease, two different feeding modes in the oxygen-limiting section were explored under the anaerobic-oxygen limiting process(for reducing the energy consumption of aeration). Based on 16SrRNA sequence analyses, the results show that the abundance of Hydrogenovora(9.57%), Zoogloea(6.73%), Thaurea(1.49%) and other bacterial genera in the microbial community had increased after enrichment. PHAs were synthesized in the oxygen-limiting stage of both one-time feeding and batch feeding mode. The maximum content of PHA reached 52.17% when C/N increased to 150 in the one-time feeding mode, and that reached 42.04% in batch feeding mode when C/N was 100. The one-time feeding mode shows a more significant accumulation potential of PHAs than the batch feeding mode. The content of PHAs shows an increasing trend with the increase of C/N ratio, and a high C/N ratio may lead to sludge bulking and other problems, making the sludge system unsteady.

scholarly journals A toothless dwarf dolphin (Odontoceti: Xenorophidae) points to explosive feeding diversification of modern whales (Neoceti)

2017 ◽  
Author(s):  
Robert Boessenecker ◽  
Danielle Fraser ◽  
Morgan Churchill ◽  
Jonathan Geisler
Keyword(s):  
Phylogenetic Analysis ◽  
South Carolina ◽  
Feeding Behaviour ◽  
Stabilizing Selection ◽  
Suction Feeding ◽  
Feeding Mode ◽  
Milk Teeth ◽  
Feeding Morphology ◽  
Tooth Count

Toothed whales (Odontoceti) are adapted for catching prey underwater and possess some of the most derived feeding specializations of all mammals, including the loss of milk teeth (monophyodonty), high tooth count (polydonty), and the loss of discrete tooth classes (homodonty). Many extant odontocetes possess some combination of short, broad rostra, reduced tooth counts, fleshy lips, and enlarged hyoid bones - all adaptations for suction feeding upon fish and squid. We report a new fossil odontocete from the Oligocene (~30 Ma) of South Carolina (Inermorostrum xenops, gen. et sp. nov.) that possesses adaptations for suction feeding: toothlessness and a shortened rostrum (brevirostry). Enlarged foramina on the rostrum suggest the presence of enlarged lips or perhaps vibrissae. Phylogenetic analysis firmly places Inermorostrum within the Xenorophidae, an early diverging odontocete clade typified by long-snouted, heterodont dolphins. Inermorostrum is the earliest obligate suction feeder within the Odontoceti, a feeding mode that independently evolved several times within the clade. Analysis of macroevolutionary trends in rostral shape indicate stabilizing selection around an optimum rostral shape over the course of odontocete evolution, and a post-Eocene explosion in feeding morphology, heralding the diversity of feeding behaviour amongst modern Odontoceti.

scholarly journals Dietary Analysis Based on 18S rDNA, and Stable Carbon and Nitrogen Isotopes in Juvenile Eriocheir sinensis Crabs Reared Under Three Feeding Modes

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhenzhen Lu ◽  
Yunfei Sun ◽  
Changlun Xiao ◽  
Yongxu Cheng
Keyword(s):  
Nitrogen Isotopes ◽  
Feeding Habits ◽  
Eriocheir Sinensis ◽  
Alternanthera Philoxeroides ◽  
Feeding Mode ◽  
Dietary Analysis ◽  
Male And Female ◽  
Feeding Modes ◽  
Mitten Crab ◽  
Significant Difference

To investigate the growth and feeding conditions of the Chinese mitten crab Eriocheir sinensis under different feeding modes: traditional (mainly consisting of wheat, bran, and soybean meal), formulated, and mixed feeds (1:1 mixture of traditional and formulated feeds) were fed in different crab breeding ponds in this study. During the experiment, the stomach contents of juvenile crabs under the different feeding modes were collected. The main potential eukaryotic food components were studied using 18S ribosomal DNA sequencing, and the contribution of different feeding modes to the feeding source of juvenile crabs were analyzed using C and N stable isotopes. The terminal weight and weight gain rate of crabs under the formulated feeding mode were significantly higher than those in the traditional and mixed feeding modes (P < 0.05). No differences were observed in the diversity and abundance of the main potential eukaryotic feed components of male and female crabs under different feeding modes (P > 0.05). Thirty-four phyla, composed mainly of benthic organisms, were identified, with Arthropoda (mainly including Malacostraca, 30.25–51.48%), Phragmoplastophyta (mainly including Embryophyta and Trebouxiophyceae, 5.08–24.74%), and Diatomea (3.13–8.43%) being the most abundant. The δ13C and δ15N values of the feeding sources and muscle of crabs ranged from −34.45 to −22.21‰, and from 0.27 to 5.66‰, respectively, varying greatly among the three feeding modes and δ15N value of muscle under formulated feeding mode was significantly higher than that in traditional feeding mode (P < 0.05). The proportion of particulate organic matter (11.92–17.50%) is similar to Alternanthera philoxeroides (11.24–16.03%) in three feeding modes. There was no significant difference in feeding habits between male and female crabs under the same and different feeding modes. Juvenile crabs feed on both plant- and animal-based feeds in an aquaculture pond, but they are not complete predators and selectively feed on animal or plant feeds as supplements of that which is deficient, in addition to their main feed.

Study on the Influence of C/N Ratio on Denitrification Efficiency in CRI System

2012 ◽  
Vol 599 ◽  
pp. 326-330
Author(s):  
Jun Min Chen ◽  
Zhen Hua Sheng
Keyword(s):  
Removal Efficiency ◽  
Soil Column ◽  
Experimental Results ◽  
Artificial Soil ◽  
National Standard ◽  
Feeding Mode ◽  
Feeding Modes ◽  
Starting Point ◽  
Anaerobic Zone ◽  
Denitrification Process

Abstract. The TN removal efficiency is very low and the TN concentration of effluent can not meet the national standard of GB18918-2002 in the CRI system. In order to increasingly improve the denitrification efficiency of the CRI system, the artificial soil column is used to simulate the CRI system with 4 kinds of wastewater step-feeding modes. A series of comparative experiments are carried out, and the experimental results show that the TN removal efficiency of the CRI system is controlled by the denitrification process, and the denitrification process takes place mainly in the 900-1400mm zone of the artificial soil column; with the step-feeding mode, the C/N ratios of effluent from the 900-1400mm zone increase obviously in the CRI system, and in the case 4, the C/N ratios of effluent from the 900-1400mm zone are about 2, which is the closest to the optimal C/N ratio of the denitrification process; the best wastewater feeding mode of the CRI system is that the wastewater is pumped into the system from the infiltration media surface and the starting point of the anaerobic zone at the same time, with the influent amount ratio of 2:1.

Association Between Infant Feeding Modes and Gastroesophageal Reflux: A Repeated Measurement Analysis of the Infant Feeding Practices Study II

2017 ◽  
Vol 33 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Pei-Lin Chen ◽  
Nelís Soto-Ramírez ◽  
Hongmei Zhang ◽  
Wilfried Karmaus
Keyword(s):  
Gastroesophageal Reflux ◽  
Human Milk ◽  
Infant Feeding ◽  
Repeated Measurement ◽  
Formula Feeding ◽  
Solid Food ◽  
Infant Feeding Practices ◽  
Feeding Mode ◽  
Feeding Modes ◽  
Risk Ratios

Background: Gastroesophageal reflux in neonates is frequently reported by parents, potentially motivating changes in infant feeding mode and/or addition of solid food. Objective: The authors prospectively analyzed associations between repeated measurement of feeding modes and reflux in infancy. Methods: The Infant Feeding Practices Study II, conducted between 2005 and 2007 (2,841 infants), provides data on reflux and feeding modes at nine time points from months 1 to 12. Feeding modes were defined based on direct breastfeeding, feeding of bottled human milk, formula feeding, their combinations, and use of solid food. Repeated measurements were investigated using 1-month delayed models to estimate risk ratios (RRs) and their 95% confidence intervals (CIs). Risk ratios of different feeding modes were estimated for reflux; addressing a reverse association, RRs for feeding mode were estimated as responses to prior reflux. Results: Compared to direct breastfeeding, combinations with formula feeding showed a statistically significant risk for reflux (bottled human milk plus formula feeding: RR = 2.19, 95% CI [1.11, 4.33]; formula feeding: RR = 1.95, 95% CI [1.39, 2.74]; and mixed breastfeeding plus formula feeding: RR = 1.59, 95% CI [1.40, 2.42]). Addition of solid food was not protective (RR = 1.21, 95% CI [0.86, 1.70]). Analyses of reverse association (reflux → feeding) showed fewer breastfed infants among those with reflux in the prior month. Conclusion: Any combination of infant feeding with formula seems to be a risk for reflux. Although breastfeeding was protective, mothers with a child with reflux were more likely to wean their child.

scholarly journals Dynamic signatures of gut microbiota and influences of delivery and feeding modes during the first 6 months of life

2019 ◽  
Vol 51 (8) ◽  
pp. 368-378 ◽  
Author(s):  
Rong Yang ◽  
Renyuan Gao ◽  
Sainan Cui ◽  
Hui Zhong ◽  
Xiaohui Zhang ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
High Throughput Sequencing ◽  
Delivery Mode ◽  
Affecting Factors ◽  
Microbial Composition ◽  
Feeding Mode ◽  
Feeding Modes ◽  
Stool Samples ◽  
And Function ◽  
Over Time

The gut microbiota of infants changes over time and is affected by various factors during early life. However, rarely have studies explored the gut microbiota development and affecting factors in the Chinese infant population. We enrolled 102 infants and collected stool samples from them at birth, 42 days, 3 mo, and 6 mo after delivery to characterize the microbiota signatures and the effects of different factors that modulate the gut microbiota diversity, composition, and function over time. DNA extracted from the bacteria in the stool samples was subjected to high-throughput sequencing and bioinformatics analysis. Microbial richness and diversity increased significantly during the first 6 mo of life. Beneficial microbes such as Bifidobacterium, Lactobacillus, and Blautia were found to be increased in the infant’s gut at 6 mo, while pathological bacteria such as Escherichia-Shigella, Enterobacter, Staphylococcus, and Klebsiella decreased over time. The changes in the infant delivery mode and infant-feeding mode only produced changes in the microbial composition, whereas changes in bacterial richness, diversity and effects sizes on the microbial architecture were all time dependent. A comparison of infant delivery modes conveyed a decrease in abundance of Bacteroidetes over time in the gut of infants born via C-section, while the Bifidobacterium was the most dominant genus in the vaginal delivery group. The gut microbiota of infants changed extensively during the first 6 mo of life. Delivery and feeding modes were strong factors that significantly affected microbial architecture and functions.

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