scholarly journals Debris-carrying camouflage among diverse lineages of Cretaceous insects

2016 ◽  
Vol 2 (6) ◽  
pp. e1501918 ◽  
Author(s):  
Bo Wang ◽  
Fangyuan Xia ◽  
Michael S. Engel ◽  
Vincent Perrichot ◽  
Gongle Shi ◽  
...  
Keyword(s):  
Fossil Record ◽  
Morphological Characteristics ◽  
Early Evolution ◽  
Behavioral Repertoire ◽  
Wood Fibers ◽  
Morphological Adaptations ◽  
Evolutionary Success ◽  
High Degree ◽  
Insect Assemblage ◽  
Insight Into

Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.

Are modern chemosynthesis-based communities a ‘glimpse of antiquity’? The changing fate of bivalves and brachiopods at ancient methane seeps as recorded in the Middle Palaeozoic of Morocco

2020 ◽  
Author(s):  
Michał Jakubowicz ◽  
Krzysztof Hryniewicz
Keyword(s):  
Middle Devonian ◽  
Fossil Record ◽  
Hydrothermal Vents ◽  
Upper Devonian ◽  
Early Evolution ◽  
Methane Seeps ◽  
The Past ◽  
Early Mesozoic ◽  
Morphological Adaptations ◽  
Chemosynthetic Ecosystems

<p>Despite much scientific effort aimed over the past three decades to better constrain the fossil record of chemosynthesis-based communities, our understanding of their early evolution remains fragmentary. Until recently, a dominant perception was that, unlike the Cenozoic, bivalve-dominated chemosynthetic ecosystems, the Paleozoic to mid-Mesozoic methane seeps and hydrothermal vents were dominated by brachiopods. Similarly, the pattern of brachiopod vs. bivalve predominance at seeps and vents over the Phanerozoic was believed to have crudely followed that observed in normal-marine benthic shelly assemblages. Recent discoveries from the Middle Palaeozoic of Morocco have questioned this simple perception, documenting the presence of late Silurian and Middle Devonian seeps dominated by mass accumulations of large, semi-infaunal, modiomorphid bivalves (Hryniewicz et al., 2017; Jakubowicz et al., 2017). While representing a lineage unrelated to modern seep-obligate bivalve taxa, the mid-Palaeozoic seep bivalves developed a set of morphological adaptations strikingly similar to those of their modern ecological counterparts, and formed analogous, densely-packed, nearly monospecific assemblages, both suggesting their chemosymbiotic lifestyle. The new documentation of Palaeozoic establishment of the bivalve-dominated seep communities provides a fresh look at the concept of modern chemosynthetic ecosystems as a 'glimpse of antiquity', showing that although it is largely not true taxonomically, it clearly is in terms of recurring morphological themes. At the same time, this refined Palaeozoic record makes the factors responsible for the apparent scarcity of seep-related bivalves during the upper Devonian to early Mesozoic, a period of the remarkable success of brachiopod-dominated seep assemblages, ever more enigmatic.</p>

scholarly journals Phytophthora Diversity in Pennsylvania Nurseries and Greenhouses Inferred from Clinical Samples Collected over Four Decades

2020 ◽  
Vol 8 (7) ◽  
pp. 1056
Author(s):  
Cody Molnar ◽  
Ekaterina Nikolaeva ◽  
Seonghwan Kim ◽  
Tracey Olson ◽  
Devin Bily ◽  
...  
Keyword(s):  
Plant Species ◽  
Morphological Characteristics ◽  
Phytophthora Species ◽  
Clinical Samples ◽  
Department Of Agriculture ◽  
Distinct Subgroup ◽  
Exotic Pathogens ◽  
Diverse Plant Species ◽  
Insight Into ◽  
Diverse Plant

The increasing movement of exotic pathogens calls for systematic surveillance so that newly introduced pathogens can be recognized and dealt with early. A resource crucial for recognizing such pathogens is knowledge about the spatial and temporal diversity of endemic pathogens. Here, we report an effort to build this resource for Pennsylvania (PA) by characterizing the identity and distribution of Phytophthora species isolated from diverse plant species in PA nurseries and greenhouses. We identified 1137 Phytophthora isolates cultured from clinical samples of >150 plant species submitted to the PA Department of Agriculture for diagnosis from 1975 to 2019 using sequences of one or more loci and morphological characteristics. The three most commonly received plants were Abies, Rhododendron, and Pseudotsuga. Thirty-six Phytophthora species identified represent all clades, except 3 and 10, and included a distinct subgroup of a known species and a prospective new species. Prominent pathogenic species such as P. cactorum, P. cinnamomi, P. nicotianae, P. drechsleri, P. pini, P. plurivora, and P. sp. kelmania have been found consistently since 1975. One isolate cultured from Juniperus horizontalis roots did not correspond to any known species, and several other isolates also show considerable genetic variation from any authentic species or isolate. Some species were isolated from never-before-documented plants, suggesting that their host range is larger than previously thought. This survey only provides a coarse picture of historical patterns of Phytophthora encounters in PA nurseries and greenhouses because the isolation of Phytophthora was not designed for a systematic survey. However, its extensive temporal and plant coverage offers a unique insight into the association of Phytophthora with diverse plants in nurseries and greenhouses.

scholarly journals 7. Ancient Fossil Record and Early Evolution (ca. 3.8 to 0.5 Ga)

2006 ◽  
Vol 98 (1-4) ◽  
pp. 247-290 ◽  
Author(s):  
Purificacón López-Garcia ◽  
David Moreira ◽  
Emmanuel Douzery ◽  
Patrick Forterre ◽  
Mark Van Zuilen ◽  
...  
Keyword(s):  
Fossil Record ◽  
Early Evolution

scholarly journals Declassifying Myrmecophily in the Coleoptera to Promote the Study of Ant-Beetle Symbioses

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Glené Mynhardt
Keyword(s):  
Classification Scheme ◽  
Morphological Characteristics ◽  
Behavioral Data ◽  
Target Species ◽  
Classification Schemes ◽  
Future Studies ◽  
Symbiotic Associations ◽  
Behavioral Studies ◽  
Morphological Adaptations ◽  
Evolutionary Studies

The symbiotic associations between beetles and ants have been observed in at least 35 beetle families. Among myrmecophiles, beetles exhibit the most diverse behavioral and morphological adaptations to a life with ants. These various associations have historically been grouped into discrete but overlapping behavioral categories, many of which are still used in the modern literature. While these behavioral classifications provide a rich foundation for the study of ant-beetle symbioses, the application of these systems in future studies may be less than effective. Since morphological characteristics often provide the only information of myrmecophilous beetles, they should be studied in a species-by-species fashion, as behavioral data are often limited or unavailable. Similarly, behavioral studies should focus on the target species at hand, avoiding discrete classification schemes. I formally propose the rejection of any classification scheme, in order to promote future studies of myrmecophily in both taxonomic and evolutionary studies.

Oil Companies and Climate Change: Inconsistencies between Strategy Formulation and Implementation?

2007 ◽  
Vol 7 (3) ◽  
pp. 42-62 ◽  
Author(s):  
Ingvild Andreassen Sæverud ◽  
Jon Birger Skjærseth
Keyword(s):  
Climate Change ◽  
Strategy Formulation ◽  
Oil Companies ◽  
Corporate Strategies ◽  
International Climate ◽  
Framework Conditions ◽  
High Degree ◽  
The Relationship ◽  
Level 2 ◽  
Insight Into

This article examines major oil companies in terms of climate strategies and their implementation. More specifıcally, it takes a critical look at Shell, BP, and ExxonMobil, and the relationship between rhetoric and action regarding investments in climate-friendly activities. Empirical evidence indicates a generally high degree of consistency between what these companies say and what they do, but interesting differences are also found: ExxonMobil has done somewhat more than its climate strategy formulations would suggest; Shell has done somewhat less; whereas BP's activities are mainly in line with its statements. Factors at three levels contribute to explaining these differences: (1) the company level, 2) the political framework conditions in the various regions where the companies operate, 3) international climate cooperation. The fındings and explanations, although restricted to the three oil companies with regard to climate change, provide insight into the relationship between corporate strategies and implementation more generally. They offer understanding and analytical categories for assessing how well and why such multinational entities put into practice stated objectives.

Postembryonic development of Dalmanitina, and the evolution of facial suture fusion in Phacopina

Paleobiology ◽  
2018 ◽  
Vol 44 (4) ◽  
pp. 638-659
Author(s):  
Harriet B. Drage ◽  
Lukáš Laibl ◽  
Petr Budil
Keyword(s):  
Fossil Record ◽  
Postembryonic Development ◽  
Large Sample Size ◽  
Upper Ordovician ◽  
Geological Time ◽  
Fusion Event ◽  
Large Sample ◽  
Prague Basin ◽  
Suture Fusion ◽  
Insight Into

AbstractA large sample of postembryonic specimens of Dalmanitina proaeva elfrida and D. socialis from the Upper Ordovician (Sandbian to Katian) Prague Basin allows for the first reasonably complete ontogenetic sequence of Dalmanitoidea (Phacopina). The material provides an abundance of morphological information, including well-preserved marginal spines in protaspides and meraspides, and hypostome external surfaces throughout. The development of D. proaeva elfrida is unusual due to variability in timing of the first trunk articulation. This broadens our developmental understanding of Phacopina, a diverse group of phacopid trilobites, and also allows us to study the evolution of their specializations in exoskeletal molting behavior. Adult phacopines, unlike most other trilobites, had fused facial sutures. This means that rather than molting through the sutural gape mode, characterized by opening of the facial sutures and separation of the librigenae, they disarticulated the entire cephalon in Salter’s mode of molting. For other phacopine clades (Phacopoidea) the transition to Salter’s mode occurs during the meraspid period or at the onset of holaspis, and its developmental timing is intraspecifically fixed. However, owing to the large sample size, we can see that facial suture fusion likely occurred later in Dalmanitina, usually during the holaspid period, and was intraspecifically variable with holaspides of varying sizes showing unfused sutures. Further, D. proaeva elfrida specimens showed an initial librigenal–rostral plate fusion event, where the librigenae began as separate entities but appear fused with the rostral plate as one structure (the “lower cephalic unit”) from M1, and are discarded as such during molting. Dalmanitoidea is considered to represent the first phacopine divergence, occurring earliest in the fossil record. This material therefore provides insight into how linked morphologies and behaviors evolved, potentially suggesting the timing of facial suture fusion in Phacopina moved earlier during development and became more intraspecifically fixed over geological time.

scholarly journals Vies en Vlaams: de literaire contestatie uit de jaren zestig

1970 ◽  
Vol 64 ◽  
pp. 117-128
Author(s):  
Liesbeth Plateau
Keyword(s):  
Literary History ◽  
Systematic Investigation ◽  
Nineteen Sixties ◽  
Literary Field ◽  
Short Life ◽  
Short Life Span ◽  
Cultural Life ◽  
Key Players ◽  
High Degree ◽  
Insight Into

This contribution presents an introductory analysis of one of the key players of the socalled“stenciled revolution” in Flanders in the nineteen sixties. Before concepts likeprovo distressed the entire societal and cultural life in the Netherlands, certain phenomenain Flanders anticipated to this. From 1963, small stenciled magazines shot up likemushrooms in the Flemish literary field. Due to their aggressive stand against the literaryestablishment, the critics quickly caught sight of them and engaged in an energeticpolemic. Because of their involvement in the literary polemics, the stenciled magazinesshortly determined the literary life to a high degree. However, partly due to their complexhistory and short life span, a systematic investigation of this phenomenon has not yet beenconducted. Nevertheless, the underground- magazines of the “stenciled revolution” are invarious ways relevant to a renewed literary history, as they explore both the literary-criticaland the creative-literary boundaries of the traditional contrast between literature andnon-literature. In this article, I focus on one of the most creative-literary oriented of theseFlemish stenciled magazines, namely daele (1966-1968), to gain an insight into the identityof the “stenciled revolution”.

scholarly journals Complex Minisatellite Rearrangements Generated in the Total or Partial Absence of Rad27/hFEN1 Activity Occur in a Single Generation and Are Rad51 and Rad52 Dependent

2006 ◽  
Vol 26 (17) ◽  
pp. 6675-6689 ◽  
Author(s):  
Judith Lopes ◽  
Cyril Ribeyre ◽  
Alain Nicolas
Keyword(s):  
Pedigree Analysis ◽  
Model System ◽  
Yeast Cells ◽  
Single Generation ◽  
Daughter Cells ◽  
Double Deletion ◽  
Mother And Daughter ◽  
Complex Events ◽  
High Degree ◽  
Insight Into

ABSTRACT Genomes contain tandem repeat blocks that are at risk of expansion or contraction. The mechanisms of destabilization of the human minisatellite CEB1 (arrays of 36- to 43-bp repeats) were investigated in a previously developed model system, in which CEB1-0.6 (14 repeats) and CEB1-1.8 (42 repeats) alleles were inserted into the genome of Saccharomyces cerevisiae. As in human cells, CEB1 is stable in mitotically growing yeast cells but is frequently rearranged in the absence of the Rad27/hFEN1 protein involved in Okazaki fragments maturation. To gain insight into this mode of destabilization, the CEB1-1.8 and CEB1-0.6 human alleles and 47 rearrangements derived from a CEB1-1.8 progenitor in rad27Δ cells were sequenced. A high degree of polymorphism of CEB1 internal repeats was observed, attesting to a large variety of homology-driven rearrangements. Simple deletion, double deletion, and highly complex events were observed. Pedigree analysis showed that all rearrangements, even the most complex, occurred in a single generation and were inherited equally by mother and daughter cells. Finally, the rearrangement frequency was found to increase with array size, and partial complementation of the rad27Δ mutation by hFEN1 demonstrated that the production of novel CEB1 alleles is Rad52 and Rad51 dependent. Instability can be explained by an accumulation of unresolved flap structures during replication, leading to the formation of recombinogenic lesions and faulty repair, best understood by homology-dependent synthesis-strand displacement and annealing.

Molecular interactions shaping the tetraspanin web

2017 ◽  
Vol 45 (3) ◽  
pp. 741-750 ◽  
Author(s):  
Sjoerd J. van Deventer ◽  
Vera-Marie E. Dunlock ◽  
Annemiek B. van Spriel
Keyword(s):  
Molecular Interactions ◽  
Intracellular Signaling ◽  
Spatial Organization ◽  
Complex Mixture ◽  
Point Of View ◽  
Intramolecular Interactions ◽  
Fundamental Understanding ◽  
High Degree ◽  
Partner Proteins ◽  
Insight Into

To facilitate the myriad of different (signaling) processes that take place at the plasma membrane, cells depend on a high degree of membrane protein organization. Important mediators of this organization are tetraspanin proteins. Tetraspanins interact laterally among themselves and with partner proteins to control the spatial organization of membrane proteins in large networks called the tetraspanin web. The molecular interactions underlying the formation of the tetraspanin web were hitherto mainly described based on their resistance to different detergents, a classification which does not necessarily correlate with functionality in the living cell. To look at these interactions from a more physiological point of view, this review discusses tetraspanin interactions based on their function in the tetraspanin web: (1) intramolecular interactions supporting tetraspanin structure, (2) tetraspanin–tetraspanin interactions supporting web formation, (3) tetraspanin–partner interactions adding functional partners to the web and (4) cytosolic tetraspanin interactions regulating intracellular signaling. The recent publication of the first full-length tetraspanin crystal structure sheds new light on both the intra- and intermolecular tetraspanin interactions that shape the tetraspanin web. Furthermore, recent molecular dynamic modeling studies indicate that the binding strength between tetraspanins and between tetraspanins and their partners is the complex sum of both promiscuous and specific interactions. A deeper insight into this complex mixture of interactions is essential to our fundamental understanding of the tetraspanin web and its dynamics which constitute a basic building block of the cell surface.

scholarly journals Early fossil record of Euarthropoda and the Cambrian Explosion

2018 ◽  
Vol 115 (21) ◽  
pp. 5323-5331 ◽  
Author(s):  
Allison C. Daley ◽  
Jonathan B. Antcliffe ◽  
Harriet B. Drage ◽  
Stephen Pates
Keyword(s):  
Fossil Record ◽  
Trace Fossils ◽  
Cambrian Explosion ◽  
Burgess Shale ◽  
Crown Group ◽  
Total Group ◽  
Stem Lineage ◽  
Coherent Picture ◽  
Insight Into ◽  
Phosphate Deposits

Euarthropoda is one of the best-preserved fossil animal groups and has been the most diverse animal phylum for over 500 million years. Fossil Konservat-Lagerstätten, such as Burgess Shale-type deposits (BSTs), show the evolution of the euarthropod stem lineage during the Cambrian from 518 million years ago (Ma). The stem lineage includes nonbiomineralized groups, such as Radiodonta (e.g., Anomalocaris) that provide insight into the step-by-step construction of euarthropod morphology, including the exoskeleton, biramous limbs, segmentation, and cephalic structures. Trilobites are crown group euarthropods that appear in the fossil record at 521 Ma, before the stem lineage fossils, implying a ghost lineage that needs to be constrained. These constraints come from the trace fossil record, which show the first evidence for total group Euarthropoda (e.g., Cruziana, Rusophycus) at around 537 Ma. A deep Precambrian root to the euarthropod evolutionary lineage is disproven by a comparison of Ediacaran and Cambrian lagerstätten. BSTs from the latest Ediacaran Period (e.g., Miaohe biota, 550 Ma) are abundantly fossiliferous with algae but completely lack animals, which are also missing from other Ediacaran windows, such as phosphate deposits (e.g., Doushantuo, 560 Ma). This constrains the appearance of the euarthropod stem lineage to no older than 550 Ma. While each of the major types of fossil evidence (BSTs, trace fossils, and biomineralized preservation) have their limitations and are incomplete in different ways, when taken together they allow a coherent picture to emerge of the origin and subsequent radiation of total group Euarthropoda during the Cambrian.

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