Absence of gregarious settling Behaviour by female cypris larvae of British parasitic rhizocephalan barnacles

1979 ◽  
Vol 59 (3) ◽  
pp. 591-596 ◽  
Author(s):  
P. S. Rainbow ◽  
M. P. Ford ◽  
I. Hepplewhite
Keyword(s):  
Growth And Development ◽  
Necessary Conditions ◽  
Selective Advantage ◽  
Closely Related Species ◽  
Settling Behaviour ◽  
As Species ◽  
Rhizocephalan Barnacles ◽  
Tactile Detection ◽  
Settling Larva ◽  
Cross Fertilization

Barnacle cypris larvae, the specialized settlement stage of the life-cycle, are classical examples of larvae showing gregarious settlement. Gregarious settlement is shown when the larva is induced to settle by established individuals of its own or of a closely related species, reflecting the ability of the larva to recognize its own type, usually by chemo-tactile detection of a particular settlement inducing factor (see Crisp (1974) for review). Sessile barnacles such as species of Balanus or Chthamalus are typically hermaphrodite and gregarious settlement is of selective advantage in promoting the possibility of cross-fertilization, in addition to allowing a settling larva to identify a habitat providing all the necessary conditions for barnacle growth and development.

Moving Targets

2012 ◽  
Author(s):  
Stephen J. Simpson ◽  
David Raubenheimer
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Growth And Development ◽  
Early Growth ◽  
Evolutionary Change ◽  
Life History Strategies ◽  
Moving Targets ◽  
Gene Frequencies ◽  
Epigenetic Effects ◽  
As Species

This chapter studies intake and growth targets. For clarity, earlier chapters have treated intake and growth targets as static points integrated across a particular period in the life of an animal. In reality they are, of course, not static but rather trajectories that move in time. In the short term, the requirements of the animal change as environmental circumstances impose differing demands for nutrients and energy. At a somewhat longer timescale, targets move as the animal passes through the various stages of its life, from early growth and development to maturity, reproduction, and senescence. On an even longer timescale, nutritional traits are subject to natural selection and move as species evolve to exploit new or changing nutritional environments and to adopt differing life-history strategies. Presaging such evolutionary change in gene frequencies within populations are epigenetic effects, whereby the nutritional experiences of parents influence the behavior and metabolism of their offspring without requiring changes in gene frequencies.

REVIEW OF HOLARCTIC TARSONEMID MITES (ACARINA: PROSTIGMATA) PARASITIZING EGGS OF IPINE BARK BEETLES

1969 ◽  
Vol 101 (S60) ◽  
pp. 5-111 ◽  
Author(s):  
Evert E. Lindquist
Keyword(s):  
Life History ◽  
Bark Beetles ◽  
Population Regulation ◽  
Species Group ◽  
The Other ◽  
Closely Related Species ◽  
As Species ◽  
Egg Parasitism ◽  
Generic Description

AbstractA group of tarsonemid mites, which are egg parasites of ipine bark beetles, is reviewed on a Holarctic basis. The genus Iponemus (new name for Moseria Beer and Nucifora) is proposed and described for the group, and 24 species or subspecies, including 19 described as new, are described, keyed, and illustrated. A detailed species-group description follows the generic description, and includes several structures hitherto not reported for species of Tarsonemidae. The variation and usefulness of the few characters available for distinguishing forms of Iponemus is discussed, and the provisional treatment of some forms as species and others as subspecies is explained.These mites are among the most host-specific associates of scolytid beetles: 16 of the 18 species or subspecies of Iponemus associated with the nearctic, pine-feeding ipines are monospecific, and each of the other two is restricted to two closely related species of hosts. The mites and the beetles together are considered with regard to size correlations, the degree of host specificity, the mites as taxonomic indicators of their hosts, biogeography, life history, and the role of egg parasitism by the mites in the population regulation of their hosts.

scholarly journals Contribution of Gene Loss to the Pathogenic Evolution of Burkholderia pseudomallei and Burkholderia mallei

2004 ◽  
Vol 72 (7) ◽  
pp. 4172-4187 ◽  
Author(s):  
Richard A. Moore ◽  
Shauna Reckseidler-Zenteno ◽  
Heenam Kim ◽  
William Nierman ◽  
Yan Yu ◽  
...  
Keyword(s):  
Carbon Source ◽  
Burkholderia Pseudomallei ◽  
Sole Carbon Source ◽  
Lethal Dose ◽  
Selective Advantage ◽  
Burkholderia Mallei ◽  
Closely Related Species ◽  
Transposon Insertion ◽  
Genes Encoding ◽  
Pathogenic Evolution

ABSTRACT Burkholderia pseudomallei is the causative agent of melioidosis. Burkholderia thailandensis is a closely related species that can readily utilize l-arabinose as a sole carbon source, whereas B. pseudomallei cannot. We used Tn5-OT182 mutagenesis to isolate an arabinose-negative mutant of B. thailandensis. Sequence analysis of regions flanking the transposon insertion revealed the presence of an arabinose assimilation operon consisting of nine genes. Analysis of the B. pseudomallei chromosome showed a deletion of the operon from this organism. This deletion was detected in all B. pseudomallei and Burkholderia mallei strains investigated. We cloned the B. thailandensis E264 arabinose assimilation operon and introduced the entire operon into the chromosome of B. pseudomallei 406e via homologous recombination. The resultant strain, B. pseudomallei SZ5028, was able to utilize l-arabinose as a sole carbon source. Strain SZ5028 had a significantly higher 50% lethal dose for Syrian hamsters compared to the parent strain 406e. Microarray analysis revealed that a number of genes in a type III secretion system were down-regulated in strain SZ5028 when cells were grown in l-arabinose, suggesting a regulatory role for l-arabinose or a metabolite of l-arabinose. These results suggest that the ability to metabolize l-arabinose reduces the virulence of B. pseudomallei and that the genes encoding arabinose assimilation may be considered antivirulence genes. The increase in virulence associated with the loss of these genes may have provided a selective advantage for B. pseudomallei as these organisms adapted to survival in animal hosts.

Molecular methods for assessing insect parasitism

2006 ◽  
Vol 96 (1) ◽  
pp. 1-13 ◽  
Author(s):  
M.H. Greenstone
Keyword(s):  
Random Amplified Polymorphic Dna ◽  
Morphological Characters ◽  
Allozyme Electrophoresis ◽  
Closely Related Species ◽  
Specific Pcr ◽  
As Species ◽  
Rapd Pcr ◽  
Parasitism Rates ◽  
Species Specific ◽  
Genomic Regions

AbstractDetermining insect parasitism rates is problematic due to the small size and lack of useful distinguishing morphological characters of many parasitoid taxa. To solve this problem, entomologists have employed one of four general methods to detect parasitoid protein or nucleic acid markers: serological assay; random amplified polymorphic DNA–polymerase chain reaction “RAPD-PCR” allozyme electrophoresis; or specific PCR. Serological methods, especially with monoclonal antibodies, are unrivalled for specificity, enabling discrimination at the stage as well as species level. However, they have not found favour with many workers, possibly due to complexity and expense. RAPD–PCR has been widely used, but can only be recommended for restricted applications because of its poor reproducibility. Allozyme electrophoresis provides reproducible detection and discrimination of closely related species. Specific-PCR is highly specific and reproducible, and also has the shortest latency for detection, usually 24 h or less after parasitization. The substantial existing literature on allozyme electrophoresis and specific PCR is used to support recommendations on what are apt to be fruitful enzyme systems or genomic regions for detecting and discriminating parasitoids in untried parasitoid–host assemblages.

scholarly journals Winter Wheat (Triticum aestivum L.) Overwintering Under Different Sowing Densities

2017 ◽  
Vol 17 (4) ◽  
pp. 307
Author(s):  
Danijela Kondić ◽  
Maja Bajić ◽  
Desimir Knežević ◽  
Đurađ Hajder
Keyword(s):  
Triticum Aestivum ◽  
Statistical Analysis ◽  
Winter Wheat ◽  
Growth And Development ◽  
Necessary Conditions ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Agronomic Practices ◽  
Winter Wheat Cultivars ◽  
Banja Luka

Wheat overwintering ability affects the final number of plants that are able to continue their growth and development when necessary conditions are established. This research was conducted to study the overwintering ability of winter wheat cultivars (NS 40S, Prima and Nova Bosanka) under different sowing densities during 2013/14 and 2014/15 in agroecological conditions of Banja Luka. Standard agronomic practices for winter wheat were performed. Wheat cultivars were sown manually, under sowing densities with different seed arrangements: 384, 424, 451, 504, 544, 584, 588, and 604 seeds m-2. Counting of wheat plants in both examined years was carried out in the second decade of February. Statistical analysis was performed using factorial analysis of variance 2×8×3, while significant differences between treatments were tested by LSD test. The average overwintering plants percentage for all three examined wheat cultivars was 50.06%. Sowing density of 588 seeds m-2 stands out as the density with a tendency of the highest percentage of overwintering plants in both years.

scholarly journals PolyCRACKER, a robust method for the unsupervised partitioning of polyploid subgenomes by signatures of repetitive DNA evolution

2018 ◽  
Author(s):  
Sean P. Gordon ◽  
Joshua J. Levy ◽  
John P. Vogel
Keyword(s):  
Repetitive Dna ◽  
Dna Sequences ◽  
Related Species ◽  
Software Package ◽  
Gc Content ◽  
Individual Species ◽  
Closely Related Species ◽  
As Species ◽  
Pooled Dna ◽  
Species Specific

AbstractExisting methods for assigning sequences to individual species from pooled DNA samples rely on differences in genome properties like GC content or sequences from related species. These approaches do not work for closely related species where gross features are indistinguishable and related genomes are lacking. We describe a method and associated software package that uses rapidly evolving repetitive DNA to circumvent these limitations. By using short, repetitive, DNA sequences as species-specific signals we separated closely related genomes without any prior knowledge. This approach is ideal for separating the subgenomes of polyploid species with unsequenced or unknown progenitor genomes.

A DNA barcode survey of Schizymenia (Nemastomatales, Rhodophyta) in Australia and British Columbia reveals overlooked diversity including S. tenuis sp. nov. and Predaea borealis sp. nov.

Botany ◽  
2015 ◽  
Vol 93 (12) ◽  
pp. 859-871 ◽  
Author(s):  
Gary W. Saunders ◽  
Taylor C. Birch ◽  
Kyatt R. Dixon
Keyword(s):  
British Columbia ◽  
Sequence Data ◽  
Dna Barcode ◽  
Sensu Stricto ◽  
Haida Gwaii ◽  
Closely Related Species ◽  
Genetic Groups ◽  
As Species ◽  
Red Algal ◽  
Algal Genus

This project explored species diversity for the red algal genus Schizymenia in Australia and British Columbia, Canada, for which the only recorded representatives are S. dubyi (Chauvin ex Duby) J. Agardh and S. pacifica (Kylin) Kylin, respectively. Through a combination of CO1-5P, ITS, and rbcL sequence data, we uncovered overlooked diversity in both regions. Australian populations attributed to S. dubyi were actually a mix of an entity from the S. dubyi complex (closest matches for individuals from Argentina and Italy), a second species from the S. apoda (J. Agardh) J. Agardh complex (thus far known from Australia only), and finally individuals of the same S. dubyi mito/ITS-type introgressed with a different S. apoda rbcL type (plastid; closest matches China, Korea, and New Zealand). We resolved a complex of three closely related species for Schizymenia pacifica: Schizymenia pacifica sensu stricto, which is widely distributed in the Northeast Pacific; S. tenuis sp. nov., which is distributed throughout British Columbia with a predominantly northern distribution; and Schizymenia sp._1Cal, which is distributed from California to Oregon. As part of ongoing surveys of crustose red algae, we uncovered crustose sporophytes for three of the six Schizymenia genetic groups resolved here, and the sporophytic phase of a new species of Predaea from northern British Columbia, Predaea borealis sp. nov., for a single crustose (sporophyte) specimen from Haida Gwaii. This last result is particularly surprising, as species of Predaea are typically confined to lower latitudes in both the northern and southern hemispheres.

Phylogenies and comparative data, a microevolutionary perspective

1995 ◽  
Vol 349 (1327) ◽  
pp. 85-91 ◽  
Keyword(s):  
Phylogenetic Tree ◽  
Related Species ◽  
General Framework ◽  
Comparative Data ◽  
Phenotypic Evolution ◽  
Closely Related Species ◽  
As Species ◽  
Evolutionary Changes ◽  
Relationship Structure ◽  
Degree Of Similarity

As species evolve along a phylogenetic tree, their phenotypes diverge. We expect closely related species to retain some phenotypic similarities owing to their shared evolutionary histories. The degree of similarity depends both on the phylogeny and on the detailed evolutionary changes that accumulate each generation. In this study, I review a general framework that can be used to translate between macroevolutionary patterns and the underlying microevolutionary process by comparing the observed relationships among measured species phenotypes and the expected relationship structure due to the phylogeny and underlying models of phenotypic evolution. I then show how the framework can be used to compare methods used (1) to reconstruct phylogenies, (2) to correct comparative data for phylogenetic non-independence, and (3) to infer details of the microevolutionary process from interspecific data and a phylogeny. Use of this framework and a microevolutionary perspective on the analysis of interspecific data opens up new fields of inquiry and many new uses for phylogenies and comparative data.

scholarly journals The spindle assembly checkpoint and speciation

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9073
Author(s):  
Robert C. Jackson ◽  
Hitesh B. Mistry
Keyword(s):  
Related Species ◽  
Spindle Assembly Checkpoint ◽  
Evolutionary Dynamics ◽  
Chromosomal Rearrangements ◽  
Spindle Assembly ◽  
Selective Advantage ◽  
Ecological Niches ◽  
Geographical Isolation ◽  
Closely Related Species ◽  
Definition Of

A mechanism is proposed by which speciation may occur without the need to postulate geographical isolation of the diverging populations. Closely related species that occupy overlapping or adjacent ecological niches often have an almost identical genome but differ by chromosomal rearrangements that result in reproductive isolation. The mitotic spindle assembly checkpoint normally functions to prevent gametes with non-identical karyotypes from forming viable zygotes. Unless gametes from two individuals happen to undergo the same chromosomal rearrangement at the same place and time, a most improbable situation, there has been no satisfactory explanation of how such rearrangements can propagate. Consideration of the dynamics of the spindle assembly checkpoint suggest that chromosomal fission or fusion events may occur that allow formation of viable heterozygotes between the rearranged and parental karyotypes, albeit with decreased fertility. Evolutionary dynamics calculations suggest that if the resulting heterozygous organisms have a selective advantage in an adjoining or overlapping ecological niche from that of the parental strain, despite the reproductive disadvantage of the population carrying the altered karyotype, it may accumulate sufficiently that homozygotes begin to emerge. At this point the reproductive disadvantage of the rearranged karyotype disappears, and a single population has been replaced by two populations that are partially reproductively isolated. This definition of species as populations that differ from other, closely related, species by karyotypic changes is consistent with the classical definition of a species as a population that is capable of interbreeding to produce fertile progeny. Even modest degrees of reproductive impairment of heterozygotes between two related populations may lead to speciation by this mechanism, and geographical isolation is not necessary for the process.

scholarly journals Polyploidization within the Funariaceae—a key principle behind speciation, sporophyte reduction and the high variance of spore diameters?

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
ANNA K. OSTENDORF ◽  
NICO VAN GESSEL ◽  
YARON MALKOWSKY ◽  
MARKO S. SABOVLJEVIC ◽  
STEFAN A. RENSING ◽  
...  
Keyword(s):  
Genome Duplication ◽  
Physcomitrella Patens ◽  
Model Organism ◽  
Single Copy ◽  
Single Copy Gene ◽  
Closely Related Species ◽  
Cytological Data ◽  
As Species ◽  
Copy Gene ◽  
Potential Impact

Although being recognized as a major force behind speciation in flowering plants, the evolutionary relevance of genome duplication (polyploidization) remains largely unexplored in mosses. Phylogenetic and-genomic insights from the model organism Physcomitrella patens and closely related species revealed that polyploidization, likely via hybridization (allopolyploidization), gives rise to new species within the Funariaceae. Based on the phylogenetic analysis of the nuclear single copy gene BRK1 combined with the measurement of DNA content by flow cytometry, we identified Entosthodon hungaricus as such an allopolyploid species. Together with Physcomitrium pyriforme, Physcomitrium eurystomum and Physcomitrium collenchymatum, which were identified previously as species that likely arose by hybridization, E. hungaricus represents an additional allopolyploid lineage of a species complex that is characterized by convergent sporophyte reduction and a considerable variance in spore sizes. Based on morphological and cytological data from 18 species, we highlight the potential impact of polyploidization on the size of the spores and on sporophyte architecture.

Sign in / Sign up

Export Citation Format

Share Document