Post-embryonic growth of longidorid nematodes

Nematology ◽  
2002 ◽  
Vol 4 (8) ◽  
pp. 883-889
Author(s):  
Brian Boag ◽  
Gregor Yeates
Keyword(s):  
Body Size ◽  
Life Histories ◽  
Body Growth ◽  
Parasitic Nematodes ◽  
Body Volume ◽  
Free Living ◽  
Plant Parasitism ◽  
Embryonic Growth ◽  
Consistent Increase ◽  
Juvenile Stages

AbstractTo investigate changes in body size of Longidoridae during growth, we used published dimensions of stages to calculate volumes of the juvenile and adult stages of 33 species. A consistent increase in body volume between the juvenile stages was found with proportionally more growth occurring between the smaller stages. In species where three, rather than four, juvenile stages are present, the ultimate size of adults was correspondingly smaller. In the Heteroderidae, greatest growth occurs in later stages and this indicates different adaptations to plant parasitism. Analysis of further groups of free-living and parasitic nematodes is required to increase understanding of body growth and life histories, both within and between families.

Developmental and growth patterns in Xiphinema parasimile and X. simile (Nematoda: Dorylaimida), members of the X. americanum-group

Nematology ◽  
2009 ◽  
Vol 11 (2) ◽  
pp. 267-273
Author(s):  
László Barsi
Keyword(s):  
Body Length ◽  
Growth Pattern ◽  
Developmental Stages ◽  
Growth Patterns ◽  
Body Volume ◽  
Data Sets ◽  
Embryonic Growth ◽  
Juvenile Stages ◽  
The Mean ◽  
The Difference

AbstractXiphinema parasimile and X. simile are morphologically and morphometrically very similar, yet molecularly different, species with different developmental and growth patterns, a different number of juvenile developmental stages (four vs three) and a different post-embryonic growth pattern. Body length, body volume and odontostyle and replacement odontostyle lengths served for comparison of the post-embryonic growth patterns in these species. A percentage method was used to make the data sets comparable between one population of X. parasimile and three populations of X. simile. The mean body lengths of the first, second and pre-adult stages in X. simile showed similarity with those of the second, third and pre-adult stages in X. parasimile. In X. simile there was no unique growth pattern of body length and body volume from stage to stage applicable for all populations, just a similar trend with more or less similar values. The difference between replacement odontostyle and functional odontostyle lengths in all juvenile stages was higher in X. simile and lower in X. parasimile, despite the very similar mean odontostyle length in the female stage of both species.

Parasite Abundance, Body Size, Life Histories, and the Energetic Equivalence Rule

1998 ◽  
Vol 151 (6) ◽  
pp. 497 ◽  
Author(s):  
Arneberg ◽  
Skorping ◽  
Read
Keyword(s):  
Body Size ◽  
Life Histories ◽  
Parasite Abundance

scholarly journals The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes

2016 ◽  
Vol 283 (1835) ◽  
pp. 20160942 ◽  
Author(s):  
Jinshui Zheng ◽  
Donghai Peng ◽  
Ling Chen ◽  
Hualin Liu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Evolutionary Process ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Free Living ◽  
C Elegans ◽  
Free Living Nematode ◽  
Plant Nematode ◽  
Ditylenchus Destructor ◽  
Plant Parasitic

Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor . We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans , the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants.

scholarly journals Ontogenetic adaptations in the visual systems of deep-sea crustaceans

2017 ◽  
Vol 372 (1717) ◽  
pp. 20160071 ◽  
Author(s):  
Tamara M. Frank
Keyword(s):  
Temporal Resolution ◽  
Deep Sea ◽  
Life Histories ◽  
Marine Species ◽  
Light Regime ◽  
Life History Stages ◽  
Visual Systems ◽  
Juvenile Stages ◽  
Dim Light ◽  
Effects Of Temperature

For all visually competent organisms, the driving force behind the adaptation of photoreceptors involves obtaining the best balance of resolution to sensitivity in the prevailing light regime, as an increase in sensitivity often results in a decrease in resolution. A number of marine species have an additional problem to deal with, in that the juvenile stages live in relatively brightly lit shallow (100–200 m depth) waters, whereas the adult stages have daytime depths of more than 600 m, where little downwelling light remains. Here, I present the results of electrophysiological analyses of the temporal resolution and irradiance sensitivity of juvenile and adult stages of two species of ontogenetically migrating crustaceans ( Gnathophausia ingens and Systellaspis debilis ) that must deal with dramatically different light environments and temperatures during their life histories. The results demonstrate that there are significant effects of temperature on temporal resolution, which help to optimize the visual systems of the two life-history stages for their respective light environments. This article is part of the themed issue ‘Vision in dim light’.

scholarly journals Body size and clonality consequences for sexual reproduction in a perennial herb of Brazilian rupestrian grasslands

2014 ◽  
Vol 74 (3) ◽  
pp. 744-749 ◽  
Author(s):  
GR Demetrio ◽  
FF Coelho ◽  
MEA Barbosa
Keyword(s):  
Body Size ◽  
Sexual Reproduction ◽  
Life Histories ◽  
Linear Regression Analysis ◽  
Clonal Plants ◽  
Flower Head ◽  
Perennial Herb ◽  
Stressful Environments ◽  
Herbaceous Perennial ◽  
Biology Research

Body size is one of the most important factors regarding herbaceous perennial plants life-histories, and several fitness components of these organisms are related to size. Clonal plants show distinct kinds of reproduction and can develop offspring by sexual or asexual ways. We aimed to understand how body size affects Comanthera nivea (Eriocaulaceae) sexual reproduction and to verify how clonal growth is related to flower head production in this species. We sampled 600 rosettes in rupestrian grasslands and performed linear regression analysis between body size and number of produced flower heads. We also compared the flower head production between isolated rosettes and rosettes within clones. Our results showed that body size was significantly related, but explained only a small part of flower head production. The flower head production was higher in rosettes within clones than in isolated ones. The clones presented a rosette or a small group of rosettes that concentrated the sexual reproduction. Clonality was positively associated with sexual reproduction. Clonality can represent an important way of allowing the persistence of plants by sexual reproduction in markedly seasonal stressful environments. The cases of clonality enhancing the sexual reproduction must be considered and put in focus on reproductive biology research.

Identification of a putative expansin gene expressed in the subventral glands of the cereal cyst nematode Heterodera avenae

Nematology ◽  
2012 ◽  
Vol 14 (5) ◽  
pp. 571-577 ◽  
Author(s):  
Haibo Long ◽  
Deliang Peng ◽  
Wenkun Huang ◽  
Yanke Liu ◽  
Huan Peng
Keyword(s):  
Cyst Nematode ◽  
Developmental Expression ◽  
Heterodera Avenae ◽  
Parasitic Nematodes ◽  
Secretory Proteins ◽  
Expansin Gene ◽  
Genes Encoding ◽  
Juvenile Stages ◽  
Stage Process ◽  
Parasitism Genes

Parasitism genes encoding secretory proteins expressed in the pharyngeal glands of plant-parasitic nematodes play important roles in the parasitic process. A new expansin gene (Ha-expb1) expressed in the subventral glands of the sedentary cyst nematode, Heterodera avenae, was cloned. Southern blot analysis suggested that Ha-expb1 is a member of a multigene family. The deduced protein Ha-EXPB1 consists of a signal peptide, a CBM II and an expansin domain, and was significantly similar to expansins and expansin-like proteins from the potato cyst nematode, Globodera rostochiensis, and the pine wood nematodes, Bursaphelenchus spp. In situ hybridisation showed that Ha-expb1 transcript specifically accumulated in the two subventral gland cells of the second-stage juveniles. Developmental expression confirmed that its transcript abundances were high in the motile juvenile stages and low in the sedentary stage of the nematode, implying a role in the early parasitic-stage process, most likely in aiding migration within the plant.

Calibration of Test Diameter and Area As Proxies For Body Size in the Planktonic Foraminifer Globoconella Puncticulata

2018 ◽  
Vol 48 (3) ◽  
pp. 241-245 ◽  
Author(s):  
Anieke Brombacher ◽  
Leanne E. Elder ◽  
Pincelli M. Hull ◽  
Paul A. Wilson ◽  
Thomas H. G. Ezard
Keyword(s):  
Body Size ◽  
Morphological Change ◽  
Statistical Power ◽  
Three Dimensional ◽  
Body Volume ◽  
Test Diameter ◽  
Linear Measurements ◽  
Cross Sectional ◽  
Test Volume ◽  
Computed Tomography Scanning

Abstract Body size is one of the most commonly measured traits in ecology and evolution because it covaries with environmental (e.g., temperature, latitude, degree of population isolation) and life-history (e.g., metabolic rate, generation time) traits. However, the driving mechanisms of body size variation in the distant geological past are poorly known and complicated by partial specimen recovery, limited population-level sampling, and the use of linear measurements as proxies for three-dimensional volumetric-size data. How much information are we missing by using approximate metrics of body size? Here we examine this question in an evolving lineage of planktonic foraminifera. We measure test diameter and surface area of over 500 individuals of the species Globoconella puncticulata using two-dimensional images. These results are compared with measurements of test volume of the same individuals as measured by a recently developed high-throughput method for analysing three-dimensional morphometrics as well as high-resolution three-dimensional computed tomography scanning. Our results show that even in a lineage showing substantial morphological change, a cross-sectional test area can provide a consistent proxy for body volume. Approximating body volume with one-dimensional (linear) size measurements is more problematic as it systematically over- and underestimates the smallest and largest tests, respectively. In our study, shape (here measured as shell-aspect ratio) only explained marginally more variation when included in the regressions. The use of 3D light microscopy introduces a small degree of scatter in the data, but the number of individuals necessary to detect trends in body size with sufficient statistical power is comparable to the sample size required for other traits. These results imply that even in an evolving lineage undergoing substantial morphological change, cross-sectional area can provide a consistent proxy for body size.

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