Collembolan Species Research Articles

Diversity of springtails (Hexapoda) according to a altitudinal gradient

The objective of this work was to elevate gradient effect on diversity of Collembola, in a temperate forest on the northeast slope of Iztaccíhuatl Volcano, Mexico. Four expeditions were organized from November 2003 to August 2004, at four altitudes (2,753, 3,015, 3,250 and 3,687 m a.s.l.). In each site, air temperature, CO2 concentration, humidity, and terrain inclination were measured. The influence of abiotic factors on faunal composition was evaluated, at the four collecting sites, with canonical correspondence analyses (CCA). A total of 24,028 specimens were obtained, representing 12 families, 44 genera and 76 species. Mesaphorura phlorae, Proisotoma ca. tenella and Parisotoma ca. notabilis were the most abundant species. The highest diversity and evenness were recorded at 3,250 m (H' = 2.85; J' = 0.73). Canonical analyses axes 1 and 2 of the CCA explained 67.4% of the variance in species composition, with CO2 and altitude best explaining axis 1, while slope and humidity were better correlated to axis 2. The results showed that CO2 is an important factor to explain Collembola species assemblage, together with slope and humidity.

Relationships of some environmental variables to the aggregation patterns of soil microarthropod populations in forests

Soil Collembola populations exhibit a non-random distribution pattern, which has been associated with a number of environmental variables. The purpose of this study is a) to investigate the patterns of aggregation and the relationship of the population density of selected soil Collembola species to environmental variables and b) to test whether numerical abundance and biomass as measures of population density lead to consistent results regarding these aspects of their ecology. A gradient of soil organic matter content and a gradient of soil pH, both occurring within limited space, were studied in two different sites. Taylor's b was used as an aggregation index. Two multiple regression models were estimated for each dominant species in each study site linking numerical abundance or biomass to environmental variables. The species studied exhibited different degrees of aggregation. These differences matched closely the differences in the strength of the association between population density and soil organic matter or pH, depending on the site. The regression models estimated for the biomass of species for which accurate methods of biomass estimation are available, exhibited a better fit than the models estimated for the numerical abundance of the same population.

Phylogeny of Collembola based on cuticular compounds:inherent usefulness and limitation of a character type

The phylogeny of Collembola, originally discussed from a morphological point of view, has more recently benefited from novel insights brought by molecular analyses. Both morphological and molecular characters produced a well-resolved phylogenetic hypothesis including all orders, most families, and a large number of genera. However, several conflicting points exist between molecular and morphological data, and new characters are clearly needed to resolve these inconsistencies. In this study the usefulness of a new character type not previously used in the phylogenetic study of Collembola was tested: the epicuticular chemical compounds. Our phylogenetic analysis was based on 380 compounds from 26 Collembola species. The results show good resolution for terminal branches but not for internal nodes. This is probably due to the partial involvement of epicuticular lipids in ecological functions such as water conservation and sexual attraction. Thus, this character type is appropriate for reconstructing phylogenetic relationships among recently diversified groups.

Differences in leaf‐litter invertebrate assemblages between radiata pine plantations and neighbouring native eucalypt woodland

Abstract We investigated the structure, composition and environmental correlates of leaf‐litter invertebrate assemblages in Pinus radiata plantations and in neighbouring native eucalypt woodland in the Jenolan Caves Karst Conservation Reserve, south‐east Australia. Invertebrate assemblages of plantations were compared with remnant eucalypt woodland located well away from the influence of plantations to determine the direct effects of plantations as a result of habitat‐replacement with a non‐native plantation species. We also included in our comparisons edge habitat of eucalypt woodland located immediately adjacent to plantations. This unique edge habitat is exposed to the intrusion of large volumes of pine leaf‐litter from plantations, which has the potential to affect indirectly invertebrate assemblages of surrounding woodland. We found that species richness of invertebrates was significantly lower in pine plantations compared with remnant eucalypt woodland. There was a complete absence of species from 12 invertebrate orders that were found in surrounding eucalypt woodland. A rich and abundant native plant understorey that provides increased habitat heterogeneity is the most likely explanation for the richer invertebrate assemblage found in remnant eucalypt woodland. The total abundance of all invertebrate taxa in pine plantations in winter was significantly higher than in remnant eucalypt woodland, pine‐litter edges and pine‐free edges. Plantations were characterized by particularly high abundances of species in two orders, Acari and Collembola. High abundances of acarine and collembolan species in plantations were associated with a decompositional environment represented by comparatively higher moisture contents and higher C : N ratios of both leaf‐litter and soil, higher soil conductivity and lower soil pH. We suggest that implementation of The Plantation Biodiversity Benefits Score will be a fruitful way forward to assess the environmental benefits that can be gained from pine plantations in this region of south‐eastern Australia.

Experimental assessment of habitat preference and dispersal ability of soil springtails

Beside biotic interactions, habitat preference and dispersal ability of species play a prominent role in the building of animal species assemblages. However, these traits are usually very poorly documented for soil organisms. A soil transfer experiment was designed to study habitat preference (including land-use and soil preference) and dispersal ability of soil springtail species living in a meadow and in an adjoining deciduous forest. The study was performed in the Morvan Regional Natural Park (Central France), using untreated or defaunated soil blocks, transferred to another land-use or replaced in their original land-use. Land-use preference was quantified in untreated and untransferred samples from meadow and forest. Dispersal ability was estimated from the time at which species colonized defaunated samples in their own habitat. Soil preference was estimated from the colonization rate of defaunated samples by comparing transferred and untransferred soil blocks. Results showed that in the community, 6% of species were land-use generalists, 30% were soil generalists and 36% recolonized defaunated soil blocks within a week. Land-use preference, soil preference and dispersal ability were largely independent components of species characteristics. Although our experiment dealt only with small-scale colonization, comparisons between species showed that the dispersal type based on anatomical features (legs, antenna, furcula, visual apparatus) does not allow predicting the dispersal ability of these species. Discrepancies between land-use preference and soil preference suggest that other habitat features must be relevant for Collembola, and that a trade-off exists between eco-physiological and biotic interactions (including food requirements).

Sex pheromone in Tetrodontophora bielanesis (Waga, 1842) (Collembola: Onychiuridae): Indirect reproduction mediated by cuticular compounds

Summary An olfactory sexual recognition signal was investigated in Tetrodontophora bielanensis (Collembola: Onychiuridae). A preliminary olfactometry experiment showed an unequivocal attraction of males by the odor of females. This led us to conduct male attraction tests using polar and apolar fractions of female cuticular extract. The polar fraction of the extract was shown to contain the component that plays an active role in sexual attraction in this Collembola species. The results of the present study are the first to show a direct relationship between an olfactory signal and sexual attraction in Collembola.

Large‐scale spatial patterns in the distribution of Collembola (Hexapoda) species in Antarctic terrestrial ecosystems

AbstractAim We tested whether the distribution of three common springtail species (Gressittacantha terranova, Gomphiocephalus hodgsoni and Friesea grisea) in Victoria Land (Antarctica) could be modelled as a function of latitude, longitude, altitude and distance from the sea.Location Victoria Land, Ross Dependency, Antarctica.Methods Generalized linear models were constructed using species presence/absence data relative to geographical features (latitude, longitude, altitude, distance from sea) across the species’ entire ranges. Model results were then integrated with the known phylogeography of each species and hypotheses were generated on the role of climate as a major driver of Antarctic springtail distribution.Results Based on model selection using Akaike’s information criterion, the species’ distributions were: hump‐shaped relative to longitude and monotonic with altitude for Gressittacantha terranova; hump‐shaped relative to latitude and monotonic with altitude for Gomphiocephalus hodgsoni; and hump‐shaped relative to longitude and monotonic with latitude, altitude and distance from the sea for Friesea grisea.Main conclusions No single distributional pattern was shared by the three species. While distributions were partially a response to climatic spatial clines, the patterns observed strongly suggest that past geological events have influenced the observed distributions. Accordingly, present‐day spatial patterns are likely to have arisen from the interaction of historical and environmental drivers. Future studies will need to integrate a range of spatial and temporal scales to further quantify their respective roles.

How taxonomic revisions affect the interpretation of specimen identification in biological field data


 
 
 
 Cumulative revisions in taxonomy of organisms over time can create difficulties for researchers in numerous scientific fields, including conservation biology. This paper compares the taxonomic names of the Collembola species named in Ivan P. Vtorov’s 1993 paper entitled Feral Pig Removal: Effects on Soil Microarthropods in a Hawaiian Rain Forest, with the more modern Collembola checklists. In comparing Vtorov’s original graphs with recreated graphs, this study finds that out of the sixteen species Vtorov collected, three had changed generic names, two had changed species names, and one was absent from modern Collembola checklists. Five taxa were identified only up to genus, making it impossible to evaluate them in comparison with modern checklists. Only six species matched current moneclature of soil microarthropods. Not only were there taxonomic reclassifications, but also differences in the descriptions of species’ ecological status indicating whether the species was endemic or adventive. None of the three species described as endemic in Vtorov’s study were listed as such in current checklists. Additionally, Vtorov did not deposit voucher specimens, so morphological comparisons or re-identification of species named in his study are impossible. Inconsistencies due to changes in nomenclature and the species’ ecological status or lack of physical documentation can, as shown here, be detrimental to researchers examining data from older studies.
 
 
 

The rapid cold hardening response of Collembola is influenced by thermal variability of the habitat

Summary 1. It has been argued that species living under unpredictable thermal conditions need to have more flexible physiological capabilities to meet with thermal stress than species living in thermally stable environments. Here we investigate if the ability to rapidly cold-harden in Collembola is influenced by thermal conditions of the habitat. 2. Collembola exploit diverse habitats and are therefore exposed to different thermal environments: soil dwelling (euedaphic) species occupy relatively stable environments, whereas surface dwelling (epedaphic) species can be exposed to more fluctuating thermal environments, but a single species can also be found in diverse thermal habitats within its geographic distribution. 3. We compared the inherent cold shock tolerance and ability to rapidly cold-harden in three epedaphic, two near surface dwelling (hemiedaphic) and four euedaphic species of Collembola using a similar experimental approach for all species. Additionally we compared three populations of the epedaphic species, Orchesella cincta , sampled along a climatic gradient (Norway, Denmark, Italy). 4. Inherent cold shock tolerance was estimated as LT 50 by assaying cold shock survival following a 2 h exposure to a range of temperatures from 1 ° C to ‐12 ° C. Rapid cold-hardening (RCH) was induced by cooling individuals from 20 ° C to a temperature 7 ° C above the LT 50 during 80 min, followed by 1 h at the specific cold shock temperature, which was close to the LT 50 of the particular species. 5. There was large variation in cold shock survival among species. The capacity to rapidly coldharden was found in all three ecotypes. 6. Genetic difference in the ability to rapidly cold-harden was seen in O. cincta from different climatic regions, consistent with the predictability of the thermal environment of their habitat. Population differences matched the daily fluctuations in temperature (CV) recorded at the site of collection as well as the day-to-day predictability (autocorrelation). The role of phylogenetic inertia was tested using sequence data from the cytochrome- c oxidase I (COI) gene and no signal of phylogeny was detected that could explain these population differences. 7. Our results show that genetic differences in RCH ability exist, consistent with latitudinal gradients in thermal fluctuations and predictability; thus comparative studies can provide important insight when exploring the role of acclimation in the geographical distribution of species.

Bioinformatics and protein expression analyses implicate LEA proteins in the drought response of Collembola

Humidity has a large impact on the distribution and abundance of terrestrial invertebrates, but the molecular mechanisms governing drought resistance are not fully understood. Some attention has been given to the role of the heat shock response as a component of desiccation tolerance, but recent focus has been on the chaperone-like LEA (late embryogenesis abundant) proteins in anhydrobiotic animals. This study investigates the expression of putative LEA proteins as well as the heat shock protein Hsp70 during drought stress in soil and surface dwelling species of Collembola (springtails). In silico analysis of four EST candidates from two species of Collembola showed the presence of a Group 3 LEA protein in Megaphorura arctica. In common with other Group 3 LEA proteins, the new sequence is predicted to be 100% natively unfolded, with a strong degree of lysine and alanine periodicity and with a negative average hydrophobicity of −1.273. The sequence clusters with members of the Group 3 LEA in plants. Furthermore, cross-species Western blotting showed drought-induced expression of putative LEA proteins in six species of Collembola. In the surface dwelling species, Orchesella cincta, degree of dehydration and length of exposure correlated with level of putative LEA protein. Hsp70 was also found to increase in individuals of O. cincta and Folsomia candida that had been exposed to drought conditions for 6 days. These results show the presence of a LEA protein-coding region in Collembola, but also indicate that several proteins are involved in response to dehydration stress, including Hsp70.

New Collembola Species from the Floodplain Forests of the Transcarpathian Lowland (Ukraine)

New Collembola Species from the Floodplain Forests of the Transcarpathian Lowland (Ukraine)As a result of an ecological study of the springtails communities of floodplain oak forests (Transcarpathian Lowland),Spinonychiurus epaphiusKaprus' et Tsalan, sp. n. andTetracanthella pericarpaticaKaprus' et Tsalan, sp. n. are collected and described.S. epaphiussp. n. belongs to species group of Onychiuridae with abdominal sternum III, divided into two subsegments. AT. pericarpaticasp. n. new species is distinguished among similar taxa by reduced chaetotaxy of body.

The Influence of Collembola on the Dissemination and Antagonistic Effect of Pseudomonas Fluorescens Against Pythium Ultimum in Soil

ABSTRACTIn this work, investigations were carried out to study the influence of the Collembola species Onychiurus fimatus or Folsomia candida and the B5 isolate of Pseudomonas fluorescens on the infection of sugar beet with Pythium ultimum. In laboratory experiments, the role of the collembolans for the transport and spread was examined of Ps. fluorescens in the soil.Both Collembola species transferred Ps. fluorescens B5 to sugar beet seedlings not treated with bacteria and so a strong colonization of the rhizoplane is induced.In container experiments it could be shown that the spread of the bacteria in soil from Ps fluorescens B5-treated to untreated sugar beet seeds by Collembola is possible. At the same time, this resulted in an inhibition of P. ultimum infection in the primordial untreated sugar beet seedlings. These plants survived in the containers with F. candida to 92% and in the containesr with O. fimatus to 78%. In the experiments without collembolans none of the untreated plants survived.

Reference genes for QRT-PCR tested under various stress conditions in Folsomia candida and Orchesella cincta (Insecta, Collembola)

BackgroundGenomic studies measuring transcriptional responses to changing environments and stress currently make their way into the field of evolutionary ecology and ecotoxicology. To investigate a small to medium number of genes or to confirm large scale microarray studies, Quantitative Reverse Transcriptase PCR (QRT-PCR) can achieve high accuracy of quantification when key standards, such as normalization, are carefully set. In this study, we validated potential reference genes for their use as endogenous controls under different chemical and physical stresses in two species of soil-living Collembola, Folsomia candida and Orchesella cincta. Treatments for F. candida were cadmium exposure, phenanthrene exposure, desiccation, heat shock and pH stress, and for O. cincta cadmium, desiccation, heat shock and starvation.ResultsEight potential reference genes for F. candida and seven for O. cincta were ranked by their stability per stress factor using the programs geNorm and Normfinder. For F. candida the succinate dehydrogenase (SDHA) and eukaryotic transcription initiation factor 1A (ETIF) genes were found the most stable over the different treatments, while for O. cincta, the beta actin (ACTb) and tyrosine 3-monooxygenase (YWHAZ) genes were the most stable.ConclusionWe present a panel of reference genes for two emerging ecological genomic model species tested under a variety of treatments. Within each species, different treatments resulted in differences in the top stable reference genes. Moreover, the two species differed in suitable reference genes even when exposed to similar stresses. This might be attributed to dissimilarity of physiology. It is vital to rigorously test a panel of reference genes for each species and treatment, in advance of relative quantification of QRT-PCR gene expression measurements.

Registros da fauna de Collembola (Arthropoda, Hexapoda) no Estado da Paraíba, Brasil

In this paper the species found in Paraiba State, northeatern Brazil are listed. The specimens were collected in six municipalities: Joao Pessoa, Cabedelo, Mataraca, Bananeiras, Cacimba de Dentro and Araruna. The specimens were collected using Berlese-Tullgren funnels, pitfall traps and entomological aspirators. After that they were mounted in glass slides for identification under microscope. It was found 54 species of collembolans, distributed in 25 genera, of 13 families. Entomobryidae was the most diverse family, with 22 species and Seira was the prevailing genus, with 15 species. Most species were found in fragments of Mata Atlântica and Mata de Restinga. Twenty new species were found and will be describe later. The data indicate that Paraiba is possibly a hotspot of diversity for the genus Seira.

The usefulness of total concentrations and pore water concentrations of pesticides in soil as metrics for the assessment of ecotoxicological effects ‐ Scientific Opinion of the Panel on Plant Protection Products and their Residues (PPR)

The usefulness of total concentrations and pore water concentrations of pesticides in soil as metrics for the assessment of ecotoxicological effects ‐ Scientific Opinion of the Panel on Plant Protection Products and their Residues (PPR)

Combined effects of organic matter and pH on acute toxicity of cadmium to Paronychiurus kimi (Collembola): Development of response surface model

A second-order central composite design was employed to investigate the effect of organic matter (OM) content and soil acidity (pH) on the cadmium toxicity to Paronychiurus kimi (Lee), a collembolan species native to Korea. Two independent variables, OM and pH, were adjusted from 0 to 10% (in total dry wt) and 4.5 to 7.0, respectively. Cadmium concentrations tested were 10, 20, 40, 80, and 160 mg/kg dry soil. The toxic effects that cadmium exerted on P. kimi (28-day median lethal concentration (LC50s)) varied significantly with different combinations of OM content and pH. The second-order response surface model was appropriate for describing combined effects of OM and pH on the cadmium toxicity to P. kimi. Linear effects (OM and pH) were predominant contributors accounting for ≈70% of the total variance of cadmium toxicity to P. kimi. No significant quadratic (pH × pH) and interaction (OM × pH) effects were observed; therefore, the final second-order response surface model could be reduced as follows: 28-day LC50 of cadmium (mg/kg) = –94.87 + 26.69 × OM + 16.64 × pH – 1.82 × OM2. Validation of the developed response surface model using 4 soil media with different OM content and pH resulted in a significant correlation coefficient (R2 = 0.97) between predicted and observed 28-day LC50. Based on physico-chemical properties of the test media, developed models can be used to explain the variation of cadmium toxicities at various environmental conditions and may improve current environmental risk assessment procedures of metals.

Three new species of Collembola from north-east Italy

Three new species of Collembola from north-east Italy

Correction to the identification of a pioneer species of Collembola found on Anak Krakatau in 1931

Correction to the identification of a pioneer species of Collembola found on Anak Krakatau in 1931

Wolbachia endosymbiont is essential for egg hatching in a parthenogenetic arthropod

Wolbachia pipientis can induce a range of sex ratio distortions including parthenogenesis. Recently Wolbachia has been detected in the diploid, parthenogenetic, collembolan species Folsomia candida. In this paper we address the effect of Wolbachia on reproduction in F. candida. Wolbachia infection was removed by antibiotic and heat treatment, and quantitative PCR techniques confirmed the success of the treatments. Complete loss of Wolbachia-infection led to the production of normal clutch sizes, but was associated with full egg hatching failure. Our results demonstrate that F. candida is strictly dependent on Wolbachia to produce viable offspring. This is one of the few cases of obligatory Wolbachia infection in arthropods. Our data suggest a unique mechanism underlying Wolbachia-dependence of egg development. One of our more salient results is that hatching success increased in consecutive egg clutches of antibiotic-treated individuals, probably due to restoration of bacterial densities over time. These observations suggest that reproduction in F. candida is a threshold effect requiring a critical Wolbachia density as is hypothesized by the bacterial dosage model. Quantitative PCR analysis showed that heat or antibiotic treated individuals with egg hatching failure had low average bacterial densities, but bacterial densities were not significantly different from those of treated individuals with successfully eclosing eggs. Additional experiments with partially cured F. candida are needed to prove the dosage model.

Antarctic Collembolans Use Chemical Signals to Promote Aggregation and Egg Laying

Terrestrial arthropods that reside in Antarctica are exposed to considerable periods of environmental stress, thus factors that promote identification of favorable microhabitats are extremely important. In this study, we report the presence of chemical cues that induce oviposition and aggregation in two species of Antarctic collembolans, Cryptopygus antarcticus and Friesea grisea. Responses of the Collembola were enhanced by low temperatures but were not altered by humidity. One of the major physiological benefits derived from an aggregation was a substantial reduction in water loss rates. Although F. grisea and C. antarcticus were commonly found in cross-species aggregations, we found no evidence to suggest cross-species attraction. When individuals were exposed to areas previously occupied by groups of Collembola, more eggs were laid. Thus, chemicals released by the collembolans appear to induce both aggregation and oviposition in these Antarctic species.