Ceratophysella Denticulata Research Articles

Avoidance Behaviour of Six Collembolan Species Shows Species-Specific Sensitivity-Impact of Ag NM300K.

Although standard testing guidelines use a species as a representative surrogate, species-specific sensitivity is well-known. The aim of this study was to investigate the species-specific difference in avoidance behaviour among Collembola species exposed to silver (Ag) nanomaterials (NM) (Ag NM300K). The avoidance test was performed with Folsomia candida, an international standard species in laboratory tests, and five widely distributed species with different life history traits, commonly used in small multispecies systems (Folsomia fimetaria, Proisotoma minuta, Mesaphorura macrochaeta, Protaphorura fimata and Ceratophysella denticulata). There was higher avoidance in euedaphic species, such as F. candida and F. fimetaria, compared to the epiedaphic species C. denticulata, which showed the least avoidance behaviour. An explanation may be that euedaphic species (living in deeper soil layers) are more directly exposed within the soil pores and have developed a pronounced avoidance behaviour. In contrast, species living on the surface are likely less directly exposed and hence only avoid at higher total concentrations. Additionally, difference in cuticula between the groups, providing different degrees of protection against exposure, can explain the different behaviours. The present results highlight the importance of biodiversity for the ecosystem and raise awareness on species sensitivity.

Food preferences of Collembola for myxomycete plasmodia and plasmodium responses in the presence of Collembola

Abstract To further understand interactions between myxomycetes and Collembola, we investigated food preferences of Collembola for myxomycete plasmodia and their responses to Collembola. We cultured two myxomycete species (Physarum melleum and Diderma sp.) and two Collembola species (Vitronura pygmaea and Ceratophysella denticulata) in different combinations for 20 d. Vitronura pygmaea consumed plasmodia, whereas C. denticulata did not consume living plasmodia, but did consume waste slime sheaths on their slime tracks. Physarum melleum fragmented frequently in the presence of V. pygmaea. These results suggest that V. pygmaea feeds on living plasmodia, whereas C. denticulata can utilise plasmodium waste products. Fragmentation may result in the escape of some fragments from consumption by V. pygmaea.

Pax6 in Collembola: Adaptive Evolution of Eye Regression.

Unlike the compound eyes in insects, collembolan eyes are comparatively simple: some species have eyes with different numbers of ocelli (1 + 1 to 8 + 8), and some species have no apparent eye structures. Pax6 is a universal master control gene for eye morphogenesis. In this study, full-length Pax6 cDNAs, Fc-Pax6 and Cd-Pax6, were cloned from an eyeless collembolan (Folsomia candida, soil-dwelling) and an eyed one (Ceratophysella denticulata, surface-dwelling), respectively. Their phylogenetic positions are between the two Pax6 paralogs in insects, eyeless (ey) and twin of eyeless (toy), and their protein sequences are more similar to Ey than to Toy. Both Fc-Pax6 and Cd-Pax6 could induce ectopic eyes in Drosophila, while Fc-Pax6 exhibited much weaker transactivation ability than Cd-Pax6. The C-terminus of collembolan Pax6 is indispensable for its transactivation ability, and determines the differences of transactivation ability between Fc-Pax6 and Cd-Pax6. One of the possible reasons is that Fc-Pax6 accumulated more mutations at some key functional sites of C-terminus under a lower selection pressure on eye development due to the dark habitats of F. candida. The composite data provide a first molecular evidence for the monophyletic origin of collembolan eyes, and indicate the eye degeneration of collembolans is caused by adaptive evolution.

Photoautotrophic microorganisms as a carbon source for temperate soil invertebrates.

We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. We exposed forest or arable soils to a (13)CO2-enriched atmosphere and quantified (13)C assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) and slugs (Gastropoda). Endogeic earthworms (Allolobophora chlorotica) and hemiedaphic springtails (Ceratophysella denticulata) were highly (13)C enriched when incubated under light, deriving up to 3.0 and 17.0%, respectively, of their body carbon from the microbial source in 7 days. Earthworms assimilated more (13)C in undisturbed soil than when the microbial material was mixed into the soil, presumably reflecting selective surface grazing. By contrast, neither adult nor newly hatched terrestrial slugs (Deroceras reticulatum) grazed on algal mats. Non-photosynthetic (13)CO2 fixation in the dark was negligible. We conclude from these preliminary laboratory experiments that, in addition to litter and root-derived carbon from vascular plants, photoautotrophic soil surface microorganisms (cyanobacteria, algae) may be an ecologically important carbon input route for temperate soil animals that are traditionally assigned to the decomposer channel in soil food web models and carbon cycling studies.

Quantitative phase imaging of arthropods.

Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy.

Trophic niche differentiation and utilisation of food resources in collembolans based on complementary analyses of fatty acids and stable isotopes

Feeding on a variety of resources, collembolans have been assumed to be food generalists. However, recent stable isotope analyses documented that collembolan species occupy different trophic levels, but detailed studies on species-specific food resources are sparse. Further, it still is little understood whether food resources of collembolan species are constant or shift, e.g., with habitats. Fatty acid (FA) and stable isotope analysis allow insight into utilisation of basal resources and trophic levels of consumers, respectively. We combined these methods to investigate variations in trophic niches of six collembolan species (Lepidocyrtus lanuginosus, Folsomia quadrioculata, Parisotoma notabilis, Ceratophysella denticulata, Isotomiella minor and Protaphorura armata) in beech and spruce forests. We correlated collembolan FAs with that of litter microorganisms at the respective study sites to identify links to resources. FA composition and stable isotope signatures in collembolan species did not differ significantly between forest types but between species suggesting pronounced trophic niche differentiation between species. The trophic niche of C. denticulata and P. armata was similar and significantly differed from the other species with 13C and 15N signatures being least depleted. We suggest that C. denticulata has a predatory life style feeding on nematodes. Due to intermediate to low 13C and 15N levels and specific FA compositions the other collembolan species could be ascribed to secondary decomposers with I. minor being more closely associated with bacterial resources and F. quadrioculata, L. lanuginosus and P. notabilis with fungal resources. However, dietary niches presumably comprise a mixture of resources rather than single resources. FAs in collembolan species correlated poorly with those in litter suggesting that the diet of collembolan species is rather independent of the structure of microbial communities in bulk litter. The results suggest that collembolans consume resources of microsites rather than bulk material thereby benefitting from the small-scale heterogeneity in resource distribution in soil. Low variation in trophic niches with forest type suggests that these microsites are similar across different forests and provide similar food resources despite marked differences in e.g., litter materials and humus structure.

Adults of European ant‐like stone beetles (Coleoptera: Staphylinidae: Scydmaeninae) Scydmaenus tarsatus Müller & Kunze and Scydmaenus hellwigii (Herbst) prey on soft‐bodied arthropods

AbstractScydmaenine beetles are commonly described as predators specialized in capturing and feeding on armored mites of the order Oribatida, and documented cases of feeding on other live arthropods have not been known. Based on laboratory observations and a broad choice of Acari (armored and soft‐bodied) and other soil arthropods, food preferences and associated behavior of two scydmaenine species are clarified and described. Adults of Scydmaenus tarsatus ignored oribatid and mesostigmatan mites, but readily attacked and fed on a soft‐bodied Rhizoglyphus sp. (Acaridae), and on small springtails, especially on Ceratophysella denticulata (Hypogastruridae). A water drinking behavior was observed for this species, not reported previously in any Staphylinidae. Scydmaenus hellwigii ignored all tested Acari (including Rhizoglyphus) and scavenged on dead neanurine collembolans or freshly cut pieces of large springtails; a long term culture was maintained by feeding beetles with isotomid springtails. Previously reported strict specialization of Scydmaenus as a predator on Oribatida was not confirmed and it is concluded that the studied species feed on live soft‐bodied organisms and scavenge on dead arthropods.

Ceratophysella taiguensis sp. nov. (Collembola, Hypogastruridae) from China, with an annotated checklist of Chinese Ceratophysella Börner, 1932

A new species of the Ceratophysella denticulata group is described from Shanxi province, China. Because of the presence of prolonged empodial appendages and reduced number of setae on dens C. taiguensis sp. nov. resembles: C. kapoviensis Babenko, 1994, C. kutyrevae Babenko, 1994, C. robustiseta Skarżyński & Smolis, 2006, C. sedecimocellata (Yosii, 1962) and C. vargovychi Skarżyński et al., 2001. A checklist of the Ceratophysella Börner, 1932 species hitherto recorded from China is also given. The present list contains 14 species, including C. anshanensis (Wu & Xie, 2007) comb. nov., C. quinidentis (Jia et al., 2005) comb. nov., C. xiaoi (Tamura, 1998) comb. nov., C. yinae (Yue & Fu, 2000) comb. nov. and C. zhangi (Zhao, 1998) comb. nov.

Population structure, propagule pressure, and conservation biogeography in the sub‐Antarctic: lessons from indigenous and invasive springtails

ABSTRACTThe patterns in and the processes underlying the distribution of invertebrates among Southern Ocean islands and across vegetation types on these islands are reasonably well understood. However, few studies have examined the extent to which populations are genetically structured. Given that many sub‐Antarctic islands experienced major glaciation and volcanic activity, it might be predicted that substantial population substructure and little genetic isolation‐by‐distance should characterize indigenous species. By contrast, substantially less population structure might be expected for introduced species. Here, we examine these predictions and their consequences for the conservation of diversity in the region. We do so by examining haplotype diversity based on mitochondrial cytochrome c oxidase subunit I sequence data, from two indigenous (Cryptopygus antarcticus travei, Tullbergia bisetosa) and two introduced (Isotomurus cf. palustris, Ceratophysella denticulata) springtail species from Marion Island. We find considerable genetic substructure in the indigenous species that is compatible with the geological and glacialogical history of the island. Moreover, by employing ecological techniques, we show that haplotype diversity is likely much higher than our sequenced samples suggest. No structure is found in the introduced species, with each being represented by a single haplotype only. This indicates that propagule pressure is not significant for these small animals unlike the situation for other, larger invasive species: a few individuals introduced once are likely to have initiated the invasion. These outcomes demonstrate that sampling must be more comprehensive if the population history of indigenous arthropods on these islands is to be comprehended, and that the risks of within‐ and among‐island introductions are substantial. The latter means that, if biogeographical signal is to be retained in the region, great care must be taken to avoid inadvertent movement of indigenous species among and within islands. Thus, quarantine procedures should also focus on among‐island movements.

TWO NEW SPECIES OF CERATOPHYSELLA (COLLEMBOLA: HYPOGASTRURIDAE) FROM KOREA

Abstract Two new species of the genus Ceratophysella from Korea, Ceratophysella biclavata n. sp. and Ceratophysella platyna n. sp. are described and illustrated. Ceratophysella biclavata differs from the closely related species Ceratophysella sigillata (Uzel 1891) by the shape of antennal bulb on antennal segment IV, the number of clavate tenent hairs and the number of granules between p1 upon abdominal segment V. Ceratophysella platyna resembles Ceratophysella denticulata (Bagnall 1941) and Ceratophysella communis (Folsom 1898), but distinctly differs from the latter by the shape of tenent hairs. A key to the identification of the Korean species of Ceratophysella is included. In addition, the known species Hypogastrura gracilis (Folsom 1899) is described and recorded for the first time from Korea.

Acclimation effects on thermal tolerances of springtails from sub-Antarctic Marion Island: Indigenous and invasive species

Collembola are abundant and functionally significant arthropods in sub-Antarctic terrestrial ecosystems, and their importance has increased as a consequence of the many invasive alien species that have been introduced to the region. It has also been predicted that current and future climate change will favour alien over indigenous species as a consequence of more favourable responses to warming in the former. It is therefore surprising that little is known about the environmental physiology of sub-Antarctic springtails and that few studies have explicitly tested the hypothesis that invasive species will outperform indigenous ones under warmer conditions. Here we present thermal tolerance data on three invasive ( Pogonognathellus flavescens, Isotomurus cf. palustris, Ceratophysella denticulata) and two indigenous ( Cryptopygus antarcticus, Tullbergia bisetosa) species of springtails from Marion Island, explicitly testing the idea that consistent differences exist between the indigenous and invasive species both in their absolute limits and the ways in which they respond to acclimation (at temperatures from 0 to 20 °C). Phenotypic plasticity is the first in a series of ways in which organisms might respond to altered environments. Using a poorly explored, but highly appropriate technique, we demonstrate that in these species the crystallization temperature ( T c) is equal to the lower lethal temperature. We also show that cooling rate (1 °C min −1; 0.1 °C min −1; 0.5 °C h −1 from 5 to −1 °C followed by 0.1 °C min −1) has little effect on T c. The indigenous species typically have low T cs (c. −20 to −13 °C depending on the acclimation temperature), whilst those of the invasive species tend to be higher (c. −12 to −6 °C) at the lower acclimation temperatures. However, Ceratophysella denticulata is an exception with a low T c (c. −20 to −18 °C), and in P. flavescens acclimation to 20 °C results in a pronounced decline in T c. In general, the invasive and alien species do not differ substantially in acclimation effects on T c (with the exception of the strong response in P. flavescens). Upper lethal temperatures (ULT50) are typically higher in the invasive (33–37 °C) than in the indigenous (30–33 °C) species and the response to acclimation differs among the two groups. The indigenous species show either a weak response to acclimation or ULT50 declines with increasing acclimation temperature, whereas in the invasive species ULT50 increases with acclimation temperature. These findings support the hypothesis that many invasive species will be favoured by climate change (warming and drying) at Marion Island. Moreover, manipulative field experiments have shown abundance changes in the indigenous and invasive springtail species in the direction predicted by the physiological data.

Taxonomy of the ceratophysellan lineage (Collembola: Hypogastruridae) in the light of laboratory hybridization studies

The results of recent laboratory hybridization studies on the ceratophysellan lineage species are synthesized, and their impact on the taxonomy of this lineage is discussed. The discovered rule that morphological similarity is proportional to the reproductive isolation degree and in consequence to the relationship between species is a good basis for distinguishing species with potential for classification of the ceratophysellan lineage. The morphological and biological species concepts appear to be fully compatible, and Schaefferia emucronata, S. willemi, Ceratophysella denticulata, C. engadinensis, C. stercoraria, C. silvatica, and C. granulata appear to be species consistent with the general lineage concept. The proposed new classification of the ceratophysellan lineage (composed of two genera: C. denticulata group + Typhlogastrura + Schaefferia and C. armata group + Bonetogastrura) is tested against the results of laboratory hybridization studies. The probable monophyly of Schaefferia and polyphyly of Bonetogastrura and Typhlogastrura show that the phylogeny of the ceratophysellan lineage is more complicated than suggested by presently accepted and proposed classifications. The obtained results are only a premise, and the probability of the conclusion being correct would increase with the number of such tests.

Soil animals influence microbial abundance, but not plant–microbial competition for soil organic nitrogen

Summary In a microcosm experiment we examined the effects of individual species of microarthropods, and variations in microarthropod diversity of up to eight species, on soil microbial properties and the short‐term partitioning of a dual‐labelled organic nitrogen source (glycine‐2‐13C‐15N) between a grassland plant, Agrostis capillaris, and the soil microbial biomass, to determine how soil fauna and their diversity influence plant–microbial competition for organic N. We hypothesized that variations in the diversity of animals would influence the partitioning of 15N inputs between plants and the microbial biomass, due to the effect of animal grazing on the microbial biomass, and hence its ability to sequester N. Certain individual species of Collembola influenced the microbial community of the soil. Folsomia quadrioculata reduced microbial biomass, whereas Mesaphorura macrochaeta enhanced arbuscular mycorrhizal (AM) colonization of A. capillaris roots. Effects of increasing species richness of microarthropods on microbial biomass and AM colonization were detected, but these effects could be interpreted in relation to the presence or absence of individual species. Microbial uptake of added 15N was not affected by the presence of any of the individual species of animal in the monoculture treatments. Similarly, increasing diversity of microarthropods had no detectable effect on microbial 15N. Root and shoot uptake of 15N was also largely unaffected by both single species and variations in diversity of microarthropods. However, one collembolan species, Ceratophysella denticulata, reduced root 15N capture when present in monoculture. We did not detect 13C in plant tissue under any experimental treatments, indicating that all N was taken up by plants after mineralization. Our data suggest that, while single species and variations in diversity of microarthropods influence microbial abundance in soil, there is no effect on microbial or plant uptake of N. Overall, these data provide little support for the notion that microbial‐feeding soil animals are regulators of microbial–plant competition for N.

A Comparative Study of the Effects of Metal Contamination on Collembola in the Field and in the Laboratory

We examined the species diversity and abundance of Collembola at 32 sampling points along a gradient of metal contamination in a rough grassland site (Wolverhampton, England), formerly used for the disposal of metal-rich smelting waste. Differences in the concentrations of Cd, Cu, Pb and Zn between the least and most contaminated part of the 35 metre transect were more than one order of magnitude. A gradient of Zn concentrations from 597 to 9080 microg g(-1) dry soil was found. A comparison between field concentrations of the four metals and previous studies on their relative toxicities to Collembola, suggested that Zn is likely to be responsible for any ecotoxicological effects on springtails at this site. Euedaphic (soil dwelling) Collembola were extracted by placing soil cores into Tullgren funnels and epedaphic (surface dwelling) species were sampled using pitfall traps. There was no obvious relationship between the total abundance, or a range of commonly used diversity indices, and Zn levels in soils. However, individual species showed considerable differences in abundance. Metal "tolerant" (e.g., Ceratophysella denticulata) and metal "sensitive" (e.g., Cryptopygus thermophilus) species could be identified. Epedaphic species appeared to be influenced less by metal contamination than euedaphic species. This difference is probably due to the higher mobility and lower contact with the soil pore water of epedaphic springtails in comparison to euedaphic Collembola. In an experiment exposing the standard test springtail, Folsomia candida, to soils from all 32 sampling points, adult survival and reproduction showed small but significant negative relationships with total Zn concentrations. Nevertheless, juveniles were still produced from eggs laid by females in the most contaminated soils with 9080 microg g(-1) Zn. Folsomia candida is much more sensitive to equivalent concentrations of Zn in the standard OECD soil. Thus, care should be taken in extrapolating the results of laboratory toxicity tests on metals in OECD soil to field soils, in which, the biological availability of contaminants is likely to be lower. Our studies have shown the importance of ecotoxicological effects at the species level. Although there may be no differences in overall abundance, sensitive species that are numerous in contaminated sites, and which may play important roles in decomposition ("keystone species") can be greatly reduced in numbers by pollution.

Biodiversity of Collembola in Urban Soils and the Use of Folsomia candida to Assess Soil ‘Quality’

The effects of metal contamination on natural populations of Collembola in soils from five sites in the Wolverhampton area (West Midlands, England) were examined. Analysis revealed that metal concentrations were elevated above background levels at all sites. One location in particular (Ladymoor, a former smelting site) was highly contaminated with Cd, Cu, Pb and Zn at more than 20 times background levels. Biodiversity indices (Shannon-Weiner, Simpson index, Margalef index, alpha index, species richness, Shaneven (evenness) and Berger-Parker dominance) were calculated. Of these indices, estimates of species richness and evenness were most effective at highlighting the differences between the Collembola communities. Indeed, the highest number of species were found at the most contaminated site, although the Collembola population also had a comparatively low evenness value, with just two species dominating. The number of individuals per species were allocated into geometric classes and plotted against the cumulative number of species as a percentage. At Ladymoor, there were more geometric classes, and the slope of the line was shallower than at the other four sites. This characteristic is a feature of polluted sites, where a few species are dominant and most species are rare. The Ladymoor soil also had a dominance of Isotomurus palustris, and was the only site in which Ceratophysella denticulata was found. Previous studies have shown that these two species are often found in sites subject to high metal contamination. Survival and reproduction of the "standard" test springtail, Folsomia candida (Willem), were determined in a 4 week exposure test to soils from all five sites. Mortality was significantly increased in adults and reproduction significantly lower in the Ladymoor soil in comparison to the other four sites. This study has shown that severe metal contamination can be related to the population structure of Collembola in the field, and performance of F. candida (in soils from such sites) in the laboratory.

Benzoic Acid Derivatives in a Hypogastrurid Collembolan: Temperature-Dependent Formation and Biological Significance as Deterrents

Two phenolic acids were identified in the collembolan Ceratophysella denticulata: 3-hydroxy-4,5 dimethoxy benzoic acid and 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid). These are localized on or in the integument of the springtail, in field-collected animals, in a ratio of 47:100 (v/v). Springtails kept under different temperature regimes showed differences in production and ratio of the benzoic acid derivatives. At 20 degrees C, C. denticulata produced only syringic acid, whereas at 10 degrees C both isomers in a ratio of 100:61 (v/v) were detected. Bioassays with C. denticulata as well as with the specialized collembolan predator Stenus comma (Staphylinidae) were carried out. Staphylinid beetles topically treated with the acids try to clean their mouthparts by rubbing them on the ground significantly more often than do control beetles. Both compounds individually and as a natural mixture have deterrent effects towards the predator S. comma.