Global diversity of springtails (Collembola; Hexapoda) in freshwater

Water-dependency appeared independently in several clades of the class Collembola, which is basically of terrestrial origin according to recent phylogenetic analyses. Though moderately diversified (less than 8,000 species), Collembola are among the most numerous terrestrial arthropods in wetland communities, with a small number of species living on the surface of water. Many species are dependent on water-saturated atmosphere of caves, and on snow or ice in high mountains. A total of 525 water-dependent species have been recognized, of which 103 are linked to free freshwaters and 109 to anchialine or marine waters. Many interstitial species are also dependent to an unknown extent on water saturation in the deep layers of the soil. The numbers provided here are underestimates, as Collembola are extremely poorly known outside the Holarctis, and the ecology of described species usually not documented. However, a general biogeographical pattern is emerging from available data. The most remarkable feature is that about 15% of the fauna is water-dependent in the holarctic region, compared to 4% in the tropics and southern hemisphere. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Checklist of the springtails (Hexapoda: Collembola) of Turkey

A checklist of the species of springtails (Hexapoda: Collembola) hitherto recorded from Turkey is presented. This list contains 53 species belonging to 39 genera in 13 families. The diversity of Collembola in Turkey is poorly known and it is clear that numerous species wait to be discovered.     

Spatial patterns in the distribution of European springtails (Hexapoda: Collembola)

Using a large database on the spatial distribution of European springtails (Collembola) we investigated how range sizes and range distribution across European countries and major islands vary. Irrespective of ecological guild, islands tended to contain more endemic species than mainland countries. Nestedness and species co‐occurrence analysis based on country species lists revealed latitudinal and longitudinal gradients of species occurrences across Europe. Species range sizes were much more coherent and had fewer isolated occurrences than expected from a null model based on random colonization. We did not detect clear postglacial colonization trajectories that shaped the faunal composition across Europe. Our results are consistent with a multiregional postglacial colonization. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 498–506.     

Environmental correlates of species richness of European springtails (Hexapoda: Collembola)

Our knowledge about environmental correlates of the spatial distribution of animal species stems mostly from the study of well known vertebrate and a few invertebrate taxa. The poor spatial resolution of faunistic data and undersampling prohibit detailed spatial modeling for the vast majority of arthropods. However, many such models are necessary for a comparative approach to the impact of environmental factors on the spatial distribution of species of different taxa. Here we use recent compilations of species richness of 35 European countries and larger islands and linear spatial autocorrelation modeling to infer the influence of area and environmental variables on the number of springtail (Collembola) species in Europe. We show that area, winter length and annual temperature difference are major predictors of species richness. We also detected a significant negative longitudinal gradient in the number of springtail species towards Eastern Europe that might be caused by postglacial colonization. In turn, environmental heterogeneity and vascular plant species richness did not significantly contribute to model performance. Contrary to theoretical expectations, climate and longitude corrected species–area relationships of Collembola did not significantly differ between islands and mainlands.     

Chromosome elimination and sex determination in springtails (Insecta, Collembola).

A post-zygotic mechanism of sex determination is described in the two symphypleonans Dicyrtomina ornata (Nicolet) and Ptenothrix italica Dallai. The process consists of the loss of two sex chromosomes from the male embryo. At the end of the first meiotic division of spermatogenesis, a second chromosome elimination occurs, allowing half the secondary spermatocytes, later transformed into spermatids, to receive a complete haploid set of chromosomes. The secondary spermatocytes, which receive an incomplete set of chromosomes, degenerate. Males of the two collembolan species, therefore, produce a reduced number (50%) of spermatozoa. Females of D. ornata have 2n = 12 and males 2n = 10 chromosomes; females of P. italica have 2n = 14 and males 2n = 12 chromosomes. In both species, oogenesis proceeds normally and chromosomes pair and form chiasmata in meiotic prophase. The adaptive significance of this post-zygotic mechanism of sex determination is discussed. The mechanism seems to be a characteristic feature of the suborder Symphypleona. The neanurid Arthropleona Anurida maritima (Guérin), which was studied for comparative analysis, has 2n = 8 chromosomes and normal spermatogenesis producing haploid nuclei with four chromosomes. J. Exp. Zool. (Mol. Dev. Evol.) 285:215-225, 1999.     

Environmental correlates of body size distributions of European springtails (Hexapoda: Collembola)

Aim Species–body size distributions (SBDs) are plots of species richness across body size classes. They have been linked to energetic constraints, speciation–extinction dynamics and to evolutionary trends. However, little is known about the spatial variation of size distributions. Here we study SBDs of European springtails (Collembola) at a continental scale and test whether minimum, average and maximum body size and the shapes of size distributions change across latitudinal and longitudinal gradients and whether SBDs of islands and mainlands differ. We also test whether the island rule and the positive body size–range size relationship of vertebrates also holds for Collembola. Location Europe. Methods We use a unique data set on the spatial distributions of 2102 species of European springtails across 52 countries and larger islands together with associated data on body size, area, climate variables, longitude and latitude. Differences in the central moments of SBDs are inferred from simultaneous spatial autoregression models. Results The SBD of the European Collembola and its largest suborder Entomobryomorpha is unimodal and symmetrical. Average, minimum and maximum body weight and the skewness of the mainland/island SBDs peaked at intermediate latitudes. We could not find simple latitudinal gradients in minimum and maximum body weight. Average and maximum body size increased with country/island area in accordance with the island rule in vertebrates, while minimum body size did not significantly differ between islands and mainlands. Finally, we found a weak but statistically significant positive correlation of range size and body size. Main conclusions We provide evidence for differences in body size distributions between islands and mainlands that are in part in line with the island rule in invertebrates. We also find evidence for an interspecific body size–range size relationship similar to that of vertebrates although the vertebrate pattern is much stronger than the springtail pattern. Our results on latitudinal gradients of maximum and average body size imply the need to account for species richness and area effects in the study of latitudinal gradients in body size. We recommend implementing sample size and area effects in the study of body size distributions on islands and mainlands.     

中国水生跳虫新种及新记录种记述 (弹尾目)

自Uchida(1948)从山西东冶县发现中国第1种水生Podura aquatica Linnaeus, 1785以来,中国弹尾目水生种类再未见报道。该文记述了采自上海植物园水塘静水表面的弹尾目5新种,水生原Podura aquatica, 尹氏球角Hypogastrura yinae sp. Nov., 沼生陷等Isotomurus palustris, 水生握角圆Sminthurides aquaticus 及刺拟勃氏圆Pseudobourletiella spinata。 其中水生握角圆和刺拟勃氏圆为中国新记录种,尹氏球角为新种。新种的模式标本及观察的其它种的标本存放在中国科学院上海昆虫研究所标本馆。     

Group-specific primers for DNA-based detection of springtails (Hexapoda: Collembola) within predator gut contents

Group‐specific, degenerate polymerase chain reaction primers for DNA‐based detection of springtails (Hexapoda: Collembola) within predator gut contents have been developed for the first time. Primers were designed from 18S rDNA and amplified fragments of 272 bp and 177 bp from 17 springtail species collected in agricultural habitats. Specificity tests against 41 nontarget species revealed no cross‐reactivity. Group‐specific polymerase chain reaction is advantageous when working in species‐rich habitats and these primers could facilitate studies of trophic links between springtails and generalist arthropod predators worldwide.     

The impact of altered precipitation on spatial stratification and activity-densities of springtails (Collembola) and spiders (Araneae)

Abstract.  1. A field experiment was conducted to determine how short-term changes in moisture can alter activity-densities of spiders and springtails.
2. In a Kentucky forest 10 unfenced 4-m² plots were divided into two rainfall treatments. A clear roof over five plots excluded rainfall to simulate severe drought conditions ( drought treatment). Water was sprayed on the five uncovered plots at a rate equal to two times the long-term mean in order to establish the high-rainfall treatment. Activity-densities of Collembola and spiders were measured using pitfall traps designed to sample the top, middle, and bottom layers of leaf litter. The experiment ran from 20 July to 23 September 2001.
3. Overall (i.e. litter layers pooled) activity-density (mean number trapped each sampling date) of Collembola was ≈ 60% lower in drought plots than in plots receiving increased precipitation. Surprisingly, overall spider activity-density was ≈ 1.6 times greater in the drought plots.
4. Differences in rainfall affected the spatial stratification of Collembola and spiders in strikingly different ways. Activity-densities of neither group differed between drought and high-rainfall treatments in the bottom litter layer. Collembola activity-density was three times greater in the top and middle litter layers in high-rainfall plots than in drought plots. In contrast, spider activity-density did not differ between treatments in the top layer, but activity-density was decreased by 50% in the middle layer of high-rainfall plots compared with drought plots.
5. Three Collembola families (Sminthuridae, Tomoceridae, and Entomobryidae) accounted for most of the Collembola pattern. The spider response was due to altered activity-density of one family of wandering spider, the Gnaphosidae.     

Distribution and diversity of springtails (Hexapoda: Collembola) on the altitudinal gradient of a temperate forest in Mexico

Mountain ecosystems have shown slow mineralization activity due to weather conditions, and to some groups with arthropods with special roles. The Collembola is an important group for litter fragmentation, showing different distribution patterns. The objective of the present study was to determine the diversity of Collembola along a volcano altitudinal gradient. For this, four sampling expeditions evaluated four altitudinal levels (I = 2 753, II = 3 015, III = 3 250 and IV = 3 687 masl) in Iztaccihuatl Volcano, from November 2003, and March, June and August 2004. Shannon diversity (H'), Pielou evenness (J') and Simpson dominance (1/lambda) indices were calculated. The similarity between the associations of springtails between the sampling sites was evaluated by a cluster analysis using the Pearson correlation coefficient, as distance and the unpaired arithmetic averages (UPGMA) as amalgamation method. A total of 24 075 springtails, distributed in 12 families, 46 genera and 86 species was collected. The higher species abundance was found at the altitudinal area II. The lowest diversity value was recorded in IV, while the higher diversity values were found in III. Significant differences between Shannon indices were found between zones II-III (t(0.01, 187) = 4.11, p < 0.05) and between III-IV (t(0.01, 187) = 3.8, p < 0.05) according to modified t-test. When considering sampling dates, no significant differences were found. The dendrogram showed that in composition the level I is more homogeneous throughout the year. In conclusion, a statistically significant seasonal variation in springtail abundances was not found, but it was observed that, the lower altitude (I) resulted more homogeneous along the studied period, followed by level II and III. There is a particular assemblage of springtails community in each altitudinal area studied; in general, the sites with low slope resulted more diverse in Collembola communities. These results show that there are important factors such as altitude, vegetation type and microhabitat heterogeneity that may affect the distribution of springtails communities along an altitudinal gradient.     

Fauna and population structure of springtails (Hexapoda,Collembola) in zonal forest-steppe biotopes of the Middle Volga River basin

A total of 92 springtail species were revealed in forest-steppe areas of the Privolzhskaya Lesostep nature reserve. The considerable part of the species (25–40%) are inhabitants of steppe and open sites with the predominance of soil forms. The specific features of the chernozem soil fauna are determined by the rare species occupying deep soil layers. In different forest-steppe biotopes, the springtail communities are similar in the species composition but differ in the structure. Steppe and forest types of communities were distinguished. When the steppe is forested, the most drastic changes in the collembolan population are revealed in the transitional shrub zone. The marginal community is characterized by the most even structure and a variable set of dominants.     

Effects of food deprivation and type of prey on predation by Notiophilus biguttatus F. (Carabidae) on springtails (Collembola)

Summary With diurnally active predators like Notiophilus biquttatus F. food deprivation is involved in predation in two ways: as a consequence of food shortage (i.e., low prey density), and as a consequence of the night period. The pattern of food intake after deprivation at night has been studied with respect to two prey species and differently deprived predators. They prey species represent a locomotory active one (Orchesella cincta) and a locomotory inactive one (Tomocerus minor). It appears that the rate of predation after deprivation shows a distinct pattern, initially high and then slowing to a more or less constant value. This pattern is influenced by food deprivation and type of prey. The beetles preying on O. cincta consumed more prey than those preying on T. minor. The more deprived predators compensated for deprivation by a higher daily predation when O. cincta was the prey, but not when T. minor was. Consequences of these findings are discussed with respect to diet composition and functional response.     

Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a polder habitat

Within the scope of the Integrated Rhine Program an ecological flood gate and channel was inserted into the polder "Ingelheim" to enhance animal and plant diversity. In 2008, carabid beetles and springtails were collected, using pitfall traps, to measure the effects of ecological flooding and a strong precipitation event at a flood-disturbed and a dry location in this area. At both localities, xerophilic and mesophilic carabid beetle species were dominant throughout the study period. The total number of individuals of hygrophilic species was comparatively constant, while species number increased, partly due to the changed moisture conditions caused by ecological flooding and strong precipitation. Carabid beetle diversity and evenness decreased marginally when ecological flooding was absent. Springtails represent a less mobile arthropod order, and as such the impact of ecological flooding was stronger. An increase in both numbers of species and individuals of hygrophilic and hygrotolerant species occurred in the flood-disturbed location after ecological flooding. After the sites at both locations had dried, the number of individuals belonging to these species declined rapidly. In contrast to carabid species, the strong precipitation event showed no influence on hygrophilic springtail species. Thus, collembolan diversity and evenness decreased markedly in the absence of flooding. We showed that ecological flooding has an influence on the spatial and temporal dynamics of different arthropod groups that inhabit the polder "Ingelheim". These findings demonstrate the importance of using different arthropod groups as bioindicators in determining the ecological value of a particular polder design.     

Entomological and ecological surveys on Mt. Usu in 1984 VI: Faunal make-up and ecological distribution of springtails (Collembola) on Volcano Usu

A survey of springtails was conducted in 1984 on Volcano Usu which suffered damage to it's ecosystem from eruptions in 1977 and 1978. The summit area, almost completely deforested by the eruptions, was still inhabited by many forest species such asDesoria notabilis, Willowsia sp. 2,Pseudachorutes sp. 2,Isotoma sp. 4,Tullbergia yosii, Onychiurus sp. 1,Entomobrya sp. 2,Isotomiella minor, Proisotoma sp. 2,Xenylla sp.,Neanura frigida, etc. These species preferred standing or fallen dead trees, mosses, bark chips, former topsoils and soil around the root of plants. The fauna in the summit area was most similar to that of coniferous or broad-leaved forests surveyed on the foot of the mountain. This suggests that the 1977–78 eruptions did not exterminate these springtail species which probably survived on the standing trees or in the former topsoil.     

Ontogenetic trajectories in Symphypleona (Collembola)

A novel approach is proposed toward quantifying changes in chaetotaxy during the development of Collembola Symphypleona. The ontogenetic trajectories method applied to the tibiotarsal chaetotaxy of Symphypleona provides a representation of their development. Every seta, through the probability of its presence, can be regarded as a character. The statistical technique of correspondence analysis is used, and new techniques for analyzing these kinds of data are discussed. Although this survey is mainly focused on methodology, biological results are also presented. The different rates and extent of chaetotaxic changes during development of the species studied are discussed. An important point demonstrated is the support this method gives to the close relationship of Mackenziella and Sminthurididae. The assumption of monophyly of the group Sminthuridae-Bourletiellidae is also reinforced, and a hypothesis of neochaetotic evolution for the genus Sminthurus is put forward. © 1996 Wiley-Liss, Inc.     

Revealing pancrustacean relationships: Phylogenetic analysis of ribosomal protein genes places Collembola (springtails) in a monophyletic Hexapoda and reinforces the discrepancy between mitochondrial and nuclear DNA markers

Background  

In recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of DNA sequences. One of the challenged hypotheses is the monophyly of hexapods. This discussion originated from analyses based on mitochondrial DNA datasets that, due to an unusual positioning of Collembola, suggested that the hexapod body plan evolved at least twice. Here, we re-evaluate the position of Collembola using ribosomal protein gene sequences.     

Anal sacks-an unknown organ in Poduromorpha (Collembola)

An undescribed organ in Collembola consisting of three eversible sacks in the last abdominal segment was first discovered in Hypogastrura socialis . Immediately prior to jumping the anal sacks become everted and appear as finger-like appendages projecting out of the hind gut. The organ was found in all Hypogastura species available for investigation and in some other primitive genera of the families Hypogastruridae, Brachystomellidae and Neanuridae. In most species, however, the anal sacks were much smaller than those of H. socialis and probably not eversible. The function of the anal sacks is in some way associated with the jumping activity of the animals; possibly as a mechanism to increase jumping efficiency or, more likely, for release of pheromones. Further research is needed to uncover the function of the organ. It is suggested that Abd. VI has been formed by the fusion of the three lobes now constituting the Abd. VI segment and that this fusion resulted in the formation of three post-rectal pockets from which the anal sacks have evolved.     

Isotomiella (Isotomidae: Collembola) of China

Seven species of the genus Isotomiella Bagnall 1939 were collected in China, two of which from Hainan and Guangxi provinces (South China) are newly described and illustrated. Isotomiella longisensilla n. sp. has bidentate mucro and long sensilla on most tergites, a character never seen before in this genus. I. deharvengi n. sp. belongs to the minor group and is characterized by a pair of strongly curved sensilla on Abd. V.