The temperature experienced by micro-invertebrates in extreme environments (such as those of Antarctica) is a pivotal parameter regarding these animals' ecology and physiology. However, at present, detailed knowledge of microhabitat physical conditions in Antarctica is limited, as well as being biased towards sub-Antarctic and Maritime Antarctic regions. To better understand the temperature conditions experienced in the microhabitats of Continental Antarctica by the native microfauna, we recorded temperatures year round in ponds and soils in an area of the Victoria Land coast and compared these measurements with air temperature data from the closest automatic weather station. We identified an important difference in temperature dynamics between the air, soil and pond datasets. Ponds were the warmest sites overall, differing by up to 7.5°C in comparison with the air temperature due to their greater thermal capacity, which also drove their patterns of freeze-thaw cycles and mean daily thermal excursion.

Previous work focused on allozymes and mitochondrial haplotypes has detected high levels of genetic variability between Cryptopygus terranovus populations, a springtail species endemic to Antarctica, until recently named Gressittacantha terranova. This study expands these biogeographical surveys using additional analytical techniques, providing a denser haplotype dataset and a wider sampling of localities. Specimens were collected from 11 sites across Victoria Land and sequenced for the cytochrome c oxidase subunit I mitochondrial gene (cox1). Haplotypes were used for population genetics, demographic, molecular clock and Bayesian phylogenetic analyses. Landscape distribution and clustering of haplotypes were also examined for the first time in this species. Only three (out of 67) haplotypes are shared among populations, suggesting high genetic structure and limited gene flow between sites. As in previous studies, the population of Apostrophe Island has a closer genetic similarity with those of the central sites, rather than with its neighbours. Molecular clock estimates point to early differentiation of haplotypes in the late/mid-Miocene, also supporting the view that C. terranovus is a relict species that survived on the Antarctic continent during the Last Glacial Maximum. The present genetic composition of populations represents a mixture of ancient and more recent haplotypes, sometimes occurring in the same localities.

Traits of primary producers associated with tissue quality are commonly assumed to have strong control over higher trophic levels. However, this view is largely based on studies of vascular plants, and cryptogamic vegetation has received far less attention. In this study natural gradients in nutrient concentrations in cryptogams associated with the proximity of penguin colonies on a Maritime Antarctic island were utilized to quantify the impact of nitrogen content on micro-arthropod communities. Proximity to penguin colonies increased the nitrogen concentration of cryptogams, and the penguin source was confirmed by decreasing δ15N values at greater distances from colonies. Micro-arthropod abundance, diversity (H’) and richness declined with distance from the penguin colonies, and was positively correlated with the nitrogen concentrations of cryptogams. Δ15N of micro-arthropods was positively correlated (r2=0.865, P<0.01) with δ15N of the moss Andreaea depressinervis indicating that penguin-derived nitrogen moves through Antarctic food webs across multiple trophic levels. Nitrogen content of cryptogams was correlated with associated micro-arthropods indicating that biotic interactions affect community development in Antarctic terrestrial ecosystems. The spatial patterns of Antarctic biodiversity can therefore be affected by local factors, such as marine vertebrates, beyond existing latitudinal patterns of temperature and water availability.

A generalist predator's ability to contribute to biological control is influenced by the decisions it makes during foraging. Predators often use flexible foraging tactics, which allows them to pursue specific types of prey at the cost of reducing the likelihood of capturing other types of prey. When a pest insect has low nutritional quality or palatability for a predator, the predator is likely to reject that prey in favour of pursuing alternative, non-pest prey. This is often thought to limit the effectiveness of generalist predators in consuming aphids, which are of low nutritional quality for many generalist predators. Here, we report behavioural assays that test the hypothesis that the generalist predator, Grammonota inornata (Araneae: Linyphiidae), preferentially forages for a non-pest prey with high nutritional quality (springtails), and rejects a pest prey with low nutritional quality (aphids). In no-choice assays, molecular gut-content analysis revealed that spiders continued to feed on the low-quality aphids at high rates, even when high-quality springtails were readily available. When provided a choice between aphids and springtails in two-way choice tests, spiders did not show the expected preference for springtails. Decision-making by spiders during foraging therefore appears to be sub-optimal, possibly because of attraction to the less frequently encountered of two preys as part of a dietary diversification strategy. These results indicate that behavioural preferences alone do not necessarily compromise the pest-suppression capacity of natural enemies: even nutritionally sub-optimal pest prey can potentially be subject to predation and suppression by natural enemies.

Polar terrestrial invertebrates are suggested as being vulnerable to temperature change relative to lower latitude species, and hence possibly also to climate warming. Previous studies have shown Antarctic and Arctic Collembola and Acari to possess good heat tolerance and survive temperature exposures above 30 °C. To test this feature further, the heat tolerance and physiological plasticity of heat stress were explored in the Arctic collembolan, Megaphorura arctica, from Svalbard and the Antarctic midge, Eretmoptera murphyi, from Signy Island. The data obtained demonstrate considerable heat tolerance in both species, with upper lethal temperatures ≥35 °C (1 h exposures), and tolerance of exposure to 10 and 15 °C exceeding 56 days. This tolerance is far beyond that required in their current environment. Average microhabitat temperatures in August 2011 ranged between 5.1 and 8.1 °C, and rarely rose above 10 °C, in Ny-Ålesund, Svalbard. Summer soil microhabitat temperatures on Signy Island have previously been shown to range between 0 and 10 °C. There was also evidence to suggest that E. murphyi can recover from high-temperature exposure and that M. arctica is capable of rapid heat hardening. M. arctica and E. murphyi therefore have the physiological capacity to tolerate current environmental conditions, as well as future warming. If the features they express are characteristically more general, such polar terrestrial invertebrates will likely fare well under climate warming scenarios.

This is the first study to examine the tolerance of Antarctic springtails (Collembola) to ultraviolet radiation (UV). Survival of extended attenuated exposure to sunlight was examined for both individuals and aggregations of the species Gomphiocephalus hodgsoni Carpenter over a 10 day period. Both individuals and aggregations demonstrated significantly higher survival and moult rates from control treatments kept in the dark to those exposed to UV. A photo-inhibitive element to moulting is indicated that may function to protect post-ecdysial springtails when their emergent cuticles are more sensitive to the external environment. DNA damage was measured in springtails directly exposed to sunlight for 5 h on a clear sunny day. Significant differences were found between treated animals and controls kept in the dark. There was some reduction of damage 12 and 24 h after exposure, when springtails had been placed in the dark to recover. This indicates the up-regulation of DNA repair mechanisms, with the 12 h treatment in particular showing no significant difference with controls. In addition to providing a first look at UV tolerance in these soil arthropods, these findings recommend employing strict protocols for collections of sample material for subsequent biological analysis in order to minimize the interactive effects of photo-damage.

The molecular detection of predation is a fast growing field, allowing highly specific and sensitive detection of prey DNA within the gut contents or faeces of a predator. Like all molecular methods, this technique is prone to potential sources of error that can result in both false positive and false negative results. Here, we test the hypothesis that the use of suction samplers to collect predators from the field for later molecular analysis of predation will lead to high numbers of false positive results. We show that, contrary to previous published work, the use of suction samplers resulted in previously starved predators testing positive for aphid and collembolan DNA, either as a results of ectopic contamination or active predation in the collecting cup/bag. The contradictory evidence for false positive results, across different sampling protocols, sampling devices and different predator-prey systems, highlights the need for experimentation prior to mass field collections of predators to find techniques that minimise the risk of false positives.

Capture by water surfaces is a frequent but stochastic phenomenon for Antarctic collembolans (springtails), with implications for both the survival and dispersal of populations. This paper provides the first field description of the characteristics of rafting aggregations of the springtail Gomphiocephalus hodgsoni and provides the first observation of the inclusion of the mite, Stereotydeus mollis, within these aggregations. Field observations of aggregations in meltwater pools are used to develop a picture of the ecological implications of rafting for Antarctic springtails. The potential for marine capture was also demonstrated by additional observations of two springtails aerially deposited on to sea ice as well as springtails floating in the tidewater cracks between the sea ice and land.

The mitochondrial COI gene of the Antarctic springtail, Gressittacantha terranova, was sequenced across a polar coastal landscape at Terra Nova Bay, northern Victoria Land. Samples from two altitudinal transects in the foothills directly south of Campbell Glacier were compared with samples from Springtail Valley (northern foothills) as an external reference population. We found that mtDNA haplotypes clustered into two lineages (clades) with a mean sequence divergence of 10% (uncorrected distance). However, there was no phylogeographic structure found at this spatial (landscape) scale with haplotypes from both divergent clades found sympatric across most populations. At the landscape scale, the considerable genetic divergence revealed within G. terranova is around five times greater than any other continental Antarctic springtail examined to date. These data indicate a Pliocene divergence event in G. terranova around 4–5 million years ago. The unusual distributional profile of haplotypes - occurrence of multiple haplotypes at single sites and genetic contiguity between sites that are not physically contiguous - suggests a subsequent ‘reshuffling’ of haplotypes in the Holocene that has an ecological basis.

Crop management practices can affect the population of phytophagous pest species and beneficial arthropods with consequences for integrated pest management. In this study, we determined the effect of no-tillage and crop residue management on the arthropod community associated with the canopy of common beans (Phaseolus vulgaris L.). Abundance and species composition of herbivorous, detritivorous, predaceous and parasitoid arthropods were recorded during the growing seasons of 2003 and 2004 in Coimbra County, Minas Gerais State, Brazil. Arthropod diversity and guild composition were similar among crop management systems, but their abundance was higher under no-tillage relative to conventional cultivation and where residues from the preceding crop were maintained in the field. Thirty-four arthropod species were recorded, and those most representative of the impact of the crop management practices were Hypogastrura springtails, Empoasca kraemeri and Circulifer leafhoppers, and Solenopsis ants. The infestation levels of major insect-pests, especially leafhoppers (Hemiptera: Cicadellidae), was on average seven-fold lower under no-tillage with retention of crop residues relative to the conventional system with removal of residues, whereas the abundance of predatory ants (Hymenoptera: Formicidae) and springtails (Collembola: Hypogastruridae) were, respectively, about seven- and 15-fold higher in that treatment. Importantly, a significant trophic interaction among crop residues, detritivores, predators and herbivores was observed. Plots managed with no-tillage and retention of crop residues had the highest bean yield, while those with conventional cultivation and removal of the crop residues yielded significantly less beans. This research shows that cropping systems that include zero tillage and crop residue retention can reduce infestation by foliar insect-pests and increase abundance of predators and detritivores, thus having direct consequences for insect pest management.

Although the effects of nutrient enhancement on aquatic systems are well documented, the consequences of nutritional supplements on soil food webs are poorly understood, and results of past research examining bottom-up effects are often conflicting. In addition, many studies have failed to separate the effects of nutrient enrichment and the physical effects of adding organic matter. In this field study, we hypothesised that the addition of nitrogen to soil would result in a trophic cascade, through detritivores (Collembola) to predators (spiders), increasing invertebrate numbers and diversity.

Nitrogen and lime were added to plots in an upland grassland in a randomised block design. Populations of Collembola and spiders were sampled by means of pitfall traps and identified to species.

Seventeen species of Collembola were identified from the nitrogen plus lime (N+L) and control plots. Species assemblage, diversity, richness, evenness and total number were not affected by nutrient additions. However, there was an increase in the number of Isotomidae juveniles and Parisotoma anglicana trapped in the N+L plots.

Of the 44 spider species identified, over 80% were Linyphiidae. An effect on species assemblage from the addition of N+L to the plots was observed on two of the four sampling dates (July 2002 and June 2003). The linyphiid, Oedothorax retusus, was the only species significantly affected by the treatments and was more likely to be trapped in the control plots.

The increased number of juvenile Collembola, and change in community composition of spiders, were consequences of the bottom-up effect caused by nutrient inputs. However, despite efforts to eliminate the indirect effects of nutrient inputs, a reduction in soil moisture in the N+L plots cannot be eliminated as a cause of the invertebrate population changes observed. Even so, this experiment was not confounded by the physical effects of habitat structure reported in most previous studies. It provides evidence of moderate bottom-up influences of epigeic soil invertebrate food webs and distinguishes between nutrient addition and plant physical structure effects. It also emphasises the importance of understanding the effects of soil management practices on soil biodiversity, which is under increasing pressure from land development and food production.

A new aspirator is proposed for the collection of springtails (Collembola) and other small arthropods. It is hand operated, safe and efficient to use.

Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin inhibitor (BSTI) were examined in laboratory assays against three earthworm and one collembolan species. BSTI is a serine protease inhibitor that can bind to the digestive trypsins of insects feeding on modified plants, resulting in reduced growth and survival. Protease inhibitors are active against a broad range of insects, so may have a large impact on non-target organisms. Survival and fecundity of the collembolan Folsomia candida were unaffected by consumption of artificial diet containing BSTI-expressing tobacco leaf or powdered freeze-dried BSTI-expressing tobacco leaf that was added to soil. Similarly, mortality and growth of earthworms Aporrectodea caliginosa and Lumbricus rubellus did not differ significantly between soil augmented with BSTI-expressing tobacco leaves or unmodified control leaves. The redworm Eisenia fetida gained less weight when provided with BSTI-expressing leaves in one assay, but when the experiment was repeated, there was no significant difference between treatments. BSTI-expressing tobacco and unmodified control leaves decomposed at the same rate, indicating that the inhibitor had no effect on the overall function of the decomposer community of micro-flora and fauna in soil.

Aerial dispersal has been frequently proposed as a potential mechanism by which polar terrestrial arthropods are transported to, and settle the ice free habitats of Antarctica, but to date there has been little substantive evidence in support of this hypothesis. Using water traps we investigated aerial deposition of arthropods on Lagoon Island, Ryder Bay, on the Antarctic Peninsula. Over a period of five weeks, trapping at three different altitudes, we captured a total of nine springtails, Cryptopygus antarcticus, all alive. This is the first study to demonstrate conclusively the survival of wind-borne native arthropods within Antarctica. By scaling the modest trapping area and success against island surface area, it is clear that hundreds, if not thousands, of springtails are regularly relocated by winds between the terrestrial habitats of Marguerite Bay. We use known desiccation rates of C. antarcticus and wind speeds to predict the likelihood of successful dispersal between the principal terrestrial habitats of the larger Marguerite Bay. Implications for local and long-range dispersal are discussed in relation to C. antarcticus and other polar arthropods.

The distribution and abundance of free-living arthropods from soil and under stones were surveyed at the Cape Hallett ice-free area (ASPA No. 106), North Victoria Land, Antarctica. A total of 327 samples from 67 plots yielded 11 species of arthropods comprised of three Collembola: Cryptopygus cisantarcticus, Friesea grisea and Isotoma klovstadi and eight mites: Coccorhagidia gressitti, Eupodes wisei, Maudheimia petronia, Nanorchestes sp., Stereotydeus belli, S. punctatus, Tydeus setsukoae and T. wadei. Arthropods were absent from areas occupied by the large Adélie penguin colony. There was some distinction among arthropod communities of different habitats, with water and a lichen species (indicative of scree slope habitats) ranking as significant community predictors alongside spatial variables in a Canonical Correspondence Analysis. Recent changes to the management plan for ASPA No. 106 may need to be revisited as the recommended campsite is close to the area of greatest arthropod diversity.

Field surveys of free-living terrestrial microarthropods were made during the 1994–95 summer at four sites in northern Marguerite Bay (Anchorage Island, Lagoon Island, Léonie Island, Rothera Point; c. 68°S, 68°W) and three on southern Alexander Island (Two Step Cliffs, Fossil Bluff, Ablation Valley; c. 71–72°S, 68°W). Detailed site descriptions are presented, as little previous information exists. Twenty species (four Collembola, 16 Acari) were recorded from the Marguerite Bay sites, with a maximum of 17 species at one site. A further four species (one Collembola, two Acari, one Diptera) have been recorded from the same area by other authors. Species diversity at these sites, in particular Léonie Island, is as great as at any known site elsewhere in the maritime Antarctic, although the total area of terrestrial habitat available is small. Individual species and total population densities are also similar to, if not greater than, published studies from the South Shetland and South Orkney Islands. None of the species is new to the maritime Antarctic, although the distributions of several are extended southwards. Only nine species (maximum seven at one site) were found on Alexander Island, concurrent with decreases in population densities to levels similar to those found in many continental Antarctic studies. This still represents a high species diversity for such a high latitude site. The richness of two sites, Ablation Valley and Mars Oasis (Two Step Cliffs), is unlikely to be repeated elsewhere on Alexander Island. The Alexander Island fauna is clearly related to that of the maritime Antarctic, as all except one species occur at more northerly sites elsewhere on the Antarctic Peninsula, and none in the continental Antarctic. One species, Friesia topo (Collembola), is known only from Alexander Island.

In order to infer the origin and the evolution of Antarctic Collembola, a correct phylogenetic analysis depicting relationships among Antarctic and non-Antarctic species is required. A preliminary assessment of the value of DNA sequences in reconstructing phylogenetic relationships among the Antarctic Isotoma klovstadi and other non-Antarctic species was carried out by sequencing one mitochondrial gene (Cytochrome c oxidase, subunit II) and two nuclear genes (a fragment of the 28S rDNA and the Elongation Factor-1α). Estimates of base composition heterogeneity revealed that in the two protein-coding genes (COII and EF-1α) 3rd codon position sites are compositionally very heterogeneous and the analysis of these two genes was therefore performed only on 1st and 2nd codon position sites. Phylogenetic analyses using Maximum Likelihood, Maximum Parsimony and Minimum Evolution revealed that the COII and the EF-1α genes are more suitable than the D3 fragment for the reconstruction of phylogenetic relationships within the Family Isotomidae to which Isotoma and several other genera of Antarctic Collembola belong.

Body size was measured for 67 of the approximately 120 invertebrate species on Marion Island. These include more than 60% of the 29 acarine families, and more than 80% of the remaining terrestrial invertebrate species. Thus the data are regarded as representative of the entire invertebrate fauna of sub-Antarctic, Marion Island. Length–mass and fresh–dry mass relationships were calculated for orders, families and species to provide a means of estimating body size parameters for species in collections and those which are known from only a few specimens. A comparison of the regression slopes for the different taxonomic ranks indicates that it is better to use regressions from the lowest possible taxonomic level for prediction of body mass. Differences between length–mass relationships for Marion Island insects and continental assemblages raises the question as to the applicability of continental regressions to sub-Antarctic species. This study provides a useful means for estimating body size parameters for Antarctic and sub-Antarctic invertebrates and provides baseline data on an important species trait that seems to be changing with local and global environmental changes.

Thirteen specimens of type and/or figured Hexapoda from the Rhynie chert are housed at The Natural History Museum, London, UK. They are listed along with a complete bibliography of where they have been cited and figured. Two taxa are present: Rhyniella praecursor Hirst & Maulik 1926 (Collembola); and Rhyniognatha hirsti Tillyard 1928 (Insecta)

In the fifth year of an agricultural conversion experiment in Pennsylvania, we studied the soil biological community under three treatment regimes planted with corn: organic-manure, organic-legume, and a conventional system. The organic treatments consisted of complex crop rotations, cultivations, and organic matter inputs to control pests and maintain soil fertility. The conventional system consisted of a simple corn/soybean rotation with synthetic fertilizer and pesticide inputs. High rates of CO2 evolution (a measure of potential microbial activity) in the organic plots corresponded with high levels of organic matter input. Soil nematodes were most abundant in organic plots, although seasonal patterns differed between the two organic treatments. Soil microarthropods were dominated by fungivorous Prostigmata mites, which reached peak abundance in organic plots two to five months after organic matter incorporation. Oribatid mites, which were rare throughout the study, followed the same pattern of abundance in each treatment and were probably most influenced by tillage disturbances. Predatory Mesostigmata were generally more abundant in organic plots. Surface-dwelling Collembola were abundant briefly in the spring, but soil-dwelling species dominated numerically throughout the cropping season. Spring tillage appeared to have a strong negative effect on earthworm populations in all plots. Small earthworm species became abundant in organic-manure plots during the summer. Larger earthworm species were abundant in organic-legume and conventional plots after the autumn harvest, when crop residues covered the undisturbed soil The systems-level nature of the Conversion Project experiment makes it difficult to identify cause-effect relationships. The data do suggest that organic amendments tend to enhance soil biological activity, while tillage disturbances tend to disrupt the biotic community.