Simple SummaryThis review summarizes adaptations and predispositions of different arthropod taxa (springtails, web spiders, millipedes and centipedes) to flood and drought conditions. The main focus sis directed to arthropod species, which are living in Middle European floodplain forests and wetlands, because of the fast change of flood and drought conditions in these habitats. Furthermore the effects of the predicted regional climate change like increasing aperiodic summer flooding and decreasing winter and spring floods are also discussed. AbstractFloodplain forests and wetlands are amongst the most diverse and species rich habitats on earth. Arthropods are a key group for the high diversity pattern of these landscapes, due to the fact that the change between flooding and drought causes in different life cycles and in a variety of adaptations in the different taxa. The floodplain forests and wetlands of Central Amazonia are well investigated and over the last 50 years many adaptations of several hexapod, myriapod and arachnid orders were described. In contrast to Amazonia the Middle European floodplains were less investigated concerning the adaptations of arthropods to flood and drought conditions. This review summarizes the adaptations and predispositions of springtails, web spiders, millipedes and centipedes to the changeable flood and drought conditions of Middle European floodplain forests and wetlands. Furthermore the impact of regional climate change predictions like increasing aperiodic summer floods and the decrease of typical winter and spring floods are discussed in this article.

Collembola are soil dwelling organisms that provide important ecosystem services within soils. To increase realism in evaluating potential effects of plant protection products a Collembola two-generation study was developed. This test assesses the potential for recovery of Collembola when exposed to plant protection products. Juvenile individuals of Folsomia candida (Willem, Ann Soc Entomol Belg 46:275-283, 1902) which hatched under conditions of exposure to a test substance in a modified OECD 232 bioassay were introduced into a second consecutive bioassay containing the same test substance aged in soil. This test system determines whether a population which was initially impacted by a substance in a 1st bioassay shows normal reproduction or survival in a 2nd bioassay after aging of the test substance in soil. An intermediate period for juvenile growth is included between the 1st and 2nd bioassay in order to reduce the control treatment variability in reproduction and mortality to fulfill the validity criteria according to the OECD 232 guideline. The Collembola two-generation study is able to differentiate between substances showing either a potential long-term risk or comprising a low risk. Comparing the results of this two generation study with data from semi-field or field studies indicates a high degree of conservatism when this test is considered within a tiered risk assessment scheme. This approach represents a valuable tool which makes the risk assessment more efficient by providing an alternative refinement option for highly conservative tier 1 Collembola risk assessment.

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-Standard ecological methods (pitfall traps, trunk eclectors and soil cores) were used to evaluate collembolan community responses to different flooding intensities. Three sites of a floodplain habitat near Mainz, Germany, with different flooding regimes were investigated. The structures of collembolan communities are markedly different depending on flooding intensity. Sites more affected by flooding are dominated by hygrophilic and hygrotolerant species, whereas the hardwood floodplain is dominated by mesophilic species. The survival strategies of the hygrophilic and hygrotolerant species include egg diapause and passive drifting. The physiological adaptations to hypoxic conditions of several collembolan species were analyzed using a microcalorimeter. The activities were tested under normoxic and hypoxic/anoxic conditions as well as during post-hypoxic recovery. Lactate was increased after hypoxic intervals in the species studied, suggesting that, in addition to a massive decrease in metabolic rate, a modest glycolytic activity may be involved in the tolerance to hypoxia.Index terms: behavioral adaptation, ecological adaptation, egg diapause, inundation, morphological adaptation, physiological adaptation. Respostas e adaptações de comunidades de colêmbolos (Hexapoda: Collembola) a condições de inundação e hipoxiaResumo -Foram utilizados os métodos ecológicos padrão (armadilhas "pitfall", armadilhas de tronco e amostras de solo) para avaliar as respostas de comunidade de colêmbolos a diferentes intensidades de inundação. Foram investigados três locais de um habitat de leitos de inundação perto de Mainz, Alemanha, com diferentes regimes de inundação. As estruturas das comunidades de colêmbolos foram nitidamente diferentes conforme a intensidade das inundações. Nos locais mais afetados por inundações, as espécies higrofílicas e higrotolerantes dominaram, ao passo que as espécies mesofílicas foram dominantes nos locais de leitos de inundação com angiospermas. As estratégias de sobrevivência das espécies higrofílicas e higrotolerantes incluem a diapausa dos ovos e o deslocamento passivo. Foi testada a adaptação fisiológica a condições hipóxicas de espécies selecionadas de colêmbolos através de análises por microcalorimetria. A atividade das espécies foi testada em condições normóxicas e hipóxicas/anóxicas e durante a recuperação pós-hipoxia. Verificou-se que o lactato aumentava após condições hipóxicas nas espécies avaliadas, o que sugere que, além de um decréscimo massivo na atividade metabólica, deve haver também certa atividade glicolítica associada à tolerância à hipoxia.Termos para indexação: adaptação comportamental, adaptação ecológica, diapausa dos ovos, inundação, adaptação morfológica, adaptação fisiológica.

Plant-parasitic nematodes (PPN) are responsible for severe yield losses in crop production. Management is challenging as effective and safe means are rare. Recently, it has been discovered that the succinate dehydrogenase (SDH) inhibitor fluopyram is highly effective against PPN while accompanying an excellent safety profile. Here we show that fluopyram is a potent inhibitor of SDH in nematodes but not in mammals, insects and earthworm, explaining the selectivity on molecular level. As a consequence of SDH inhibition, fluopyram impairs ATP generation and causes paralysis in PPN and Caenorhabditis elegans. Interestingly, efficacy differences of fluopyram amongst PPN species can be observed. Permanent exposure to micromolar to nanomolar amounts of fluopyram prevents Meloidogyne spp. and Heterodera schachtii infection and their development at the root. Preincubation of Meloidogyneincognita J2 with fluopyram followed by a recovery period effectively reduces gall formation. However, the same procedure does not inhibit H.schachtii infection and development. Sequence comparison of sites relevant for ligand binding identified amino acid differences in SDHC which likely mediate selectivity, coincidently revealing a unique amino acid difference within SDHC conserved among Heterodera spp. Docking and C.elegans mutant studies suggest that this minute difference mediates altered sensitivity of H.schachtii towards fluopyram.

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.

Collembola are ancient arthropods living in soil with extensive exposure to dirt, bacteria, and fungi. To protect from the harsh environmental conditions and to retain a layer of air for breathing when submerged in water, they have evolved a superhydrophobic, liquid-repelling cuticle surface. The nonfouling and self-cleaning properties of springtail cuticle make it an interesting target of biomimetic materials design. Recent research has mainly focused on the intricate microstructures at the cuticle surface. Here we study the role of the cuticle chemistry for the Collembola species Orchesella cincta (Collembola, Entomobryidae). O. cincta uses a relatively simple cuticle structure with primary granules arranged to function as plastrons. In contrast to the Collembolan cuticle featuring structures on multiple length scales that is functional irrespective of surface chemistry, we found that the O. cincta cuticle loses its hydrophobic properties after being rinsed with dichloromethane. Sum frequency generation spectroscopy and time-of-flight secondary ion mass spectrometry in combination with high-resolution mass spectrometry show that a nanometer thin triacylglycerol-containing wax layer at the cuticle surface is essential for maintaining the antiwetting properties. Removal of the wax layer exposes chitin, terpenes, and lipid layers in the cuticle. With respect to biomimetic applications, the results show that, combined with a carefully chosen surface chemistry, superhydrophobicity may be achieved using a relatively unsophisticated surface structure rather than a complex, re-entrant surface structure alone.

Soil life supports the functioning and biodiversity of terrestrial ecosystems1,2. Springtails (Collembola) are among the most abundant soil animals regulating soil fertility and flow of energy through above- and belowground food webs3-5. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset collected from 2,470 sites, we estimate total soil springtail biomass at 29 Mt carbon (threefold higher than wild terrestrial vertebrates6) and record peak densities up to 2 million individuals per m2 in the Arctic. Despite a 20-fold biomass difference between tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the increase in temperature. Neither springtail density nor community metabolism were predicted by local species richness, which was highest in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation7,8, and resource limitation7,9,10 in soil communities. Contrasting temperature responses of biomass, diversity and activity of springtail communities suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting major soil functions.