Academic literature on the topic 'Springtail (Collembola)'

Biochar was reported to improve the chemical and physical properties of soil. The use of biochar as a soil amendment have been found to improve the soil structure, increase the porosity, decrease bulk density, as well increase aggregation and water retention. Knowing that springtails (Collembola) are closely related to soil properties, the effect of biochar on morphological diversity of these organisms was evaluated. The main concept was the classification of springtails to the life-form groups and estimation of QBS-c index (biological quality index based on Collembola species). We conducted the field experiment where biochar was used as soil amendment in oilseed rape and maize crops. Wood-chip biochar from low-temperature (300 °C) flash pyrolysis was free from PAH (polycyclic aromatic hydrocarbon) and other toxic components. Results showed that all springtail life-form groups (epedaphic, hemiedaphic, and euedaphic) were positively affected after biochar application. The QBS-c index, which relates to springtails’ adaptation to living in the soil, was higher in treatments where biochar was applied. We can recommend the use of Collembola’s morphological diversity as a good tool for the bioindication of soil health.

The objective of this work was to compare the oribatid mite and springtail communities in three plots with different soil use - Coffee (CP), secondary vegetation or fallow fields (acahual, A) and a cloud mountain forest (CMF) - within a coffee plantation located in Santa Maria Huatulco, Oaxaca State, Mexico. In each plot 20 samples (10 of soil, 10 of litter) were taken and processed in Berlese funnels. The extracted fauna was preserved in 70% ethanol. A total of 3,031 oribatid mites belonging to 33 species, and 1,177 specimens of springtails belonging to 43 species, were collected. The number of species recorded was: 27 at CP (14 oribatids; 13 springtails), 44 at A (19 oribatids; 25 springtails) and 62 at CMF (32 for each group). A total of 26 oribatid and 27 springtail species was found in the soil, and 25 oribatid and 32 springtail species were found in the litter. The most abundant species were the oribatids Rostroztes foveolatus (Haplozetidae), Tectocepheus sp. (Tecocepheidae), Karenella sp. (Oppidae), Atropacarus (Hoplophorella) cf. fonseciai (Phthiracaridae), Epilohmannia pallida americana (Epilohmannidae), and the springtails Ceratophysella cf. gibbosa (Hypogastruridae), Mesaphorura sp. (Tullbergidae) and Proisotoma cf. minuta (Isotomidae). Fourteen families and 18 species of Oribatida species and 5 families and 34 species of Collembola were recorded for the first time for the State.

Hemocyanins are respiratory dioxygen carrier proteins found in many arthropods including ancient terrestrial species such as spiders and scorpions as well as marine horseshoe crabs. As hemocyanins are highly conserved in this lineage, it is possible to observe an evolutionary descent through its subunits and their overall structure. Unfortunately, little is known about the structure and function of hexapod hemocyanins. Using recent springtail taxa (Collembola) as models for basal hexapods, and the help of electron microscopy, light scattering, SDS PAGE, and Western blot, we could demonstrate for the first time the presence of 2 × 6-meric hemocyanins in the hemolymph of hexapods. The quaternary structure is composed of at least two different subunits and looks nearly identical to the hemocyanin found in decapod crustaceans. In addition, homology modeling and western blotting suggest a close structural relationship between collembolan and crustacean hemocyanin. Such a respiratory protein was possibly helpful in the early terrestrialization process of ancient Collembola. In addition, physiological adaptations to hypoxic or temporarily anoxic conditions could be a possible explanation for the presence of this respiratory protein. Nevertheless, it has to be concluded that the primary benefit of hemocyanin for springtails remains unclear.

Climate changes are likely to have major influences on the distribution and abundance of Antarctic terrestrial biota. To assess arthropod distribution and diversity within the Ross Sea region, we examined mitochondrial DNA (COI) sequences for three currently recognized species of springtail (Collembola) collected from sites in the vicinity, and to the north of, the Mackay Glacier (77°S). This area acts as a transition between two biogeographic regions (northern and southern Victoria Land). We found populations of highly divergent individuals (5%–11.3% intraspecific sequence divergence) for each of the three putative springtail species, suggesting the possibility of cryptic diversity. Based on molecular clock estimates, these divergent lineages are likely to have been isolated for 3–5 million years. It was during this time that the Western Antarctic Ice Sheet (WAIS) was likely to have completely collapsed, potentially facilitating springtail dispersal via rafting on running waters and open seaways. The reformation of the WAIS would have isolated newly established populations, with subsequent dispersal restricted by glaciers and ice-covered areas. Given the currently limited distributions for these genetically divergent populations, any future changes in species’ distributions can be easily tracked through the DNA barcoding of springtails from within the Mackay Glacier ecotone.

Acknowledging the bio indicator importance of springtails (Hexapoda: Collembola) for soil quality, this study aimed to determine the abundance of these arthropods in different systems of rotation/succession with commercial and cover crops, while also verifying the agricultural factor associated to these arthropods’ population. In the Instituto de Desenvolvimento Rural do Paraná (IAPAR-EMATER), during six years, areas with differing crops in rotation/succession adopting the no-tillage system were studied. For each system, chemical analyses of the soil were conducted and the number of captured springtails in pitfall traps was counted. The phytosanitary products applied during the evaluations and the quantity of vegetal cover remaining after harvest were considered as well. No difference was found between the rotation/succession systems in relation to chemical soil attributes, however the largest number of springtails was found in crop covers from corn, Brachiaria sp., and canola. These crop covers, including wheat, resulted in the highest straw dry mass. When removing the system in which the predecessor crop had the highest quantities of fungicide application, a positive correlation (r = 0.63; p < 0.01) was found, between springtail abundance and highest amount of straw after the harvest. If no fungicide applications occur, the crops with the largest amount of vegetal cover favor springtail populations.

Collembola (springtails) are an early diverging class of apterygotes, and mark the first substantial radiation of hexapods on land. Despite extensive work, the relationships between major collembolan lineages are still debated and, apart from the Early Devonian fossil Rhyniella praecursor, which demonstrates their antiquity, the time frame of springtail evolution is unknown. In this study, we sequence two new mitochondrial genomes and reanalyze all known Collembola mt-genomes, including selected metagenomic data, to produce an improved phylogenetic hypothesis for the group, develop a tentative time frame for their differentiation, and provide a comprehensive overview of gene order diversity. Our analyses support most taxonomically recognized entities. We find support for an Entomobryomorpha + Symphypleona clade, while the position of Neelipleona could not be assessed with confidence. A Silurian time frame for their basal diversification is recovered, with an indication that divergence times may be fairly old overall. The distribution of mitochondrial gene order indicates the pancrustacean arrangement as plesiomorphic and dominant in the group, with the exception of the family Onychiuridae. We distinguished multiple instances of different arrangements in individual genomes or small clusters. We further discuss the opportunities and drawbacks associated with the inclusion of metagenomic data in a classic study on mitochondrial genome diversity.

Terrestrial carbon cycling is largely mediated by soil food webs. Identifying the carbon source for soil animals has been desired to distinguish their roles in carbon cycling, but it is challenging for small invertebrates at low trophic levels because of methodological limitations. Here, we combined radiocarbon ( 14 C) analysis with stable isotope analyses ( 13 C and 15 N) to understand feeding habits of soil microarthropods, especially focusing on springtail (Collembola). Most Collembola species exhibited lower Δ 14 C values than litter regardless of their δ 13 C and δ 15 N signatures, indicating their dependence on young carbon. In contrast with general patterns across all taxonomic groups, we found a significant negative correlation between δ 15 N and Δ 14 C values among the edaphic Collembola. This means that the species with higher δ 15 N values depend on C from more recent photosynthate, which suggests that soil-dwelling species generally feed on mycorrhizae to obtain root-derived C. Many predatory taxa exhibited higher Δ 14 C values than Collembola but lower than litter, indicating non-negligible effects of collembolan feeding habits on the soil food web. Our study demonstrated the usefulness of radiocarbon analysis, which can untangle the confounding factors that change collembolan δ 15 N values, clarify animal feeding habits and define the roles of organisms in soil food webs.

The cuticles of most springtails (Collembola) are superhydrophobic, but the mechanism has not been described in detail. Previous studies have suggested that overhanging surface structures play an important role, but such structures are not a universal trait among springtails with superhydrophobic cuticles. A novel wetting experiment with a fluorescent dye revealed the extent of wetting on exposed surface structures. Using simple wetting models to describe the composite wetting of the cuticular surface structures results in underestimating the contact angles of water. Including the three-phase line tension allows for a prediction of contact angles in the observed range. The discrepancy between the contact angle predicted by simple models and those observed is especially large in the springtail Cryptopygus clavatus which changes, seasonally, from superhydrophobic to wetting without a large change in surface structure; C. clavatus does not have overhanging surface structures. This large change in observed contact angles can be explained with a modest change of the three-phase line tension.

A description is given of the abiotic and biotic factors that affect edaphic springtail distribution and the main role that collembola play in soil development. Collembola degrade organic matter that has been inoculated with microorganisms, which they control and disperse. They also help decompose recalcitrant molecules in ecosystems, release nitrogen, phosphorus and other elements into soils, and control phytopathogenic fungi in crops, as well as stimulate microbial respiration and serve as soil quality bioindicators. Water is the main factor that determines whether springtail populations are present, followed by temperature, which in turn controls whether new generations will occur. Enzyme metabolism and even DNA structure is affected by pH. Collembola populations are also affected by materials that enter the soil, including the leaf litter dropped by plant coverage, manures and soil fertilizers, and are regulated by the ascending forces in an ecosystem.

The study was carried out in July 2009 in Murmansk (68°57’ N; 33°03’E) and involved algae that had washed up at the edge of the intertidal zone of Kola Bay. Two areas of algae were selected for this study: uncontaminated (algae I) and algae contaminated with waste products (algae II). The material was collected using a frame with an area of 100 cm2. A total of 40 samples were taken. The abundance of the springtails was almost three times lower in the contaminated algae than in the uncontaminated algae, whereas the species diversity of the springtail communities was much higher in the contaminated algae. The littoral species Hypogastrura viatica was the dominantspecies in the uncontaminated algae, and that in the contaminated algae was the cosmopolitan species Folsomia quadriuculata. It appears that the contamination of the algae with waste products can promote the intensification of competition among springtails and between springtails and other saprophagous invertebrates.

Omniphobic surfaces found in nature have great potential for enabling novel and emerging products and technologies to facilitate the daily life of human societies. One example is the water and even oilrepellent cuticle of springtails (Collembola). The wingless arthropods evolved a highly textured, hierarchically arranged surface pattern that affords mechanical robustness and wetting resistance even at elevated hydrostatic pressures. Springtail cuticle-derived surfaces therefore promise to overcome limitations of lotus-inspired surfaces (low durability, insufficient repellence of low surface tension liquids). In this review, we report on the liquid-repellent natural surfaces of arthropods living in aqueous or temporarily flooded habitats including water-walking insects or water spiders. In particular, we focus on springtails presenting an overview on the cuticular morphology and chemistry and their biological relevance. Based on the obtained liquid repellence of a variety of liquids with remarkable efficiency, the review provides general design criteria for robust omniphobic surfaces. In particular, the resistance against complete wetting and the mechanical stability strongly both depend on the topographical features of the nano- and micropatterned surface. The current understanding of the underlying principles and approaches to their technological implementation are summarized and discussed.

Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Understanding the distribution, abundance and diversity of species and the mechanisms causing these patterns has been the interest of ecologists and taxonomists for decades. The exceptionally high plant diversity in the Fynbos biome has been well studied. Whilst early arguments suggested that the high plant diversity is not reflected in the arthropod diversity and that insect species richness is low compared to other comparable areas, these observations might have been hampered by the taxonomic impediment. Despite global recognition of the significance of this below-ground component of diversity for ecosystem functioning, soil is one of the most poorly studied habitats of terrestrial ecosystems. Although knowledge is increasing for epigaeic groups, other significant groups such as the Collembola remain especially poorly understood. This thesis starts addressing this serious gap in knowledge concerning the below-ground component of biodiversity in the Fynbos biome and the effects of landscape transformation thereon. As part of the work, considerable attention was given to resolving the taxonomic impediment for the springtail fauna of the Fynbos biome using modern morphological and DNA barcoding methods, while also examining the correlates of soil animal diversity in the biome, by using Collembola (springtails) as exemplars. First, using a combination of published records of Collembola from South Africa, various sampling methods and DNA barcoding, a species list is compiled for the Western Cape. Currently 213 species are known to exist from the Western Cape. A high level of cryptic diversity was also found in several genera, together with several potential species radiations in the Ectonura, Seira, Parisotoma and Cryptopygus. A start is a made at addressing the lack of taxonomic knowledge by describing five new species. Two Ectonura Cassagnau 1980 species are described from Betty’s Bay and Grootvadersbosch respectively and a key to the Neanurinae of South Africa is provided. The first record of the genus Triacanthella Schäffer, 1897 is described from a cave in Table Mountain, while two new species of Delamarephorura are described and the genera Spicatella Thibaud 2002 and Delamarephorura Weiner & Najt 1999 are synonymized. Although fire is thought to be the main form of decomposition in the Fynbos biome, recent work has shown that biological decomposition may be more important than previously thought. I examine the resilience of Collembola after a large-scale fire in Jonkershoek Nature Reserve using quantitative sampling which is temporally replicated. The resilience of invertebrate fauna in the fynbos is not well understood, thus I investigate the diversity of Collembola before and after a major fire. Results show Collembola species richness and abundance recovered surprisingly quickly after the fire. On a larger scale, litterbags were deployed at six sites across the Western Cape using different litter types. Here, a total of 113 morphospecies species was found. Local richness was found to be highest in Kogelberg (32 species), while the turnover between sites was also high. Thus, the degradation of local habitat patches will be as much of a threat to Collembola as to the endemic plants in this region.
AFRIKAANSE OPSOMMING: Begrip van die verspreiding, spesierykheid en verskeidenheid van spesies en die meganismes wat hierdie patrone veroorsaak is al die belangstelling van ekoloë en taksonome vir dekades. Die buitengewoon hoë plant diversiteit in die Fynbos-bioom is goed bestudeer. Terwyl vroeë argumente voorstel dat die hoë plantdiversiteit nie weerspieël word in die geleedpotige diversiteit nie en dat insekspesierykheid laag is in vergelyking met ander gebiede, kon hierdie waarnemings nie gemaak word nie as gevolg van taksonomiese hindernisse. Ten spyte van die wêreldwye erkenning van die belangrikheid van hierdie ondergrondse komponent van diversiteit vir die funksionering van die ekosisteem, is die grond een van die swakste bestudeerde habitatte van terrestriële ekosisteme. Alhoewel kennis vermeerder vir bogrondse groepe, word ander belangrike groepe soos die Collembola swak verstaan. Hierdie tesis begin hierdie ernstige leemte in kennis aanspreek, met betrekking tot die ondergrondse komponent van biodiversiteit in die Fynbos bioom en die gevolge van die landskap transformasie daarop. As deel van die werk, is heelwat aandag gegee aan die oplossing van die taksonomiese hindernis vir die springstert fauna van die fynbos bioom met behulp van moderne morfologiese en DNA metodes, terwyl dit ook die ooreenkomste van grond diere diversiteit ondersoek in die bioom, deur gebruik te maak van Collembola (springsterte) as voorbeelde. Eerste, met behulp van 'n kombinasie van gepubliseerde rekords van Collembola van Suid-Afrika, verskillende kolleksie metodes en DNA metodes is 'n spesielys saamgestel vir die Wes-Kaap. Tans is 213 spesies bekend vir die Wes-Kaap. 'n Hoë vlak van kriptiese diversiteit is ook gevind in verskeie genera, saam met verskeie potensiële spesies radiasies in die Ectonura, Seira, Parisotoma en Cryptopygus. 'n Begin is gemaak op die aanspreek van die gebrek van taksonomiese kennis deur vyf nuwe spesies te beskryf. Twee Ectonura Cassagnau 1980 spesies van Bettiesbaai en Grootvadersbosch is beskryf en 'n sleutel tot die Neanurinae van Suid-Afrika word verskaf. Die eerste rekord van die genus Triacanthella Schaffer, 1897 word beskryf van 'n grot in Tafelberg, terwyl twee nuwe spesies van Delamarephorura beskryf word en die genera Spicatella Thibaud 2002 en Delamarephorura Weiner & Najt 1999 gesinomiseer word. Hoewel vuur beskou word as die belangrikste vorm van ontbinding in die Fynbos bioom, het onlangse werk getoon dat die biologiese ontbinding belangriker mag wees as wat voorheen vermoed was. Ek ondersoek die veerkragtigheid van Collembola na 'n groot skaal vuur in Jonkershoek Natuurreservaat met behulp van kwantitatiewe steekproefneming wat tydelik herhaal. Die veerkragtigheid van ongewerwelde fauna in die fynbos word nie goed verstaan nie, dus het ek ondersoek ingestel na die diversiteit van Collembola voor en na 'n groot vuur. Resultate toon dat Collembola se spesierykheid en hoveelheid verbasend vinnig herstel na die vuur. Op 'n groter skaal, is kolleksies by ses plekke regoor die Wes-Kaap gebruik en verskillende blaarafval word vergelyk. Hier word 'n totaal van 113 morfologiese spesies gevind. Daar is gevind dat die hoogste aantal spesies in Kogelberg is (32 spesies), terwyl die omset tussen plekke baie hoog was. So sal die agteruitgang van plaaslike habitatte net soveel van 'n bedreiging inhou vir Collembola as vir die endemiese plante in hierdie streek.

Springtails (Collembola) are wingless arthropods that are impressively adapted to cutaneous respiration in temporarily rain-flooded habitats by non-wetting skin morphology. Recapitulating the robust and effectively liquid-repellent surface characteristics of springtail skin in engineered materials may offer exciting opportunities for demanding applications. Herein, we present a strategy for mimicking morphological surface features of springtail skin in polymer membranes produced by reverse imprint lithography. We report the fabrication of multi-level silicon masters that, in turn, serve as templates for the replication of flexible polymer membranes. We examined the robust wetting characteristics of polymer membranes by in situ plastron collapse tests and condensation tests. The mechanical stability of the polymer membranes was tested using a tribometer set-up and compared with needle-shaped pillar structures made from similar material. The fabricated membranes are flexible, free-standing, and adaptable to various substrate materials and shapes that allow for emerging applications.

Vegetables are one of the most important crops in the world and especially in Australia. Under this research, three study cases were investigated for controlling vegetable pests, purple scum springtail Hypogastrura vernalis in export celery and green peach aphid Myzus persicae in Brassica crops. They are a serious quarantine and production pests of economically important celery and crucifer crops and hence were selected for the current study. This research investigates and assesses the impact of the use of various fumigants on infested celery with H. vernalis along with the use of plant volatiles and natural plant-based essential oils for control of M. persicae. Celery bunches become host to the Australian native springtail (Hypogastrura vernalis) (Collembola: Hypogastruridae). Springtails live inside the celery bunch and do not cause damage to the product. Springtails are, however, considered a quarantine pest and have had a significant impact on celery exports. On the other side, using chemical pesticides against aphids has led to resistant aganist chemical pesticides so that require further experiments on the prospective role of factors affecting M. persicae pest status, including plant volatile compound and essential oils are urgently needed. Australia has widely grown celery Apium graveolens var. dulce for domestic and export markets. In the field, celery bunches become host to the Australian native springtail. These insects live inside the celery head, contaminating fresh celery but do not cause any visible damage. In chapter study, evaluation of ethyl formate (EF), phosphine (PH3) and their combination were used for celery fumigation against purple scum springtails that naturally infest celery. The selection of EF and PH3 was because both provide fast kill of insect within a few hours and are registered as fumigants in Australia. The material of EF breakdown is ethanol and formic acid, while the PH3 is slightly soluble in water and be broken down quickly into other products in the atmosphere. These are the first experiments that have used EF and PH3 for harvest celery fumigation. In the laboratory experiments, three concentrations of EF 50, 60 and 90 mg L-1; four concentrations of PH3 1, 1.5, 2 and 2.5 mg L-1 and three concentrations of EF 20, 30 and 40 mg L-1 combined with 1 mg L-1 of PH3 were used for various exposure times at the laboratory temperature 25˚C. The result indicated that 100% mortality was achieved at 90 mg L-1 of EF for 2 h and 100% mortality was also achieved at 30 and 40 mg L-1 EF combined with 1 mg L-1 of PH3 for 2 and 4 h exposure time, however, phytotoxicity was observed in celery treated with EF at all concentrations both in combination and alone. PH3 at 2.5 mg L-1 achieved 100% mortality within 6 h, and no phytotoxicity was evident. From these data, we conclude that PH3 alone has potential as a fumigant for the pre-shipment treatment of celery infested with purple scum springtails. In order to further develop natural or biological methods to manage the interaction between insect pests and host plants (three replicates per treatment) was studied using volatile organic compounds (VOCs). The VOCs from uninfested and infested Brassica plants with M. persicae were investigated by headspace solid microextraction (HS-SPME) combined with gas chromatography mass spectrometry (GC-MS). There is a need for chemical pesticides replacement with environmentally friendly alternatives because of chemical pesticides have been widely used against various pests including aphids have been shown a negative side of environments and an effect on non-target organisms and to understand the communication between aphid and the host plant. Understanding the biological and chemical basis of volatiles could lead to new approaches to the biocontrol of aphids. In Chapter two, the study was evaluated on VOCs from uninfested and infested Brassica plants with M. persicae. The results show that 29 compounds were detected in both infested and uninfested cabbage Brassica oleracea L. var. capitata, and 25 compounds were identified in both infested and uninfested broccoli Brassica oleracea L. var. italica plant samples. The HS-SPME combined with GC-MS analysis of the volatiles describes the differences between the infested and uninfested Cruciferous plant samples. Based on peak area from the GC-MS analysis, the VOCs from infested cabbage consisted of Propane, 2-methoxy, alpha- and beta-pinene, Myrcene, 1-Hexanone, 5-methyl-1-phenyl, Limonene, Decane, gamma-Terpinen and 2,4,4-trimethyl Heptane, all these volatiles were higher in the infested cabbage compared with their peak area in the uninfested cabbage. Similarly, the VOCs from infested broccoli were significantly greater than that from uninfested broccoli, such as D-limonene, Undecane, 3,4-dimethyl-, Heptane, alpha-Pinene, Oxalic acid, Citronellol, Tridecane, n-Decanoic acid, Cyclopentane, pentyl and n-Hexadecanoic acid compared with volatiles released from uninfested broccoli. The results presented in this chapter three outline the response of aphids and parasitoids to plant volatiles by using Y-tube olfactometer. The results show that M. persicae were significantly attracted to infested and uninfested cabbage and broccoli plants compared with clean air; the percentage of aphid choice was 80% and 70% toward infested cabbage and broccoli, respectively, and 7% and 10% were attracted to the clean air choice. While 75.5% and 84% of aphids attracted to uninfested plants comparison with clean air 3% and 7%, for the cabbage and broccoli, respectively. Comparing infested and uninfested plants, the aphids were attracted by 63% and 26.6% for infested cabbage and broccoli respectively, versus 57% and 30% for uninfested cabbage and broccoli, respectively. The results indicate that using an olfactometer, tested parasitoids prefer and are attracted to, the cabbage plants infested with M. persicae compared with clean air. Parasitoids can discriminate the infested plant and significantly responsed to the infested plant odour and attracted by 86.6% and 100% for both parasitoids toward infested Brassica plants. Another way to reduce chemical pesticides usage is with alternatives such as biopesticides for insect pest management. Therefore, chapter four describes the use of different essential oils (black pepper, eucalyptus, rosemary and tea tree), in combination and alone, against M. persicae. These essential oils have insecticidal activity and repellency against many insects including aphids and bioassay studies showed significant control of the green peach aphid through higher mortality. The results show that black pepper and tea tree pure essential oils were effective and caused 80% mortality of aphids for the contact treatment. However, the residual toxins were the most effective on aphids with 100% mortality for pure black pepper and tea tree oil and less than 96% for eucalyptus and rosemary. The combination of essential oils was tested with bioassay as contact and residual toxins. For the contact treatment, the mortality was 98.33% for black pepper + tea tree and rosemary + tea tree. While, in the residual treatment, the mortality was 100% for black pepper + eucalyptus, rosemary + eucalyptus and rosemary tea tree. The essential oil combinations exhibited synergistic, additive and antagonistic interactions for insecticidal activity. The combination of binary essential oils black pepper + tea tree oil showed enhanced activity, with a synergistic rate of 2.19. Essential oil formulation showed effective mortality of aphids, but phytotoxicity appeared on cabbage plants. The Fourier Transform Infrared Spectroscopy (FTIR) analysis of stability of a mixture of essential oils showed that it was not affected by store temperature (15, 25 and 35˚C) and all functional groups were not changed during the storage for three months. Based on the results, essential oils can be used as a commercial insecticide against M. persicae thereby reducing the use of chemical pesticides and their negative impact on the environment and human health. Natural products based on essential oils can be an excellent alternative to synthetic pesticides. In summary, the use of EF fumigant in combination with PH3 and alone achieved high mortality on purple scum springtails, however, phytotoxicity on treated celery is a negative. Alternatively, PH3 alone achieved 100% mortality after 6 h without any observed phytotoxicity, therefore, PH3 has potential as a fumigant for the pre-shipment treatment of celery infested with purple scum springtails. Plant volatile organic compounds that release from the infested cabbage and broccoli can use as an indicator tool for the field infestation related to the differences between the infested and uninfested plant. Base on Y-tube olfactometer, Myzus persicae response to both infested and uninfested plants and parasitoids response to the infested plants. From the laboratory experiments, essential oils show high mortality on green peach aphids and could be used as an alternative to chemical pesticides. According to the FTIR analysis, essential oils can be stored at between 15 and 35˚C with no effect on the properties of the oil. Therefore, I suggest that tested essential oil constituents both pure and in combination could be screened as a potential natural insecticides. Further they could be involved in the chemical synthesis of new types of pesticides, based on essential oils and their constituents.

Desert environments are characterised by harsh conditions and possess low biodiversity largely caused by abiotic factors such as; low precipitation, soil organic matter, high temperatures, high levels of evapo-transpiration, pH and salinity. These factors significantly reduce primary production, which influences the availability of food resources for deserts organisms. The diversity and the drivers of diversity for below ground invertebrates including Collembola (springtails) are relatively unknown in the Namib Desert. Previous morphological studies have found only five species on the basis of traditional taxonomy. This study assesses the diversity of Namib Desert Collembola and determines the effect of environmental parameters on this diversity, The diversity of Namib Desert Collembola was assessed using DNA Barcoding. The sequence information of the 178 Collembola specimens, taken from mitochondrial barcoding using the Cytochrome-c oxidase subunit I (COI) gene, was analyzed and Molecular Operational Taxonomic Units (MOTUs) were defined. Collembola community responses to soil physicochemical properties were investigated by using Redundancy Analysis (RDA). MOTUs were successfully indentified to family level (Isotomidae, Neanuridae and Sminthuridae). The researcher found a total of 30 MOTUs, most of which showed limited geographical localisation. The mtDNA COI (barcode) locus revealed high levels of previously unreported genetic diversity of Collembola in the Namib Desert. The RDA indicated that none of the soil physicochemical properties significantly drove variation in Collembola community composition. However, total soil nitrogen was shown to be a strong but not significant driver of variation in community composition (p<0,054). The taxonomic identification of the Collembola specimens was also attempted using traditional morphological analysis. A total of 23 individuals, collected from pitfall traps or extracted from soil samples, were selected for identification. Available European keys were used for identification to genus level where possible. A total eight of specimens were identified to genus level (Folsomides sp), 14 to family level (Entomobryidae) and one to order level (Symphypleona). Both Symphypleona and Entomobryidae were previously unreported from the Namib Desert. The Folsomides genus and the family Entomobryidae were the most abundant groups. This research suggests that soil dwelling Collembola in the Namib Desert have a much higher level of diversity than previously known. However, the study also highlighted the need for a more comprehensive database for Namib Collembola that includes COI sequence data as well as the morphological identification of species.
Dissertation (MSc)--University of Pretoria, 2018.
National Research Foundation (NRF)
Genetics
MSc
Unrestricted

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
As long as the agricultural expansion progresses over the Pampa biome, the simplification and contamination of environments have become the main causing agents of loses of diversity of several soil organisms, among them the springtails. The Collembola class is one of the most plentiful groups present in the soil fauna; being responsible for the fragmentation of plant detritus, fungi dispersion, decomposition, nutrient mineralization and others; developing this way an elementary function at the dynamic of ecosystem operation. Springtails have a cosmopolitan distribution and can be found in almost all ecosystems, from the flooded areas until the higher elevations. Besides performing fundamental role at the ecosystem operation and be present in all zoogeographic regions, studies about Collembola class are overlooked and incipient at many areas, which is the case of Rio Grande do Sul. To that end, this study had as objective to schedule the distribution of springtails in different soil uses at the Central Depression Area of Rio Grande do Sul, allying taxonomic study to ecological parameters, aiming to contribute for the knowledge about dynamics of Collembola population in different soil uses at this region. Collects were performed with the aid of PROVID traps between November of 2013 and June of 2014, covering the annual seasonality. At all, were identified nineteen species and eighteen genders belonging to seven different families. The results showed indications of seasonality on the springtails distribution, and a preference for protected forest area, with eleven species belonging to six families collected. The area with less richness of species was the impacted one, with seven species belonging to four families, and the tillage with eight species belonging to four families collected. These data suggest to the loses of diversity caused, mainly, by ecosystem fragmentation and indiscriminate use of agrochemicals.
A medida que a expansão agrícola avança sobre os ecótopos do Bioma Pampa, a simplificação e a contaminação de ambientes tem se tornado os principais agentes causadores da perda de diversidade de vários organismos do solo entre eles os colêmbolos. A Classe Collembola é um dos grupos mais abundantes na fauna do solo, sendo responsável pela fragmentação de detritos vegetais, dispersão de fungos, decomposição, mineralização de nutrientes, entre outros, desempenhando assim papel fundamental na dinâmica do funcionamento dos ecossistemas. Os colêmbolos possuem distribuição cosmopolita e estão presentes em quase todos os ecossistemas, desde áreas alagadas até altitudes mais altas. Apesar de desempenhar papel fundamental no funcionamento dos ecossistemas e estarem presentes em todas as regiões zoogeográficas, estudos da Classe Collembola, são negligenciados e incipientes em várias regiões, como é o caso do Rio Grande do Sul. Neste intuito, o presente estudo teve como objetivo inventariar a distribuição dos colêmbolos em diferentes usos de solos na Depressão Central do Rio Grande do Sul, aliando o estudo taxonômico à parâmetros ecológicos, com fins de contribuir para o conhecimento da dinâmica populacional da Classe Collembola em diferentes usos de solo nesta região. Foram realizadas coletas com auxílio de armadilhas do tipo PROVID no período de novembro de 2013 à junho de 2014, de modo a cobrir a sazonalidade anual. Ao todo foram identificadas dezenove espécies, dezoito gêneros, pertencentes a sete famílias. Os resultados demostraram indícios de sazonalidade na distribuição dos colêmbolos e uma preferência pela área de floresta conservada, com onze espécies pertencentes a seis famílias, coletadas. Sendo que as áreas com menores riquezas de espécies foram a floresta impactada, com sete espécies pertencentes a quatro famílias e a lavoura com oito espécies, pertencentes a quatro famílias, coletadas. Esses dados sugerem para as perdas de diversidade causadas principalmente pela fragmentação de ecossistemas e pelo uso indiscriminado de agrotóxicos.

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Capes
The springtails (Collembola) are edaphic organisms with enormous morphological diversity and are affected by physical, chemical and biological soil properties. The aim of this study was to evaluate if the land-use influences the morphological diversity of springtails and to relate with the occurrence of these physical, chemical and microbiological soil attributes. Samples were collected in the eastern region of Santa Catarina, Brazil, involving three municipalities: Joinville, Blumenau and Timbó in the land-use systems (LUS) of native forest (NF), Eucalyptus plantation (EP), pasture (PA), integrated crop-livestock (ICL) and no-tillage crops (NT). The soil samples for determination of the edaphic attributes and the installation of Pitfall traps were carried in winter and summer, in the same points, from a sample grid of 3×3 points. The springtails captured were counted and morphotyped, observing characteristics such as: presence or absence of ocelli and fur, pigmentation, antenna length and furcula. For each one of these characteristics a score was assigned and by summing these values the morphotype and its adaptation to the soil were defined. The data were analyzed using abundance, Shannon-Wiener diversity index (H'), Pielou uniformity index (J), morphotypes richness and Margalef index, and modified Soil Biological Quality Index (QBS). Abundance was submitted to principal component analysis (PCA) to verify the relationship between morphotypes and LUS, using edaphic attributes as explicative environmental variables. The richness of springtails morphotypes was higher in NF and ICL, while the abundance was higher in ICL and PA in winter. The H' e Margalef indexes were higher in winter in the LUS where the intensity of use is lower (NF). In the summer, only H' differed significantly between LUS and was higher in NF. In all systems, the QBS index was higher in the summer season, with the exception of PA. The PCA showed a distinction between the seasons and the LUS, in which the occurrence of morphotypes was more related to microbiological attributes in the winter: microbial biomass carbon, microbial respiration and metabolic quotient; and chemical: potential acidity, organic matter and magnesium/potassium ratio. While in the summer, the morphotypes were explained by physical attributes: total porosity, biopores, soil moisture and macroporosity; and soil chemistry: organic matter and carbon/nitrogen ratio. The morphological diversity of springtails was influenced by conditions found in each LUS, showing sensitivity to changes in land-use, and thus can be considered a good tool for evaluation the biological quality of soil
Os colêmbolos (Collembola) são organismos edáficos com enorme diversidade morfológica e são influenciados pelas propriedades físicas, químicas e biológicas do solo. O objetivo deste estudo foi avaliar se o uso do solo influencia na diversidade morfológica de colêmbolos e relacionar a ocorrência destes com atributos físicos, químicos e microbiológicos do solo. Foram coletadas amostras na região do Leste Catarinense, envolvendo três municípios: Joinville, Blumenau e Timbó nos sistemas de usos do solo (SUS) de floresta nativa (FN), reflorestamento de eucalipto (RE), pastagem perene (PA), integração lavoura-pecuária (ILP) e plantio direto (PD). As coletas de solo para determinação dos atributos edáficos e a instalação de armadilhas de solo (Pitfall traps) foram realizadas no inverno e verão, nos mesmos pontos, em grade amostral de 3×3 pontos. Os colêmbolos capturados foram contados e morfotipados, observando características como: presença ou ausência de ocelos e pelos, pigmentação, comprimento de antenas e tamanho de fúrcula. Para cada uma destas características se atribuiu uma pontuação e por meio da soma desses valores definiu-se o morfotipo e a sua adaptação ao solo. Os dados foram analisados por meio da abundância, diversidade de Shannon-Wiener (H’), uniformidade de Pielou (J), riqueza de morfotipos e de Margalef, e Índice de Qualidade Biológica do Solo (QBS) modificado. A abundância foi submetida à análise de componentes principais (ACP) para verificar a relação entre os morfotipos e os SUS, usando os atributos edáficos como variáveis ambientais explicativas. A riqueza de morfotipos de colêmbolos foi mais elevada em FN e ILP, enquanto a abundância de colêmbolos foi maior em ILP e PA, no inverno. Os índices H’ e Margalef foram maiores no inverno no SUS em que a intensidade de uso é menor (FN). No verão, somente H’ diferiu significativamente entre os SUS e foi maior em FN. Em todos os SUS estudados o índice QBS foi mais elevado na época do verão, com exceção da PA. A ACP mostrou distinção entre as épocas e os SUS. No inverno a ocorrência de morfotipos esteve mais relacionada aos atributos microbiológicos: carbono da biomassa microbiana, respiração microbiana e quociente metabólico; e químicos: acidez potencial, matéria orgânica e relação magnésio/potássio. Enquanto no verão, a ocorrência dos morfotipos foi mais explicada pelos atributos físicos: porosidade total, bioporos, umidade e macroporosidade; e químicos do solo: matéria orgânica e relação carbono/nitrogênio. A diversidade morfológica de colêmbolos foi influenciada pelas condições encontradas em cada SUS, mostrando sensibilidade às alterações no uso do solo, e desta forma, pode ser considerada uma boa ferramenta para avaliação da qualidade biológica do solo

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in Jo?o C?mara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory
Collembola constitui um dos grupos mais abundantes e diversos de artr?podes terrestres, estando na base da cadeia alimentar e atuando no processo de decomposi??o. Possuem ampla distribui??o no mundo e podem ser encontrados em praticamente todos os habitats. O conhecimento desta distinta fauna ainda ? deficiente em territ?rio brasileiro, especialmente no semi?rido. O objetivo desse estudo foi investigar quais as vari?veis clim?ticas podem atuar como preditoras da riqueza de esp?cies, abund?ncia de indiv?duos e da estrutura composicional da taxocenose de Collembola ao longo de 12 meses em uma ?rea semi?rido dominada por vegeta??o de Caatinga, Nordeste brasileiro; e descrever novas esp?cies encontradas do g?nero Seira, t?xon mais diverso de Collembola no Brasil. As coletas foram realizadas em Jo?o C?mara, Rio Grande do Norte. Dez parcelas de 20 x 20 metros foram estabelecidas e os esp?cimes foram coletados com esfor?o de coleta de uma hora por pessoa utilizando um aspirador entomol?gico. A identifica??o e descri??o das esp?cies foram realizadas atrav?s do estudo da morfologia e quetotaxia dos exemplares. Foi realizada uma an?lise de regress?o m?ltipla entre a riqueza de esp?cies e a abund?ncia de indiv?duos com as vari?veis clim?ticas. Foi coletado um total de 1231 indiv?duos, distribu?dos em 15 esp?cies, 12 g?neros e nove fam?lias. As maiores riqueza e abund?ncia de Collembola foram encontradas durante a esta??o chuvosa. O g?nero Seira foi o mais abundante. A precipita??o explicou varia??o temporal da riqueza de esp?cies e abund?ncia de Collembola no semi?rido, o que condiz com a biologia desses animais. As popula??es de Collembola apresentaram distribui??o agrupada. Tr?s esp?cies novas de Seira foram descritas e ilustradas e todas apresentam semelhan?as com esp?cies j? registradas em territ?rio nacional

The effect of the addition of detrital subsidy on the winter wheat ecosystem was evaluated. Already during the first growing season after the addition, detrital subsidy led to an increase in yield by 17% and twofold population growth of soil saprophagous macrofauna. A significant correlation (r = 0.39) between abundance of Collembola species P. notabilis and Fusarium species in soil was revealed.