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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Glycoside Hydrolase Gene Families Of Termite Hindgut Protists

January 2019 (has links)
abstract: This project was completed to understand the evolution of the ability to digest wood in termite symbiotic protists. Lower termites harbor bacterial and protist symbionts which are essential to the termite ability to use wood as a nutritional source, producing glycoside hydrolases to break down the polysaccharides found in lignocellulose. Yet, only a few molecular studies have been done to confirm the protist species responsible for particular enzymes. By mining publicly available and newly generated genomic and transcriptomic data, including three transcriptomes from isolated protist cells, I identify over 200 new glycoside hydrolase sequences and compute the phylogenies of eight glycoside hydrolase families (GHFs) reported to be expressed by termite hindgut protists. Of those families examined, the results are broadly consistent with Todaka et al. 2010, though none of the GHFs found were expressed in both termite-associated protist and non-termite-associated protist transcriptome data. This suggests that, rather than being inherited from their free-living protist ancestors, GHF genes were acquired by termite protists while within the termite gut, potentially via lateral gene transfer (LGT). For example one family, GHF10, implies a single acquisition of a bacterial xylanase into termite protists. The phylogenies from GHF5 and GHF11 each imply two distinct acquisitions in termite protist ancestors, each from bacteria. In eukaryote-dominated GHFs, GHF7 and GHF45, there are three apparent acquisitions by termite protists. Meanwhile, it appears prior reports of GHF62 in the termite gut may have been misidentified GHF43 sequences. GHF43 was the only GHF found to contain sequences from the protists not found in the termite gut. These findings generally all support the possibility termite-associated protists adapted to a lignocellulosic diet after colonization of the termite hindgut. Nonetheless, the poor resolution of GHF phylogeny and limited termite and protist sampling constrain interpretation. / Dissertation/Thesis / Masters Thesis Biological Design 2019
22

Termitofauna (Blattodea: Termitidae) associada a esp?cies arb?reas em ?rea de reserva da Ilha do Catal?o da UFRJ, RJ / Termitofauna (Blattodea:Termitidae) Associated Tree Species in Reserve Area of the UFRJ Catalan Island, RJ

Santos, Aline Barreto 15 December 2015 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-03-13T13:52:35Z No. of bitstreams: 1 2015 - Aline Barreto Santos.pdf: 883584 bytes, checksum: 8c172d2d89cd730277fc41a3b05b4e69 (MD5) / Made available in DSpace on 2017-03-13T13:52:35Z (GMT). No. of bitstreams: 1 2015 - Aline Barreto Santos.pdf: 883584 bytes, checksum: 8c172d2d89cd730277fc41a3b05b4e69 (MD5) Previous issue date: 2015-12-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The arboreal termites that are part of the Brazilian fauna attack urban areas that have expanded into areas of wild vegetation. The urban trees when not follow the proper principles of planting and management, transforms the trees into nesting sites and feeding termites. Thus, arboreal species of termites begin to assume increasing importance as pests. This study aimed to identify the species of termites associated with tree species and verify, under field conditions, if these termites exhibit preference for nesting and foraging, in the sandbank area of Catalan Island, in the municipality of Rio de Janeiro, RJ. For this, 95 were chosen randomly planting rows of trees located in this area. These lines has traveled a path of 100 m, also randomly chosen, and during that route all the trees were inspected to verify the occurrence of termites. Termites found were collected, preserved in 70% alcohol for later identification. To assess the preferred nesting, all the trees were inspected for the presence nests of N. corniger. The occurrence of termites was registered in all tree rows sampled (n = 95). Of the total of 545 inspected trees, 77% were infested by termites, identified four species distributed into two families: three native species Termitidae (Nasutitermes corniger Motschulsky, Nasutitermes jaraguae Holmgren and Microcerotermes strunckii Soerensen) and an exotic species of Rhinotermitidae (Coptotermes gestroi Wasmann). The most frequent species was N. corniger (?2 = 82.04, df = 3, p <0.001), occurring in 79% of infested trees, followed by N. jaraguae (6% of infested trees). The termite species least infested trees were found in C. gestroi (1%) and M. strunckii (1%). In general , the exotic tree species Albizia Lebeck is the most infested by termites and also exotic Leucaena leucocephala is less infested. 114 Nest establishment of N. corniger were identified, and the tree species Schinus terebinthifolius the most nidificada. So the trees of the Catalan's Island salt marsh area are infested with native and exotic termites, however, the native termite N. corniger is predominant. / Os t?rmitas arbor?colas que fazem parte da fauna brasileira atacam ?reas urbanas que expandiram sobre ?reas de vegeta??o silvestre. A arboriza??o urbana quando n?o segue os preceitos adequados de plantio e manejo, transforma as ?rvores em locais de nidifica??o e alimenta??o dos cupins. Dessa forma, esp?cies arbor?colas de cupins passam a assumir import?ncia crescente como pragas. Esse estudo objetivou identificar as esp?cies de cupins associadas a esp?cies arb?reas e verificar, em condi??es de campo, se esses t?rmitas exibem prefer?ncia para nidifica??o e forrageamento, na ?rea de restinga da Ilha do Catal?o, no munic?pio do Rio de Janeiro, RJ. Para isso, foram sorteadas aleatoriamente 95 linhas de plantio de ?rvores localizadas nessa ?rea. Nestas linhas foi percorrido um trajeto de 100 m, tamb?m escolhido aleatoriamente, e durante esse percurso todas as ?rvores foram inspecionadas para verificar a ocorr?ncia de cupins. Os cupins encontrados foram coletados, preservados em ?lcool 70% para posterior identifica??o. Para avaliar a prefer?ncia de nidifica??o, todas as ?rvores foram inspecionadas quanto a presen?a de ninhos de N. corniger. A ocorr?ncia de t?rmitas foi registrada em todas as linhas de plantio amostradas (n=95). Do total de 545 ?rvores inspecionadas, 77% estavam infestadas por cupins, sendo identificadas quatro esp?cies distribu?das em duas fam?lias: tr?s esp?cies nativas de Termitidae (Nasutitermes corniger Motschulsky, Nasutitermes jaraguae Holmgren e Microcerotermes strunckii Soerensen) e uma esp?cie ex?tica de Rhinotermitidae (Coptotermes gestroi Wasmann). A esp?cie mais frequente foi N. corniger (?2 =82,04; g.l.=3; p<0,001), ocorrendo em 79% das ?rvores infestadas, seguida por N. jaraguae (6% das ?rvores infestadas). As esp?cies de t?rmitas menos encontradas nas ?rvores infestadas foram C. gestroi (1%) e M. strunckii (1%). De maneira geral, a esp?cie arb?rea ex?tica Albizia lebeck ? a mais infestada pelos t?rmitas e a tamb?m ex?tica Leucaena leucocephala ? a menos infestada. Foram identificadas 114 nidifica??es de N. corniger, sendo a esp?cie arb?rea Schimus terebinthifolius a mais nidificada. Portanto, as ?rvores da ?rea de restinga da Ilha do Catal?o s?o infestadas por t?rmitas nativos e ex?ticos, no entanto, o t?rmita nativo N. corniger ? predominante
23

Unravelling the termite digestion process complexity - a multi-omics approach applied to termites with different feeding regimes

Marynowska, Martyna 24 April 2020 (has links) (PDF)
With its unique consortium of microorganisms from all domains of life, termite gut is considered one of the most efficient lignocellulose degrading systems in nature. Recently, host diet and taxonomy as well as gut microenvironmental conditions have emerged as main factors shaping microbial communities in termite guts. The aim of this thesis was to investigate this highly efficient lignocellulolytic system at holobiont level, with a particular focus on gut microbiome function and composition in relation to the host diet. As a starting point, we optimised a complete framework for an accurate termite gut prokaryote-oriented metatranscriptomics, which was at the basis of all subsequent sequencing assay designs and analyses performed in the course of the work. Afterwards, we characterised the compositions and functions of biomass-degrading bacterial communities in guts of plant fibre- and soil-feeding higher termites, proving the existence of functional equivalence across microbial populations from different termite hosts. We also showed that each termite is a reservoir of unique microorganisms and their accompanying genes. We further extended above approach to metagenomics and bacterial genomes reconstruction and we applied it to explore the process of biomass digestion in the different sections of the highly compartmented gut of soil feeding Labiotermes labralis. We showed that primarily cellulolytic activity of the termite host was restricted to foregut and midgut, while bacterial contribution was most pronounced in P1 and P3 hindgut compartments and included activities targeting broad range of lignocellulose components. Finally, we investigated the adaptation of a laboratory-maintained grass-feeding higher termite colony of Cortaritermes spp. to Miscanthus diet at host and symbiont levels. A natural system of a termite gut was shown to progressively change in composition to yield a consortium of microbes specialised in degradation of a specific biomass. Overall, the integrative omics approach proposed here provide a framework for a better understanding of a complex lignocellulose degradation by a higher termite gut system and pave a road towards its future bioprospecting. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
24

Environmental Natural Processes that Achieve Thermal Comfort in Multifamily Buildings in Hot Arid Regions

Moreno, Paola January 2015 (has links)
Buildings, especially in hot climates, consume a lot of energy when people want to be comfortable inside them, which translates to very expensive fees each month. The most innovative response to this problem is renewable energy, that is used, in this case, to run mechanical HVAC systems. Renewable energy is the solution for many problems, but to avoid urban heat islands when using excessive HVAC systems (powered by renewables), and to solve thermal comfort-related problems, there has to be other solution. The major challenge to find it would be to have a change of thinking process. If a building in a hot-arid region uses natural processes to emulate the functions of HVAC systems, and the proper passive strategies, then, it will provide thermal comfort to its users, diminishing the need of a mechanical system. This hypothesis will be carried out by extracting the natural processes found in a specific case in nature, applying them into a building's design, and then simulating its energy efficiency with the adequate software. There will be a comparison of the same proposed building without the natural processes, to have tangible numbers showing that these proposed strategies, in fact, work. With explanatory detailed diagrams and the energy analysis, the hypothesis could be proven correct or incorrect. The significance of this approach relies on the proximity to the natural processes that have been working in different aspects of life since the beginning of time. They have been there all the time, waiting until architects, engineers, and people in general use them, instead of making more new energy-using inventions. By having the numbers from a conventional building and the ones of the proposed building, and the right environmental diagrams, the experiment should be valid. In the near future, there should be more research focused on nature and its processes, in order to be able to reduce the use of mechanical systems, and with that, reduce the energy use and the carbon footprint.
25

Riqueza de cupins (Insecta, Isoptera) em uma ?rea de caatinga e outra de cerrado senso restrito na Chapada Diamantina, Bahia, Brasil

Alves, Emerson Almeida 27 March 2013 (has links)
Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-07-29T22:20:23Z No. of bitstreams: 1 DISSERTA??O FINAL EMERSON ALVES_2.pdf: 2388512 bytes, checksum: d8b84c1bc9f5b98b73b7052c3b2d26b2 (MD5) / Made available in DSpace on 2015-07-29T22:20:23Z (GMT). No. of bitstreams: 1 DISSERTA??O FINAL EMERSON ALVES_2.pdf: 2388512 bytes, checksum: d8b84c1bc9f5b98b73b7052c3b2d26b2 (MD5) Previous issue date: 2013-03-27 / The current study had as a goal the analysis of termites species in Chapada Diamantina, at two different areas: one through Caatinga and the other at,cerrado restricted sense, Palmiras city, state of Bahia, Brazil and as well as to compare the wealth coming from these organisms considering the physical factors of climate, edaphic and vegetation factors. This study was made at two different areas, the first one in Caatinga and the second place was at cerrado sensu stricto, in Palmeiras city, state of Bahia. there were 12 transects installed for each area studied ( six of them in dry season and the other six in rainy season) which was 65 meters lenght, 2 meters wide and so it owned 5 plots, measuring 5 meters lenght, 2 meters wide, one away from the other 10 meters. There were made soil gathering up to 30 cm depth with the help coming from an 10 cm diameter auger at different spots from each area of study and the analysis of this material was made at the Brazilian Agricultural Research corporation. So, 50 termites species were found belonging to 25 genres, split into three families. The occurance of collected species at Caatinga was slightly richer counting 44 of species, mentioning that 39 from these ones were observed happening at cerrado areas. The results obtained from the curves of accumulation of species through Jacknife estimator first order showed different results as for collection eficiency for both areas. The analysis of wealth variation from both ecosystems and so the analysis of sorting calculated from the Nonmetric Multidimensional Scaling (NMDS) shows a high similarity of species among different studied areas. The results that were here found evidenced from the two studied ecosystems the guild of humivoros as the most meaningful with twenty species showed, however the xylophagous were then the most usual among the samples. The presence of stratum arboreal in both areas may be the determining factor for the finding of these results, as well as for the greatest wealth of termite species at Caatinga, cause the presence of greenery may promote important resources offer for these insects survival. / O presente estudo teve como objetivo analisar a ocorr?ncia das esp?cies de cupins na Chapada Diamantina, em duas ?reas distintas uma de Caatinga e outra de cerrado senso restrito no munic?pio de Palmeiras, Bahia, Brasil e comparar a riqueza destes organismos levando-se em considera??o os fatores f?sicos do clima, ed?ficos e vegetacional. Este estudo foi realizado em duas ?reas distintas, a primeira de Caatinga e a segunda de cerrado sensu restrito, no Munic?pio de Palmeiras, Bahia.Para cada ?rea estudada foram instalados 12 transectos, (seis na esta??o seca e outros seis na esta??o chuvosa) que mediam 65m de comprimento por dois metros de largura (65x2m) e possu?am cinco parcelas, medindo 5m de comprimento por 2m de largura (5x2m), distantes dez metros umas das outras. Foram realizadas coletas de solos at? 30 cm de profundidade com o aux?lio de um trado de 10 cm (di?metro) em diversos pontos de cada ?rea trabalhada e a an?lise deste material foi realizada na Empresa Brasileira de Pesquisa Agropecu?ria (EMBRAPA). Foram encontradas, no total, 50 esp?cies de cupins pertencentes a 25 g?neros, distribu?das em tr?s fam?lias. A ?rea de ocorr?ncia de Caatinga foi ligeiramente mais rico com 43 esp?cies coletadas, enquanto que 39 destas foram observadas ocorrendo nas ?reas do Cerrado. Os resultados obtidos a partir das curvas de ac?mulo das esp?cies atrav?s do estimador Jacknife de 1? ordem mostraram resultados distintos quanto ? efici?ncia de coleta para ambas as ?reas. As an?lises de varia??o de riqueza de ambos os ecossistemas (ANOVA) e a an?lise de ordena??o calculado a partir do ?Nonmetric Multidimensional Scaling? (NMDS), apontam uma alta similaridade das esp?cies entre as distintas ?reas estudadas. Os resultados aqui encontrados evidenciaram que nos dois ecossistemas estudados a guilda dos hum?voros foi a mais representativa com vinte esp?cies amostradas, contudo os xil?fagos foram os mais frequentes entre as amostras. A presen?a do estrato arb?reo em ambas as ?reas pode ter sido o fator determinante para a constata??o destes resultados, bem como para a maior riqueza de esp?cies de cupins na Caatinga, pois a presen?a de vegetais pode promover a oferta de recursos importantes para a sobreviv?ncia destes insetos.
26

Ecological Associations of the Hooded Parrot (Psephotus dissimilis)

Cooney, Stuart John Norman, stuart.cooney@anu.edu.au January 2009 (has links)
Interactions between nesting birds and invertebrates are a common, yet poorly understood ecological phenomenon. Many of these types of interactions are close and prolonged, and therefore potentially critical to one or both of the species involved in the interaction. However it is unusual for the nature of the interaction to be evaluated in a manner that reveals the impact of the relationship on both parties to the interaction. This study examines two relationships between nesting birds and invertebrates, both of which involve the hooded parrot (Psephotus dissimilis), a small grass parrot that inhabits the tropical savannas of northern Australia. ¶ The field-work for this project was conducted over two parrot breeding seasons in 2006 and 2007 near Katherine, Northern Territory, in the Australian dry tropics. In chapter II, I present data on the breeding biology of the hooded parrot as background for the study that follows. Nest building commenced in January, with peak activity in February and the last chicks fledged in April. Fifty three active nests were located. The mean number of eggs laid per nest was 4.5 (s.d. ± 0.9), of which 3.0 (± 1.79) hatched and 2.0 (± 2.0) fledged. Clutches were laid asynchronously over a period of a week and chicks remained in eggs for 18.6 (± 1.95 days). Chicks were 29.2 (± 2.9) days old when they fledged from the nest. These data are typical for Australian parrots. ¶ In chapter III, the unusual nature of the parrot’s nest site is examined. Many species of bird nest in natural cavities or those they excavate. Whilst cavity nesters as a whole experience increased nesting success, the greatest success is experienced by species that can excavate their own nests. Certain arboreal cavity nesters, such as woodpeckers, require extensive morphological adaptation for this behaviour, but this has not occurred in Australia, despite competition among birds and a suite of arboreal mammals for naturally occurring cavities. Some species, however, have adapted their behaviour to make use of substrates that are not as hard as wood. Hooded parrots excavate nests in terrestrial termitaria, releasing them from competition for limited arboreal cavities. However, I show that only termitaria with a high level of termite activity, and which are more than two metres tall, are suitable, and that the parrots exhibit a strong preference for the cathedral mounds of Nasutitermes triodiae. Nests placed in highly active mounds had a significantly higher success rate than those in mounds where activity was somewhat lower, suggesting that the behaviour is adaptive. ¶ The thesis then shifts focus from the parrot to its nest symbiont, first describing the species involved in the interaction in chapter IV, and then its behaviour in the nests of hooded parrots in chapter V. Trisyntopa neossophila sp. n. (Lepidoptera: Oecophoridae) was reared from the nest of the hooded parrot and described using morphological characters. Aspects of its biology are reported and similarities to the biology of Trisyntopa scatophaga found in the nests of the golden-shouldered parrot (Psephotus chrysopterygius) are discussed. The possibility that a moth was associated with the extinct paradise parrot (Psephotus pulcherrimus) is considered in the light of the phylogenetic relationships between the parrots. ¶ Trisyntopa neossophila is an unusual moth whose breeding cycle is shown to be closely synchronised with the hooded parrot. T. neossophila is one of three coprophagous, nest dwelling moths in the genus Trisyntopa. True coprophagy is rare in the Lepidoptera, although some species occasionally consume faeces to gain rare nutrients. T. neossophila lays its eggs in the nest of hooded parrots so that larvae hatch in synchrony with the hatching of the parrot’s eggs. The larvae spend their larval period in the nest and exclusively consume the excrement of the nestling parrots. When the parrot chicks fledge, the larvae move to the walls of the nest cavity to pupate, emerging the following wet season to repeat the process during the next parrot breeding season. ¶ With a description of the ecology of both species involved in the nesting symbiosis, chapter VI reviews the literature surrounding other interactions between nesting birds and invertebrates. A large number of birds are shown to nest in, or in close proximity to, structures made by invertebrates and avian nesting material provides a reliable shelter for many invertebrate species. However, the nature of such relationships has rarely been experimentally demonstrated. I propose that in order to understand the nature of these relationships they need to be explored within the theoretical framework of community ecology. Putative commensal and parasitic relationships have all been documented in the bird/invertebrate nesting literature, yet researchers, with few exceptions, repeatedly overlook the impact that these relationships are having on the invertebrate, at best assuming the nature of its impact, but more often ignoring its impact entirely. Here I present a framework for formulating hypotheses to ensure that the nature of the relationship can be identified. Only by explicitly stating the level of organisation at which the experiment is to occur (individual or population), identifying the net cost or benefit of the interaction, the range of conditions under which such costs or benefits would apply and the spatial and temporal context in which they apply, can an investigator expect to recognise and describe the often complex nature of these relationships. ¶ While parasitic and commensal relationships between nesting birds and invertebrates are commonly reported, mutualisms between birds and invertebrates have not been reported. Despite this, candidates for this type of relationship exist. Chapter VII uses the framework outlined in the literature review (chapter VI) to experimentally examine the relationship between the hooded parrot and Trisyntopa neossophila. By manipulating the populations of moth larvae in a sample of hooded parrot nests, we sought to establish the impact of the relationship on each species. The moth depends on the parrot for provision of shelter and a reliable food source. The parrot however, was neither benefited nor harmed by the interaction in terms of short term reproductive output or chick growth, although differences between the experimental and control nests were noted. The relationship between the hooded parrot and T. neossophila, at least during the study period, is therefore concluded to be commensal. ¶ Collectively, the chapters of this thesis explore the complicated interactions between species. The dependence of the moth on the parrot and the parrot on the termite, demonstrate the importance of understanding interactions between species in a manner that reveals the impacts of the interactions, the range of conditions under which they would apply and the level of organisation at which they apply, as outlined in chapter VI. The dependence of the animals in this study on each other makes them more vulnerable to extinction than previously thought. Whilst this may not be immediately significant for the hooded parrot/T. neossophila system, which is thought to be secure, the ecologically similar system on the Cape York Peninsula, involving the golden-shouldered parrot and its nest attendant moth Trysintopa scatophaga, is vulnerable to extinction and subject to intensive management to ensure its persistence. This study brings new information to the management of the golden-shouldered parrots and urgently recommends increased protection for Trysintopa scatophaga.
27

Nature et propriétés de l'horizon diagnostic de Latosols du Plateau Central brésilien

Reatto-Braga, Adriana 26 March 2009 (has links) (PDF)
Les Latosols correspondent à environ 40% du Plateau Central brésilien. Ils sont caractérisés par une faible activité de l'argile, une faible différenciation de leurs horizons, une macrostructure peu développée et une microstructure en revanche très développée représentée par des microagrégats de 50 à 300 µm de diamètre. Dix Latosols (L) ont été sélectionnés le long d'une toposéquence régionale d'environ 350 km de long qui recoupe la Surface Sud Américaine (SAS) (L1 à L4) et la Surface Velhas (VS) (L5 à L10). Ces différents Latosols rendent compte de la variabilité de composition granulométrique et minéralogique, et de celle de matériau parental que l'on peut rencontrer dans le Plateau Central brésilien. Nos résultats montrent que la variabilité de proportion de gibbsite et de kaolinite peut s'expliquer à la fois par l'âge de la surface géomorphologique et les conditions hydriques en fonction de la position topographique au sein de chaque toposéquence. Les résultats montrent également que la structure microagrégée ne varie pas en fonction de la composition granulométrique ou minéralogique. Elle est apparue en revanche liée à la bioturbation du sol par les termites. Il a aussi été montré que les microagrégats des Latosols étudiés ne sont pas rigides mais diminuent de volume lors de la dessiccation. De plus, la composition minéralogique de la fraction argileuse ne jouerait qu'un rôle marginal dans les variations du volume poral lors de la dessiccation. Les microagrégats des Latosols situés sur la SAS diminuent moins de volume lors de la dessiccation que les microagrégats situés sur la VS, cette différence serait liée à leur histoire hydrique. Enfin, les propriétés de rétention en eau et la conductivité hydraulique à saturation varient respectivement en fonction de la teneur en argile et du développement des pores de diamètre supérieur à 300 µm, et par conséquent sans lien étroit avec la minéralogie de la fraction argileuse.
28

Ecological Impact of Epigeal Termitaria on Vertebrates in the Tsavo Region of Southeast Kenya

Mahan, Margaret M. 01 August 2009 (has links)
Termites ecologically engineer their environment by producing termitaria (mounds) used by many other species as dens, lookouts or food sources. The role of termite mounds in biological communities is relatively unknown, despite their ubiquitous nature. I investigated their impact on vertebrates in the Tsavo region of Kenya. Through the characterization of mounds, trapping, direct observation, and collecting microclimate data, I was able to determine the importance of mounds to vertebrates. I found uniform dispersion of mounds, that soil type is correlated with the size of mounds, and that vertebrate activity increases with mound size. I also found no significant differences in overall numbers of animals and species between mound and non-mound areas. Reptiles were found at mound sites significantly more than at non-mound sites, especially the great plated lizard and short-necked skink. I determined that mounds’ microclimate is less variable than that of the ambient. More work is needed to further our understanding of termite mounds' impacts on vertebrates. This study led to discoveries of species not known to be in the area by myself or my affiliated parties.
29

Field studies of exterior-only applications with fipronil (Termidor SC) for the post-construction control of interior populations of subterranean termites (Isoptera: Rhinotermitidae)

Waite, Troy David 17 February 2005 (has links)
Thirty-two privately owned structures were treated with a 0.06% exterior and interior, 0.06% exterior-only, or 0.125% exterior-only application of fipronil (Termidor SC®) in order to compare their efficacies in the post-construction control of interior populations of Reticulitermes spp. (Holmgren). The concentration of fipronil in the soils from the structures was measured pre-treatment and at 1 week, 3, 6, 9, 12, and 18 months post-treatment. Bioassays conducted with fipronil-treated soils from five locations in Texas determined the minimum effective concentration (minimum concentration necessary to stop termites from breeching a 50 mm column of treated soil) was < 1.0 ppm. Lethal concentration (LC50) values ranged from 0.19 to 0.60 ppm for Reticulitermes flavipes (Kollar). All structures receiving a 0.06% fipronil exterior and interior or 0.125% exterior-only application showed full control of interior termite populations within 6 months. In contrast, 36% of the structures that received a 0.06% fipronil exterior-only application still had termites 6 months post-treatment. When taking the point of termite entry into account, it was shown that only structures treated with fipronil at the point of entry into the structure by termites showed full control within 6 months. This indicated that the placement of the termiticide at the point of subterranean termite entry, and not the rate at which it was applied, was the most important factor that predicted whether a post-construction application of fipronil provided full control of an interior infestation. Results also indicated that Termidor SC® was effective when used according to the current product label, which calls for a thorough application including exterior and interior applications for post-construction termite control. Soil monitoring data for fipronil indicated that the technical material provided by the manufacturer of Termidor SC® was labeled appropriately in terms of concentration. Tank mix samples, while variable, were between 83 - 96% of the labeled concentrations. Post-treatment soil samples and bioassays with treated soil showed that fipronil concentrations were adequate to effectively control termites through the first 18 months.
30

COMPUTATIONAL IDENTIFICATION AND MOLECULAR VERIFICATION OF MIRNA IN EASTERN SUBTERRANEAN TERMITES (RETICULITERMES FLAVIPES)

Yu, Tian 01 January 2014 (has links)
Reticulitermes flavipes is one of the most common termite species in the world, and has been an intriguing research model due to its ecological and biological and economic significance. The fundamental biological question addressed by this study is to elucidate the role of miRNAs in termite development and how miRNA can influence labor division. miRNAs are short non-coding RNAs that have an important role in gene regulation at post-transcriptional level, and can potentially be involved in the regulation of caste polyphenism. Using a computational approach, I identified 167 conserved and 33 novel miRNAs in the dataset. miR-iab-4 and 19 other miRNAs showed highly differential expression between worker and soldier, and their possible roles in termite biology are discussed. To reliably quantify miRNA expression in experiments, I tested the stability of 10 miRNAs as reference gene using quantitative real-time PCR. miR-8_3, bantam and miR-276a-3p are the most stable miRNAs in different castes, pre-soldier formation, and different tissues, respectively. Lastly, the predicted miRNA expression is verified by the qRT-PCR for 8 miRNAs. Overall, this study shows that miRNA plays a role in mediating the work-soldier transition in R. flavipes.

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