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1
Hardy, Adam. "New midge resistance for Australian grain sorghum." University of Southern Queensland, Faculty of Sciences, 2007. http://eprints.usq.edu.au/archive/00003566/.
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[Abstract]: The development and commercial release of midge resistant grain sorghum hybrids in Australia has been one of the real success stories of the sorghum industry. Almost all the current commercial sorghum hybrids grown contain a significant baseline of midge resistance that has greatly reduced that pest status of this insect. However while breeding efforts have been successful, it seems only one mechanism of resistance remains present in commercial hybrids. This mechanism of resistance known as ‘ovipositional-antixenosis’ is polygenic in nature and has contributed to the gradual reduction in the genetic base of commercial sorghum hybrids, potentially limiting the advancement of other agronomic traits.In order to expand both the level of resistance and the genetic diversity within Australian commercial sorghum hybrids, research was undertaken to capture new sources of midge resistance. Initially the goal of this work was to isolate and characterise the most promising new antibiosis sources of midge resistance previously documented within international breeding lines. However as the work progressed the discovery of a previously undescribed tolerance source of midge resistance led to more detailed studies of midge larval biology within a narrow range of sorghum germplasm lines to better characterise the resistance mechanism.To complete this work a new water-injection technique was developed to allow more precise studies of midge larval biology where previous traditional screening methods were deemed inadequate. Using this method several antibiotic lines were shown to contain diverse modes of action, while the tolerance mechanism of resistance was confirmed and more accurately characterised. In all cases plant characters within the developing spikelet were associated with each resistance mechanism.Overall, one source of resistance, found in lines derived from the Indian land race line DJ6514, was identified as superior to the others tested. Germplasm derived from this source was found to confer inter-related antibiosis and tolerance mechanisms. Both mechanisms were indirectly shown to be caused by the unique antibiotic properties of the developing caryopsis. Larval mortality (antibiosis) increased in this line, in line with increased feeding against the developing caryopsis. A second tolerance mode of action was also linked to anti-feeding properties of the developing caryopsis. Larvae were recorded at higher than normal rates feeding away from the caryopsis resulting in the survival of both larvae and grain in a significant proportion of spikelets. This escape ‘tolerance’ mechanism of resistance was confirmed indirectly in several studies and could be artificially induced in other genotypes when larval feeding against the caryopsis was delayed. As such the resistance is better described as antixenosis to caryopsis feeding.When both resistance mechanisms are present, the resistance isolated from DJ6514 was found to cause a three to four fold increase in seed set in resistant lines. This source of resistance has been directly selected for incorporation into the Australian breeding program and has been shown to be inherited simply as a single gene that needs to be deployed on both sides of the breeding program to ensure stable expression. When breeding efforts are complete a new suite of highly resistant and genetically diverse midge resistant sorghum hybrids will emerge into the marketplace.
2
Amarawardana, Lakmali. "The chemical diversity of midge pheromones." Thesis, University of Greenwich, 2009. http://gala.gre.ac.uk/5656/.
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The hypothesis that midge sex pheromones could be chemically more diverse in structure than previously thought was tested in the context of four midge species of importance to UK horticulture: pear leaf midge, Dasineura pyri; pear midge, Contarinia pyrivora; blackcurrant midge, D. tetensi; and blackberry midge, D. plicatrix. The major component of the pheromone of D. pyri was identified as (2R, 13R, 8Z)-2, 13-diacetoxy-8-heptadecene. Four isomers were separated by HPLC and in field tests the first eluting isomer only was attractive to male midges. Analysis of volatile collections from female C. pyrivora showed two consistent responses from male midges and they were identified as 2,7-diacetoxyundecane and 7-acetoxyundecane-2-one. The field testing with isomers of 2,7-diacetoxyundecane separated by HPLC revealed that the first and the third eluting isomers were attractive. The racemic 7-acetoxyundecane-2-one was active as well as the first eluting isomer from HPLC. Two EAG active components were detected in D. tetensi female volatile collections. The major component was identified as (Z)-2,12-diacetoxy-8-heptadecene and after separation of stereoisomers by HPLC the third eluting isomer has shown to be attractive to male D. tetensi in the field. The structure for the minor component was proposed as a keto-acetate homologue of the corresponding major component. Preliminary work carried out on identification of the female sex pheromone of D. plicatrix indicated two responses from conspecific males. These were shown to be 15-carbon acetates with the acetate function at C-2, probably with two and one double bonds respectively.
3
Mutaliano, Joaquim Americo. "Evaluation of the value of sorghum midge resistant hybrids in the USA." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3149.
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Sorghum (Sorghum bicolor [L.] Moench) production in many areas of the world
is reduced due to damage caused by sorghum midge (Stenodiplosis sorghicola). There
are several methods of control to reduce losses due to sorghum midge, which include
cultural practices, biological control, chemical control and resistant cultivars. The best
long-term solution for sorghum midge control is the use of genetic resistance in cultivars
and hybrids. Recently, sorghum midge resistant hybrids have been developed by several
sorghum breeding programs, but there is limited information about agronomic
performance relative to planting dates compared to susceptible standards. Thus, the
objectives of this research project are: (1) to evaluate the value of sorghum midge
resistant sorghum hybrids in the USA production system, (2) to confirm the presence of
sorghum midge insect resistance in sorghum hybrids, and (3) to determine whether the
resistance in eighteen sorghum hybrids is stable across two environments in Texas where
sorghum midge is a damaging pest. Sorghum hybrids with different levels of resistance
to sorghum midge were evaluated at College Station and Corpus Christi, Texas in 2003
and 2004, using two different planting dates and the presence or absence of an insecticide treatment. Agronomic data, sorghum midge incidence ratings and number of
adult midges, were determined for all entries. All entries designated as resistant did
have some resistance compared to susceptible checks. Across all hybrids, grain yield
was higher in sorghum with normal planting dates compared to late planting. Under
midge pressure resistant hybrids performed better than susceptible hybrids, but lacking
midge pressure the susceptible hybrids were higher performing. The use of midge
resistant hybrids in commercial production is only warranted when producers are
reasonably sure that midge will be a problem. Otherwise, they should continue to plant
early using traditional hybrids.
4
Crompton, Francis Benedict. "Aerobatics and body size in the midge Chironomus plumosus L." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289177.
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Franzmann, Bernard Anthony. "Resistance to sorghum midge and management of panicle pests in sorghum /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18293.pdf.
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6
Hooper, Helen Louise. "Pesticide effects on resource-limited populations of the midge Chironomus riparius." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271583.
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7
Roubos, Craig Richard. "Monitoring and managing blueberry gall midge (Diptera: Cecidomyiidae) in rabbiteye blueberries." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024872.
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8
Du, Chen. "Global analysis of microrna species in the gall midge Mayetiola destructor." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20375.
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Master of ScienceEntomology
Ming-Shun Chen
Robert "Jeff" J. Whitworth
MicroRNA (miRNA) plays a role in nearly all the biological pathways and therefore may provide opportunities to develop new means to combat the Hessian fly, Mayetiola destructor, a destructive pest of wheat. This study presents a comprehensive analysis of miRNA species via deep-sequencing samples from Hessian fly second instar larvae, pupae and adults. A total of 921 unique miRNA species were identified from approximately 30 million sequence reads. Among the 921 miRNA species, only 22 were conserved among Hessian fly and other insect species, and 242 miRNA species were unique to Hessian fly, the remaining 657 share certain sequence similarities with pre-miRNA genes identified from various insect species. The abundance of the 921 miRNA species based on sequence reads varies greatly among the three analyzed stages, with 20 exclusively expressed in adults, two exclusively expressed in pupae and two exclusively expressed in second instar larvae. For miRNA species expressed in all stages, 722 were with reads lower than 10. The abundance of the remaining 199 miRNA species varied from zero to more than eight-fold differences among different stages. Putative miRNA-encoding genes were analyzed for each miRNA species. A single putative gene was identified for 594 miRNA species. Two putative genes were identified for 138 miRNA species. Three or more putative genes were identified for 86 miRNA species. The three largest families had 14, 23 and 34 putative coding genes, respectively. No gene was identified for the remaining 103 miRNA species. In addition, 1516 putative target genes were identified for 490 miRNA species based on known criteria for miRNA targets. The putative target genes are involved in a wide range of processes from nutrient metabolism to encoding effector proteins. Analysis of the expression patterns of miRNA and pre-miRNA for the miRNA family PC-5p-67443, which contains 91 genes, revealed that miRNA and pre-miRNA were expressed differently in different developmental stages, suggesting that different isogenes are regulated by different mechanisms, or pre-miRNAs had other functions in addition to as an intermediate for miRNA biogenesis. The large set of miRNA species identified here provides a foundation for future research on miRNA functions in Hessian fly and for comparative studies in other species. The differential expression patterns between a pre-miRNA and its encoded mature miRNA in a multigene family is an initial step toward understanding the functional significance of isogenes in dramatically expanded miRNA families.
9
Murchie, Archie Kelso. "Parasitoids of cabbage seed weevil and brassica pod midge in oilseed rape." Thesis, Keele University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318159.
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Oilseed rape (Brassica napus (L. )), the second most important arable crop in the UK after cereals, is attacked during the summer by cabbage seed weevil Ceutorhynchus assimilis (Paykull) and brassica pod midge Dasineura =brassicae (Winnertz). In mainland Europe, these two 'pests are known to be attacked by a range of hymenopteran parasitoids but virtually nothing is known about their parasitoids in the UK. This study found that the ectoparasitic Trichomalus perfectus (Walker) (Pteromalidae) was the most abundant species attacking C. assimilis, achieving, in unsprayed crops, levels of parasitism up to 73%. The egg-larval Platygaster subuliformis Kieffer (Platygastridae) was reared from D. brassicae for the first time and is probably a new species record for the UK; it was the most abundant species attacking the midge in winter rape. The endoparasitic Omphale clypealis (Thomson) (Eulophidae) was the most abundant species attacking D. brassicae in spring rape. The complexity of assessing parasitism in the multivoltine D. brassicae is discussed. In-field temporal and spatial distributions of hosts and parasitoids were studied using a novel randomization test and the results related to known biological characteristics of species. Using a new design of insect flight trap, P. subuliformis was shown to respond to 2-phenylethyl isothiocyanate and O. clypealis to 2-propenyl isothiocyanate, both volatile secondary plant compounds, produced by brassicaceous plants on damage. Field trials demonstrated that the post-flowering application of the organophosphate insecticide triazophos, has a detrimental effect on T. perfectus, killing adults and larvae, whereas the synthetic pyrethroid alphacypermethrin was less harmful because it was applied before the main migration of T. perfectus into the crop. The importance of the parasitoids ' of rape pests to integrated protection strategies for the crop are discussed.
10
Carpenter, Simon. "Colonisation and dispersal studies of the Scottish biting midge, Culicoides impunctatus Goetghebuer." Thesis, University of Aberdeen, 2001. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=237733.
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This study investigates aspects of the biology of C. impunctatus with a view to producing an optimised laboratory culture of this species. Artificial membrane feeding of C. impunctatus is shown to be enhanced by the addition of blood vestiges to the outer surface of the feeding apparatus. The effects of holding temperature, environment and conspecific density upon oogenesis in blood fed female midges are assessed through mortality, digestion of the blood meal and development of the eggbatch over time. Oviposition in C. impunctatus is investigated through choice and nochoice bioassays which show Sphagnum spp. Mosses to be highly effective in this regard. Juncus articulatuslacutiflorus infusions also significantly increase the number of eggs laid by females in comparison to oviposition substrates used in colonisation of other midge species. Preliminary studies are also carried out to provide a suitable larval medium for colonisation purposes. The possibility of future colonisation is discussed with reference both to those experiments carried out, and to those areas not yet addressed in the C. impunctatus lifecycle. Dispersal of C. impunctatus is also examined, both on a local scale and in terms of gene flow between UK populations. Capture, mark, recapture studies showed the marked population of C. impunctatus remained relatively close to the release site in the habitat used for the study. The effect of prevailing winds, however, was found to be highly important in terms of passive directional movements of individuals. Daily survival rates of parous females were calculated as very low in relation to other species of midge making this species an unlikely candidate for pathogen transfer in Scotland. Polymorphism in the molecular markers used to examine gene flow in C. impunctatus across the UK was minimal and precluded phylogenetic analysis. This result is interpreted in terms of both possible long-distance dispersal and the effects of rapid post-glacial popUlation expansion into the UK.
11
Williams, Ryan Williams. "Application of Spatial Analysis in the Incidence of the Gall Midge in Jamaican Hot Pepper Production." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34155.
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Jamaican farmers are experiencing constraints to hot pepper (Capsicum chinense) export production due to a quarantine pest -- the gall midge (Contarinia lycopersici; Prodiplosis longifila). There is a threat of gall midge introduction into the United States, where the insect pest is not known to occur. This research tests the significance of a range of variables to gall midge incidence. The purpose was to explain the spatial patterns that result from the relationships between gall midge incidence in hot pepper production and production methods and/or environmental conditions. There were three components to the sample of 47 farm visits: the interview, the hot pepper sampling, and the measurements of physical and locational attributes. Producers responded to questions about production methods, marketing, and quarantine issues. The percent of infested fruits per plot was calculated. GPS was used to record farm location. Using ArcView, environmental and climatic datasets were overlaid with farm locations and their attributes. Multiple regression was used to measure significance of variables to gall midge incidence. Cluster analyses were used to demonstrate the spatial patterns of the variability of gall midge incidence and its associated variables. There was significant effect on incidence by farm elevation, observance of pesticide-use recommendations, producer awareness of pre-clearance fumigation, and the use of intercropping in hot pepper production.Master of Science
12
Harrup, Lara Ellen. "The influence of fram-level factors on midge abundance and transmission of arboviruses." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531821.
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13
Hellqvist, Sven. "Dasineura tetensi and black currant : on a variable gall midge and its variable host /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5824-2.pdf.
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14
Nowak, Carsten. "Consequences of environmental pollution on genetic diversity in populations of the midge Chironomus riparius." Göttingen Cuvillier, 2008. http://d-nb.info/989862658/04.
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15
Howell, Jeffrey L. "Host location and host-associated divergence in parasitoids of the gall midge, Asteromyia carbonifera." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1464032496.
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Brion, Gemelle Laureen. "Swede Midge, Contarinia Nasturtii (diptera: Cecidomyiidae), Response To Brassica Oleracea In Simulated Intercropping Systems." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/351.
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Monoculture agriculture has developed as a result of the Western agricultural growth model, which emphasizes reduced on-farm labor and maximum yield. As a result soil health, which is reliant on a diversity of soil-dwelling organisms, is compromised, pest problems are intensified, and biodiversity is lost when vast land areas are devoted to simplified vegetation schemes. There has been a tremendous rise in interest in alternative cropping schemes. The traditional practice of intercropping has received renewed interest as the emphasis on agricultural growth shifts from a purely development-based model to one of conservation and enhanced biodiversity.
Although intercropping has shown promising results in controlling specialist herbivorous insects, how intercropping works is not known. Theories that explain the underlying mechanism of intercropping success include chemical repellency and physical masking. We tested these two theories by creating a simulated intercropping system in mesocosm cages in a laboratory environment. We tested twenty intercrops that varied in their vegetation type, size, and phylogenetic distance for their ability to repel an insect pest that recently invaded into North America, the swede midge (Contarinia nasturtii), from its host plant, Brassica oleracea. We found that different non-host plant treatments significantly influenced larval abundance, which indicates that C. nasturtii responded to some aspect of the varying plant combinations. We found that phylogenetic distance did not influence larval densities. Additionally, non-host plant height and leaf area of non-host plants did not influence larval densities. We found that vegetation type significantly affected larval densities. Brassica oleracea planted in combination with groundcover non-host plants had the fewest number of larvae, followed by B. oleracea planted in combination with vegetables. The highest number of larvae was found on B. oleracea plants planted in combination with herb non-host plants. Our research did not support a chemical repellency or visual masking theory of intercrop success.
17
Masumoto(Okamoto), Tomoko. "Chemical composition and ecological role of floral scent in moth- and midge- pollinated plants." Kyoto University, 2009. http://hdl.handle.net/2433/123923.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第14708号
人博第444号
新制||人||109(附属図書館)
20||人博||444(吉田南総合図書館)
UT51-2009-D420
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 加藤 眞, 教授 松井 正文, 准教授 市岡 孝朗, 准教授 酒井 章子
学位規則第4条第1項該当
18
Anderson, Troy D. "Toxicological, biochemical, and molecular effects of atrazine to the aquatic midge Chironomus tentans (Diptera: Chironomidae) /." Search for this dissertation online, 2006. http://wwwlib.umi.com/cr/ksu/main.
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Chitra, Eric, and n/a. "Bionomics of Culicoides molestus (Diptera: Ceratopogonidae): a pest biting midge in Gold Coast canal estates." Griffith University. School of Environmental and Applied Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20041119.101151.
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Culicoides molestus (Skuse) is the major species of biting midge that plagues human comfort in the estuarine Gold Coast region of southeast Queensland. Local authorities have initiated a search for an effective, non-chemical means of control, that would minimize human-midge interaction. The effectiveness of a program to control an organism, such as a biting midge, is dependent upon knowledge of the biology of the particular organism of interest. This project revolved examines the lifecycle of C. molestus in detail. It addresses questions regarding the location, seasonal distribution, and dispersal of its juvenile stages in the sand of infested beaches, and their response to chemical treatment, the monthly and annual cycles of the adult midge, and the possibilities of achieving laboratory oviposition, as a first step to laboratory colonisation. The distribution of eggs, larvae and pupae of C. molestus was found to be mostly concentrated around, but below, mean tide level. They also occurred well below the mean tide level. Eggs and larvae have been recovered from as deep as 10 cm in the sand. A seasonal study of the juveniles of this species indicated that they were more strongly influenced by tides than seasons. After a routine pest-control larviciding treatment, a beach recolonisation study revealed that beaches become suitable for oviposition approximately two months after treatment. Large larvae invaded the sprayed areas within days of treatment, which suggests the existence of a refuge outside of the reach of the insecticide. Larvae found in clean (egg- and larva-free), isolated sand containers, placed on the study beach, indicated that larvae could swim in or on the water as a way of moving around the beach. Extended bite-rate studies highlighted the existence of four peaks in adult midge biting activity during the course of a year, around the mid seasons. The strongest peaks of activity were found to be in autumn and spring, but the data suggest that the species undergoes four generations in a year. Through a series of trial-and-error experiments, oviposition under laboratory conditions was achieved. Although the time from blood-feeding to egg maturation is not yet well determined, it occurs within an eight day mean survival period. Blood quality appears critical for adult blood-fed midge survival. Midges fed on the blood of a volunteer who was frequently exposed to midge bites do not live long enough to mature its eggs. The partial ovarial development of one unfed adult female, reared in the laboratory, indicates that C. molestus is facultatively anautogenous.
20
Kavanaugh, Jeffrey L. "A genetic basis for life history differences among populations of the midge, Chironomus riparius (Diptera:Chironomidae)." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/35502.
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Laboratory and field experiments were conducted with six populations of Chironomus riparius to test for variation among the populations in life history parameters such as growth. mortality and/or reproductive rates. Egg masses of C. riparius from five field populations and one laboratory population were obtained and used to initiate laboratory cultures for experimentation. Environmental effects on life history variations could be ruled out because experiments were conducted with larvae that had been reared in the laboratory for several generations under identical conditions. Populations were compared under a variety of experimental conditions to test whether they would respond similarly, if genetically similar. or differently, if their genotypes were different.
The populations were subjected to a variety of experimental conditions in the laboratory in which temperature and food quality were manipulated. The population collected from Strouble''s Creek. Virginia demonstrated a pattern of high growth rate and low mortality rate. While the population collected from the final clarifier at the Madison, Wisconsin sewage treatment plant showed a pattern of low growth rate and high mortality rate. When several populations were transplanted into a high chlorine environment at the Blacksburg, Virginia sewage treatment plant, the population that had been previously exposed to the chlorine showed a significantly lower mortality rate than the other populations. A series of toxicity tests revealed different sensitivities among several populations to an experimental pesticide. Differences among populations were also found in numbers of egg masses produced, numbers of eggs per egg mass, length of time until the onset of adult emergence, and the overall length of the emergence period.
The results of this study show the importance of genetic differences among populations of C. riparius. Many commonly measured life history parameters that are usually assumed to vary primarily from differences in environment have been shown to vary as well from underlying genetic differences between populations. The role of genetics should be assessed, whenever possible. in studies where comparisons between populations of aquatic insects are made, in order to determine the degree to which genetics and environmental variables contribute to observed population differences.Ph. D.
21
Hodgdon, Elisabeth Ann. "Evaluation of candidate pheromone blends for mating disruption of the invasive swede midge (Contarinia nasturtii)." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1063.
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Swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae) is a small invasive fly that is currently threatening Brassica vegetable and oilseed production in the Northeastern U.S. and Canada. Larvae feed on plant meristems, resulting in deformed leaves, stems, and heads. Extremely low damage thresholds for heading Brassica vegetables, multiple overlapping generations, and lack of effective organic insecticide options present serious challenges for managing this pest. Pheromone mating disruption (PMD), which involves confusing male insects with unnaturally large doses of sex pheromones, is particularly promising for swede midge management because it prevents mating and subsequent oviposition. One major challenge to PMD for swede midge management is that the chiral female pheromone blend, a 1:2:0.02 blend of (2S, 9S)-diacetoxyundecane, (2S, 10S)-diacetoxyundecane and (S)-2-acetoxyundecane, is expensive to synthesize due to the structural complexity of the compounds. Here, we explored three ways to reduce the cost of swede midge PMD: the use of lower-cost racemic pheromones containing all possible stereoisomers, single-component blends, and the possibility of using timed pheromone dispensers by testing for diel patterns of midge reproductive behavior.
Although we found that males were not attracted to blends containing the racemic stereoisomers of the main pheromone component, (2S, 10S)-diacetoxyundecane, racemic blends functioned equally as well as chiral blends in confusing males and altering female behavior in PMD systems. We observed 95% and 87% reductions in males caught in monitoring traps in three-component chiral and racemic PMD plots of broccoli, respectively. In addition to confusing males, we also found that females altered their reproductive behavior in response to both chiral and racemic pheromones. Females released pheromones more frequently when exposed to three-component chiral and racemic blends, and were less likely to mate afterward. Single-pheromone treatments containing either chiral or racemic 2,10-diacetoxyundecane neither confused males nor influenced female behavior.
We identified a total of eight hours during the day and night when midges do not exhibit mate-seeking behavior, during which programmable PMD dispensers could be turned off to save pheromone inputs. We found that up to 81% of females released pheromones to attract males for mating in the early morning shortly after dawn. Most females emerged in the morning as well, releasing pheromones soon after eclosing. Because midges are receptive to mates shortly after emergence, they may mate at their emergence site.
Overall, we found relatively high levels of crop damage in our pheromone-treated plots, likely due to the migration of mated females into our plots. If midges mate at emergence sites, rotation of Brassica vegetable crops may result in overwintered midges emerging in fields where host plants are not currently grown. Further research is needed to determine where midges mate in order to determine where to install PMD dispensers.
22
Swansburg, Erin O. "Effects of trace metal enrichment in cobble streams and rivers on the aquatic midge (Diptera: Chironomidae)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0034/MQ62291.pdf.
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Crook, Damon. "Interactions of the blackcurrant leaf curling midge, Dasineura tetensi, with resistant and susceptible host plant cultivars." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263531.
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Oviposition behaviour Dasineura tetensi and its host plant Ribes nigrum was studied in both the laboratory and field. Monitoring of an unsprayed infested fieldsite using watertraps in S.E. Kent revealed that there were four generations occurring between the April - August 1996. 'Baldwin' (susceptible), 'Ben Alder' (susceptible) and 'Ben Connan' (resistant) Ribes cultivars were sampled for eggs in the field and assessed for midge shoot damage throughout the season. Oviposition was shown to be indiscriminate, however plant damage between cultivars varied significantly. In laboratory choice experiments using pairs of plants, mated female midges did not prefer susceptible shoots of 'Ben Alder' over resistant shoots of 'Ben Connan' for oviposition. In larval performance studies, larvae reared on resistant 'Ben Connan' shoots were significantly smaller than larvae reared on shoots of the susceptible variety of 'Ben Alder', suggesting that larval antibiosis to be the main mechanism for resistance to D. tetensi. Olfactory responses of D. tetensi to leaf volatiles of 'Baldwin' were also tested in a 4-way olfactometer. Newly emerged virgin males and females that were individually tested showed no attraction to the leaf volatiles emitted from a 'Baldwin' shoot. Mated females (2 hr post mating) however, responded positively in the olfactometer to leaf volatiles emitted from a 'Baldwin' shoot, showing that leaf volatiles play an important role in host plant finding. Scanning and Transmission electron microscopy of the antennae of D. tetensi show that males and females share five sensillum types. Sensilla chaetica have a structure typical of mechanoreceptors. They possess a single sensory neurone whose dendrite ends in a tubular body at the base of the hair.
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Dinwiddie, April. "The structure and function of a unique wing organ in an extinct biting midge, Eohelea (Diptera: Ceratopogonidae) /." Connect to online version, 2008. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2008/.pdf.
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Epp, Liam Jonathan. "Assessing the Effect of Bacillus Thuringiensis Var. Israelensis on Nontarget Chironomidae Emergence." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41118.
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Bacillus-derived larvicides, which selectively target mosquito (Diptera: Nematocera: Culicidae) populations to reduce nuisance and health risks, were applied in the South March Highlands Conservation Forest near residential neighbourhoods in Ottawa, Ontario. The objective was to assess effects of application on the nontarget mosquito relative, Chironomidae (Diptera: Nematocera: Chironomidae), and other nontarget aquatic taxa captured using emergence traps. A secondary objective was to assess physicochemical variables that influence Chironomidae emergence. Study ponds received an application of Bacillus thuringiensis var. israeliensis, a subset also received an application of Bacillus sphaericus, and a group of control ponds were left untreated over 3 years (2016-2018). Weekly sampling included trap collections and measurements of water temperature, pH, water depth, conductivity, dissolved oxygen, ammonia, nitrate, and sulphate. Drought in 2016, high precipitation throughout 2017, and seasonal precipitation in 2018 influenced variable physicochemical conditions. Principal component analyses identified differences between sampling groups and between years. Redundancy analyses correlated insect emergence with pond pH, average water depth and water temperature and indicated a strong relationship between Chironomidae emergence and average water depth.
Although significantly less Chironomidae annual emergence was observed at treated sites in 2017 and 2018, zero-inflated negative binomial generalized linear mixed modelling failed to detect a significant Bti treatment effect when controlling for within group variation. Rather, variations in pH, mean water depth and water temperature were identified as drivers of Chironomidae emergence. Culicidae emergence was reduced to zero briefly following treatment in 2017 and 2018. The model detected a marginal negative treatment effect on Culicidae in 2017 only, and a positive treatment effect in 2018 at the onset of a secondary hydroperiod, in the absence of treatment. Variations in pH and water temperature were also identified to be drivers of Culicidae emergence. Modelling failed to detect treatment effects on any of the nontarget taxa abundance, including Diptera, Lepidoptera, Ephemeroptera, Odonata, Coleoptera, Hymenoptera, and Arachnida. An inverse relationship between insectivore and prey taxa abundance was observed. In 2018, taxa richness increased between years and trended higher at treated sites and a positive relationship between insectivore and prey taxa richness was observed. In 2017, Shannon-Weiner index and Simpson’s index of diversity were higher at untreated sites, and in 2018 diversity indices were higher at treated sites, with taxa richness increasing between years and higher evenness trending at treated sites.
Our data suggest that treatment effects were potentially shrouded by natural variability of physicochemical variables, especially due to the varying hydroperiod observed over the three years of sampling. Additional work is needed to capture average conditions and separate confounding variables from treatment effects. This study provides an inventory of the current wetland insect community in the South March Highlands Conservation Forest landscape that offers a reference for ongoing mosquito management.
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Corlay, Herrera Favio Raul. "Seasonal development and natural enemies of an invasive exotic species, the swede midge Contarinia nasturtii (Kieffer), in Quebec." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100787.
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In Quebec, the swede midge (Contarinia nasturtii), a newly invasive pest, was found for the first time in 2003. During a two year study (2004-2005) I studied the seasonal development of the swede midge, the presence of natural enemies and tested entomopathogenic nematodes for its control. Results showed that the overwintering generation of the swede midge emerged during the second half of June. Based on adult captures and abundance of larvae in the field, there were three to four overlapping generations. Late transplants were more heavily attacked by the swede midge and broccoli and cauliflower were the most susceptible crops. No parasitoids were found in the experimental sites during either year of the study and two polyphagous coccinellid predators (Harmonia axyridis and Coccinella septempunctata) were field-collected for further evaluation under laboratory conditions. Although these two coccinellid species fed on swede midge larvae in plastic containers, further experiments demonstrated that H. axyridis was not able to prey on swede midge larvae on infested broccoli plants. The susceptibility of swede midge larvae to three species of entomopathogenic nematodes (Steinernema feltiae, S. carpocapsae, and Heterorhabditis bacteriophora) was also evaluated in laboratory assays. Heterorhabditis bacteriophora was the only species that caused significant mortality to swede midge larvae and, at a concentration of 1000 IJs/larva, caused 90-100% mortality in loam, sandy loam, clay and muck soil. This is the first study describing the seasonal development of the swede midge in Quebec. In addition, the potential use of entomopathogenic nematodes as biological control agents against the swede midge is demonstrated.
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Chaloner, Dominic Thomas. "The role of particles in structuring the midge (Diptera chironomidae) community of temporary ponds (slow sand filter beds)." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309319.
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Stoeckel, Denise Boulet. "The Effect of Environmental Factors on The Bioaccumulation of Neutral, Lipophilic Organic Compounds by The Midge, Chironomus riparius /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487928649989513.
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Hillbur, Ylva. "Tracking the tiny : identification of the sex pheromone of the pea midge as a prerequisite for pheromone-based monitoring /." Alnarp : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5810-2.pdf.
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Mills, Mary Katherine. "Vector-pathogen interactions within the vector, Culicoides sonorensis." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38154.
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Doctor of PhilosophyDivision of Biology
Kristin Michel
The biting midge, Culicoides sonorensis, vectors orbiviruses of economic importance, such as epizootic hemorrhagic disease virus (EHDV). Due to the limitations in available molecular tools, critical Culicoides-orbivirus interactions underlying vector competence remain unclear. To provide a foundation for the study of midge-EHDV interactions, RNA interference (RNAi) was developed as a reverse genetic tool, and EHDV-2 infection dynamics were determined within C. sonorensis. To develop RNAi, exogenous double-stranded RNA (dsRNA) was injected into C. sonorensis adults specific to the C. sonorensis inhibitor of apoptosis protein 1 (CsIAP1) ortholog (dsCsIAP1). A significant decrease in CsIAP1 transcripts was observed in whole midges, with highest reduction in the midgut. In addition, dsCsIAP1-injected midges had increased mortality, a loss of midgut tissue integrity, and increased caspase activity. The longevity and midgut phenotypes were partially reversed by the co-injection of dsRNA specific to the C. sonorensis initiator caspase Dronc ortholog and CsIAP1. These results demonstrated that RNAi can be achieved in the midge midgut through injection of target dsRNAs into the hemolymph. Furthermore, the time course of EHDV-2 infection within C. sonorensis was characterized. EHDV-2 infection was observed in the midgut and secondary tissues, including the salivary glands, by 5 days post-feeding (dpf). These data are consistent with dissemination of EHDV-2 to secondary susceptible tissues throughout the midge via the hemolymph and indicate that virus transmission by C. sonorensis may occur as early as 5 dpf. This work provides a foundation for the future study of Culicoides-orbivirus interactions, including the antiviral role of RNAi at the midgut barrier.
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Kobelt, Dennis. "Klinische Studie und experimentelle Untersuchungen zur nicht-viralen Gentherapie solider Tumoren." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16598.
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Krebs gehört zu den häufigsten Todesursachen weltweit. Ein großer Hoffnungsträger für die Behandlung maligner Tumore ist die Gentherapie. Die nicht-virale Gentherapie gilt als sicherere Alternative zur viralen Gentherapie. Für den nicht viralen Gentransfer sind sowohl Vektor als auch Gentransfertechnologie von entscheidender Bedeutung. Im Rahmen dieser Arbeit wurde die Gentransfereffizienz und Sicherheit der Jet-Injektion in einer klinischen Phase I Gentransferstudie mit Hilfe des Swiss-Injektors untersucht. Es konnte gezeigt werden, dass diese Technologie sicher klinisch angewendet werden kann, dass jedoch die Sicherheit der Vektoren und vor allem die Gentransfereffizienz weiter optimiert werden müssen. Ausgehend von diesen Ergebnissen wurden optimierte nicht-virale Vektoren (Minicircle, MIDGE) miteinander und mit ihren parentalen Plasmiden verglichen. Mit Hilfe des MIDGE Vektors konnte die höchste Transgenexpression aufgrund einer erhöhten Transkription erzielt werden. In Vorbereitung der klinischen Anwendung des MIDGE-Vektors wurde die Kombination von hTNF-alpha Gentransfer und Vindesin Chemotherapie untersucht. Auch hier zeigte der MIDGE-Vektor eine erhöhte in vitro Genexpression, die in vitro zu einer erhöhten Zytotoxizität von Vindesin aufgrund einer verstärkten Aktivierung der Apoptose führte. Auch in vivo konnte die verbesserte hTNF-alpha-Genexpression des MIDGE-Vektors nach Jet-Injektion gezeigt werden. Dies führte in Kombination mit Vindesin zu einem signifikant reduzierten Tumorwachstum. Durch Analyse der systemischen Vektorverteilung im Blut und in den Organen sowie in einer präklinischen toxikologischen Untersuchung konnte die sichere Anwendung des MIDGE-Vektors bestätigt werden. Abschließend wurden weitere Anwendungsmöglichkeiten des MIDGE-Vektors für die stabile Genexpression und für die Verwendung in kombinierten Gentransferprotokollen untersucht.Cancer is one leading causes of death worldwide. Gene therapy belongs to the promising options for treatment of malignant tumors. The non-viral gene therapy is known as safer alternative to the viral gene therapy. For non-viral gene transfer the vector and the transfer technology are of crucial importance. As part of this work a clinical trial was performed to assess efficiency and safety of the non-viral jet-injection. It was shown, that this technology can be used safely in a clinical setting. As a result of this clinical trial we concluded, that vector safety and especially efficiency need further improvements. Based on this optimized non-viral vectors (minicircle, MIDGE) were compared with each other and their respective parental plasmids. The MIDGE vector showed the highest transgene expression due to increased transcription. In preparation of a clinical trial the combined treatment of hTNF-alpha gene transfer and Vindesine chemotherapy was analyzed. Again, the MIDGE vector showed the highest transgene expression. This expression led to an increased cytotoxicity of Vindesine in vitro due to an elevated apoptosis signaling. Furthermore, these results could be assigned to an in vivo model. The increased hTNF-alpha expression after MIDGE vector jet-injection in combination with Vindesine led to a significant decrease in tumor growth. Detailed analysis of systemic vector distribution in the blood and organs as well as the preclinical toxicity evaluation showed the safety of the non-viral MIDGE vector. Initial experiments were performed to show further options for stable gene expression and combined gene transfer protocols using the MIDGE vector.
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Skenteridis, Pavlos. "Biology and behaviour of the predatory midge Feltiella acarisuga (Vallot) (Cecidomyiidae) feeding on Tetranychus urticae (Koch) (Tetranychidae) on cotton plants." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407406.
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Logan, James G. "Differential responses of the yellow fever mosquito, Aedes aegypti, and the Scottish biting midge, Culicoides impunctatus to human host odours." Thesis, University of Aberdeen, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430401.
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Behavioural studies using a Y-tube olfactometer confirmed the differential attractiveness of human volunteers to the yellow fever mosquito, Aedes aegypti. Volatile chemicals were collected from all volunteers by air entrainment. The extracts were analysed behaviourally with Ae. aegypti and the Scottish biting midge, Culicoides impunctatus in a Y-tube olfactometer. The behavioural responses were similar to those previously observed to the hands of the volunteers. Electrophysiological responses of Ae. aegypti and C. impunctatus, to volatiles from the air entrainment extracts, were recorded using coupled gas chromatography-electroantennography (GC-EAG). EAG-active compounds were tentatively identified using GC-mass spectrometry (GC-MS) and were confirmed by peak enhancement. A quantitative and qualitative analysis of compounds within the extracts revealed significant differences in chemical profiles. The mean absolute amounts of benzaldehyde, 6-methyl-5-hepten-2-one, octanal, nonanal, naphthalene, decanal and geranylacetone were significantly greater in the unattractive group than the attractive group. Similarly, the mean relative amounts of 6-methyl-5-hepten-2-one, octanal and decanal in the unattractive group were significantly greater than the attractive group. Five compounds caused significant reductions in behavioural responses of Ae. aegypti when presented alongside a human hand in the Y-tube olfactometer, thus accounting for the lack of attraction towards the volunteers’ hands in the unattractive group. The identification of such behaviourally active compounds could lead to improved control technologies, whereby such compounds could potentially be incorporated into new, safe and natural repellents against biting insects.
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Teets, Nick M. "In vivo and in vitro rapid cold-hardening in the Antarctic midge, Belgica antarctica: Evidence of a role for calcium." Miami University Honors Theses / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177956294.
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Galling, Nele R. [Verfasser]. "Intratumorale Verteilung, systemische Biodistribution und Clearance eines TNFα exprimierenden MIDGE Vektors nach nicht-viraler in vivo Jet-Injektion / Nele R. Galling." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1075757290/34.
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Kawarasaki, Yuta. "SURVIVAL AND PHYSIOLOGICAL RESPONSES TO SUBZERO TEMPERATURES IN THE ANTARCTIC MIDGE, BELGICA ANTARCTICA: TO FREEZE OR NOT TO FREEZE." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1377681162.
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McKinnell, Stephen Arthur. "The use of non-biting midge species Chironomus riparius Meigen (Diptera: Chironomidae) as a toxicity test species with particular reference to surfactants." Thesis, Liverpool John Moores University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261342.
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Evans, Adrian. "Investigation into the effects of parasitoids on a gall midge Dasineura sp. (Cecidomyiidae), a biological control agent of Australian myrtle, Leptospermum laevigatum." Bachelor's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/25779.
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Leptospermum laevigatum is one of the top five invading species in the fynbos biome and its biocontrol is of high conservation priority in the Western Cape. The first species used as a biocontrol agent was a leaf-mining moth Parectopa thalassias that became established and wide-spread. The second agent a Dasineura sp (Cecidomyiidae) gall midge whose origin in unknown but was probably introduced accidentally. As it was not screened before release an investigation into the effect of parasitism on its effectiveness as a control agent is important. Midges were found to select plants for oviposition that have high growth rates and result in large galls. This results in plants with lots of large galls. These plants are conspicuous to parasites and levels of parasitism are highest at these sites. Once the plant has been selected by the parasitoid, gall selection for oviposition was not related to density of the midges within. The spatial scale showed the dispersal of the midge was primarily related to the prevailing westerly wind. Parasitism levels followed the spread of the midge and increased as midge densities increased. The midge is still spreading and indications show parasitiods do not prevent establishment into new areas. As this is the midges most vulnerable phase, once they are established they should persist. However even at the sites with high number of galls the plants still produced fruits with seeds. Thus high parasitism levels could reduce the population densities of the midge and inhibit is usefulness as a biocontrol agent. A further biocontrol agent that attacks these reproductive parts could result in the successful control of this invasive species.
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Wheat, Nicola M. "Patterns of parasitism and emergence in the gall midge Dasineura Dielsii (Diptera: Cecidomyiidae) : a biological control agent of Acacia cyclops in South Africa." Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/25722.
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Acacia cyclops A. Cunn. ex G. Don is an invasive alien plant that invades fynbos and coastal dunes. Several acacia species are grown commercially in South Africa and this has limited biocontrol agents to those that reduce only reproductive capacity. Dasineura dielsii was released in 2002 as a biocontrol agent for A. cyclops. This gall-forming midge destroys inflorescences and prevents seedpods from forming, but allows continued harvesting. Insects overwinter as larvae within their galls. This study examined the levels of parasitism experienced by dormant D. dielsii larvae, as well as the trigger that causes them to break dormancy. Gall clusters were sampled over autumn and early winter, and were dissected to determine occupancy. The effects of temperature and light on dormant larvae were also examined. Observations showed that as the season progressed, more D. dielsii larvae entered dormancy. At the same time, a greater proportion of dormant larvae were parasitized. Parasitism was highest, at 18.5%, at the end of the study period, but this level of parasitism is not enough to reduce the biocontrol power of D. dielsii. A positive relationship between mass of gall clusters and the number of galls they contain was established. Larval dormancy could not be artificially broken by either light or temperature, and it appears that neither factor alone can trigger a break in dormancy.
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Sawyer, Heidi Nadene. "Larval development of the predatory midge Feltiella acarisuga Vallot (Diptera: cecidomyiidae) in response to limited availability of its prey Tetranychus urticae Koch (acari: tetranychidae)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24237.pdf.
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Fleming, Erin Mattea. "Reconstruction of holocene environmental changes in northern British Columbia using fossil midges." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2811.
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Lake sediments contain the remains of midge communities that may be used as biological proxies for inferring past environmental changes. Freshwater midges, including Chironomidae and Chaoboridae, from two alpine tarns (Pyramid Lake and Bullwinkle Lake) in the Cassiar Mountains of northern British Columbia were used to estimate Holocene palaeotemperature changes, and more specifically, to test for the presence of the Milankovitch thermal maximum, an early Holocene warm interval coinciding with peak Holocene summer solar insolation. Mean July air temperatures were reconstructed using midge-inference models developed via weighted averaging-partial least squares (WA-PLS) regression. Cold-tolerant midge taxa dominate the stratigraphies from both Pyramid and Bullwinkle Lakes; however, warm-adapted species are more common in Bullwinkle Lake. Early Holocene warming is apparent at both lakes, however it is unclear whether this is indicative of the Milankovitch thermal maximum. A decrease in temperature occurs from 8,700-7,900 cal. yr BP at Pyramid Lake, around the same time that the 8,200 cal. yr BP cooling event occurred in the northern hemisphere. During the middle Holocene, records from Pyramid Lake indicate an overall decrease in temperature, with a short period of warmer temperatures that peak at 5,100 cal. yr BP. Temperatures fluctuate little during this time at Bullwinkle Lake. A short warming phase is apparent at both lakes during the late Holocene. July temperatures are highest at 2,000 cal. yr BP (10.5°C) in Pyramid Lake and at 1,200 cal. yr BP (13°C) in Bullwinkle Lake. Thereafter, temperatures return to what they were before the warming occurred, and at Bullwinkle Lake, vary little throughout the remainder of the Holocene.
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Lydy, Michael James. "The usefulness of partition coefficients in predicting the fate and effects of neutral lipophilic and moderately water soluble metabolizable compounds in the midge, Chironomus riparius /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487685204968602.
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Tassou, Koffi Tcha [Verfasser]. "Assessment of potential endocrine disrupting agrochemicals in freshwater systems: full life-cycle testing over two generations with the aquatic midge Chironomus riparius (Meigen) / Koffi Tcha Tassou." Landau : Universitätsbibliothek Landau, 2013. http://d-nb.info/1032060654/34.
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Mdlangu, Thabisa Lynette Honey. "Influence of mite predation on the efficacy of the gall midge Dasineura sp. as a biocontrol agent of Australian myrtle Leptospermum laevigatum (Myrtaceae) in South Africa." Thesis, University of Fort Hare, 2010. http://hdl.handle.net/10353/272.
Full textAbstract:
Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
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Johnston, Marc. "The searching behaviour of the predatory midge larva, Feltiella acarisuga Vallot (Diptera: cecidomyiidae), in response to the density and distribution of its prey, tetranychus urticae koch (Acari: tetranychidae)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq24167.pdf.
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Tuffnail, William. "A 1H NMR metabolomic study of the metabolic effects of pesticides on the non-target invertebrates the blue mussel Mytilus edulis and the non-biting midge larvae Chironomus riparius." Thesis, University of Portsmouth, 2010. https://researchportal.port.ac.uk/portal/en/theses/a-1h-nmr-metabolomic-study-of-the-metabolic-effects-of-pesticides-on-the-nontarget-invertebrates-the-blue-mussel-mytilus-edulis-and-the-nonbiting-midge-larvae-chironomus-riparius(d1a98b08-2fc6-4302-95a4-0f616556441d).html.
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Metabolomics is a technique that can be used to investigate the metabolic profiles of an organism by measuring a large number of the low molecular weight metabolites in the metabolic pool. 1H NMR spectroscopy is an analytical tool that is unbiased, and a non-destructive way of investigating metabolic perturbations in organisms exposed to environmental stress. In this study two model organisms, Mytilus edulis and Chironomus riparius were used to investigate the effects of several pesticides: lindane and atrazine in the mussels, and fenitrothion, methiocarb and permethrin in the midge larvae. The impact of hypoxia and starvation were also investigated alongside the exposure to atrazine in the mussel. The pesticides used in the mussel study have different modes of action, but produce similar changes to behaviour and can cause starvation and mild hypoxia. Acetonitrile/2H2O (60/40 % v/v) extracts of foot muscle of mussels subjected to hypoxia, or starvation, or to low or high doses of pesticide were analysed using 1H NMR spectroscopy to produce metabolic profiles associated with these treatments. Discriminant analysis showed significant differences between treated and control animals and gave a clear separation between all treatment groups. Atrazine profiles were clearly separated from the starved and hypoxic animals and the animals exposed to high and low doses were also separated. Lindane treatment was separated from control animals in a dose-dependent way. This was associated with an increase in alanine concentrations and a decrease in all other identified metabolites. The study of midge larvae used the same approach, but using extracts of pooled whole body homogenates (10 animals per sample) instead of tissue from individuals. The animals were subjected to low, environmentally relevant dose levels of three pesticides; fenitrothion, methiocarb and permethrin. The first two of these have a similar mode of action, inhibition of acetylcholine esterase, whilst the latter is an axonal poison acting on cation channels. The metabolic profiles associated with these treatments showed a clear separation between all treatment groups and between treated and control animals. Fenitrothion treatment was associated with an increase in alanine (on average of 93.3 M relative to controls) and lactate concentrations compared with controls and other treatments. Methiocarb caused a reduction in arginine, leucine and lysine concentrations to half of the control level. Permethrin produced a reduction in tyrosine and phenylalanine concentrations to half that of the control group. In both these experiments the use of 1H NMR metabolomics enabled the separation the effects of all of the treatments and stressors from each other and from the controls. It demonstrates the potential of the metabolomic approach to provide separation of the effects of poisoning from those of environmental stress, and to distinguish between toxicants with similar modes of action.
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St, George Ryan. "A Comparative Evaluation of Mitigation Wetlands in Broward County, Florida, Using Chironomid (Ditera) Pupal Exuviae: A Potential Technique for Assessing Mitigation Success." Thesis, NSUWorks, 2015. https://nsuworks.nova.edu/occ_stuetd/388.
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Wetland resources in South Florida are regulated at three redundant jurisdictional levels: local or municipal regulations set forth by many independent jurisdictions, State regulations derived directly from Florida Statutes, and Federal regulations promulgated primarily under the Clean Water Act. All three levels of government can have jurisdiction over projects that affect regulated wetland resources, yet inconsistent policies and standards remain and continue to confound regulators despite decades of intensive coordination efforts and a rapidly growing scientific research base. The size of a wetland mitigation area is of primary consideration when evaluating its perceived ecological value, although wetland mitigation areas constructed in developed areas are typically isolated and generally make use of similar designs regardless of wetland size.
The Chironomidae (Order: Diptera) are the most diverse and abundant faunal taxon in all healthy freshwater bodies and are generally considered to be a reliable and effective ecological indicator. I conducted a preliminary comparison of chironomid communities between a suite of natural and artificial wetlands, and also evaluated the effect of wetland size on the community structure of the insect family Chironomidae. Using the Chironomid Pupal Exuviae Technique (CPET), collections of chironomid exuviae from a total of seven natural and artificial mitigation wetlands were compared across site groups and also correlated to recorded environmental conditions at each study site.
Chironomid species assemblages at nearly all sites were dominated by Parakiefferiella coronata, comprising nearly 36% of all collected exuviae. Species assemblages from mitigation wetlands exhibited strong similarity to the aggregate species assemblage from all sites. A greater abundance of exuviae was collected from artificial sites than from natural sites, and species assemblages collected from natural sites were dissimilar from those collected from artificial sites. No statistically significant differences in community structure were detected between larger and smaller wetlands. Environmental site conditions between natural and mitigation sites generally varied greatest in conductivity and pH. No significant gradient was identified in environmental conditions or chironomid community structure across wetlands of different size. A minor seasonal gradient in TP concentrations was observed and site S6 was the most enriched site included in this study while site S1 exhibited high conductivity for the duration of the project.
Differences between chironomid species assemblages collected from natural and artificial communities may be explained by the relatively static topography, more consistent substrate composition, and less diverse hydrophyte communities present in the natural sites which have generally reached a greater state of homeostasis. However, statistical tests generally support the null hypothesis. No statistically significant differences were detected between sites based on collected chironomid communities when grouped by wetland origin (artificial vs. natural) or size.
Observed differences between communities sampled from natural and artificial wetlands support regulatory concerns that artificial wetlands may not sufficiently emulate natural systems and that a constructed wetland system may take generations, or even centuries to sufficiently mimic its natural counterpart. Mitigation design complexity does appear to provide a diversity of microhabitats favorable to a greater variety of chironomids. However, a lack of statistical significance may support assertions that mitigation sites are successfully replacing natural wetlands. Implementation of CPET-based community structure analyses requires intensive labor and expertise and is not practical for regulatory purposes, but can provide robust data for effective and detailed site analysis.
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Sommers, Mitchell. "Absolute Midget." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/440.
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Mählmann, Kathrin [Verfasser]. "Minimalistic immunologically defined gene expression T helper cell 1 (MIDGE-Th1®) vectors coding for Interleukin 12 and -18 in combination with the transfection agent SAINT-18 have systemic antitumoral effects on equine melanomas / Kathrin Mählmann." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2012. http://d-nb.info/1030346402/34.
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Dickson, Travis. "Assessing midges as paleoecological indicators." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/45760.
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Three exclusive studies (in-vitro, observational and empirical) comprise this doctorate dissertation aimed at assessing the capacity of midges (Order Diptera: Families Chironomidae, Chaoboridae and Ceratopogonidae) as paleoecological indicators.
In-vitro experiments were conducted to determine the impact that temperature and salinity have on midge development and survival. Results indicate that some taxa may achieve optimal development at cooler temperatures; most taxa are cued for emergence by, and require, warmer temperatures; exposure to temperatures that are too warm may result in developmental stress and sometimes death; midge emergence events appear more or less synchronous; and emergences may be controlled by a threshold temperature as opposed to accumulated degree-days.
Also, in-vitro experiments were conducted to assess larval midge salinity thresholds (LD50s). Dasyhelea (Ceratopogonidae), Cricotopus/Orthocladius, and Cladotanytarsus mancus type appeared to have the highest salinity LD50s while Chironomus anthracinus type and subtribe Tanytarsina displayed the lowest.
In the second study, water chemistry and environmental data were compared with midge assemblage data using multivariate analysis to assess the environmental gradients that limit midge distributions in the Hudson Bay Lowlands (northeastern Manitoba). The results demonstrate the midges’ potential as paleosalinity indicators.
The third study involved extracting sediment cores from four separate lakes within the Hudson Bay Lowlands, each extracted from a pond at a different elevation (range from 127 to 10 m above sea level) and distance from the current Hudson Bay shoreline (range from 104 to 2.5 km). My reconstructions suggest that two inland ponds experienced an initial gradual freshening trend from their inception to <1,000 cal. years BP, followed by more recent rapid freshening. Reconstructions for two ponds situated proximal to Hudson Bay indicate stable salinity through the entirety of the sediment records. Quantitative salinity reconstructions for each of the four sampled ponds were ‘statistically insignificant’ (P ≤ 0.05). Predicted isostatic rebound rates, inferred by linear extrapolation of age depth models constructed for four Hudson Bay Lowland ponds, do not indicate an exponentially declining salinity trend as expected.