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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.
1

A quantification of the behaviourial dynamics of certain Lepidoptera in response to light

Gaydecki, P. A. January 1984 (has links)
Many types of insect, in particular the nocturnal Lepidoptera, will fly towards artificial sources of illumination. Such animals are often described as being positively phototactic, but although little progress has been made towards a fundamental understanding of this phenomenon, its existence continues to be exploited with the use of light-traps. This thesis attempts to explain, in part, why certain British night-flying Lepidoptera are caught, or fly close to, light-traps. The experimentation and analysis has been structured into three separate but inter-related studies. The first is an investigation into the effects that weather factors exert on light-trap catch. Standard analytical procedures were extended to reveal that sensitivity to these factors is related to insect size and gross morphology. The second of these studies is an analysis of the types of moth flight pattern produced when these insects are exposed to various forms of illumination under field conditions. Moth tracks were recorded on video with the help of image intensification, and the frame-by-frame co-ordinates transferred to, and processed by, a microcomputer, which produced matrix maps of speeds, accelerations and time-surface densities around a light-trap. Instantaneous windspeeds were recorded. The dynamical analysis suggests that moth flight towards light arises primarily from a misinterpretation of the stimulus, competing at short distances with a strong escape response, thus evoking a profound state of disorientation. Furthermore, the data indicated that the types of pattern found were species linked. In the third study, a remotesensing technique was used to quantify moth aerial density, which was compared with simultaneous light-trap catches nearby, giving an estimate of absolute trap catching efficiency under various meteorological conditions. Because of their mode of operation, and their increasing loss of effectiveness in higher windspeeds, light-traps have only a limited capacity to reflect aerial density.
2

Applications of computer modelling to behavioural coordination

Ludlow, Anthony Richard January 1983 (has links)
No description available.
3

Pheromone trap interaction and dose-response experiments with Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Downham, Mark Crispin Anthony January 1999 (has links)
No description available.
4

Behavioural ecology and life history evolution in the Larger Grain Borer, Prostephanus truncatus (Horn)

Li, L. January 1988 (has links)
No description available.
5

Social information use and its consequences in adult and larval stages of fruit flies

Golden, Shane 11 1900 (has links)
Recent evidence has shown that fruit fly adults and larvae are heavily attracted to food sites occupied by larvae. This attraction is especially strong in mated females that are looking for a suitable site for egg laying. In the first set of experiments, we compared the value assigned to social information provided by larvae at a site to the nutritional information that a female has access to by sampling a food. Lowering food quality did decrease egg-laying preference for a food, but females still showed a much stronger preference for occupied foods. We theorized that the social egg-laying preference may be due to an advantage of developing near older larvae. However, eggs that developed near larvae showed lower survival to adulthood, slower development time, and lower adult body mass. Females were also not able to reduce their social egg-laying preference, even when foods were already heavily occupied by larvae. Finally, we found that larvae were not better able to identify a high quality food site than an adult female, and thus the smell of used food was not a reliable cue to the quality of a site. These results provide evidence that the preference for females to lay eggs near larvae is very robust but the exact benefit it provides for the female and her offspring is unknown. We then ran a series of experiments to test larval social information use to see if they value it as heavily as adult females. Our experiments consisted of focal larvae being put on lower quality food and trying to find a higher quality food nearby that was either occupied or unoccupied by a single model larva. Larvae did not reliably use this social information. Overall, it is unclear whether the larvae are using social information to help them find higher quality foods. / Thesis / Master of Science (MSc)
6

Cabbage and turnip root flies on resistant and susceptible Brassicas : host selection and chemical interactions

Hopkins, Richard James January 1994 (has links)
During post-alighting behaviour gravid female turnip root fly, D.jloralis, select a plant for oviposition predominantly during the initial landing phase; the cabbage root fly, D.radicum, also utilise the leaf resting phase. The post-alighting behaviour exhibited by D.radicum and D.floralis infers that oviposition site selection is primarily based upon positive stimuli present on the leaf surface. Ranking of four genotypes of plants for antixenotic resistance to oviposition by D.radicum and D.jloralis was found to be the same for both fly species, tested in the laboratory (swede cv Doon Major, most susceptible; kale cv Fribor, most resistant) and varied x80 (D.floralis) and x5 (D.radicum). Field experiments showed that oviposition (which was dominated by D.radicum) varied x2 between plant genotypes (swede cv Doon Major, most susceptible; swede cv GRL aga, most resistant). Testing of Brassica leaf surface extracts, applied to surrogate plants, indicated that leaf surface chemicals strongly influence the site of oviposition of D.floralis. Methanol soluble polar compounds are the most stimulatory element for D.floralis and a fraction which contained aliphatic glucosinolates stimulated oviposition strongly although glucosinolates were not the primary oviposition stimulant. Collaborative experiments indicate that "CIF" (cabbage identification factor) is probably present in this fraction. The concentrations of Brassica root sugars are generally reduced by the damage of both D.radicum and D.floralis and appear to influence larval development. The percentages of plant fibre and lignin in the roots of Brassicas rise following the damage of D.floralis. The concentrations of individual glucosinolates in Brassica roots arc radically altered by the damage of D.floralis and D.radicum. D.floralis damage resulted in a rise in the concentration of aromatic glucosinolates and a fall in the concentration of aliphatic glucosinolates. D.radicum damage generally resulted in an elevated concentration of both aliphatic and aromatic glucosinolates. There was no clear evidence that glucosinolatc profiles were associated with different levels of antibiotic resistance to D.radicum and D.floralis. GRL aga (SCRI breeding line) was consistently resistant to the oviposition and larval feeding of D.radicum and D.floralis both in the laboratory and in the field. It was shown that the use of end-of-season chemical analysis to assess the influence of plant chemistry on insect development or host plant resistance in field experiments and the use of damage indexes based on the percentage of a plant root damaged by D.radicum may be flawed.
7

Ecologia de Bruchidae na preda??o pr?-dispers?o de sementes de Albizzia lebbeck (L.) Benth. em arboriza??o urbana / Bruchidae ecology on pre-dispersion predation of seeds of Albizzia lebbeck (L.) Benth. In urban afforestation

Nascimento, Luiz Santana do 28 August 2009 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-11T12:15:06Z No. of bitstreams: 1 2009 - Luiz Santana do Nascimento.pdf: 2500157 bytes, checksum: 032a65fbfdb3472167b24e484317dd31 (MD5) / Made available in DSpace on 2017-05-11T12:15:06Z (GMT). No. of bitstreams: 1 2009 - Luiz Santana do Nascimento.pdf: 2500157 bytes, checksum: 032a65fbfdb3472167b24e484317dd31 (MD5) Previous issue date: 2009-08-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The pre-dispersal seed predation by insects has great importance for seed production. The germination is affected due to damage caused by insects in larval development inside the seed. If this damage occurs in the cotyledons, it mainly affects the performance and survival of seedlings, otherwise, if it occurs directly in the embryonic axis, the seed mortality is unavoidable. There are few studies about species of Albizzia lebbeck (L.) Benth. in urban trees, especially when it comes to ecology and behaviour of insect predators of their seeds. In this context, this study aims to evaluate and quantify the damage in seeds, the occurrence and population fluctuation of insects on pods and seeds with emphasis mainly on the stage of pods ripening at different levels of human disturbance and air pollution caused by motor vehicles. The samples of pods were carried out on mother trees of A. lebbeck located on the campus of UFRRJ (Serop?dica), km 32 of old road Rio-S?o Paulo (Nova Igua?u) and km 47 (Serop?dica), Rio de Janeiro and the pods analyzed at the Laboratory of Forest Entomology, DPF, IF, UFRRJ. It was observed low levels of insect infestation in prematurely ripening pods which should be linked to the low number of specimen in oviposition on the first pods. However, for late ripening pods, especially those collected at sites with high levels of human disturbance and influence of air pollution, it was observed an increase in insect infestation. The same was observed in the final processing of seeds in pods of quarantine. In general, 9% of the seeds presented intact (healthy), 31% aborted and 60% damaged. 83% of damaged seeds were from the mother trees located in central reservation of Highway (Km 32), 43% of its margin (km 47) and 42% in the conservation area of Universidade Federal Rural do Rio de Janeiro Botanical Garden. Percentage of 92.68 was found of insect seed predators distributed in the following species: Bruchidius sp. (57.39%), Merobruchus paquetae (33.98%), Stator limbatus (0.27%), an unidentified species of Lepidoptera (1.04%) and the rest of emerging insects (7.32%) belonging to Order Hymenoptera. Specimen of Bruchidius sp. presented emergency period with well-defined peak in mid-September (approximately 135 days after observation of the first ovipositions in the field) and species M. paquetae average occurrences rather homogeneous, with low numbers of specimen and few variations throughout the period of emergency quarantine on pods. The largest number of bruchids was recorded in an area of high human disturbance, being the species Bruchidius sp. predominant in pods of trees placed in central reservation of the highway and the species M. paquetae on mother trees located beside of the highway. The number of bruchids in seeds of A. lebbeck was reduced with decreasing levels of human disturbance in urban trees which resulted in a lower percentage of damaged seeds and higher number of healthy seeds / A preda??o pr?-dispers?o de sementes por insetos ? de suma import?ncia para a produ??o de sementes, uma vez que o potencial germinativo ? afetado devido a danos provocados pelos insetos em desenvolvimento larval em seu interior. Quando este ataque acontece somente nos cotil?dones, as reservas energ?ticas do embri?o s?o drasticamente reduzidas afetando o desempenho e sobreviv?ncia das pl?ntulas, enquanto que, diretamente ao eixo embrion?rio, a mortalidade das sementes. H? poucos trabalhos na literatura sobre a esp?cie Albizzia lebbeck (L.) Benth. em arboriza??o, principalmente em se tratando da ecologia e comportamento dos insetos predadores de suas sementes. Neste contexto, este trabalho teve como objetivo avaliar e quantificar os danos em sementes, a ocorr?ncia e flutua??o populacional dos insetos em frutos e sementes com ?nfase, principalmente, ? fase de matura??o dos frutos em diferentes n?veis de antropiza??o e polui??o do ar provocada por ve?culos automotores. As amostragens de frutos foram realizadas em matrizes de A. lebbeck localizadas no Campus da UFRRJ (Serop?dica), Km 32 da antiga Estrada Rio-S?o Paulo (Nova Igua?u) e Km 47 (Serop?dica), Estado do Rio de Janeiro e analisadas no Laborat?rio de Entomologia Florestal, DPF, IF, UFRRJ. Foram observados baixos n?veis de infesta??o por insetos em frutos de matura??o prematura o que deve estar associado ao baixo n?mero de indiv?duos em oviposi??o nos primeiros frutos. J? para frutos de matura??o tardia, sobretudo aqueles coletados em locais com maior n?vel de antropiza??o e influ?ncia da polui??o do ar, foi observado aumento na infesta??o por insetos. O mesmo foi verificado no beneficiamento final das sementes em frutos de quarentena. No total, 9% das sementes apresentaram-se intactas (sadias), 31% abortadas e 60% danificadas sendo estas ?ltimas 83% provenientes de matrizes localizadas no canteiro central da Rodovia (Km 32), 43% ? sua margem (Km 47) e 42% em ?rea de conserva??o do Jardim Bot?nico da UFRRJ. Foi encontrado percentual de 92,68 de insetos predadores de sementes distribu?dos nas seguintes esp?cies: Bruchidius sp. (57,39%), Merobruchus paquetae (33,98%), Stator limbatus (0,27%), uma esp?cie de Lepidoptera n?o identificada (1,04%) e, o restante dos insetos emergentes (7,32%), pertencentes ? Ordem Hymenoptera. Os indiv?duos da esp?cie Bruchidius sp. apresentaram per?odo de emerg?ncia bem definida com pico em meados de setembro (cerca de 135 dias ap?s a observa??o das primeiras posturas no campo) e a esp?cie M. paquetae m?dias de ocorr?ncias bastante homog?nea, com baixo n?mero de indiv?duos e poucas varia??es ao longo de todo o per?odo de emerg?ncia em frutos de quarentena. O maior n?mero de bruqu?deos foi registrado em ?rea de elevada antropiza??o, sendo a esp?cie Bruchidius sp. predominante em frutos de matrizes localizadas no canteiro central e a esp?cie M. paquetae em matrizes localizadas ? margem da rodovia. O n?mero de bruqu?deos em sementes de A. lebbeck foi reduzido com a diminui??o do n?vel de antropiza??o local em matrizes em arboriza??o o que refletiu em menor taxa de sementes danificadas e maior n?mero de sementes sadias.
8

Sexual Selection on Females: Comparing Two Estimates of Mating Success in a Sex-role Reversed Insect

Robson, Laura J. 15 February 2010 (has links)
While there has long been interest in the form of sexual selection in males, studies characterizing this selection in females remain sparse. Sexual selection on females is predicted for sex-role reversed Mormon crickets, where males are choosy of mates and nutrient-deprived females compete for matings to gain nutritious nuptial gifts. I used selection analyses to describe the strength and form of sexual selection on female morphology. There was no positive sexual selection on the female body size traits predicted to be associated with male preferences and female competition. Instead, I detected selection for decreasing head width and mandible length. Additionally, I tested the validity of a commonly-used instantaneous measure of mating success (mated vs. unmated) by comparing selection results with those determined using a more detailed fitness measure (cumulative mating rate). The two fitness measures yielded similar patterns of selection, supporting the common sampling method comparing mated and unmated fractions.
9

Sexual Selection on Females: Comparing Two Estimates of Mating Success in a Sex-role Reversed Insect

Robson, Laura J. 15 February 2010 (has links)
While there has long been interest in the form of sexual selection in males, studies characterizing this selection in females remain sparse. Sexual selection on females is predicted for sex-role reversed Mormon crickets, where males are choosy of mates and nutrient-deprived females compete for matings to gain nutritious nuptial gifts. I used selection analyses to describe the strength and form of sexual selection on female morphology. There was no positive sexual selection on the female body size traits predicted to be associated with male preferences and female competition. Instead, I detected selection for decreasing head width and mandible length. Additionally, I tested the validity of a commonly-used instantaneous measure of mating success (mated vs. unmated) by comparing selection results with those determined using a more detailed fitness measure (cumulative mating rate). The two fitness measures yielded similar patterns of selection, supporting the common sampling method comparing mated and unmated fractions.
10

Preparados homeopáticos, iscas fitoterápicas, conhecimento popular e estudo do comportamento para o manejo das formigas cortadeiras no Planalto Serrano Catarinense / Homeopathic preparations, phytoterapic baits, local knowledge and behaviour studyes for managing leaf cut ants in the "Planalto Serrano Catarinense" Region

Giesel, Alexandre 12 December 2007 (has links)
Made available in DSpace on 2016-12-08T16:44:32Z (GMT). No. of bitstreams: 1 PGPV07MA019.pdf: 983013 bytes, checksum: af67f91f15946eb87d559e480ef2fc06 (MD5) Previous issue date: 2007-12-12 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The increasing of insect epidemics in the agro-ecosystem is due to ecologucal perturbations like reduction in biodiversity and improverishment of soils. Ant s species of the genus Acromyrmex and Atta can become importante pest, requiring frequente interventions for their control, usually done by toxicant baits that presente side effects. In this work, it was studied the management of the leaf cutter ants through out techniques of low cost and less environmental impact by using homeopathic/phytoterapic preparations. Etiological data, sepcies assessment and ethnic considerations were evaluated as well. Theresearch work was carried out in the Planalto Serrano /catarinense region. The effectiveness of homeopathic/phytoterapic preparations was evaluated in field conditions. For that, two independente experiments in randomized blocks design were installed considering block as local effect. The treatments forAcromyrmrx ants were: triturated ant nosode, triturade fungus colony nosode, softened of ant s nosode, softned fungus colony nosode, homeopathy Belladonna, homeopathic water, nem bait, sesame bait, placebo, and without intervention. For the experimente with Atta ants, the treatments were: triturated and nosode, softned ant nosode, homeopathy Belladonna, homeopathic water, nem bait, sesame bait, placebo, and without intervention. All the homeopathic preparations were applied in the thirtieth centesimal hahnemanniana dilution (30CH), made accordingto Farmacopéia Homeopática Brrasileira (1977). The phytoterapy baits were obtained by the mixture of wheat flour, flour of sesame or neem oil and water, in the proportion 2:2:1. Placebo baits were made by wheat flour and water. The identification of species of leaf cutter ants was done from 60 anthills of the genus Acromyrmex and 40 anthills of the genus Atta. Ethnology studies were from three anthills of both genus, Atta and Acromyrmex. Observations of beavior forage preference were taken along the year, in one day per month for each two hours during a period of 24 hours. The ethno-entomology studies were done through out a qualitative and quantitative questionnaire applied to Family farms regarding the man s perceptions in diferente production systems, organic, in transition, and conventional systems. The questions approached the characteristics of the production system; period in the activity; identification and knowledge on natural methods of control among others. The analysis of data showed that the phytoterapy baits, and the homeopathic preparations reduced the total acrivities and forage acrtivity of Acromyrmex and Atta as well. The total and forage activities were vairable during the year, for both genus Atta and Acromyrmex, being dependente of the temperature conditions and relative humidity of the air. The taxonomiv studies revealed that in the genus Acromyrmex the most frequente species were Acromyrmex laticeps, Acromyrmex heyeri, Acromyrmex. A. coronata and A. lundi are considered species rare in this region. The genus Atta presented the specie Atta sexdens piriventris. According to tyhe farmers interviewees the ants represent importante cause of damages to the crops and their control has been made mostly by toxicant baits. The homeopathic preparations showed importante tool for the control to both genus of leaf cutter ants. The best bait was homeopathic preparation based on ants. Neem Baits and sesame bait affected also the behavior on both genus of leaf cutter ants / A proliferação epidêmica de insetos no agroecossistema é sintoma de desequilíbrio, associado à redução da biodiversidade e empobrecimento dos solos. Formigas dos gêneros Acromyrmex spp. e Atta spp. podem se tornar importantes pragas, requerendo intervenções freqüentes, normalmente realizadas por iscas tóxicas de alto poder residual. Neste trabalho estudou-se o controle de formigas cortadeiras, através de técnicas de baixo custo e impacto ambiental pela utilização de preparados homeopáticos e iscas fitoterápicas. Adicionalmente, coletaram-se dados etológicos, identificação de espécies ocorrentes e considerações étnicas em propriedades familiares da região do Planalto Serrano Catarinense. A eficácia dos preparados homeopáticos e fitoterápicos foram avaliadas a campo em dois experimentos independentes, delineamento em blocos ao acaso, separados por tempo e local. Os tratamentos para o experimento com formigas Acromyrmex spp. foram: nosódio triturado de formigas, nosódio triturado do cultivo fúngico, nosódio macerado de formigas, nosódio macerado do cultivo fúngico, homeopatia Belladonna, água dinamizada, isca de nim, isca de gergelim, placebo e sem intervenção, como testemunha. Para o experimento com formigas do gênero Atta os tratamentos constaram de: nosódio triturado de formiga, nosódio macerado de formiga, homeopatia Belladonna, água dinamizada, isca de nim, isca de gergelim, placebo e sem intervenção. Todos os preparados homeopáticos foram aplicados na trigésima diluição centesimal hahnemanniana (30CH), obtidos segundo a Farmacopéia Homeopática Brasileira (1997). As iscas fitoterápicas foram obtidas pela mistura de farinha de trigo, farinha de gergelim/ou óleo de nim e água, na proporção 2:2:1. Para isca placebo utilizou-se farinha de trigo e água. Foi realizada a identificação de espécies de formigas cortadeiras em 60 formigueiros para o gênero Acromyrmex e 40 formigueiros para o gênero Atta. Para o estudo de etologia foram marcados três formigueiros de ambos os gêneros, Atta e Acromyrmex. Observações foram feitas quanto ao comportamento e preferência por espécies de vegetais forrageadas ao longo do ano, por um período de 24 horas, para cada mês/época avaliada. Para o estudo etnoentomológico foi aplicado um questionário qualitativo e quantitativo referente ao envolvimento do homem com a formiga cortadeira em diferentes sistemas de produção, orgânico, de transição e convencional. As questões abordaram os tópicos: características do sistema de produção; período na atividade; identificação e conhecimento sobre métodos naturais de controle. A análise dos resultados mostrou que as iscas fitoterápicas, e os preparados homeopáticos reduziram as atividades total e forrageira para ambos os gêneros, Acromyrmex e Atta, respectivamente a partir do terceiro e sétimo dia consecutivo de aplicação para ambas atividades. O comportamento de ambos os gêneros Atta e Acromyrmex, para as atividades total e forrageira foram variáveis ao longo ano, sendo dependente das condições de temperatura e umidade relativa diária. Os estudos taxonômicos revelaram que no gênero Acromyrmex, predominaram as espécies Acromyrmex laticeps, Acromyrmex heyeri, Acromyrmex coronatus e Acromyrmex lundi, sendo as duas últimas espécies consideradas de ocorrência rara na região. O gênero Atta apresentou uma única espécie Atta sexdens piriventris. Segundo os agricultores entrevistados as formigas representam a maioria dos danos gerados nas culturas, e o seu controle, na maioria das vezes é realizado por iscas tóxicas. Os preparados homeopáticos mostraram ser uma importante ferramenta para o controle das atividades total e forrageira, para ambos os gêneros de formigas cortadeiras, com destaque para preparado homeopático nosódio de formigas. Iscas fitoterápicas de nim e gergelim afetaram o comportamento de ambos os gêneros de formigas cortadeiras.

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