Submitted by (edna.saturno@ufrpe.br) on 2016-12-01T12:21:44Z No. of bitstreams: 1 Wendel Jose Teles Pontes.pdf: 861006 bytes, checksum: 961fa7bfa809cad4e7404803afd41260 (MD5) / Made available in DSpace on 2016-12-01T12:21:44Z (GMT). No. of bitstreams: 1 Wendel Jose Teles Pontes.pdf: 861006 bytes, checksum: 961fa7bfa809cad4e7404803afd41260 (MD5) Previous issue date: 2006-02-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present work has the objective to verify the chemical composition and the bio activity of essential oils form fruits and leaves of Protium heptaphyllum and of X. sericea, and the fresh and old oil resins of Protium bahianum, as well as the effect of plant extracts of Croton sellowii, C. micans, C. rhamnifolium, C. jacobinensis and Xylopia sericea, all native species of Pernambuco, on the mite T. urticae. Major constituent identified in the essential oil of fruits from P. heptaphyllum is α-terpene (47.57 %) whereas in the leaves are the sesquiterpenes 9-epi-cariofileno (21.35 %), trans-isolongyfolanone (10.70 %) and 14-hydroxy-9-epi-cariofilene (16.70 %). The fruit oil is more efficient against mites in comparison with the leaf oil. Both oils show a property of mortality and deterrence in oviposition in the highest concentration (10μL L-1 air) and only the essential oil of fruits induces repellence on T. urticae. The essentialoils of the two resins of Protium bahianum were analysed. The old resin shows a high percentage of oxygen containing sesquiterpenes (85.40 %) with high predominance of β-(Z)-santalol acetate (83.08 %). No sesquiterpene was found in the essential oil of the fresh resin, which comprises basically monoterpenes of hydrocarbons (42.37 %) and oxygenated monoterpenes (27.71 %), from which α-phellandrene (13.86 %) and 4-terpineol (7.44 %) arte the major components, respectively. The oils show toxicity against ants, but only the essentialoil of the fresh resin show repellence. Of the studied Croton extracts, the one of the leaves of C. sellowii is the most efficient, causing 69 % of mortality and only the leaf extract of C. jacobinensis is inactive. Mites’ fecundity was affected and all extract show repellence in the concentration of 1%. The major compounds in the essential oil of fruits of X. sericea are β-pinene and α-pinene. The leaf oil is comprised basically by cubenol followed by α-epi-muurolol. Hexane extracts of fruits and the essential oils of fruits and leaves show toxicity against mites. The xylopic acid even not provoking mortality reduces mites’ fecundity. / O presente trabalho tem por objetivo verificar a composição química e a bioatividade dos óleos essenciais de frutos e folhas de Protium heptaphyllum e de Xylopia sericea, e os óleos das resinas velha e fresca de Protium bahianum, bem como o efeito de extratos vegetais de Croton sellowii, C. micans, C. rhamnifolius, C. jacobinensis e X. sericea, todas estas espécies nativas de Pernambuco, sobre o ácaro rajado Tetranychus urticae. O constituinte majoritário identificado no óleo essencial dos frutos de P. heptaphyllum foi α-terpineno (47,57%), enquanto que nas folhas foram os sesquiterpenos 9-epi-cariofileno (21,35%), trans-isolongifolanona (10,70%) and 14-hidroxi-9-epi-cariofileno (16,70%). O óleo dos frutos foi mais eficiente contra o ácaro, comparado com o óleo das folhas. Ambos os óleos apresentaram mortalidade e efeitos sobre a oviposição na maior concentração (10μL / L de ar) e apenas o óleo essencial dos frutos provocou repelência à T. urticae. Os óleos essenciais dos dois exsudatos resinosos de P. bahianum foram analisados. A resina velha mostrou alta percentagem de sesquiterpenos, contendo oxigênio (85,40%) com alta predominância de β-(Z)-santalol acetato (83,08 %). Contudo, nenhum sesquiterpeno foi detectado no óleo essencial de resina fresca, sendo este constituído basicamente de monoterpenos hidrocarbonados (42,37%) e monoterpenos oxigenados (27,71%), dos quais α-phellandrene (13,86 %) e 4-terpineol (7,44 %) foram os componentes majoritários, respectivamente. Os óleos mostraram ação fumigante, mas somente o óleo essencial de resina fresca foi repelente. Dentre os extratos de Croton estudados, verificou-se que o extrato de folhas de C. sellowii apresentou melhor performance, causando 69% de mortalidade e apenas o extrato de folhas de C. jacobinensis foi inativo. A fecundidade dos ácaros também foi afetada e todos os extratos foram repelentes na concentração de 1%. Os compostos majoritários encontrados no óleo essencial dos frutos de X. sericea foram β-pineno e α-pineno. O óleo das folhas foi majoritariamente constituído por cubenol seguido por α-epi-muurolol. Os extratos hexânicos de frutos e os óleos essenciais de frutos e folhas foram tóxicos ao ácaro rajado. O ácido xylópico, apesar de não ter provocado mortalidade, reduziu a fecundidade do ácaro.

Submitted by (edna.saturno@ufrpe.br) on 2016-12-01T14:41:32Z No. of bitstreams: 1 Flavia de Souza Born.pdf: 858418 bytes, checksum: 5785147d20d21fb9c69b74322ff6448b (MD5) / Made available in DSpace on 2016-12-01T14:41:32Z (GMT). No. of bitstreams: 1 Flavia de Souza Born.pdf: 858418 bytes, checksum: 5785147d20d21fb9c69b74322ff6448b (MD5) Previous issue date: 2012-02-01 / Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), has been controlled mainly chemical synthetic acaricides. The use of essential oils can be an alternative to this method of control. The aim of this study was to determine the effect of essential oils from plants of Families Burseraceae, Lamiaceae, Rutaceae and Verbenaceae against T. urticae and the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). Repellent and toxic activities of the oils were determined and compared to eugenol. Toxicity was evaluated by fumigation and residual effect in the laboratory and by direct contact in a greenhouse. The results showed that the oils of Ocimum basilicum L. and Thymus vulgaris L. were the most repellent, with RC50 = 3.43 x 10-7 and 2 x 10-4 μL/mL, respectively. The toxicity against eggs of T. urticae revealed T. vulgaris, Rosmarinus officinalis L., Citrus reticulata Blanco and O. basilicum oils as more active. Estimates of mortality concentration curves for fumigation of adult females of T. urticae revealed that was more toxic eugenol, with LC50 = 4 x 10-3 μL/L air. The test results showed that residual C. reticulata, T. vulgaris and O. basilicum oils present the same toxicity observed for eugenol. The toxicity tests to N. californicus indicated that all the oils are selective fumigation and that the O. basilicum, R. officinalis and C. reticulata oils were more selective by residual effect. The relative toxicity of the individual constituents of the essential oils and their contribuition to the acaricidal activity on T. urticae are also discussed. The highest average mortality on T. urticae in the greenhouse after 72 h of exposure were 100%, 98.85% and 96.59%, promoted by Citrus sinensis Osbek x Citrus reticulata Blanco, R. officinalis and Lippia gracilis Schauer oils, respectively. / O ácaro rajado, Tetranychus urticae Koch (Acari: Tetranychidae), tem sido controlado principalmente com acaricidas químicos sintéticos. O uso de óleos essenciais pode ser uma alternativa a esse método de controle. O objetivo deste trabalho foi determinar o efeito de óleos essenciais de plantas das Famílias Burseraceae, Lamiaceae, Rutaceae e Verbenaceae sobre T. urticae e o ácaro predador Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). As atividades repelente e tóxica dos óleos foram determinadas e comparadas ao eugenol. A toxicidade foi avaliada por fumigação e efeito residual, em laboratório e por contato direto em casa de vegetação. Os resultados demonstraram que os óleos de Ocimum basilicum L. e Thymus vulgaris L. foram mais repelentes, com CR50 de 3,43 x 10-7 e 2 x 10-4 μL/mL, respectivamente. A toxicidade sobre ovos de T. urticae revelou os óleos de T. vulgaris, Rosmarinus officinalis L., Citrus reticulata Blanco e O. basilicum como mais ativos. As estimativas das curvas de concentração mortalidade para fumigação sobre fêmeas adultas de T. urticae revelaram que eugenol foi mais tóxico, com CL50 de 4 x 10-3 μL/L de ar. Os resultados dos testes de efeito residual demonstraram que os óleos de C. reticulata, T. vulgaris e O. basilicum apresentaram a mesma toxicidade observada para o eugenol. Os testes de toxicidade a N. californicus indicaram que todos os óleos foram seletivos por fumigação e os óleos de O. basilicum, R. officinalis e C. reticulata foram os mais seletivos por efeito residual. A toxicidade relativa de constituintes individuais dos óleos e sua contribuição para a atividade sobre T. urticae também são discutidos. As maiores médias de mortalidade sobre T. urticae em casa de vegetação após 72 h de exposição foram de 100%, 98,85% e 96,59%, promovidas pelos óleos de Citrus sinensis Osbek x Citrus reticulata Blanco, R. officinalis e Lippia gracilis Schauer, respectivamente.

The Allee effect corresponds to a positive relationship between population size and individual fitness. This positive relationship can cause thresholds, that is, critical population sizes below which the population becomes extinct. For species submitted to the Allee effect, the formation and cohesion of groups is therefore crucial to survival. Animals can achieve this collective behaviour through local interactions. Each individual interacts locally with conspecifics and, at the scale of the group, a unity of behaviour emerges: the animals move together, rest in the same place, or choose the same habitat patch to settle on. <p><p>We use a combination of mathematical modelling and experimental work to study certain mechanisms of collective behaviour. In particular we assess the extent to which different individual interactions can induce collective patterns and thereby influence the dynamics of dispersal and settlement of populations. First, we study the collective settlement induced by the arresting effect of a marker secreted by conspecifics. Then, two potential mechanisms for collective movement are examined: following the conspecifics and following a trail laid by conspecifics. Finally, we integrate explicit mechanisms of dispersal behaviour in a dynamic model involving a set of interconnected populations. This allows the study of the interplay between collective movements and Allee effects at the scale of the metapopulation.<p><p>Our work is inspired by the lifestyle of the two-spotted spider mite, Tetranychus urticae, a phytophagous pest of recognised agricultural importance. These subsocial mites live in aggregates on the leaf surface, protected by a collectively spun silk web. Experimental evidence suggests that its population dynamics are subject to the Allee effect. Moreover, these mites show a tendency to migrate collectively, which makes them an appropriate biological model. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Las arañas rojas constituyen una de las plagas más importantes en la producción de hortalizas del litoral mediterráneo español, tanto en invernadero como al aire libre. Estos ácaros son controlados por medios químicos, lo cual representa costos significativos en términos económicos y ecológicos. Otra alternativa sería el control biológico usando fitoseidos que son depredadores naturales de los tetraníquidos. Sin embargo, se desconocen informaciones básicas sobre la dinámica y la óptima relación depredador-presa necesarias para que el control biológico sea efectivo. Este trabajo evaluó la relación depredador-presa de los fitoseidos nativos Phytoseiulus persimilis Athias- Henriot y Neoseiulus californicus (McGregor) con las arañas rojas T. urticae Koch, T. turkestani Ugarov y Nikolski y T. evansi Baker y Pritchard. El estudio incluyó ensayos de laboratorio y de invernadero, realizados en plantas de judía (Phaseolus vulgaris L.) y patata (Solanum tuberosum L.), al igual que simulaciones de la dinámica poblacional de los fitoseidos depredadores y los ácaros fitófagos. En el laboratorio se estudió el consumo de presa y los principales parámetros biológicos y demográficos de los dos depredadores cuando se alimentan de T. urticae. Los resultados del laboratorio indicaron que la duración del desarrollo, la fecundidad y los parámetros demográficos de poblaciones locales de N. californicus y P. persimilis eran similares a los de otras regiones geográficas y que cuando estos depredadores consumían T. urticae sus parámetros alcanzaban valores óptimos. En el invernadero se evaluó su eficacia en tres relaciones depredador-presa: 1:12, 1:8 y 1:4 para los ensayos con T. urticae, y de1:16, 1:8 y 1:4 para ensayos con T. turkestani y T. evansi. También se determinó el índice de daño y la distribución de los ácaros en las plantas y su comportamiento dispersivo en función del tiempo y de la densidad poblacional. / Gómez Moya, CA. (2007). Dinámica del sistema depredador-presa de las arañas rojas y los fitoseidos (Acari: Tetranychidae, Phytoseiidae) en cultivos hortícolas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/15228

The spider mite occurrence, on soybean (Glycine max (L.) Merril), is sporadic and associated whit dry periods. Recently, in continuous years, was reported mite outbreaks in soybean, in some sites of Rio Grande do Sul State. In this context two research was conducted, one in summer crop 2004/05 and other in 2005/06. The first was carried for study the mite occurrence and geographic distribution, on soybean, from some place of Rio Grande do Sul State. The second was conducted for study the effect of the two soybean cultivars and of some weed management systems on mite density and study their population dynamic on soybean. In summer crop 2004/05 was carried some mite samplings in soybean field at State. The mite species found, all beloung to the Tetranychidae family, are Mononychellus planki (McGregor), Tetranychus desertorum Banks, T. gigas Pritchard & Baker, T. ludeni Zacher and T. urticae Koch. Most of this species are well distributed in the diferents sampling regions of this study. From the results was made a species distribution map and a taxonomic key. In summer crop 2005/06, in Santa Maria, RS, 11 treatments was study. Its was constitute in two soybean cultivars, one transgenic glyphosato-tolerant and other non-transgenic, every one whit five weed management systems: (1) without management; (2) hand management; (3) herbicide bentazone + sethoxydim; (4) bentazone only; (5) sethoxydim only. The 11th treatment was the herbicide glyphosate sprayed on the transgenic soybean. The mite species found in this study are M. planki and T. gigas. The weed management systems is more determinant, on the spider mite population on soybean, than the soybean cultivar. The mite population presenteded inverse correlation whit weed infestation and weed density. The climatic fators determined the mite population flutuation and the population peak occured in the initial period of soybean pods development. / A ocorrência de ácaros-praga em soja (Glycine max (L.) Merril) é esporádica e está, comumente, associada à períodos de estiagem. Recentemente, em safras seguidas, foram observados ataques severos de ácaros à soja em algumas regiões do estado do Rio Grande do Sul. Neste contexto foram realizados dois experimentos, um na safra agrícola 2004/05 e outro em 2005/06. O primeiro teve objetivo de estudar a ocorrência e a distribuição geográfica de ácaros fitófagos, associados à soja, em municípios de seis regiões produtoras do estado do Rio Grande do Sul. O segundo objetivou avaliar o efeito de duas cultivares de soja e de diferentes sistemas de manejo de plantas daninhas sobre a densidade populacional de ácaros em soja e estudar a dinâmica populacional destes ácaros na cultura. Em 2004/05 foram realizadas amostragens de ácaros em lavouras de soja no Estado. As espécies de ácaros encontradas são Mononychellus planki (McGregor), Tetranychus desertorum Banks, T. gigas Pritchard & Baker, T. ludeni Zacher e T. urticae Koch, todos são tetraniquídeos. A maior parte destas espécies estiveram bem distribuídas nas diferentes regiões amostradas neste levantamento. Com base nestes resultados foi elaborado um mapa com a distribuição das espécies e uma chave de identificação. Em 2005/06 foram estudados, em Santa Maria, RS, 11 tratamentos. Estes consistiram em duas cultivares de soja, uma transgênica glifosato-tolerante e a outra não-transgênica, cada uma sob cinco sistemas de manejo de plantas daninhas: (1) sem controle; (2) arranquio manual; (3) manejo tradicional com os herbicidas bentazona e setoxidim; (4) apenas com bentazona; (5) apenas com setoxidim. E adicionalmente um tratamento com o herbicida glifosato sobre a cultivar de soja transgênica. Os ácaros-praga ocorrentes foram M. planki e T. gigas. A densidade populacional destes ácaros em soja foi mais afetada pelos sistemas de manejo de plantas daninhas do que pela cultivar, e esteve inversamente correlacionada com a quantidade e diversidade de plantas daninhas. A flutuação populacional destes ácaros foi influenciada por fatores climáticos e o pico populacional ocorreu na fase de início da formação de legumes da soja.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Under natural conditions, plants release volatile organic compounds (VOCs) that can differ either qualitative or quantitatively from those induced by herbivory. Induced VOCs are specific, varying with the attacked plant species, with the herbivore, and the developmental stages and conditions from both species. Induced VOCs mediate important ecological interactions. They can attract predators and parasitoids, repel herbivores and mediate communication between neighboring plants and different parts of the same plant. Cassava (Manihot esculenta) is a native plant from Brazil cultivated in all regions, but mainly in the northeast region. It has an important role in animal and human feeding, manufacturing of industrial products and the creation of jobs and income. Several studies have been conducted to identify the volatile compounds induced by herbivory and observe their influence in the behavior of herbivores and their natural enemies, however, to date little is known about the VOCs emissions of cassava plants and their role in arthropod-plant interactions. This study aimed at identifying the volatiles induced by herbivory from the herbivorous mites Mononychellus tanjoa, Tetranychus urticae and T. gloveri in cassava plants, and how these herbivorous mites and the predatory mite Neoseiulus idaeus respond to induced VOCs blends. Twenty three compounds (monoterpenes, sesqueterpenes, aldehyde, alcohol, esters, oxime, phenylpropanoid and indole) were identified in the headspace of healthy and mite-damaged cassava plants. Herbivore-damaged plants released novel compounds that weren’t emitted by the healthy plants. Significant difference were found in the emission of methyl salicylate by M. tanajoa and T. gloveri infested plants, and (Z)-3-hexen-1-ol infested with T. urticae, when compared to healthy plants. The compounds (Z)-β-ocimene, 2-methyl propanol oxime, 2-methyl butanoloxime, indole, methyl anthranilate and (E)-nerolidol were only induced by herbivory from T. urticae, and may be involved in the attraction of N. idaeus, since the predator with experience in cassava significantly preferred plants infested with T. urticae compared to healthy plants. Tetranychus gloveri with cassava experience preferred healthy cassava plants compared to clean air, demonstrating that the plant produces volatiles that are attractive to herbivores. It can be concluded that after the herbivory cassava plants emit VOCs that differ qualitatively and quantitatively from those released by healthy plants and the total amount emitted increases with the density of mites in the plant. Despite the emission of VOCs known to attract predatory mites by plants infested with M. tanajoa and T. gloveri, N. idaeus did not prefer infested plants, suggesting that the level of induction was not sufficient or these herbivorous mites are not attractive to the predator. / As plantas constantemente liberam um conjunto de compostos orgânicos voláteis (COVs) para a atmosfera que pode diferir qualitativa e quantitativamente dos voláteis que são liberados quando são atacadas por herbívoros. A composição desses voláteis é específica, variando de acordo com a espécie de planta e do herbívoro, e com os estágios de desenvolvimento e condições dessas espécies. Os COVs são importantes na mediação de interações específicas, podendo atrair predadores e parasitoides, repelir herbívoros e mediar a comunicação entre plantas vizinhas e diferentes partes de uma mesma planta. A mandioca, Manihot esculenta, é uma planta nativa do Brasil, sendo cultivada em todas as regiões, destacando-se a região Nordeste, com importante papel na alimentação humana e animal, como matéria-prima para produtos industriais e geração de emprego e renda. Diversos estudos têm sido realizados com o objetivo de identificar os COVs induzidos por herbivoria e observar a sua influência no comportamento dos herbívoros e seus inimigos naturais, porém pouco se sabe sobre as emissões de COVs das plantas de mandioca e seu papel nas interações artrópodes-plantas. No presente estudo buscou-se identificar os voláteis induzidos pela herbivoria dos ácaros Mononychellus tanajoa, Tetranychus urticae e T. gloveri em plantas de mandioca, e como esses ácaros herbívoros e o ácaro predador Neoseiulus idaeus respondem aos conjuntos de COVs induzidos. Foram identificados 23 compostos (monoterpenos, sesquiterpenos, aldeídos, álcool, oximas, éster, indole e fenilpropanoide) liberados pelas plantas de mandioca sadias e submetidas à herbivoria. Plantas com herbivoria emitiram novos compostos que não foram liberados pelas plantas sadias. Foi encontrada diferença significativa na emissão de salicilato de metila pelas plantas com herbivoria de M. tanajoa e T. gloveri, e (Z)-3-hexen-1-ol pelas plantas com herbivoria de T. urticae, quando comparadas com as plantas sadias. Os compostos (Z)-β-ocimeno, 2-metil propanol oxima, 2-metil butanol oxima, indole, metil anthranilate e (E)-nerolidol foram induzidos apenas pela herbivoria de T. urticae e podem estar envolvidos na atração de N. idaeus, uma vez que o predador com experiência em mandioca preferiu significativamente as plantas infestadas com T. urticae em comparação às plantas sadias. Tetranychus gloveri com experiência em mandioca preferiu plantas de mandioca sadias em comparação ao ar limpo, demonstrando que a planta produz voláteis atraentes para os herbívoros. Pode-se concluir que após a herbivoria plantas de mandioca emitem COVs que diferem qualitativa e quantitativamente daqueles liberados pelas plantas sadias e a quantidade total emitida aumenta com a densidade de ácaros na planta. Apesar da emissão de COVs conhecidos por atraírem ácaros predadores pelas plantas infestadas com M. tanajoa e T. gloveri, N. idaeus não preferiu as plantas infestadas, sugerindo que o nível de indução não foi suficiente ou esses ácaros herbívoros não são atraentes para o predador.

A major goal of evolutionary developmental biology is to explore mechanisms and events underlying evolution of the myriad body plan morphologies expressed both genetically and phenotypically within the animal kingdom. Arthropods exhibit an astounding array of morphological diversity both within and between representative sub-phyla, thus providing an ideal phylum through which to address questions of body plan innovation and diversification. Major arthropod groups are recognised and defined by the distinct form and number of articulated appendages present along the antero-posterior axis of their segmented bodies. A great deal is known about the developmental genetics of limb development in the model insect Drosophila melanogaster, added to which, much comparative gene expression data and a growing body of functional genetic data is emerging for other arthropod species. Arthropod limb primordia are consistently marked by expression of the homeobox gene Distal-less (Dll), and the focus of this thesis is to compare signalling mediated by early Dll regulatory genes activity along antero-posterior and dorso-ventral embryonic axes during limb specification in Drosophila, with the activity of their orthologs in the widely disparate chelicerate, the spider mite Tetranychus urticae - interpreting new data with that available for other arthropods. Having made a detailed study of spider mite embryonic (and post-embryonic) development, to provide a basis for understanding mRNA transcription and protein activity patterns, I confirmed typical expression of Tetranychus Dll in prosomal limb primordia. I obtained limited results for the candidate antero-posterior positioning genes wingless and engrailed, although one of the two engrailed paralogs I identified is reportedly expressed in posterior segmental compartments, consistent with possible conservation of Engrailed-Wingless interactions in metameric patterning and positive regulation of Dll in arthropod limb specification. In Drosophila, wingless-dependent Dll transcription is restricted along the dorso-ventral axis by dorsal Dpp-mediated and ventral EGFR-mediated signalling gradients. Based on data from Tetranychus and other arthropods, neither dorsal nor ventral signalling regimes appear conserved outside the Drosophila system. Dll suppression in fly abdominal segments occurs due to powerful Hox (Ubx/AbdA) repression of the early Dll cis-regulatory element; this is discussed in relation to the independently evolved limbless chelicerate opisthosoma, informed by hypothetical scenarios of cis (regulatory DNA) and trans (coding sequence) evolution. Given practical difficulties and limitations encountered while working with spider mites, I offer a final assessment of the place of Tetranychus urticae as a non-model, and yet still valuable chelicerate species to consider carrying into the exciting future of evolutionary developmental biology.

The aim of this study was to investigate the usefulness of image analysis for studying mite behaviour. Image analysis was used to convert video recordings of mites' locomotory behaviour into a series of x,y coordinates that, when joined, closely resemble the paths of mites. The coordinates were also used to calculate walking speed, direction of travel, turning frequency, turn bias and tortuosity. Two experimental arenas were developed and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi (Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten. Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute period. Mites exhibited a significant decline in distance travelled, whereas the mean stationary time (per four minute interval) more than doubled, and the duration of stationary events increased steadily over the same period. A reduction in sampling frequency of mite coordinates from one per second to one every two seconds and every four seconds produced a 5% and 12% 'loss' in path length respectively. Sample period length was shown to greatly influence the results produced for some of the mean parameters calculated, however, a reduction in sample length from 3000 to 1500 coordinates was not considered to cause a major loss in information. The influence of the inherent mite movement could not be ignored and made it difficult to make decisions on the 'best' sample length to use. Some strong correlations were found between parameters used to analyse mite locomotory behaviour. In particular, arithmetic mean vector length, speed, total stationary time and total distance travelled were significantly correlated with each other. Mean angular deviation and weighted mean vector length, which both measure the degree of clustering around the mean heading angle, were strongly negatively correlated. Parameters which differentiated between 'straight' and 'tortuous' mite movement were found to be mean meander, absolute mean turn and fractal dimensions. Mean meander was thought to be the most 'powerful', while coefficient of a straight line, a commonly used parameter for measuring tortuosity, did not significantly differentiate between the two different behaviours. Frequency distributions of turns and standard deviations of the three mite species were very similar. All three species had a slight bias to turning right (clockwise) rather than to the left (counter-clockwise) and for each species certain angles occurred more often than would be expected in a 'perfect' normal distribution. A similar pattern also occurred with the frequency distribution of two-spotted spider mite heading angles, in that angles which were expected to occur more often, did not, and vice versa. The potential to use saturated salt solutions to control relative humidity on the arena was` demonstrated and indicated that relative humidity is likely to have an important influence on mite behaviour. Two-spotted spider mites appeared to move more quickly in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture conditions. All three mite species displayed a characteristic edge-walking behaviour around the arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander was the only parameter (of the parameters tested) which gave a significant difference. Behavioural responses of European red mite and T. pyri to sub-lethal (field rate) esfenvalerate were investigated and the results indicated that these mites did not seek the unsprayed halves of the arenas during the first 48 minutes. However, significant differences in most behavioural parameters to esfenvalerate residues were found with European red mite when whole arenas were compared. Image analysis is an extremely useful research tool for studying mite behaviour because of its ability to measure many parameters quickly. Careful choice of the environmental conditions, the sampling framework, and interpretation of data is essential for meaningful results.

The aim of this study was to investigate the usefulness of image analysis for studying mite behaviour. Image analysis was used to convert video recordings of mites' locomotory behaviour into a series of x,y coordinates that, when joined, closely resemble the paths of mites. The coordinates were also used to calculate walking speed, direction of travel, turning frequency, turn bias and tortuosity. Two experimental arenas were developed and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi (Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten. Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute period. Mites exhibited a significant decline in distance travelled, whereas the mean stationary time (per four minute interval) more than doubled, and the duration of stationary events increased steadily over the same period. A reduction in sampling frequency of mite coordinates from one per second to one every two seconds and every four seconds produced a 5% and 12% 'loss' in path length respectively. Sample period length was shown to greatly influence the results produced for some of the mean parameters calculated, however, a reduction in sample length from 3000 to 1500 coordinates was not considered to cause a major loss in information. The influence of the inherent mite movement could not be ignored and made it difficult to make decisions on the 'best' sample length to use. Some strong correlations were found between parameters used to analyse mite locomotory behaviour. In particular, arithmetic mean vector length, speed, total stationary time and total distance travelled were significantly correlated with each other. Mean angular deviation and weighted mean vector length, which both measure the degree of clustering around the mean heading angle, were strongly negatively correlated. Parameters which differentiated between 'straight' and 'tortuous' mite movement were found to be mean meander, absolute mean turn and fractal dimensions. Mean meander was thought to be the most 'powerful', while coefficient of a straight line, a commonly used parameter for measuring tortuosity, did not significantly differentiate between the two different behaviours. Frequency distributions of turns and standard deviations of the three mite species were very similar. All three species had a slight bias to turning right (clockwise) rather than to the left (counter-clockwise) and for each species certain angles occurred more often than would be expected in a 'perfect' normal distribution. A similar pattern also occurred with the frequency distribution of two-spotted spider mite heading angles, in that angles which were expected to occur more often, did not, and vice versa. The potential to use saturated salt solutions to control relative humidity on the arena was` demonstrated and indicated that relative humidity is likely to have an important influence on mite behaviour. Two-spotted spider mites appeared to move more quickly in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture conditions. All three mite species displayed a characteristic edge-walking behaviour around the arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander was the only parameter (of the parameters tested) which gave a significant difference. Behavioural responses of European red mite and T. pyri to sub-lethal (field rate) esfenvalerate were investigated and the results indicated that these mites did not seek the unsprayed halves of the arenas during the first 48 minutes. However, significant differences in most behavioural parameters to esfenvalerate residues were found with European red mite when whole arenas were compared. Image analysis is an extremely useful research tool for studying mite behaviour because of its ability to measure many parameters quickly. Careful choice of the environmental conditions, the sampling framework, and interpretation of data is essential for meaningful results.