Host plant selection is an important process during the life cycle of lepidopterans, providing ovipositing sites for adults and food resources for the larvae. The processes behind host plant selection have been extensively studied, especially in closely related species in the context of niche separation. Empirical and theoretical studies have shown that multiple processes, such as resource competition, parasitoid avoidance and reproductive interference between interspecific individuals can affect host plant selection, often leading to niche separation. The aim of this study was to create and analyze a mathematical model using the adaptive dynamics techniques, in order to study the evolution of habitat selection. Our model incorporated three processes: Resource competition in the form of density dependent growth, parasitoid attacks and repro- ductive interference in a two species-two habitat system. It was hypothesized that the presence of parasitoids would promote co-existence through top-down control, while reproductive inter- ference would promote niche separation. The results confirmed both hypotheses. The analysis incorporating only the effect of parasitism showed the evolution of habitat separation when parasitoids attacked randomly and the evolution of co-existence in both habitats in the case of switching parasitoids. On the other hand, incorporating reproductive interference promoted the evolution of partial or complete niche separation. The extent of this process was shown to depend on the strength of reproductive interference and the initial habitat choice of the two species. Stronger reproductive interference increased the size of the set of initial conditions leading to the evolution of complete niche separation. The analysis conducted in this study demonstrated the opposing effects of parasitism and reproductive interference on the evolution of habitat selection, promoting co-existence and separation respectively.

Um dos fatores que influenciam o crescimento e desenvolvimento das plantas cultivadas é a presença de plantas de ocorrência espontânea, também conhecidas como invasoras, plantas daninhas ou mato. Estas podem afetar negativa ou positivamente diferentes cultivos em que são encontradas. O efeito negativo usualmente se refere à competição com a cultura por água, nutrientes e luz, proliferação de doenças e pragas, e outros. O efeito positivo se refere à proteção do solo contra erosão, reservatório de agentes de controle biológico e outros. O objetivo do presente trabalho foi determinar a composição da acarofauna plantícola de três culturas e das plantas de ocorrência espontânea a estas associadas, assim como estudar a biologia de duas importantes espécies de ácaros encontradas. As culturas consideradas no estudo foram café (Coffea arabica L.), laranja (Citrus sinensis (L.)) e coqueiro (Cocos nucifera L.). Brevipalpus phoenicis (Geijskes) sensu lato (Tenuipalpidae), um dos principais ácaros danosos ao cafeeiro, foi encontrado nesta cultura, assim como em Amaranthus deflexus L., Panicum maximum Jacq, Richardia brasiliensis Gomes e Spermacoce suaveolens (G. Mey.) Kunthze. Polyphagotarsonemus latus (Banks) (Tarsonemidae), também importante em cafeeiro, foi encontrado em cafeeiro e em C. mucunoides Desv.. Brevipalpus phoenicis s.l. foi o único ácaro muito danoso ao citros encontrado sobre esta cultura. Este foi também encontrado em Digitaria insularis (L.) e Chamaesyce hirta L.. Um dos principais ácaros potencialmente danoso ao coqueiro, Raoiella indica Hirst (Tenuipalpidae), foi encontrado nesta cultura e também em 27 espécies de plantas de ocorrência espontânea. Estudos complementares poderão indicar quais das plantas de ocorrência espontânea estavam realmente servindo de hospedeiros aos ácaros sobre elas encontrados. Além dos ácaros fitófagos, várias espécies de ácaros predadores foram encontradas sobre as culturas consideradas e também sobre várias espécies vegetais de ocorrência espontânea, destacando- se Euseius citrifolius Denmark & Muma e Euseius concordis (Chant), ambos Phytoseiidae. Com isto, se observa que muitas das plantas de ocorrência espontânea podem funcionar como reservatório destes e outros predadores. Os resultados sugerem que o uso do termo erva daninha para as plantas de ocorrência espontânea em cultivos de café, laranja e coco não seja apropriado, tendo em vista que estas plantas abrigam diversas espécies de agentes de controle biológico, especialmente ácaros predadores da família Phytoseiidae. Avaliações em laboratório indicaram a capacidade de R. indica de colonizar as seguintes plantas: Amaranthus spinosus L., Ambrosia artemisiifolia L., Bidens pilosa L., Commelina diffusa Burm, Calopogonium mucunoides Desv, e Leonurus sibiricus L. No entanto, a colonização foi tênue, com a manutenção de poucos indivíduos de diferentes estágios na colônia. Estudos de laboratório também mostraram a possibilidade do desenvolvimento e reprodução deste ácaro em Phoenix roebelenii O\'Brien, planta introduzida no Brasil, comumente utilizada como ornamental, podendo ser importante como reservatório de R indica. Mononychelus planki (McGregor) (Tetranychidae) foi encontrado neste trabalho em nove plantas de ocorrência espontânea, dentre as quais, C. mucunoides. O presente estudo confirmou a importância desta planta na manutenção da população de M. planki no campo em condições naturais. O desenvolvimento e a reprodução do ácaro sobre C. mucunoides possibilita sua sobrevivência, sem que sua população atinja níveis que possam comprometer o desenvolvimento da planta, quando comparado ao que se observa na soja, planta cultivada de introdução relativamente recente no país. / One of the factors influencing growth and development of cultivated plants is the presence of plants of spontaneous occurrence, also known as invasives or weeds. These can negatively or positively affect different crops in which they are found associated with. The negative effect usually refers to competition with the crop for water, nutrients and light, proliferation of diseases and pests, and others. The positive effect refers to soil protection against erosion, reservoir of biological control agents and others. The objective of the present work was to determine the composition of the mite fauna of three crops and of plants of spontaneous occurrence associated to them, as well as to study the biology of two impotent mite species. The crops considered in the study were coffee (Coffea arabica L.), orange (Citrus sinensis (L.)) and coconut (Cocos nucifera L.). Brevipalpus phoenicis (Geijskes) sensu lato (Tenuipalpidae), one of the main mites harmful to coffee, was found on the crop as well as in Amaranthus deflexus L., Panicum maximum Jacq, Richardia brasiliensis Gomes and Spermacoce suaveolens (G. Mey.) Kunthze. Polyphagotarsonemus latus (Banks) (Tarsonemidae), also important on coffee, was found in coffee and on Calopogonium mucunoides Desv. Brevipalpus phoenicis s.l. was the only damaging citrus mite found on this crop. One of the main potentially harmful mites to coconut, Raoeilla indica Hirst (Tenuipalpidae), was found on this crop and also on 27 spontaneously growing plant species. Complementary studies may indicate which of the spontaneously occurring plants actually serve as hosts to the mites found on them. In addition to phytophagous mites, several predatory mite species were found on the crops and also on several spontaneously growing plant species, such as Euseius citrifolius Denmark & Muma and Euseius concordis (Chant), both Phytoseiidae. Hence, many of the plants of spontaneous occurrence can function as reservoir of these and other predators. The results suggest that the use of the term weed for plants of spontaneous occurrence in coffee, orange and coconut plantations is not appropriate, considering that these plants harbor several species of biological control agents, especially predatory mites of the family Phytoseiidae. Laboratory evaluations indicated the ability of R. indica to colonize the following plants: Amaranthus spinosus L., Ambrosia artemisiifolia L., Bidens pilosa L., Commelina diffusa Burm, C. mucunoides and Leonurus sibiricus L. However, colonization was tenuous, with the presence of few individuals of different stages in the colony. Laboratory studies have also shown the ability of this mite to develop and reproduce on Phoenix roebelenii O\'Brien, a plant introduced to Brazil, commonly used as ornamental, which may be important as a reservoir of R indica. Mononychelus planki (McGregor) (Tetranychidae) was found on nine plants of spontaneous occurrence, among which, C. mucunoides. The present study confirmed the importance of this plant in the maintenance of the M. planki population in the field under natural conditions. The development and reproduction of the mite on C. mucunoides allows its survival, without reaching population levels that could compromise the development of the plant, when compared to what is observed in soybean, cultivated plant of relatively recent introduction to the country.

Made available in DSpace on 2014-06-11T19:30:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-20Bitstream added on 2014-06-13T21:01:35Z : No. of bitstreams: 1 daud_rd_dr_sjrp.pdf: 374546 bytes, checksum: 6286f38c9fc3dc578888faa92f95d070 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Através de experimentos de campo, laboratório e de casa de vegetação foi analisada a susceptibilidade de diferentes clones de seringueira ao ataque de Calacarus heveae Feres (Acari, Eriophyidae). Em campo foram estudadas a dinâmica populacional de ácaros fitófagos e sua influência na estrutura da comunidade de ácaros em seis clones da seringueira, em área pertencente a empresa Plantações Edouard Michelin, Itiquira, MT. Para isso, foram amostrados 10 folíolos de 10 diferentes plantas em seis parcelas clonais, num intervalo médio de 14 dias, no período de março de 2004 a março de 2005. Em experimentos realizados no Laboratório de Acarologia do Depto. de Zoologia e Botânica, UNESP, São José do Rio Preto, foram acompanhados o ciclo biológico, a reprodução e sobrevivência populacional de 20 indivíduos de C. heveae em folíolos destacados dos clones GT 1, PB 235 e RRIM 600. Os ensaios foram repetidos quatro vezes, sendo cada repetição realizada em período em que se registrou a ocorrência do ácaro no campo. Em ensaio realizado em casa de vegetação, no campus da UNESP, São José do Rio Preto, SP, foi verificada a influência do ataque de C. heveae nos processos fisiológicos foliares e na produção de látex em 9 e 11 mudas dos clones RRIM 600 e GT 1, respectivamente, com cinco meses de idade. Foi verificado que a abundância de cada espécie fitófaga diferiu entre os seis clones estudados e, consequentemente, exerceu influência na ocorrência e distribuição das espécies diretamente ou indiretamente relacionadas. Os clones mais susceptíveis ao ataque de C. heveae foram PB 260 e RRIM 600, enquanto os mais resistentes PB 235, PB 217 e GT 1. Em arenas confeccionadas com folíolos destacados, C. heveae apresentou rápido ciclo biológico e maior taxa reprodutiva... / The susceptibility of different rubber tree clones to the attack of Calacarus heveae Feres (Acari, Eriophyidae) was analyzed through field, laboratory and greenhouse essays. In the field essay, we studied the population dynamics of phytophagous mites and its influence on the mite community structure in six rubber trees clones, in a farm belonging to the Plantações Edouard Michelin, Itiquitira, MT. For that, 10 leaflets of 10 different plants were sampled from each of the six clonal plots, from March 2004 to March 2005. We observed in essays performed in the Laboratory of Acarology of Depto. Zoology and Botany, UNESP, São José do Rio Preto, the biological cycle, reproduction and population survivorship of 20 C. heveae individuals reared on detached leaflets of clones GT 1, PB 235 and RRIM 600. The essays were repeated four times, in the periods when C. heveae was more abundant in the field. For the greenhouse essay, performed in UNESP, São José do Rio Preto, SP, we verified the influence of C. heveae attack on physiological processes and on the latex yield in 9 and 11 five-months aged seedlings of the clones RRIM 600 and GT 1, respectively. The phytophagous species had different abundances on the six rubber tree clones and, consequently, influenced the occurrence and distribution of other mite species. The most susceptible clones to the attack of C. heveae were PB 260 and RRIM 600, while the most resistant were PB 235, PB 217 and GT 1. In the arenas made of detached leaflets, C. heveae had faster development, high reproductive rate and survivorship increase on PB 235 and RRIM 600. Probably, the different ages of the plants used in field and laboratory essays influenced the conflicting results in relation to PB 235 susceptibility to C. heveae. The C. heveae attack decreased the photosynthetic rate... (Complete abstract click electronic access below)

Populations of Delphinium occidentale (Ranunculaceae)were monitored over two summers for the presence and dispersion of various life stages of several host specific phytophagous insects. Observations were made at several sites in the Wasatch National Forest east of Logan, Utah. Two species of larkspur aphid (Aphis rociadae and Kakimia wahinkae) were encountered. Although dispersal of alate individuals resulted in widespread infestation of the host plant population, aphids occurred initially on the same one or few plants at each site both springs. Little coexistence of the two species of aphid on the same plant was observed, perhaps because they partitioned the host plant resource according to light intensity under the incomplete aspen canopy. Several species of lepidopteran larvae, of uncertain host specificity, were observed. Two species (Autographa californica and pyrrhia expremins: Noctuidae) are known from cultivated host plants. Eggs of an unidentified geometrid (Lepidoptera) were located on the host plants in large numbers and their dispersion was analysed. The eggs were distributed nonrandomly over the host plant population, but attempts to further characterize the pattern were fruitless. Parasitism of the eggs by an unidentified hymenopteran was observed. Mortality of all larvae was high. Successful migration of larvae was not observed. Mature larvae were not sufficiently abundant to permit statistical study of pattern. Mature fruits were examined at the end of the growing season for larkspur maggots (Hylemya laxifrons). Maggots were found in 85 percent of the inflorescences sampled. Pteromalids (Hymenoptera) were also found in an apparently parasitic relationship with the maggots in the fruits. Maggots were not found in the surviving fruits of inflorescences infested with either species of aphid. Suggestions are given for future work.

Addendum in pocket. Biblography: leaves 162-173. Phytophagous sucking insects, aphids in particular, are common pests of plants. These insects secrete salivary enzymes into their food material. One plant defence mechanism is the induction and/or accumulation of deterrent phytochemicals. In the present study, a model enzyme system was chosen to mimic the oxidative activity of insect saliva. Isolation and sructural identification of the products of plant allelochemicals was achieved for several substrates. Insects were also exposed to individual plant chemicals in feeding "choice" tests. Preliminary examinations suggest that plants containing increased levels of phenolic allelochemicals show correlated increases in resistance to attack by aphids.

Addendum in pocket. / Biblography: leaves 162-173. / v, 177, [5] leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Phytophagous sucking insects, aphids in particular, are common pests of plants. These insects secrete salivary enzymes into their food material. One plant defence mechanism is the induction and/or accumulation of deterrent phytochemicals. In the present study, a model enzyme system was chosen to mimic the oxidative activity of insect saliva. Isolation and sructural identification of the products of plant allelochemicals was achieved for several substrates. Insects were also exposed to individual plant chemicals in feeding "choice" tests. Preliminary examinations suggest that plants containing increased levels of phenolic allelochemicals show correlated increases in resistance to attack by aphids. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1996

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Orientador: Reinaldo José Fazzio Feres / Banca: Carlos Holger Wenzel Flechtmann / Banca: Carlos Amadeu Leite de Oliveira / Banca: Gustavo Q. Romero / Banca: Antonio Carlos Lofego / Resumo: Através de experimentos de campo, laboratório e de casa de vegetação foi analisada a susceptibilidade de diferentes clones de seringueira ao ataque de Calacarus heveae Feres (Acari, Eriophyidae). Em campo foram estudadas a dinâmica populacional de ácaros fitófagos e sua influência na estrutura da comunidade de ácaros em seis clones da seringueira, em área pertencente a empresa Plantações Edouard Michelin, Itiquira, MT. Para isso, foram amostrados 10 folíolos de 10 diferentes plantas em seis parcelas clonais, num intervalo médio de 14 dias, no período de março de 2004 a março de 2005. Em experimentos realizados no Laboratório de Acarologia do Depto. de Zoologia e Botânica, UNESP, São José do Rio Preto, foram acompanhados o ciclo biológico, a reprodução e sobrevivência populacional de 20 indivíduos de C. heveae em folíolos destacados dos clones GT 1, PB 235 e RRIM 600. Os ensaios foram repetidos quatro vezes, sendo cada repetição realizada em período em que se registrou a ocorrência do ácaro no campo. Em ensaio realizado em casa de vegetação, no campus da UNESP, São José do Rio Preto, SP, foi verificada a influência do ataque de C. heveae nos processos fisiológicos foliares e na produção de látex em 9 e 11 mudas dos clones RRIM 600 e GT 1, respectivamente, com cinco meses de idade. Foi verificado que a abundância de cada espécie fitófaga diferiu entre os seis clones estudados e, consequentemente, exerceu influência na ocorrência e distribuição das espécies diretamente ou indiretamente relacionadas. Os clones mais susceptíveis ao ataque de C. heveae foram PB 260 e RRIM 600, enquanto os mais resistentes PB 235, PB 217 e GT 1. Em arenas confeccionadas com folíolos destacados, C. heveae apresentou rápido ciclo biológico e maior taxa reprodutiva... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The susceptibility of different rubber tree clones to the attack of Calacarus heveae Feres (Acari, Eriophyidae) was analyzed through field, laboratory and greenhouse essays. In the field essay, we studied the population dynamics of phytophagous mites and its influence on the mite community structure in six rubber trees clones, in a farm belonging to the Plantações Edouard Michelin, Itiquitira, MT. For that, 10 leaflets of 10 different plants were sampled from each of the six clonal plots, from March 2004 to March 2005. We observed in essays performed in the Laboratory of Acarology of Depto. Zoology and Botany, UNESP, São José do Rio Preto, the biological cycle, reproduction and population survivorship of 20 C. heveae individuals reared on detached leaflets of clones GT 1, PB 235 and RRIM 600. The essays were repeated four times, in the periods when C. heveae was more abundant in the field. For the greenhouse essay, performed in UNESP, São José do Rio Preto, SP, we verified the influence of C. heveae attack on physiological processes and on the latex yield in 9 and 11 five-months aged seedlings of the clones RRIM 600 and GT 1, respectively. The phytophagous species had different abundances on the six rubber tree clones and, consequently, influenced the occurrence and distribution of other mite species. The most susceptible clones to the attack of C. heveae were PB 260 and RRIM 600, while the most resistant were PB 235, PB 217 and GT 1. In the arenas made of detached leaflets, C. heveae had faster development, high reproductive rate and survivorship increase on PB 235 and RRIM 600. Probably, the different ages of the plants used in field and laboratory essays influenced the conflicting results in relation to PB 235 susceptibility to C. heveae. The C. heveae attack decreased the photosynthetic rate... (Complete abstract click electronic access below) / Doutor

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