Orientador: João Vasconcellos Neto / Tese ( doutorado) - Universidade Estadual de Campinas, Instituto de Biologias / Made available in DSpace on 2018-08-14T07:02:45Z (GMT). No. of bitstreams: 1 Paro_ClaudiaMoreno_D.pdf: 4764996 bytes, checksum: cbd200321d1b685a790530ab2b7f2a91 (MD5) Previous issue date: 2008 / Resumo: A estrutura da comunidade e as dinâmicas populacionais dos serra-paus (Onciderini; Cerambycidae: Coleoptera) foram investigadas na Serra do Japi, Jundiaí-SP, sudeste do Brasil, durante quatro anos, de dezembro de 2002 a dezembro de 2006. Este estudo também verificou o padrão de uso de plantas hospedeiras, incluindo preferências e relações com as características estruturais das plantas. Os adultos ocorreram entre outubro e maio, período utilizado para reprodução. Foi observado um total de 1113 indivíduos, de 12 espécies dos gêneros Oncideres e Psyllotoxus. Dos besouros observados, 1,0% foram classificados como espécies raras (Oncideres miniata, Oncideres bueki e Oneideres macra), 2,6% como espécies dispersas (Oneideres cervina), 37,8% como espécies comuns (Oneideres impluviata, Oncideres ulcerosa, Oneideres dejeani, Psyllotoxus griseocinetus e Oneideres irrorata) e 59,0 % como espécies muito abundantes (Oneideres saga, Oneideres captiosa e Oneideres humeralis). A razão sexual para a maioria das espécies foi de 1: 1 no mês de recrutamento das populações e deslocou a favor das fêmeas nos outros meses. Fatores abióticos, como precipitação e temperatura influenciaram a dinâmica e fenologia dessas populações. Na tribo Onciderini, as fêmeas cortam ramos de árvores, removendo a casca e a madeira com suas mandíbulas. Então colocam seus ovos dentro da madeira ao longo do ramo serrado desprendido, que, quebra e cai ao solo. A larva se desenvolve dentro do ramo morto da sua planta hospedeira. As plantas hospedeiras estão distribuídas em 15 famílias na seguinte ordem de importância: Vochysiaceae 44,6%, Mimosaceae 14,8%, Melastomataceae 11,4%, Lauraceae 9,3% e Anarcadinaceae 5,7%. As outras dez famílias utilizadas representaram 14,1% do total de espécies hospedeiras. Oeideres saga, dejeani, O. impluviata e P. griseocinetus são as espécies de Onciderini mais polífagas. Oneideres irrorata foi à única espécie aparentemente monófaga e especialista. Este trabalho também incluiu parâmetros da biologia e do comportamento destes serra-paus relacionando-os ao uso de cada espécie de planta hospedeira. Os seguintes parâmetros foram medidos: comprimento do ramo serrado, diâmetro, tipo de corte e padrão arquitetura da planta hospedeira e número de incisões para desova. Diferenças nos diâmetros médios dos ramos utilizados por diferentes Oniciderini foram estatisticamente significativas. Oncideres saga serrou os maiores diâmetros de ramos (X = 4,7 ± 0,89), enquanto que O. dejeani apresentou a maior média de incisões para desova (X = 64,9 ± 1,61). Houve relações significativas entre os diâmetros e comprimentos dos ramos cortados com os investimentos reprodutivos médios (n° de ovos/ramo). Estas relações indicam diferentes estratégias reprodutivas, que podem contribuir para reduzir à competição interespecífica e intraespecifica. De modo semelhante, houve também relação positiva entre o 'tamanho médio dos ramos serrados e o tamanho médio das fêmeas de Onciderini, isto apóia a idéia de "parking" na comunidade destes besouros. As estratégias e diferenças no comportamento entre as espécies de serra-paus foram associadas às características das plantas hospedeiras utilizadas, como, por exemplo, defesas físicas e químicas e ainda defesas indiretas por associações inseto-planta. De um modo geral, a diversidade encontrada neste grupo de insetos foi considerada alta, baseada em dados de literatura, mostrando a relevância da Serra do Japi como área a ser preservada. / Abstract: Community structure and dynamics on twig-girdlers populations were investigated from December 2002 to December 2006 in Serra do Japi, Southeaster Brazil. The adults occur between October and May, period utilized mainly for reproduction. It was observed a total of 1113 individuals, grouped in 12 species. From the beetles observed, 1 % was classified as rare species (Oncideres miniata, Oncideres bucki and Oncideres macra), 2,61% as disperse (Oncideres cervina), 37,83% as common (Oncideres impluviata, Oncideres ulcerosa, Oncideres dejeani, Psyllotoxus griseocinetus and Oncideres irrorata) and 59 % as very abundant (Oncideres saga, Oncideres captiosa and Oncideres humeralis). Sex ratio of most ofthe species was of 1: 1 in the recruitment of the populations, and it was deviated towards female in the other months. Abiotic factors, such as precipitation and temperature influenced the dynamics and phenology ofthese populations. In the tribe Onciderini (Coleoptera: Cerambycidae), the female girdles the trees by removing the bark and some of the wood using its mandibles. Then, it digs deep into the wood above the cut and lays its eggs. So, the branch breaks and falls on the ground and the larvae develop on the dead stems of their host plants. This study verified both the patters of host plant used by the insect and the species selection and its relation to structural characteristics of plants in Serra do Japi. 15 families of host plants were found in a whole, and they are listed in decreasing order of the most used ones: Vochysiaceae 44,62%, Mimosaceae 14,78%, Melastomataceae 11 ,41 %, Lauraceae 9,35% and Anarcadinaces 5,71 %, the other species summed 14,13% ofthe studied species. O. saga, O. dejeani, O. impluviata and P. griseocinetus were the most poliphagous species. O. irrorata was the only monophagous and specialist specie. Some other aspects like: 1) bioecological parameters of twig girdlers while using each host plant; 2) girdled stem len7 3) stem diameter; 4) cut type of the branch and 5) architectural pattern of the host plant w1 also included in this study. The differences of the diameter average were statistically significant. It was observed that O. saga cut branches of larger diameter ( X = 4,77 ± 0,89 DP). The average number of posture incisions by O. dejeani (X = 64,94 ±1,61 DP) was greater than the other species. There was significative relation between the average diameter and the twig length of the host plants with the reproductive investment (number of eggs/twig) of the twig-girdlers species from Serra do Japi. These relations indicate different reproductive strategies which contribute for reducing inter-specific competition. Likewise, the positive relation between the average size of the twig and the female size of the specie Onciderini indicates organizational standards of their community. The strategies and different behavior among the twig-girdler species were associated with characteristics of the used host plants. For instance: not only physical and chemical defenses but also indirect defenses by insect-plant associations. The diversity of this group of insects found in Serra do Japi was considered high. This, was based on a literature review, and thus shows that the place is environmentally and ecologically balanced in richness of species. Therefore, it is necessary that the site be preserved. / Doutorado / Doutor em Ecologia

Orientador: João Vasconcellos Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T07:06:44Z (GMT). No. of bitstreams: 1 Salomao_AdrianaTrevizoli_M.pdf: 945367 bytes, checksum: a2ebde1c7012c999bad6a17ba9fbbf0f (MD5) Previous issue date: 2007 / Resumo: Phloea subquadrata (Heteroptera: Phloeidae) é um pentatomóideo fitófago que vive sobre troncos de árvores, aos quais se assemelha devido à coloração e ao corpo altamente modificado. Este trabalho verificou os padrões de uso de plantas hospedeiras pelo inseto, incluindo seleção de espécies e sua relação com características estruturais das plantas na Serra do Japi, Sudeste do Brasil. Também foram investigadas a estrutura e dinâmica populacional durante três anos em plantas de Myrciaria jaboticaba. P. subquadrata foi registrado em dez espécies de Myrtaceae, ocorrendo preferencialmente em plantas com caules descamantes em relação a plantas com caules não-descamantes, e ocupou os maiores ramos disponíveis de cada espécie hospedeira. Não houve relação entre agrupamento dos ramos (isolados vs. moitas) e densidade de plantas hospedeiras e a ocupação e densidade de P. subquadrata. Adicionalmente, ninfas e adultos ocorreram durante todo o ano sobre M. jaboticaba, mas o período reprodutivo foi restrito à estação quente e chuvosa. A densidade populacional tendeu a aumentar no fim desta estação, e os indivíduos atingiram as fases subadulta e adulta no início da estação chuvosa subseqüente. A razão sexual não diferiu de 1:1 apenas no período de recrutamento dos adultos, e foi desviada a favor de machos nos outros meses. Os indivíduos ocorreram mais próximos ao solo na estação seca que na chuvosa, o que sugere que condições climáticas afetaram a seleção de micro-hábitats sobre a planta. Fatores abióticos, como chuvas e temperatura, também influenciaram a oviposição, dinâmica e fenologia desta população. Existem alguns poucos trabalhos sobre a biologia de Phloeidae, e este é o primeiro estudo que trata da ecologia desses insetos / Abstract: Phloea subquadrata (Heteroptera: Phloeidae) is a phytophagous pentatomoidean that lives on tree trunks, resembling to them because of its coloration and its body strongly modified. This study verified the patterns of host plant use by the insect, including species selection and its relation to structural characteristics of plants in Serra do Japi, Southeastern Brazil. Population structure and dynamics on plants of Myrciaria jaboticaba also were investigated along three years. P. subquadrata was recorded on ten species of Myrtaceae, occurring preferentially on plants that have shedding bark than on plants that have persistent bark, and occupying the largest branches of each host species. The density of P. subquadrata was not influenced neither by the level of grouping of the branches nor by the density of host plants. Additionally, nymphs and adults occurred through the year on M. jaboticaba, but the reproductive period was restricted to the warm and rainy season. Population density tended to grow at the end of this season, and the individuals attained the subadult and adult phases at the beginning of the subsequent rainy season. Sex ratio did not differ to 1:1 only during the adult recruitment period, and it was deviated towards males in the other months. Individuals occurred closest to the soil in the dry season, and this suggests that climatic conditions affected the microhabitat selection on plants. Abiotic factors, such as precipitation and temperature, also influenced the oviposition, dynamics and phenology of this population. There are some few works concerning the biology of Phloeidae, but this is the first study on the ecology of these insects / Mestrado / Ecologia / Mestre em Ecologia

Orientador: Paulo Sergio Moreira Carvalho de Oliveira, Andre Victor Lucci Freitas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T07:08:56Z (GMT). No. of bitstreams: 1 SendoyaEcheverry_SebastianFelipe_M.pdf: 1152705 bytes, checksum: f4c1b0194f043988353ca041df10f1d9 (MD5) Previous issue date: 2007 / Resumo: As larvas de Eunica bechina (Lepidóptera; Nymphalidae) se alimentam das folhas jovens do pequi Caryocar brasiliense (Caryocaraceae), uma planta que apresenta nectários extraflorais (NEFs). Estes nectários são intensamente visitados por muitas espécies de formigas forrageadoras de néctar no cerrado brasileiro. As formigas exercem uma forte pressão seletiva nas larvas devido à predação e/ou remoção das lagartas na planta hospedeira. Este estudo examina experimentalmente se a presença de formigas nas plantas de C. brasiliense media as decisões de oviposição por fêmeas de E. bechina. O objetivo foi determinar a importância do espaço livre de inimigos para a seleção de locais de oviposição pela borboleta. Neste estudo desenvolvemos experimentos de oviposição em campo em ramos pareados de uma planta de C. brasiliense, desenhados para testar em campo as preferências da borboleta em relação à presença na planta de diferentes tipos de insetos, incluindo algumas espécies de formigas. A presença de um herbívoro especialista do pequi (Edessa rufomarginata, Pentatomidae), ou de uma formiga não agressiva e visitante da planta (Cephalotes pusillus), não influenciaram a oviposição por fêmeas de E. bechina quando comparadas com ramos sem insetos (controle). Por outro lado, detectamos uma redução significativa na freqüência de oviposição em ramos com qualquer uma de duas espécies de formigas do gênero Camponotus quando comparado com ramos controle sem insetos. A tendência de evitar locais da planta ocupados por formigas agressivas não foi afetada com o incremento na demanda de galhos para oviposição pelas fêmeas da população. Sugerimos que as fêmeas de E. bechina utilizam características como forma e tamanho dos insetos como sinais de reconhecimento para mediar a decisão de oviposição. O comportamento das fêmeas de evitar ramos com formigas agressivas pode reduzir a mortalidade da prole sobre a planta hospedeira Esta capacidade de discriminação, além de um conjunto de defesas morfológicas e comportamentais das larvas, aparentemente é fundamental para permitir à E. bechina se especializar em uma planta defendida por formigas tal como o pequi / Abstract: Larvae of Eunica bechina Lepidoptera (Nymphalidae) feed on young leaves of Caryocar brasiliense (Caryocaraceae), a shrub bearing extrafloral nectaries that is intensively visited by many nectar-gathering ant species in the Brazilian cerrados. Visiting ants exert strong predation pressure on the caterpillars of E. bechina on the host plant. This field study examines experimentally whether ant presence on C. brasiliense shrubs mediates oviposition decisions by E. bechina females. The aims of this study were to determine the importance of an enemy-free space for the selection of plant locations for oviposition by the butterfly. Oviposition experiments on paired branches of C. brasiliense were designed to test egg-laying preference by Eunica in relation to the presence or absence of different types of insects on the plant. Field experiments demonstrated that presence of a specialist insect herbivore of Caryocar (Edessa rufomarginata, Pentatomidae), or of the non-aggressive visiting ant Cephalotes pusillus, had not effect on oviposition by E. bechina females compared to insect-free control branches. On the other hand, there was a significant reduction in oviposition frequency on branches with either of two aggressive ant species of the genus Camponotus compared to insect-free control branches. Avoidance of plant locations occupied by such aggressive ants persists even under high levels of oviposition sites demand by the females of the local population. We suggest that E. bechina butterflies use ant traits such as size and form as visual recognition cues to mediate oviposition decisions. By doing so, the egg-laying female reduces the probability of larval offspring encountering aggressive ants on the host plant. This discrimination capacity, in addition to an array of behavioral and morphological defenses of the caterpillars, is apparently crucial to permit the butterfly to specialize on such a risky, ant-defended host plant / Mestrado / Ecologia / Mestre em Ecologia

Made available in DSpace on 2014-07-29T16:21:16Z (GMT). No. of bitstreams: 1 dissertacao_walter.pdf: 583099 bytes, checksum: 9b692b715751bbe0fea761a5fd508f6b (MD5) Previous issue date: 2011-02-16 / The idea that host plants influence the richness of galling is widespread and has several approaches in literature. Many of these approaches take into account the hosts richness, the density of vegetation, plant species composition and architecture of plants, as factors that influence the diversity patterns of gall-inducing insects. In this study we investigated the importance of structure, richness and community composition of plants to the distribution of galling. Inventories on the diversity of gall morphotypes and host plants were conducted in various areas of the Brazilian Cerrado, in the states of Distrito Federal, Goiás, Minas Gerais and Tocantins. Altogether we sampled 1882 plants belonging to 131 species and 43 plant families, among which 64 species (48.8%) and 31 families (72.1%) had galling. We recorded 112 species of galling that occurred mainly in Vochysiaceae (with 19 species), followed by Fabaceae and Malpighiaceae (with 13 and 12 species respectively). Were recorded five genera and 13 species of plants, considered as a super-host of galling. These taxa housed together 45 morphotypes of gall, which represents 40% of the total diversity sampled. The genus Qualea (Vochysiaceae) alone sheltered 18 morphotypes of gall. No specific level Qualea parviflora was the species with the greatest richness of gall (eight types). At the structural level, the vegetal cover hypothesis was the best predictor of the richness of galling, explaining 45%. We also find results which show that factors such as the density and architecture of plants positively influenced the diversity of galling. The richness of plant species and plant community composition were also important for the distribution of galling. For example, where the super-host taxa were present occurred two times more galls than where they were absent. Our results indicate that both the structure and the richness and composition of the flora influenced the diversity of galling. Thus, the results provide an expanding knowledge of the diversity of gallinducing insects, under the botanical point of view. / A ideia de que plantas hospedeiras influenciam na riqueza de insetos galhadores é bastante difundida e tem diversas abordagens na literatura. Algumas dessas abordagens levam em conta a riqueza de hospedeiras, a densidade da vegetação, a composição de espécies vegetais e a arquitetura das plantas, como fatores que influenciam nos padrões de diversidade dos galhadores. Nesse trabalho investigamos a importância da estrutura, riqueza e composição da comunidade de plantas para a distribuição de insetos galhadores. Inventários sobre a diversidade de morfotipos de galhas e plantas hospedeiras foram realizados em várias áreas do Cerrado brasileiro, nos estados do Distrito Federal, Goiás, Minas Gerais e Tocantins. Ao todo foram amostradas 1882 plantas pertencentes a 131 espécies e 43 famílias vegetais, sendo que 64 espécies (48,8%) e 31 famílias (72,1%) hospedaram insetos galhadores. Registramos 112 espécies de insetos galhadores que ocorreram principalmente em Vochysiaceae (com 19 espécies), seguida de Fabaceae e Malpighiaceae (com 13 e 12 espécies, respectivamente). Foram registrados cinco gêneros e 13 espécies de plantas, consideradas como super-hospedeiras de insetos galhadores. Esses taxa abrigaram juntos 45 morfotipos de galhas, o que representa 40% da diversidade total amostrada. O gênero Qualea (Vochysiaceae) abrigou sozinho 18 morfotipos de galhas. No nível específico Qualea parviflora foi a espécie com maior riqueza de galhas (oito tipos). Ao nível estrutural, a hipótese da cobertura vegetal foi o melhor preditor da riqueza de galhadores, explicando 45%. Também encontramos resultados que mostram que fatores como a densidade e a arquitetura das plantas influenciam positivamente a diversidade de insetos galhadores. A riqueza de espécies de plantas e a composição da comunidade vegetal também foram importantes para a distribuição dos insetos galhadores. Por exemplo, locais onde os taxa super-hospedeiros estavam presentes tiveram duas vezes mais galhas do que onde estavam ausentes. Nossos resultados apontam que tanto a estrutura quanto a riqueza e composição da flora podem ter influências na diversidade de insetos galhadores. Desse modo, os resultados obtidos proporcionam uma ampliação dos conhecimentos da diversidade de insetos galhadores, sob o ponto de vista botânico.

The infestation of the cultivated grain crops by phloem feeding aphids has generated a great deal of interest over the years, due to the serious damage they cause to the crops and yield losses that result. The mechanism of the interaction between aphids and host plants remains largely unknown in spite of efforts to understand the basis of aphid feeding on grain crops. Greater efforts are required to explain the mechanism(s) of this interaction in order to achieve sustainable agriculture. This thesis focused on an investigation of the mechanism of feeding by the Russian wheat aphid, Diuraphis noxia Mordvilko (RWA) and the bird cherry-oat aphid, Rhopalosiphum padi L. (BCA) on barley and wheat cultivars. These two aphids co-occur naturally, but they inflict very different feeding effects on host plants. Structural and functional approaches were employed to investigate their feeding habits and these were then related to the observed differences in their host plants. Transmission electron microscopy (TEM) techniques were used to study the ultrastructural damage, while fluorescence microscopy techniques – using aniline blue fluorochrome (a specific stain for callose) and 5, 6-CFDA (a phloem-mobile fluorophore) – were employed to investigate the functional response to damage via wound callose formation and phloem transport capacity respectively. RT-PCR and quantitative real-time RT-PCR techniques were used to investigate the regulation of the genes involved in callose synthesis and degradation at the transcriptional level. Morphological observation of the damage caused by the aphids show that infestation by RWA results in extensive leaf chlorosis, necrosis and rolling, while infestation by BCA does not lead to any observable symptoms within the same period. Interestingly, the population study shows that BCA breeds faster than RWA within the two-week experimental period. The ultrastructural study of feeding damage caused by the two aphids on the vascular bundles of susceptible barley cv Clipper, shows a different patterns of damage. Probing the vascular bundles results in the puncturing of vascular parenchyma by both aphids, but severe damage occurs in sieve tubes-companion cell complex during sustained feeding by RWA. In contrast, less damage occurs when BCA feeds on the phloem. Drinking from the xylem by RWA results in deposition of a large quantity of electron-dense watery saliva, which apparently seals the xylem vessels completely, by blocking all the pit membrane fields between the xylem vessels and associated parenchyma cells. In contrast, drinking from xylem by BCA results in deposition of a dense, granular saliva into the xylem vessels only, which does not appear to totally occlude the pit membrane fields. This is the first known report in which ultrastructural evidence of aphids’ drinking in xylem is provided. The comparative effects of RWA feeding on a susceptible Betta and resistant Betta-Dn1 wheat cultivars showed that after two weeks, the Betta cultivar expressed damage symptoms such as chlorosis, necrosis and leaf roll, while few chlorotic patches and necrotic spots occur in resistant Betta-Dn1 cultivars. An ultrastructural investigation of the feeding damage caused to all leaf tissues revealed, for the first time, that RWA is capable of both intra- and inter-cellular probing within mesophyll cells. Probing in the mesophyll cells induces a more severe damage in susceptible Betta than in the resistant Betta-Dn1 counterpart. Similar differences in damage occurred during feeding in the thin-walled sieve tubes of the phloem, with the sieve tubes of the Betta showing more damage than that of the resistant Betta-Dn1. However, drinking from xylem resulted in the characteristic occlusion of metaxylem vessels by copious deposition of saliva by RWA in both Betta and Betta-Dn1 cultivars. In all cases of probing, feeding, and drinking by RWA in both cultivars, all probed cells with evidence of salivary material deposit and those cells adjacent to salivary material deposit, exhibit significant damage in susceptible Betta cultivar, whereas similar cells in Betta-Dn1 cultivars do not show as damage as severe. Investigation of the functional response of the plants to feeding by aphids through the deposition of wound-induced callose shows that formation and deposition of wound callose occurs in both longitudinal and cross veins within 24h of feeding by RWA. This deposition increases through short-term feeding (72h) and prolonged feeding (14d). This is in sharp contrast to the observations with BCA feeding,where little or no callose formation occurs within the same time frame. Callose formation and deposition occurs only when a higher population of BCA feeds on barley leaves. This is the first report of aphid-induced wound callose by BCA. In all cases of callose deposition, aphid stylet tracks were associated with callose and the deposition of callose appears to be a permanent feature, because wound callose remained in the leaf tissues even after 120h of the aphids’ removal. Wound callose signals (defence and anti-defence) are discovered to be transported in the phloem tissues and are dependent on the direction of assimilate flow. Examination of the possible regulation of wound callose genes at the transcriptional level shows that the two expressed glucan synthase gene sequences (GSL – genes involved in callose formation) analysed did not show any significant increase or regulation upon aphid infestation. Contrary to expectation, all three aphid-induced β-1, 3-glucanases (genes which are thought to be involved in callose degradation) showed higher expression in RWA-infested tissue than in BCA-infested tissue. The results of the feeding damage on the transport capacity of the phloem shows that BCA infestation does not lead to a significant reduction in the phloem transport capacity during short-term feeding (72h), while RWA-infested leaves showed considerable reduction in the transport capacity of the phloem within the same period. However, prolonged feeding (14d) by BCA induces a considerable reduction on the transport capacity of the phloem on the infested tissues. In contrast, a marked reduction in the transport capacity of the phloem occurs in RWA-infested leaves and in most cases, complete cessation of transport ensues. In conclusion, these data collectively suggest that RWA is a serious and most destructive phloem feeder in comparison to the BCA. RWA causes severe damage to all cellular tissues of the host plants, which result in apoplasmic and symplasmic isolation of xylem and phloem tissues, while BCA infestation does not result in such isolation within the same time and population levels. Resistance genes appear to function by conferring resistance to cell damage on the resistant cultivars during aphid feeding. Responses by plants to aphid infestation via wound callose deposition are again shown to be species-specific. A quick response results when RWA feeds, even at a very low population level, while a response occurs only at a higher infestation level by BCA, and this response was shown as not regulated at the transcriptional level. Differences in the damage to leaf tissues and wound callose deposition eventually lead to varying degrees of damage to the transport capacity of the phloem. These differences in the damage signatures are hereby suggested to be the cause of the diversity in the observed damage symptoms and the yield losses upon infestation by the two aphid species.

Host-plant resistance is an important component of integrated pest management. Host resistance to phytophagous insects and mites based on chemical and morphological characteristics has been identified in various agronomic crops. The present study was undertaken to examine how variation in selected morphological and chemical characteristics of beach strawberry Fragaria chiloensis (L.) Duchesne affects population parameters of the twospotted spider mite Tetranychus urticae Koch. The results from this study show that clones of F. chiloensis and the cultivar "Totem" vary in suitability for the twospotted spider mite. Selected clones of F. chiloensis and the cultivar "Totem" differed also in the following foliar characteristics: densities of glandular and nonglandular trichomes and concentrations of total and catechol-based phenolics. In contrast, qualitative analysis of phenolic compounds, determined via HPLC, revealed a close similarity between F. chiloensis and F. x ananassa (cultivated strawberry) and among selected clones of F. chiloensis. Mite oviposition was negatively correlated with densities of glandular and nonglandular trichomes and concentrations of total foliar phenolics. In spite of these significant relationships, mite oviposition was best predicted by a combination of interacting plant characteristics rather than by any individual characteristic. Entrapment by sticky exudates from glandular trichomes appears to explain the negative relationship between mite survival and density of glandular trichomes. Spider mite development was negatively related to concentrations of foliar phenolics; twospotted spider mite development is delayed on leaves with high concentrations of phenolics. The correlation between mite development and foliar phenolics was greater when catechol-based phenolics were used. / Land and Food Systems, Faculty of / Graduate

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