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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.
61

Ecological interaction among natural enemies and its consequences for biological control /

Chang, Gary C. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 121-139).
62

Patterns and economic impacts of livestock predation in rural communities bordering Makgadikgadi Pans National Park in Botswana.

Dikobe, Leonard Mogopodi. January 1997 (has links)
Northern Botswana's rural agricultural settlements bordering national parks and game reserves. In two study areas (Khumaga and Gweta, bordering Makgadikgadi Pans National Park), spatial, temporal and prey-type patterns of livestock predation were assessed. Cattle, goats, horses, donkeys and sheep were the key livestock types. Lion, leopard, cheetah, wild dog, black-backed jackal, spotted hyena and the Nile crocodile (occurring only in Khumaga) were the key predators. Oral interviews with farmers in these villages provided insights into the patterns and impacts of livestock predation on rural economies. Khumaga's livestock predation scenario is dominated by lion predation on cattle, goats and donkeys, leopard predation on small stock and calves, and crocodile on goats. Wet season predation rates were higher than dry seasons', except for spotted hyena, black-backed jackal and leopard. Leopard and black-backed jackal are dominant small stock predators in Gweta. lion are the main cattle and donkey predators (though at lower frequencies). Dry season predation rates are higher. Farmers who own more livestock appear to lose more Northern Botswana's rural agricultural settlements bordering national parks and game reserves. In two study areas (Khumaga and Gweta, bordering Makgadikgadi Pans National Park), spatial, temporal and prey-type patterns of livestock predation were assessed. Cattle, goats, horses, donkeys and sheep were the key livestock types. Lion, leopard, cheetah, wild dog, black-backed jackal, spotted hyena and the Nile crocodile (occurring only in Khumaga) were the key predators. Oral interviews with farmers in these villages provided insights into the patterns and impacts of livestock predation on rural economies. Khumaga's livestock predation scenario is dominated by lion predation on cattle, goats and donkeys, leopard predation on small stock and calves, and crocodile on goats. Wet season predation rates were higher than dry seasons', except for spotted hyena, black-backed jackal and leopard. Leopard and black-backed jackal are dominant small stock predators in Gweta. lion are the main cattle and donkey predators (though at lower frequencies). Dry season predation rates are higher. Farmers who own more livestock appear to lose more cattle than those who own few. Gweta contrasts with Khumaga, having livestock predation highest during dry seasons, less reduction in livestock sales and a lower value of pending compensation claims. These predation patterns synchronise with movements of zebra and wildebeest to and from the Boteti river. Losses of livestock affect the utility derived from livestock and monetary gains from direct sales. Costs due to loss of biodiversity, though not quantified, add to those borne by the State through predator control. Both the State and the farmers loose. These losses reduce the incentives of the latter to conserve species that contribute reduction in their returns. The issue of State expenditure on predator control illustrates the possible need for re-direction of such funds into farmer-based predator control, much as an integral part of the current southern African trend of community-based natural resource management. Key words: livestock predation, predator control, economics, conservation, Botswana. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.
63

Movements, population dynamics and predatory behaviour of stoats inhabiting alpine grasslands in Fiordland

Smith, Derek, n/a January 2006 (has links)
Stoats are introduced mammalian carnivores implicated in the decline of several of New Zealand�s endemic species. Most research into stoats in New Zealand has focused on beech forest habitat, especially in years of peak stoat abundance following heavy beech seedfall and peak cohorts of mice. In New Zealand, alpine grasslands occur above the altitudinal limit of beech forest (900-1000 m a.s.l.). Although previous research has shown stoats to be present there, little is known about the ecology of stoats in alpine grasslands. This research aimed to test whether alpine grasslands were a marginal habitat occupied by surplus stoats that had spilled over from beech forest populations, i.e. a sink habitat. The alternative is that alpine grasslands are a desirable habitat deliberately exploited by stoats. This question was answered using mark-recapture, radio-tracking, diet analysis and a food addition experiment. Another objective was to determine whether nest survival is higher in alpine grassland compared to beech forest and whether stoats are likely to be a frequent predator of ground nests in alpine grasslands relative to other introduced mammals that inhabit them. If nest survival is higher in alpine grassland then alpine grasslands may be a refuge from predation. However, if it is not then it is important for management to know the relative risk posed by stoats compared with other predators. An artificial nest experiment was used to answer these questions. This research was undertaken during two years of low to intermediate beech seedfall and therefore provided an opportunity to look at the ecology of stoats in a New Zealand National Park outside years of peak abundance. The principal study site for this research was the Borland Valley, Fiordland National Park. Compositional analysis showed that stoats in alpine grassland selected for it over adjacent beech forest. The range cores of these stoats were high up in alpine grassland away from the ecotone with beech forest. Stoats occurred at similar densities in alpine grasslands as they did in beech forest and observed survival was similar between the two habitats (with the exception of 2004 when it may have been higher in alpine grassland). The most frequent prey of stoats inhabiting beech forest were birds and mice. Although stoats in alpine grasslands also ate birds and mice their most frequent prey were ground weta and hare. Food addition appeared to cause diet switching but did not reduce the distances moved by stoats, suggesting that other factors may be more important in regulating their summer home range size in alpine grasslands. All of these factors lead to the conclusion that alpine grasslands in the Borland are not a marginal habitat for stoats, but may instead be a desirable one. Artificial nests had a higher probability of survival in alpine grassland compared to adjacent beech forest, but survival was too low to support the idea that alpine grasslands are a refuge. Stoats were the most frequent predator of artificial nests in both habitats, but 95 % confidence intervals overlapped the predation rate by possums, which was also high. These findings illustrate the need for a comprehensive landscape approach to stoat control in montane National Parks, for two reasons: 1) endemic biodiversity in alpine grasslands may be under threat from stoat predation, 2) alpine grasslands may act as a source for dispersing stoats that reinvade lowland stoat control areas. In the absence of heavy beech seedfall and peak mouse abundance, stoats occurred at densities of around 1 km⁻� in both habitats and there was recruitment into these populations. This raises the important question: What regulates the distribution and abundance of stoats in years of low beech seedfall and low mouse abundance? In these years birds, ground weta and hares may be as important as mice are in years of peak abundance following heavy beech seedfall.
64

Comparison of nekton utilization of smooth cordgrass (Spartina alterniflora) marsh based on marsh size and degree of isolation from like habitat : do size and site location matter? /

Meyer, David L. January 2006 (has links) (PDF)
Thesis (Ph.D.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 198-208)
65

Morfologia comparada, ontogenia e alometria de estruturas das tíbias anteriores e descrição de imaturos de percevejos predadores (Hemiptera: Pentatomidae: Asopinae)

Brugnera, Ricardo January 2018 (has links)
Estudos morfológicos representam ferramentas básicas para ampliação do conhecimento sobre determinado táxon e abrem caminhos para o desenvolvimento de outros estudos em diversas áreas como taxonomia, filogenia, etologia e ecologia. Neste trabalho, buscamos aprimorar o conhecimento morfológico na família Pentatomidae, investigando as variações presentes nas pernas de percevejos e como elas se desenvolvem ao longo do ciclo de vida. Estudando comparativamente as expansões tibiais e o aparato tibial na subfamília Asopinae, e verificamos que ambas as estruturas possuem uma ampla variação morfológica. As expansões podem estar presentes nas superfícies dorsal e ventral da tíbia, ou apenas na dorsal. A estrutura pode apresentar diferentes tamanhos entre as espécies, podendo ser até duas vezes a largura do eixo central da tíbia como nos gêneros Cazira e Heteroscelis, ou em outros casos como Alceorrhynchus, que se apresenta de forma diminuta. Além disso, as expansões podem ocorrer ao longo de toda a tíbia, ou apenas apicalmente. Em relação ao aparato tibial, verificamos que o número de cerdas é bastante variável entre as espécies analisadas, e que possui relação com o tamanho geral do inseto. Ainda, verificamos que a região circundante à estrutura apresenta morfologia variável. Com base nas variações encontradas, dez caracteres morfológicos foram propostos. Além dos adultos, estudamos a morfologia e alometria da tíbia ao longo da ontogenia em nove espécies de Pentatomidae das subfamílias Asopinae, Pentatominae e Edessinae. Foi constatado que o número de cerdas aumenta em cada estágio de desenvolvimento nas espécies de Asopinae, enquanto nas demais o número se mantém praticamente o mesmo. A alometria do aparato tibial se demonstrou positiva para todas as espécies de Asopinae nos testes realizados, enquanto nas subfamílias Pentatominae e Edessinae a alometria da estrutura foi maioritariamente negativa ou isométrica. Foi demonstrado que assim como em outros insetos, as pernas apresentam um crescimento acelerado em comparação com outras estruturas do corpo, neste caso, da cabeça. Além disso, constatamos que a largura de tíbia apresenta uma queda de tamanho do quinto ínstar para o estágio Adulto, e hipotetizamos que este fenômeno possa ter relação com a perda de estruturas presentes nas pernas das ninfas responsáveis por dar maior suporte ao peso do inseto. Os estágios imaturos de Tynacantha marginata Dallas são descritos, estruturas corporais são exploradas e comparadas morfologicamente, e características diagnósticas que permitem a identificação dos ovos e ninfas da espécie são fornecidas. / Morphological studies are basic tools to increase knowledge about a given taxon, opening paths for the development of other studies in several areas such as taxonomy, phylogeny, ethology and ecology. In this work, we aimed to improve the morphological knowledge in the Pentatomidae family, examining the variations present in the legs of stink bugs and how they develop throughout the life-cycle. Comparatively studying the tibial expansions and the foretibial apparatus in the Asopinae subfamily, we found that both structures have a wide morphological variation. The expansions may be present on the dorsal and ventral surfaces of the foretibia, or only on the dorsal surface. The structure can present different sizes between the species, being able to be up to twice the width of the tibial axis as in the genus Cazira and Heteroscelis, or in other cases like Alceorrhynchus, appears in a diminutive form. Besides, the expansions may occur along the entire tibia, or only apically. In relation to the foretibial apparatus, we verified that the number of setae is quite variable among the analyzed species, and that it is related with the general size of the insect. Also, we verified that the region surrounding the structure presents variable morphology. Based on the variations found, ten morphological characters are proposed. In addition to the adults, we studied the morphology and allometry of the foretibia along the ontogeny in nine species of Pentatomidae of the subfamilies Asopinae, Pentatominae and Edessinae. It was observed that the number of setae increases at each stage of development in the Asopinae species, while in the others the number remains practically the same. Allometry of the tibial apparatus was shown to be positive for all Asopinae species in the performed tests, while in the Pentatominae and Edessinae subfamilies the allometry of the structure was mostly negative or isometric. It has demonstrated that, as in other insects, the legs exhibit accelerated growth compared to other structures of the body, in our case, the head. In addition, we verified that tibia width shows a decrease in size of the fifth instar for the adult stage, and hypothesized that this phenomenon is related to the loss of structures present in the legs of the nymphs responsible for giving support to the weight of the insect. The immature stages of Tynacantha marginata Dallas are described, body structures are explored and morphologically compared and diagnostic features that allow identification of the eggs and nymphs of the species are provided.
66

Resposta funcional e numérica do predador Orius insidiosus (Say, 1832) (Hemiptera: Anthocoridae) com diferentes presas

Guedes, Ivone Vilar [UNESP] 17 May 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:25:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-17Bitstream added on 2014-06-13T19:52:56Z : No. of bitstreams: 1 guedes_iv_me_jabo.pdf: 895213 bytes, checksum: 0549961d1699d944d1bad7717cd9a621 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo avaliar a capacidade predatória, aspectos comportamentais, reprodutivos e estabelecer a curva de resposta funcional do predador O. insidiosus predando ovos e lagartas de primeiro ínstar de Diatraea sacchara/is, P/utella xy/ostella, Spodoptera frugiperda e Anticarsia gemmatalis, e ninfas de terceiro/quarto ínstar de Aphis gossypii. Além destas avaliações, observou-se alguns aspectos reprodutivos de O. insidiosus, todos em função das diferentes densidades de A. gossypii. Para as espécies estudadas o predador apresentou curva de resposta funcional tipo 11, mostrando uma tendência de estabilização nas densidades mais altas. A taxa de ataque foi de 42,16; 9,35 e 22,81 ovos/hora e o tempo de manipulação de 1,56; 1,91 e 1,74 horas, para S. frugiperda, A. gemmatalis e P. xy/ostella, respectivamente. Observou-se também uma baixa capacidade predatória do O. insidiosus sobre ovos de D. saccharalis, proporcionando valores quase nulos para taxa de ataque e tempo de manipulação. A taxa de ataque foi de 15,55; 18,06; 1,77 e 3,68 lagartas/hora, e o tempo de manipulação de 2,13; 1,32; 0,86 e 1,99 horas para S. frugiperda, A. gemmatalis, D. saccharalis e P. xy/ostella, respectivamente. Para A. gossypii a taxa de ataque foi de 0,10 pulgão/hora e tempo de manipulação de 1, 82 h. O predador passou de 3,10 a 4,08 h se alimentando de seiva no nectário foliar do algodoeiro, não tendo a densidade da presa influência direta sobre esse comportamento. A proporção de postura por fêmea foi crescente até 10 ninfas, enquanto a proporção do número de ovos por postura aumentou com o aumento de presas disponíveis. / The aim of this research was to evaluate the predatory capacity, behavior aspects and to establish O. insidiosus functional response curve preying Diatraea saccharalis, P/utella xy/ostella, Spodoptera frugiperda and Anticarsia gemmatalis eggs and first instar larvae, and Aphis gossypii third/fourth instar nymphs. By these evaluations it was observed some reproductive aspects of O. insidiosus, in function of A. gossypii different densities. The functional response type 11 was observed for ali species, showing a tendency of stability in the highest densities. The attack rate was 42.16, 9.35 e 22.81 eggs/hour and the handling time 1.56, 1.91 e 1.74 hours for S. frugiperda, A. gemmatalis and P. xy/ostella, respectively. It was also verified a low predatory capacity of O. insidiosus on D. saccharalis eggs, with almost null values for attack rate and handling time, making them despicable. The attack rate was 15.55,18.06,1.77 and 3.68Iarvae/hour, and the handling time 2.13, 1.32,0.86 e 1.99 hours for S. frugiperda, A. gemmatalis, D. saccharalis and P. xy/ostella, respectively. For A. gossypii the attack was 0.10 aphid/hour and the handling time 1.82 h. The predator teal on cotton sap and foliar nectary for 3.10 to 4.08 h, and there was no straight influence of the prey on this behavior. The egg-Iaying by female was crescent, until 10 nymphs, while the egg rate by egg-Iaying increased as the number of preys increased.
67

Caracterização biológico-comportamental de Podisus nigrispinus (Dallas, 1851) predando Plutella xylostella (L., 1758)

Vacari, Alessandra Marieli [UNESP] 02 October 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-02Bitstream added on 2014-06-13T19:21:09Z : No. of bitstreams: 1 vacari_am_dr_jabo.pdf: 1971272 bytes, checksum: ace10ce0cc4ae6151160dfa37942d2df (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo deste trabalho foi efetuar a caracterização biológicocomportamental de Podisus nigrispinus alimentado com lagartas e pupas de Plutella xylostella, com o intuito de aumentar os conhecimentos dessa interação predador-presa para que, no futuro, se possa estabelecer um programa de controle biológico para a traça-das-crucíferas. Os experimentos foram conduzidos em sala climatizada a 25±1°C, umidade relativa de 70±10% e fotofase de 12 horas. Foram verificados aspectos biológicos de P. nigrispinus, elaboradas tabelas de vida de fertilidade e de esperança, verificada a preferência de alimentação entre as diferentes fases de desenvolvimento da presa (larvas ou pupas) e o comportamento de predação em função de diferentes densidades de presas (larvas e pupas). Os dados biológicos obtidos indicaram que larvas e pupas de P. xylostella foram presas adequadas para o desenvolvimento dos predadores. Larvas e pupas de P. xylostella proporcionaram bom desempenho reprodutivo e alta longevidade de fêmeas do predador. Os predadores preferiram consumir larvas a pupas de P. xylostella. P. nigrispinus apresentou resposta funcional do tipo II quando consumiu larvas e pupas da traça-das-crucíferas e apresentou maior consumo de presas principalmente nas maiores densidades. Essas informações indicam que P. nigrispinus possui potencial como agente de controle de P. xylostella e que novos estudos podem ser realizados em casa de vegetação e em campo para que, no futuro, esse inimigo natural possa ser utilizado em programas de controle biológico em culturas de brassicáceas / The objective of this work was to study the biological behavioral characterization of Podisus nigrispinus feeding on larvae and pupae of Plutella xylostella, aiming to increasing the knowledge of predator-prey relationship to establish a future biological control program of diamondback moth. The experiments were led in acclimatized room to 25±1°C, RH 70±10% and photophase 12h. The biological aspects were verified, fertility and expectancy life table were elaborated, the preference feeding between the different phases in development of the prey (larvae or pupae) was determined, and verified the consumption behavior in function of different densities of preys (larvae and pupae) was studied. The biological data indicated that larvae and pupae of P. xylostella were appropriate preys to predators development. Larvae and pupae provided good reproductive performance and high longevity of females of the predator P. nigrispinus. The predators preferred to consume larvae than pupae of P. xylostella. P. nigrispinus presented functional response of the type II when it consumed larvae and pupae of diamondback moth and it presented larger consumption of preys mainly in the largest densities. All those information indicate that P. nigrispinus have potential as control agent for P. xylostella and that new studies can be accomplished in greenhouse and in field. For that, in the future, this natural enemy can be used in biological control programs in brassica’s crops
68

Caracterização biológico-comportamental de Podisus nigrispinus (Dallas, 1851) predando Plutella xylostella (L., 1758) /

Vacari, Alessandra Marieli. January 2009 (has links)
Orientador: Sergio Antonio De Bortoli / Banca: José Ednilson Miranda / Banca: Luis Garrigos Leite / Banca: Nelson Wanderley Perioto / Banca: Francisco Jorge Cividanes / Resumo: O objetivo deste trabalho foi efetuar a caracterização biológicocomportamental de Podisus nigrispinus alimentado com lagartas e pupas de Plutella xylostella, com o intuito de aumentar os conhecimentos dessa interação predador-presa para que, no futuro, se possa estabelecer um programa de controle biológico para a traça-das-crucíferas. Os experimentos foram conduzidos em sala climatizada a 25±1°C, umidade relativa de 70±10% e fotofase de 12 horas. Foram verificados aspectos biológicos de P. nigrispinus, elaboradas tabelas de vida de fertilidade e de esperança, verificada a preferência de alimentação entre as diferentes fases de desenvolvimento da presa (larvas ou pupas) e o comportamento de predação em função de diferentes densidades de presas (larvas e pupas). Os dados biológicos obtidos indicaram que larvas e pupas de P. xylostella foram presas adequadas para o desenvolvimento dos predadores. Larvas e pupas de P. xylostella proporcionaram bom desempenho reprodutivo e alta longevidade de fêmeas do predador. Os predadores preferiram consumir larvas a pupas de P. xylostella. P. nigrispinus apresentou resposta funcional do tipo II quando consumiu larvas e pupas da traça-das-crucíferas e apresentou maior consumo de presas principalmente nas maiores densidades. Essas informações indicam que P. nigrispinus possui potencial como agente de controle de P. xylostella e que novos estudos podem ser realizados em casa de vegetação e em campo para que, no futuro, esse inimigo natural possa ser utilizado em programas de controle biológico em culturas de brassicáceas / Abstract: The objective of this work was to study the biological behavioral characterization of Podisus nigrispinus feeding on larvae and pupae of Plutella xylostella, aiming to increasing the knowledge of predator-prey relationship to establish a future biological control program of diamondback moth. The experiments were led in acclimatized room to 25±1°C, RH 70±10% and photophase 12h. The biological aspects were verified, fertility and expectancy life table were elaborated, the preference feeding between the different phases in development of the prey (larvae or pupae) was determined, and verified the consumption behavior in function of different densities of preys (larvae and pupae) was studied. The biological data indicated that larvae and pupae of P. xylostella were appropriate preys to predators development. Larvae and pupae provided good reproductive performance and high longevity of females of the predator P. nigrispinus. The predators preferred to consume larvae than pupae of P. xylostella. P. nigrispinus presented functional response of the type II when it consumed larvae and pupae of diamondback moth and it presented larger consumption of preys mainly in the largest densities. All those information indicate that P. nigrispinus have potential as control agent for P. xylostella and that new studies can be accomplished in greenhouse and in field. For that, in the future, this natural enemy can be used in biological control programs in brassica's crops / Doutor
69

Dinâmica populacional e comportamento predatório individual da aranha social Parawixia bistriata (Rengger) (Araneae: Araneidae)

Barbieri, Eduardo Feltran [UNESP] 07 April 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-04-07Bitstream added on 2014-06-13T19:18:45Z : No. of bitstreams: 1 barbieri_ef_me_rcla.pdf: 850116 bytes, checksum: 1746f10eae01263d21d6e490a44a4098 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Parawixia bistriata é a única espécie da família Araneidae que apresenta comportamento social. Refúgio comunal e cooperação de caça são duas características interessantes observadas nessa espécie. O presente trabalho teve como objetivos analisar a dinâmica populacional das colônias de Parawixia bistriata durante seu desenvolvimento e estudar o comportamento de caça individual das aranhas dessa espécie. Por meio de observações de campo de sete colônias de Parawixia bistriata foi possível verificar que estas passaram por um intenso processo de forrageio, bem como de procura por um hábitat ideal, na medida em que se observa uma constante mudança no local de construção do refúgio comunal. Durante esse processo de forrageio, devido à deficiência na quantidade de recursos, bem como de espaço físico, é comum observar fissões de colônias dessa espécie. Em experimentos realizados na presente pesquisa observou-se que, apesar de ocorrer decréscimo acentuado no número de indivíduos em algumas colônias, a razão sexual das mesmas não foi alterada (1:1) no período em que foi realizada a sexagem dos indivíduos. Também foi observada uma grande tolerância entre indivíduos coespecíficos não aparentados, ou seja, de colônias não irmãs. Essa aceitação confirma a significativa existência de fusões de colônias durante o desenvolvimento dos indivíduos dessa espécie, que reforçam a idéia da formação das super-colônias, mencionada anteriormente por outros autores. No que diz respeito ao comportamento de caça individual em colônias dessa mesma espécie de aranha orbitela, observou-se que estas aranhas conseguem, de certa forma, escolher um determinado tipo de presa. Isso ocorre na medida em que se observa o total desprezo pelas presas de pequeno porte, bem como a preferência pela captura de presas de tamanho grande. Um outro fator importante é o fato de que essas... . / Parawixia bistriata is the unique species of Araneidae that shows social behaviour. Communal refuge and cooperative hunting are two interesting features observed in this species. The objectives of this research were to analyze the population dynamics in colonies of Parawixia bistriata and to study the individual predatory behaviour of this species. Field observations of seven colonies of Parawixia bistriata showed that these colonies developed an intense hunting activity and search for an ideal place to build the nest. During these two activities the colonies can separate its members on account of the lack of food or space to build their webs. Although the number of spiders is significantly reduced during the development in some colonies, this research showed that the sex ratio of the colonies is almost 1:1 when it is possible to do the sexual identification. It was also noted that there is a great tolerance between spiders from different colonies and because of this there are fusions of colonies that become supercolonies. In relation to the individual predatory behaviour in Parawixia bistriata it was possible to see that this spider can recognize and choose its prey. Another experiment of this research showed that the spiders refused a small prey or left it after a while, if a bigger prey was captured. It was also observed that the spider prefers a big prey than a small one, and the spider feeds on a big prey in the same place of the web where it was caught. This fact can be explained by the existence of intra colonial competition for food and this behaviour maybe is a strategy to avoid the robbery of food by a co-specific that lies beside it.
70

Morfologia comparada, ontogenia e alometria de estruturas das tíbias anteriores e descrição de imaturos de percevejos predadores (Hemiptera: Pentatomidae: Asopinae)

Brugnera, Ricardo January 2018 (has links)
Estudos morfológicos representam ferramentas básicas para ampliação do conhecimento sobre determinado táxon e abrem caminhos para o desenvolvimento de outros estudos em diversas áreas como taxonomia, filogenia, etologia e ecologia. Neste trabalho, buscamos aprimorar o conhecimento morfológico na família Pentatomidae, investigando as variações presentes nas pernas de percevejos e como elas se desenvolvem ao longo do ciclo de vida. Estudando comparativamente as expansões tibiais e o aparato tibial na subfamília Asopinae, e verificamos que ambas as estruturas possuem uma ampla variação morfológica. As expansões podem estar presentes nas superfícies dorsal e ventral da tíbia, ou apenas na dorsal. A estrutura pode apresentar diferentes tamanhos entre as espécies, podendo ser até duas vezes a largura do eixo central da tíbia como nos gêneros Cazira e Heteroscelis, ou em outros casos como Alceorrhynchus, que se apresenta de forma diminuta. Além disso, as expansões podem ocorrer ao longo de toda a tíbia, ou apenas apicalmente. Em relação ao aparato tibial, verificamos que o número de cerdas é bastante variável entre as espécies analisadas, e que possui relação com o tamanho geral do inseto. Ainda, verificamos que a região circundante à estrutura apresenta morfologia variável. Com base nas variações encontradas, dez caracteres morfológicos foram propostos. Além dos adultos, estudamos a morfologia e alometria da tíbia ao longo da ontogenia em nove espécies de Pentatomidae das subfamílias Asopinae, Pentatominae e Edessinae. Foi constatado que o número de cerdas aumenta em cada estágio de desenvolvimento nas espécies de Asopinae, enquanto nas demais o número se mantém praticamente o mesmo. A alometria do aparato tibial se demonstrou positiva para todas as espécies de Asopinae nos testes realizados, enquanto nas subfamílias Pentatominae e Edessinae a alometria da estrutura foi maioritariamente negativa ou isométrica. Foi demonstrado que assim como em outros insetos, as pernas apresentam um crescimento acelerado em comparação com outras estruturas do corpo, neste caso, da cabeça. Além disso, constatamos que a largura de tíbia apresenta uma queda de tamanho do quinto ínstar para o estágio Adulto, e hipotetizamos que este fenômeno possa ter relação com a perda de estruturas presentes nas pernas das ninfas responsáveis por dar maior suporte ao peso do inseto. Os estágios imaturos de Tynacantha marginata Dallas são descritos, estruturas corporais são exploradas e comparadas morfologicamente, e características diagnósticas que permitem a identificação dos ovos e ninfas da espécie são fornecidas. / Morphological studies are basic tools to increase knowledge about a given taxon, opening paths for the development of other studies in several areas such as taxonomy, phylogeny, ethology and ecology. In this work, we aimed to improve the morphological knowledge in the Pentatomidae family, examining the variations present in the legs of stink bugs and how they develop throughout the life-cycle. Comparatively studying the tibial expansions and the foretibial apparatus in the Asopinae subfamily, we found that both structures have a wide morphological variation. The expansions may be present on the dorsal and ventral surfaces of the foretibia, or only on the dorsal surface. The structure can present different sizes between the species, being able to be up to twice the width of the tibial axis as in the genus Cazira and Heteroscelis, or in other cases like Alceorrhynchus, appears in a diminutive form. Besides, the expansions may occur along the entire tibia, or only apically. In relation to the foretibial apparatus, we verified that the number of setae is quite variable among the analyzed species, and that it is related with the general size of the insect. Also, we verified that the region surrounding the structure presents variable morphology. Based on the variations found, ten morphological characters are proposed. In addition to the adults, we studied the morphology and allometry of the foretibia along the ontogeny in nine species of Pentatomidae of the subfamilies Asopinae, Pentatominae and Edessinae. It was observed that the number of setae increases at each stage of development in the Asopinae species, while in the others the number remains practically the same. Allometry of the tibial apparatus was shown to be positive for all Asopinae species in the performed tests, while in the Pentatominae and Edessinae subfamilies the allometry of the structure was mostly negative or isometric. It has demonstrated that, as in other insects, the legs exhibit accelerated growth compared to other structures of the body, in our case, the head. In addition, we verified that tibia width shows a decrease in size of the fifth instar for the adult stage, and hypothesized that this phenomenon is related to the loss of structures present in the legs of the nymphs responsible for giving support to the weight of the insect. The immature stages of Tynacantha marginata Dallas are described, body structures are explored and morphologically compared and diagnostic features that allow identification of the eggs and nymphs of the species are provided.

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