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Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-05-09T14:22:29Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO ATUALIZADA _ Ranilson Aquino.pdf: 1800812 bytes, checksum: 8ba3d3ee5ead19d5f5002d11ee2c10b8 (MD5) / Made available in DSpace on 2016-05-09T14:22:29Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO ATUALIZADA _ Ranilson Aquino.pdf: 1800812 bytes, checksum: 8ba3d3ee5ead19d5f5002d11ee2c10b8 (MD5) Previous issue date: 2015-07-30 / CAPEs / A herbivoria é o consumo de partes das plantas que pode afetar negativamente seu fitness, sendo um dos fatores responsáveis pela estruturação e composição das comunidades vegetais. Fatores, como disponibilidade de recursos e perturbações antrópicas, possuem papel relevante nas respostas à atuação dos herbívoros. Entretanto, as plantas não são passivas frente à herbivoria, desenvolvendo diversas estratégias de defesa no decorrer do seu tempo evolutivo, como a síntese de metabólitos secundários. O objetivo do estudo foi analisar se existe relação entre as taxas de herbivoria em áreas de Caatinga, com e sem perturbações antrópicas, e a quantidade de compostos fenólicos e taninos totais presentes em indivíduos de Aspidosperma pyrifolium Mart. (Pereiro). Foram avaliados 270 indivíduos de Pereiro em 9 áreas preservadas e 9 áreas impactadas distribuídas na microrregião de Itaparica, Pernambuco. Foram realizadas medidas biométricas, além da coleta arbitrária de 30 folhas, de cada indivíduo para avaliação das taxas de herbivoria foliar, carbono, nitrogênio, compostos fenólicos e taninos. Os dados foram analisados através de Análise de Regressão Linear Simples e ANOVA fatorial seguida de teste de Tukey 5% “a posteriori”. Análises biométricas não verificaram diferenças significativas entre as áreas e nem relação com o conteúdo de compostos fenólicos. Taxas de nitrogênio foram maiores no mês mais seco nas áreas impactadas e preservadas (17,66 ± 0,63 e 17,04 ± 0,58), enquanto os teores de carbono foram maiores no fim da estação chuvosa (26,51 ± 1,08 e 27,57 ± 1,91), para ambas as áreas. As concentrações de compostos fenólicos (R = -0,51 e p = 0) e taninos (R = -0,50 e p = 0) tiveram relação negativa com as taxas de herbivoria das áreas impactadas, que também apresentaram maior taxa de herbivoria, enquanto nas áreas preservadas essa relação não foi observada. Embora a influência da pecuária extensiva possa ser notada nas áreas tidas como impactadas ela não pode ser considerada a causa única das taxas de herbivoria/produção de compostos de defesa. / Herbivory is the consumption of plant parts that can negatively affect your fitness, one of the factors responsible for the structuring and composition of plants communities. Factors such as resources availability and human disturbances, have an important role in the herbivores responses. However, plants aren’t passive front herbivory, developing various defense strategies in the course of its evolutionary time, as the synthesis of secondary metabolites. The aim of the study was to examine whether there is relationship between herbivory rates in areas of Caatinga, with and without human disturbances, and the amount of phenolic compounds and total tannins presents in Aspidosperma pyrifolium Mart. individuals (Pereiro). We evaluated 270 individuals from Pereiro in 9 preserved areas and 9 impacted areas distributed in Itaparica’s region, Pernambuco. Biometric measurements were performed, as well as arbitrary collection of 30 leafs, each individual to assess the rates of leaf herbivory, carbon, nitrogen, phenolics and tannins. Data were analyzed by Simple Linear Regression Analysis and factor ANOVA followed by Tukey test 5% "a posteriori". Biometric analysis found no significant differences between areas and not related to the content of phenolic compounds. Nitrogen rates were higher in the driest month in the impacted and preserved areas (17.66 ± 0.63 and 17.04 ± 0.58), while the carbon levels were higher at the end of the rainy season (26.51 ± 1.08 and 27.57 ± 1.91), for both areas. The concentrations of phenolic compounds (R = -0.51 p = 0) and tannins (R = -0.50 p = 0) had negative relationship with herbivory rates of impacted areas, which also had higher herbivory rate while in preserved areas this relationship was not observed. Although the influence of extensive livestock farming can be noticed in impacted areas it can’t be considered the sole cause of the rates of herbivory/production of defense compounds.

Chemical senses play a critical role in predator-prey and social interactions of many animals. Predators often evoke adaptive escape responses by prey, one of which is the release of chemicals that induce adaptive avoidance behaviors from both predators and conspecifics. I explore the use of chemicals in predator-prey and social interactions, using a crustacean model system, the spiny lobster. As predators, spiny lobsters are opportunistic, polyphagous feeders, and they rely heavily on their chemical senses during feeding. Some of their potential prey deter attacks through chemical defenses that act through the spiny lobsters’ chemical senses. An example of this is sea hares, Aplysia californica, which secrete an ink when vigorously attacked by sympatric spiny lobsters, Panulirus interruptus. I show that that this ink defends sea hares from spiny lobsters through several mechanisms that include phagomimicry, sensory disruption, and deterrence, and that the ink’s efficacy is enhanced by its naturally high acidity. As prey, spiny lobsters rely heavily on their chemical senses to assess risk from predators. One way to assess risk of predation is through ‘alarm cues’, which are injury-related chemicals. I show that injured Caribbean spiny lobsters, Panulirus argus, release alarm cues in their hemolymph, and that nearby conspecifics detect these cues using olfaction. Hemolymph from conspecifics induces primarily alarm behavior in the form of retreat, sheltering, and suppression of appetitive responses. In contrast, hemolymph from heterospecifics, depending on phylogenetic relatedness, induces either mixed alarm and appetitive behaviors or primarily appetitive behaviors. Spiny lobsters also use chemical cues to assess risk during social interactions with conspecific. I show that spiny lobsters use urine-borne chemical signals and agonistic behaviors to communicate social status and that these chemical signals are detected exclusively by the olfactory pathway. Dominant animals increase urine release during social interactions, whereas subordinates do not. Experimental prevention of urine release during interactions causes an increase in agonism, but this increase is abolished when urine of dominants is reintroduced. My findings lay the foundation for neuroethological studies of risk-assessment systems mediated by intraspecific chemical cues.

Invasive exotic species threaten native biodiversity, alter ecosystem structure and function, and annually cost over $100 billion in the US alone. Determining the ecological traits and interactions that affect invasion success are thus critical for predicting, preventing, and mitigating the negative effects of biological invasions. Native herbivores are widely assumed to facilitate exotic plant invasions by preferentially consuming native plants and avoiding exotic plants. Here, I use freshwater plant communities scattered broadly across the Southeastern U.S. to show that herbivory is an important force driving the ecology and evolution of freshwater systems. However, native consumers often preferentially consume rather than avoid exotic over native plants. Analyses of 3 terrestrial datasets showed similar patterns, with native herbivores generally preferring exotic plants. Thus, exotic plants appear defensively nave against these evolutionarily novel consumers, and exotic plants may escape their coevolved, specialist herbivores only to be preferentially consumed by the native generalist herbivores in their new ranges. In further support of this hypothesis, a meta-analysis of 71 manipulative field studies including over 100 exotic plant species and 400 native plant species from terrestrial, aquatic, and marine systems revealed that native herbivores strongly suppressed exotic plants, while exotic herbivores enhanced the abundance and species richness of exotic plants by suppressing native plants. Both outcomes are consistent with the hypothesis that prey are susceptible to evolutionarily novel consumers. Thus, native herbivores provide biotic resistance to plant invasions, but the widespread replacement of native with exotic herbivores eliminates this ecosystem service, facilitates plant invasions, and triggers an invasional meltdown. Consequently, rather than thriving because they escape their co-evolved specialist herbivores, exotic plants may thrive because their co-evolved generalist herbivores have stronger negative effects on evolutionarily nave, native plants.

Dans le cadre de ce travail, nous avons poursuivi l’étude de la biosynthèse d’alcaloïdes défensifs des coccinelles. Trois espèces ont été plus particulièrement étudiées :Adalia bipunctata (qui produit l’adaline [32]), Coccinella septempunctata (contenant la coccinelline [29]) et Harmonia axyridis (produisant l’harmonine [34]).<p>Afin d’identifier le (ou les) acide(s) gras précurseur(s) de ces alcaloïdes, nous avons dans un premier temps synthétisé des acides gras spécifiquement marqués. Nous avons ainsi préparé les acides [14-3H]myristique, [16-3H]palmitique, [18-3H]stéarique, [18-13C]stéarique et [11,11,12,12,13,13,14,14,15,15,16, 16,17,17,18,18,18-2H]stéarique.<p>Les différents acides gras marqués au tritium sur le méthyle terminal ont ensuite été incorporés successivement chez les trois espèces de coccinelles mentionnées ci-dessus, en utilisant la technique d’incorporation in vitro mise au point par Laurent et al. ( )<p>Les incorporations chez Adalia bipunctata ont montré que l’acide myristique est incorporé préférentiellement dans l’adaline. <p>Chez Coccinella septempunctata par contre, l’acide stéarique est incorporé dans la coccinelline environ 25 fois plus efficacement que les acides myristique et palmitique.<p>Enfin, les incorporations chez Harmonia axyridis ont établi que l’acide stéarique est le précurseur de l’harmonine. De plus, grâce à l’incorporation de l’acide [11,11,12,12,13,13,14,14,15,15,16,16,17,17,18,18,18-2H]stéarique, le mécanisme de formation de l’amine secondaire a été précisé.<p>/<p>In spite of their red-orange colors, which could increase risks of predation, Coccinellidae are rarely exploited as food sources by predators. Many of them owe their protection, at least in part, to the presence of repellents and, in some cases, toxic alkaloids in the hemolymph emitted during a process called "reflex bleeding". Previous studies have shown that the biosynthesis of these alkaloids is related to fatty acid metabolism. <p>In our doctoral thesis, we wanted to clarify what are the fatty acids precursors of adaline (Adalia bipunctata), coccinelline (Coccinella septempunctata) and harmonine (Harmonia axyridis), with the use of various techniques of labelling (3H, D, 13C, etc.).<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished