Daniela Rodrigues

ROLES OF FOOD QUALITY AND ENEMY‐FREE SPACE IN HOST USE BY A GENERALIST INSECT HERBIVORE

The relative importance of food quality vs. enemy-free space remains an unresolved but central issue in the evolutionary ecology of host use by phytophagous insects. In this study, we investigate their relative importance in determining host-plant use by a generalist caterpillar, Estigmene acrea (Lepidoptera: Arctiidae). In nature, E. acrea late- instar caterpillars preferred Senecio longilobus (Asteraceae), which contains pyrrolizidine alkaloids that the caterpillars sequester, over Viguiera dentata (Asteraceae), a natal host, and typically suffered a 28% mortality risk from parasitoids. We hypothesized that the natural, mixed diet of caterpillars provides high-quality food via hosts like Viguiera as well as antiparasitoid defense via sequestered toxins from Senecio. We found that a pure Viguiera diet provides superior growth performance over a pure Senecio or mixed diet in the absence of parasitism. However, when parasitism risk is at least moderate, the mixed diet provides a survival advantage over the pure diets of Viguiera or Senecio. We therefore conclude that the balance between benefits of growth (food quality) and defense (enemy-free space) maintains the use of a mixed diet in nature. Furthermore, the value of enemy-free space supercedes the value of food quality in determining the host-plant preference of late-instar caterpillars.

Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae) and consequences for adult life history

Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Aguas Belas Experimental Station-Viamão County), one in a Myrtaceae Forest (Itapuã State Park-Itapuã County) and one in the Atlantic Rain Forest (Maquiné Experimental Station-Maquiné County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this character is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

Ontogenetic trajectories and hind tibia geometric morphometrics of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera: Coreidae)

Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera: Coreidae) are distributed in southern Brazil and belong to the poorly studied tribe Anisoscelini. Preliminary observations indicate an ample coexistence of these species in terms of host-plant use. There is also a strong similarity regarding egg and nymph morphology. We characterized and compared their ontogenetic trajectories by means of growth curves and multivariate ontogenetic allometry, since the only apparent difference between these species is a remarkable growth in the hind tibia of A. foliacea marginella. Because their hind tibia is similar in the early instars, the shape variation of this structure was quantified by the thin plate splines function with the relaxed algorithm for semilandmarks. H. clavigera was significantly larger than A. foliacea marginella in all stages. Their ontogenetic trajectories were significantly different, and the allometric vectors did not present a significant correlation. Hind tibia shape was not statistically different in the first instar, but was different in the second instar. In the third instar, this difference became visually apparent. Thus, although these bugs are almost morphologically identical in the immature stages, their growth patterns and general size are different. We found size to be a useful parameter for species differentiation at these stages.

Comparative description of the immature stages of two very similar leaf footed bugs, Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera, Coreidae, Anisoscelini)

Comparative description of the immature stages of two very similar leaf footed bugs, Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera, Coreidae, Anisoscelini). Holymenia clavigera (Herbst, 1784) and Anisoscelis foliacea marginella (Dallas, 1852) (Hemiptera, Coreidae) present a remarkable similarity regarding egg and nymphal morphology. On the contrary, their adult stages are remarkably different. This study describes and compares the immature stages of these two coreid species. Excepting for the last instar and the shape of the hind tibia from third to last instar, nymphs of both species were identical in their gross morphologies and ultrastructures. However, H. clavigera was significantly larger than A. foliacea marginella in all stages. Thus, we suggest that these species may have evolved through evolutionary convergence, parsimony between the immature stages after speciation, Mullerian mimicry or genetic drift.

FRESHLY ISOLATED HEPATOCYTE TRANSPLANTATION IN ACETAMINOPHEN-INDUCED HEPATOTOXICITY MODEL IN RATS

CONTEXT Hepatocyte transplantation is an attractive therapeutic modality for liver disease as an alternative for orthotopic liver transplantation. OBJECTIVE The aim of the current study was to investigate the feasibility of freshly isolated rat hepatocyte transplantation in acetaminophen-induced hepatotoxicity model. METHODS Hepatocytes were isolated from male Wistar rats and transplanted 24 hours after acetaminophen administration in female recipients. Female rats received either 1x10(7) hepatocytes or phosphate buffered saline through the portal vein or into the spleen and were sacrificed after 48 hours. RESULTS Alanine aminotransferase levels measured within the experiment did not differ between groups at any time point. Molecular analysis and histology showed presence of hepatocytes in liver of transplanted animals injected either through portal vein or spleen. CONCLUSION These data demonstrate the feasibility and efficacy of hepatocyte transplantation in the liver or spleen in a mild acetaminophen-induced hepatotoxicity model.

Feeding preference of Holymenia clavigera and Anisoscelis foliacea marginella (Hemiptera: Coreidae: Anisoscelini) in relation to intra- and interspecific features of host plants (Passifloraceae).

The interactions of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) with their hosts (Passifloraceae) in southern Brazil are poorly understood. Previous studies have indicated that both species use several host species and plant parts and have superior performance on wild hosts. This study evaluated feeding preferences and host plant use under both laboratory and field conditions. Choice tests were performed to determine preference for Passiflora suberosa parts, preference for P. suberosa and Passiflora misera immature and ripe fruits, and preference for P. suberosa, P. misera, and Passiflora edulis shoots. A field survey was carried out to assess H. clavigera and A. foliacea marginella use of P. suberosa parts. In addition, immature and ripe fruits of P. suberosa and P. misera were characterized in relation to pH, phenols, and anthocyanins. First-instar nymphs preferred the terminal buds, shifting to immature fruits in the second instar. Both coreids more frequently fed on immature fruits than on ripe ones. Neither species showed a significant preference among host species. The immature fruits presented higher phenol content as compared with the ripe fruits; the opposite was observed for anthocyanins. In the field, immature fruits and mature leaves were selected for feeding and resting. Thus, this study confirms the food mixing condition of these coreids, as well as the importance of fruits for their nutrition. Phenols, and presumably water, in the fruits may play a role in their feeding choices.

Performance consequences of food mixing in two passion vine leaf-footed bugs, Holymenia clavigera (Herbst, 1784) and Anisoscelis foliacea marginella (Dallas, 1852) (Hemiptera; Coreidae)

Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera: Coreidae: Anisoscelini) are distributed in southern Brazil and use various passion vine species (Passifloraceae) as host-plants. Preliminary observations indicate a high coexistence of these species in terms of host-plant use; in addition, there is a strong similarity regarding egg and nymph morphology. In this study, the most suitable feeding sites for nymph performance on wild (Passiflora suberosa Linnaeus and Passiflora misera Humbold, Bonpland et Kunth) and cultivated (Passiflora edulis Sims) hosts were determined by rearing them on each host and on the combination of hosts. Performance was determined by evaluating nymph development and survivorship, and adult size at emergence. Plant parts used were also recorded. For both species, P. suberosa was the most suitable host plant. First instar nymphs of both species fed on terminal buds more frequently when compared to other plant parts. Second instar nymphs switched to green fruits, whose behavior was more pronounced for H. clavigera. Thus, H. clavigera and A. foliacea marginella immatures are extremely similar in terms of host-plant use and consequences for performance, in addition to their morphological similarity. We suggest that these coreids may have evolved through several processes, including parsimony between the immature stages after speciation, evolutionary convergence, mimicry or genetic drift.

Xylem and Seed Feeding by Two Passion Vine Leaffooted Bugs, Holymenia clavigera and Anisoscelis foliacea marginella (Hemiptera: Coreidae: Anisoscelini), with Notes on Mouthpart Morphology

Abstract Holymenia clavigera Herbst and Anisoscelis foliacea marginella Dallas (Hemiptera: Coreidae: Anisoscelini) use the same host plants (Passifloraceae), especially Passilfora suberosa L., and they have a very similar egg and nymphal morphology. This study compares the mouthparts of these coreids both intra- and interspecifically through scanning electron microscopy. Also, it determines the feeding sites for the fifth instars and for adults when offered some of their preferred structures (green fruit and mature leaves) of P. suberosa. Histological sections were performed on feeding sites, on plant pieces having the penetrated stylet in situ. Mouthpart morphologies were extremely similar between H. clavigera and A. foliacea marginella throughout ontogeny. The stylets reached the xylem, in almost all situations, followed by a low use of phloem. Nymphs and adults of both species consumed several fruit parts, including the seeds. When feeding upon the latter, endosperm and embryo were used for feeding. Feeding frequencies indicated that seeds are the main resource used by these coreids and that xylem feeding is probably related to water acquisition. Thus, H. clavigera and A. foliacea marginella are also extremely similar concerning use of host plant feeding sites and mouthpart morphology.

Candidúria: revisão atual - doi:10.5020/18061230.2011.p142

Objective: To summarize the current knowledge about candiduria, describing the epidemiology in Brazil and worldwide, pathogenesis, laboratorial diagnosis and prescribed therapy. Data Synthesis: A non-systematic review carried out from the databases: Pubmed, Cochrane and Scielo in scientific articles related to the theme candiduria and published in the last twenty years. The terms “candiduria”, “Candida” and “hospital infection” were used as descriptors, individually or in association. Articles that addressed other types of Candida infection or were not suitable for the aim of the study were excluded. The studies reviewed indicate that the most prevalent species are in descending order Candida albicans, C. parasilosis, C. tropic alis, C. glabrata, C. krusei, C. guilliermondii, C. lusitaniae, C. dubliniensis, C. kefyr and C. rugosa. When treatment is indicated, the drug of choice is fluconazole, provided that the isolates do not possess intrinsic resistance. Conclusion: Despite its high incidence and clinical relevance, the candiduria is not yet been fully elucidated, remaining the need to clarify its epidemiology and pathogenesis in emerging species and reach consensus on treatment protocols.