The shared influence of phylogeny and ecology on the reproductive patterns of Myrteae (Myrtaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological patterns of extrafloral nectaries in woody plant species of the Brazilian cerrado

Extrafloral nectaries are nectar-secreting structures that are especially common among the woody flora of the Brazilian cerrado, a savanna-like vegetation. In this study, we provide morphological and anatomical descriptions of extrafloral nectaries (EFNs) occurring on vegetative and reproductive organs of several plant species from the cerrado, and discuss their function and ecological relevance. We describe the morphology and anatomy of EFNs of 40 species belonging to 15 woody families using scanning electron microscopy and light microscopy. We categorise EFNs following a structural-topographical classification, and characterise the vascularised and complex nectaries, amorphous nectaries and secretory trichomes. Fabaceae, Bignoniaceae, Malpighiaceae and Vochysiaceae were the plant families with the majority of species having EFNs. Ten species possess more than one morphotype of gland structure. Observations and experimental field studies in the cerrado support the anti-herbivore role of EFN-gathering ants in this habitat. Additional morphological studies of EFNs-bearing plants, including other growth forms (e.g. herbs and lianas), are being undertaken and will hopefully cast further light on the ecological relevance of these glands in the cerrado, especially with respect to their attractiveness to multiple visitors.

Temporal patterns of parasitism in Diatraea saccharalis Fabr. (Lep., Crambidae) populations at different spatial scales in sugarcane fields in Brazil

Biological control of Diatraea saccharalis is regarded as one of the best examples of successful classical biological control in Brazil. Since the introduction of the exotic parasitoid, Cotesia flavipes, from Pakistan at the beginning of the 1970s, decrease in D. saccharalis infestation in sugarcane fields has been attributed to the effectiveness of this agent. Recently, the native Tachinidae fly parasitoids (Lydella minense and Paratheresia claripalpis) have also been implicated in this success. However, quantitative data confirming the actual contribution of these agents to the control of D. saccharalis are rather limited. The purpose of this study was to investigate the dynamics of the interactions between D. saccharalis and its parasitoids, emphasizing the temporal patterns of parasitism. To investigate this question, a large data set comprising information collected from two sugarcane mills located in the state of São Paulo, Brazil (Barra and Sao Joao sugarcane mills), was analysed. Basically, the data set contained monthly information about the number of D. saccharalis larvae and their parasitoids in each sample (man-hour per sample), the sugarcane varieties cultivated, the age of the sugarcane plants (only at the Sao Joao sugarcane mill) as well as the sugarcane cut at sampling time. The data were collected from March 1984 to March 1997 and from May 1982 to December 1996 for the Barra and Sao Joao sugarcane mills, respectively. Temporal inverse density-dependent parasitism was predominant for both parasitoid species with respect to all spatial scales. Although the temporal pattern of parasitism was not directly density dependent, it was evident that the tachinids and C. flavipes presented positive numerical responses according to variations in D. saccharalis densities through time.

Population structure, distribution and abundance patterns of the patagonian smoothhound Musmlus schmitti springer, 1939 (Chondrichthyes,Elasmobranchii, Triakidae) in the rio de la plata and inner continental shelf, SW Atlantic ocean (34 degrees-30'-39 degrees-30's)

A total number of 4824 Mustelus schmitti was sampled. Females ranged from 25 to 93 em in spring and from 28 to 90 cm in summer. Males ranged from 34 to 82 and from 28 to 77 cm, respectively. Length composition of the population showed significant differences between spring and summer being females larger than males. Total length distribution did not show significant differences between cruises. Males density varied significantly between cruises while for the females no significant variation was observed. In the spring cruise, both sexes occurred at depths lower than 50 in. Females occurred in the whole area with adult occurrence only above 35 degrees 30'S. Mature males occurred throughout the area, immature males occurring in two trawls in Samborombon Bay. The summer cruise showed a discontinuous distribution of the species along the study area resulting in spatial segregation in two groups with immature females predominating in both of them.

Pulmonary receptors in reptiles: discharge patterns of receptor populations in snakes versus turtles

This study examines the effects of lung inflation/deflation with and without CO2 on the entire population of pulmonary receptors in the vagus nerve in two species of snakes and two species of turtles. We asked the question, how does the response of the entire mixed population of pulmonary stretch receptors (PSR) and intrapulmonary chemoreceptors (IPC) in species possessing both differ from that in species with only PSR? This was studied under conditions of artificial ventilation with the secondary goal of extending observations on the presence/absence of IPC to a further three species. Our results indirectly illustrate the presence of IPC in the Burmese python and South American rattlesnake but not the side necked turtle, adding support to the hypothesis that IPC first arose in diapsid reptiles. In both species of snake, CO2-sensitive discharge (presumably from IPC) predominated almost to the exclusion of CO2-insensitive discharge (presumably arising from PSR) while the opposite was true for both species of turtle. The data suggest that for animals breathing air under conditions of normal metabolism there is little to distinguish between the discharge profiles of the total population of receptors arising from the lungs in the different groups. Interestingly, however, under conditions of elevated environmental CO2 most volume-related feedback from the lungs is abolished in the two species of snakes, while under conditions of elevated metabolic CO2, it is estimated that volume feedback from the lungs would be enhanced in these same species.

Seasonal changes in daily metabolic patterns of tegu lizards (Tupinambis merianae) placed in the cold (17 degrees C) and dark

Oxygen consumption rate was measured continuously in young tegu lizards Tupinambis merianae exposed to 4 d at 25 degrees C followed by 7-10 d at 17 degrees C in constant dark at five different times of the year. Under these conditions, circadian rhythms in the rate of oxygen consumption persisted for anywhere from 1 d to the entire 2 wk in different individuals in all seasons except the winter. We also saw a progressive decline in standard oxygen consumption rate (at highly variable rates in different individuals) to a very low rate that was seasonally independent (ranging from 19.1 +/- 6.2 to 27.7 +/- 0.2 mL kg(-1) h(-1) across seasons). Although this degree of reduction appeared to take longer to invoke when starting from higher metabolic rates, tegu lizards reduced their metabolism to the low rates seen in winter dormancy at all times of the year when given sufficient time in the cold and dark. In the spring and summer, tegus reduced their standard metabolic rate (SMR) by 80%-90% over the experimental run, but only roughly 20%-30% of the total fall was due to the reduction in temperature; 70%-80% of the total fall occurred at constant temperature. By autumn, when the starting SMR on the first night at 25 degrees C was already reduced by 59%-81% (early and late autumn, respectively) from peak summer values, virtually all of the fall (63%-83%) in metabolism was due to the reduction in temperature. This suggests that the temperature-independent reduction of metabolism was already in place by autumn before the tegus had entered winter dormancy.

Integrating species life-history traits and patterns of deforestation in amphibian conservation planning

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P-herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

Morphological patterns of the heteropycnotic chromatin and nucleolar material in meiosis and spermiogenesis of some Pentatomidae (Heteroptera)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Patterns of spatial distribution in macroalgal communities from tropical lotic ecosystems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Automatic Classification of Three-Phase Flow Patterns of Heavy Oil in a Horizontal Pipe Using Support Vector Machines

The pipe flow of a viscous-oil-gas-water mixture such as that involved in heavy oil production is a rather complex thereto-fluid dynamical problem. Considering the complexity of three-phase flow, it is of fundamental importance the introduction of a flow pattern classification tool to obtain useful information about the flow structure. Flow patterns are important because they indicate the degree of mixing during flow and the spatial distribution of phases. In particular, the pressure drop and temperature evolution along the pipe is highly dependent on the spatial configuration of the phases. In this work we investigate the three-phase water-assisted flow patterns, i.e. those configurations where water is injected in order to reduce friction caused by the viscous oil. Phase flow rates and pressure drop data from previous laboratory experiments in a horizontal pipe are used for flow pattern identification by means of the 'support vector machine' technique (SVM).

Population structure, distribution and abundance patterns of the patagonian smoothhound Mustelus schmitti Springer, 1939 (Chondrichthyes, Elasmobranchii, Triakidae) in the rio de La Plata and inner continental shelf , sw Atlantic ocean (34º30'-39º30'S)

Um total de 4824 Mustelus schmitti foi amostrado. As fêmeas apresentaram comprimento total de 25-93 cm na primavera e 28-90 cm no verão enquanto os machos apresentaram 34-82 e de 28-77 cm, respectivamente. A composição de comprimentos da população mostrou diferenças significativas entre primavera e verão sendo as fêmeas maiores do que os machos. A distribuição de comprimento total não variou significativamente entre cruzeiros. A densidade variou significativamente entre cruzeiros nos machos sendo que a variação não foi expressiva nas fêmeas. No cruzeiro da primavera, ambos os sexos ocorreram em profundidades menores do que 50 m, as fêmeas ocorrendo em toda a área de estudo, as adultas somente acima da latitude 35°30'S. Os machos adultos foram observados em toda a área sendo que os imaturos somente em dois arrastos na Bahia de Samborombón. O cruzeiro de verão mostrou uma distribuição descontínua da espécie ao longo da área de estudo, resultando na segregação espacial em dois grupos, com predominância de fêmeas imaturas em ambos.

Karyotypic patterns of seven species of molossid bats (Molossidae, Chiroptera)

G- and C- banding patterns of seven species of the bat family Molossidae, Eumops glaucinus, E. perotis; Molossops abrasus, M. remminckii, Molossus ater, M. molossus, and Nyctinomops laticaudatus, were identified. Comparisons among the karyotypes of these species showed extensive homologies between E. perotis, M. ater, M. molossus, M. abrasus, and N. laticaudatus, demonstrating inter- and intrageneric conservatism, and a lesser degree of homologies in M. temminckii and glaucinus, reflecting intrageneric variation, Chromosomal variation was due to inversions, Robertsonian rearrangements, translocations, and variations in the location of constitutive heterochromatin and nucleolus organizer regions. The chromosome corresponding to No. 5 in the M. ater karyotype is discussed. We suggest that the Nyctinomops and Molossops karyotypes represent the primitive condition and that Molossus and Eumops have derived karyotypes.

PATTERNS OF COLONIZATION AND INCIPIENT NEST SURVIVAL IN ACROMYRMEX-NIGER AND ACROMYRMEX-BALZANI (HYMENOPTERA, FORMICIDAE)

Patterns of colonization by queens and incipient nest survival of the leaf-cutting ants Acromyrmex niger and Acromyrmex balzani were studied by means of belt transects and individually marked incipient nests. No relation was found between colony density and the number of colonization attempts. Both species are not claustral, and high rates of queen mortality were attributed to conspecific executions and predation. of other discernable mortality factors, failure of fungal garden establishment was the most important. Only 34 of 296 A. balzani and 13 of 154 A. niger marked colonies were alive at the end of one year. These figures are higher than those reported for species of Atta. These results are contrasted with those of claustral-founding Atta species. Small colonies are occasionally raided by larger colonies which robbed brood.