475 resultados para Haplodiplosis marginata


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Los bosques nativos cumplen diversas funciones en el desarrollo de las poblaciones humanas, la protección de cuencas hídricas y suelos, reservorio de biodiversidad y recursos genéticos. Ante la destrucción del bosque nativo de Córdoba, resulta imperiosa la aplicación de programas integrados de conservación de los recursos genéticos a través de la creación de bancos de germoplasma y programas de restauración por medio de técnicas de reforestación de áreas degradadas. El objetivo del proyecto es Conservar in y ex situ especies leñosas nativas del Bosque Serrano de Córdoba: Polylepis Australis, Maytenus boaria, Schinopsis marginata, Zanthoxilus coco, Celtis erhembergiana, Kageneckia lanceolata, Ruprechtia apetala, Lithrea molleoides, Myrcianthes cisplatensis, Escallonia cordobensis. A campo, se identificarán y georreferenciarán los árboles semilleros de diez especies forestales nativas del Chaco Serrano de la provincia de Córdoba, como fuente de semillas. En el Laboratorio de Semillas de la FAV-UNRC se realizará el acondicionamiento de las semillas, se determinará el peso de 100 y el contenido de humedad para definirlas entre ortodoxa, intermedia, recalcitrante. Los tratamientos pre-germinativos para quebrar dormancia serán: Escarificación mecánica y/o húmeda; Estratificación fría; Lavado previo; Inmersión en agua. Se utilizarán papel como sustrato y 20 semillas por repetición. En la prueba de germinación se evaluarán distintas condiciones de luz (fotoperíodo con 12 horas y oscuridad) y temperaturas (fija de 20 y 25 °C y variable de 20-30 °C). Se obtendrá la siguiente información: Caracterización de las plántulas; Porcentaje de germinación; Tiempo medio y total de germinación. La producción de plantines se realizará en la Unidad de Vivero de la FAV-UNRC. A las semillas de aquellas especies que presentan dormancia se les aplicará el tratamiento pre-germinativo correspondiente según resultados de laboratorio. Se evaluará el número de plántulas emergidas y parámetros de calidad de los plantines (diámetro a la altura del cuello y la altura total) hasta que éstos alcancen 30 a 35 cm y 4 a 5 mm de diámetro. La etapa de reforestación se llevará a cabo en parcelas georreferenciadas y clausuradas. Se registrará la sobrevivencia y el desarrollo aéreo de las plantas al final de la estación de crecimiento. El proyecto permitirá definir las estrategias de germinación de las especies en estudio y las condiciones de almacenamiento de semillas para iniciar un banco de germoplasma de especies leñosas del Bosque Serrano de la provincia de Córdoba. Los datos obtenidos en la etapa de vivero permitirán conocer las características de los plantines adecuadas para la etapa de reforestación. En esta última se conocerá la capacidad de adaptación a campo y las estrategias de sobrevivencia de plantas de cada una de las especies que fueron cultivadas en vivero a partir de semillas de árboles seleccionados. A partir de los resultados del proyecto se obtendrá información del ciclo completo de la conservación in y ex situ de la biodiversidad del Chaco Serrano. Se generará información valiosa para la conservación en Banco de germoplasma de especies que aún no han sido estudiadas ni conservadas. La información obtenida contribuirá al conocimiento sobre la reforestación como técnica de restauración de áreas de distinto grado de degradación utilizando las especies leñosas nativas. El proyecto permitirá generar nuevas áreas de conservación in situ (rodales semilleros y parcelas reforestadas) determinando un primer ciclo de mejoramiento genético de especies nativas estudiadas. El proyecto ofrecerá un espacio de estudio y de trabajo en un área incipiente que favorecerá la generación de conocimientos y el crecimiento académico de los integrantes. Permitirá establecer vínculos concretos entre los grupos de trabajo de las instituciones participantes. La sociedad dispondrá de técnicas para la conservación y producción de las especies vegetales estudiadas.

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The present work is destinated to prove that the castes : workers and queens, in Melipona bees are due to genetic factors and not to differences in food. 2) Material used: Hives of Melipona quadri-fasciata anthidioides (Lep. 1836), M. schenki schenki (Gribodo, 1893), M. fasciata rufiventris (Lep. 1836), M. quadri-fasciata vicina (Lep. 1836), M. marginata marginata (Lep. 1836), Apis mellifera (L. 1758). 3) It should be pointed out that in Melipona bees there are no royal cells for the queens, but all the cells are of the same size independently of being destinated for workers, queens or drones. The numerous queens which are born are killed soon after emerging from their cells. 4) Changes of feeding in quality and in quantity caused no variation of castes. The only variable factor is the size, which becomes bigger when the bee is well nourished. 5) The offsprings of 5 hives were examined : 3 of M. quadri-fasciata anthidioides (n.o 1, n.o 2 and n.o 3), 1 of M. quadri-fasciata vicina (n.o 4) and 1 of M. marginata marginata (n.o 5). Combs of about 40 cells were taken into laboratory and the type of bee registered immediately after emerging. The results of the counts were: BOX COMB WORKER QUEEN PERCENTAGE Σ X2 to 12,5% Nº 1 1th 69 8 10,4% 0, 3139 " 1 2nd 144 18 11,1% 0, 2856 " 2 1th 52 8 13,3% 0, 0384 " 3 1th 45 10 18,2% 1, 6736 " 4 1th 56 4 6,7% 1, 8686 " 4 2nd 29 4 12,1% 0,00432 Σ X2 to 25% " 5 1th 34 14 29,2% 0,44444 "5 2nd 83 27 24,5% 0, 0121 In the 4 first boxes there is a percentage of 11,63% queens and in the last there is a percentage of 25,95%. 6) These percentages are very near two genetical ratios: 12,5% or 7:1, and 25% or 3:1, which correspond to a trifactorial and a bifactorial back-cross. Carrying out a X² test no significant deviations were found ( X² to 12,5% and to 25% and table 1 to 4). 7) We suppose that the formula for the queen in the first case (11,65%) is: AaBbCc. Since the Melipona bees are arrhenotokous hymenopteres, the drones are haploid and may have any one of the following eight formulas, corresponding to the gonic segregation of the queem : ABC, ABc, Abc, Abc, AbC, aBC, aBc, abC, abc. Anyone combination of these males with the queen will give a segregation of 7 workers to 1 queen, since there is always only one triple heterozygote among the eight possible segregates (table 5). 8) In order to explain the second case, it is suffient to assume that in this species there are only two pairs of factors, the queen being the double heterozygote : AaBb, while the drones may have any one of the following constitutions: AB, Ab, aB and ab. Workers are again all diploids which are homozygous for one or both factors, for instance: AABB, AABb, AaBB, aaBb, AAbb, etc. (table 6). 9) It is suggested that the genus Melipona is an intermediary type between the solitary bees, where all females are fertile independently of their feeding, and the genera Apis and Trigona, where without special feeding all females are born sterile, while only specially fed females develop into fertile queens. 10) No speculations are put forward with regards to the evolutionary mechanism which may have been responsible for the development of the genetical determination of castes in Melipona, since it seems advisable point to extend the studies to other insects with complicated caste systems.

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1° - Cita-sé a evolução das abelhas segundo MICÍÍENÉR" (1944). 2.° - A evolução dos Melíponíneos é estudada sob o ponto de vista da sua biologia, estabelecendo-se o tipo do meliponíneo primitivo. 3.° - São feitas considerações sobre a distribuição geográfica dos meliponíneos, entrando-se em detalhes sobre os seus fosseis, sobre a influência dos deslocamentos geológicos do cenozoico sobre sua distribuição, com particular referência ao seu estabelecimento na América do Sul. Considera-se também o e$eito das glaciações e a descontinuidade por ela provocada na distribuição dos meliponíneos. 4.° - São feitas hipóteses sobre a época em que se formaram as Meliponas, sobre o processo de determinação das castas e sua influência na evolução das mesmas. O tipo M. marginata é considerado o mais primitivo dos existentes atualmente. É dada uma hipótese, baseada na biologia e genética das Meliponas, para explicar sua evolução a partir de uma Trígona primitiva. 5.° - Sugere-se que a M. fascisrfta (excluidas a M. punc-ticollis e M. concinnula, que necessitam de estudos) seja do tipo da Meliponatrifatorial primitiva, tomando-se por base a sua proximidade a M. marginata, sua distribuição e sua variação. 6.° - Sugere-se como centro de origem das Meliponas a Bacia Amazônica, por ser esse lugar a zona onde há maior variação e por ser o centro geográfico da área habitada pelas Meliponas.

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This paper deals with problems on population genetics in Hymenoptera and particularly in social Apidae. 1) The studies on populations of Hymenoptera were made according to the two basic types of reproduction: endogamy and panmixia. The populations of social Apinae have a mixed method of reproduction with higher percentage of panmixia and a lower of endogamy. This is shown by the following a) males can enter any hive in swarming time; b) males of Meliponini are expelled from hives which does not need them, and thus, are forced to look for some other place; c) Meliponini males were seen powdering themselves with pollen, thus becoming more acceptable in any other hive. The panmixia is not complete owing to the fact that the density of the breeding population as very low, even in the more frequent species as low as about 2 females and 160 males per reproductive area. We adopted as selection values (or survival indices) the expressions according to Brieger (1948,1950) which may be summarised as follows; a population: p2AA + ²pq Aa + q2aa became after selection: x p2AA + 2pq Aa + z q²aa. For alge-braics facilities Brieger divided the three selective values by y giving thus: x/y p2 AA + y/y 2 pq Aa + z/y q²aa. He called x/y of RA and z/y of Ra, that are survival or selective index, calculated in relation to the heterozygote. In our case all index were calculated in relation to the heterozygote, including the ones for haploid males; thus we have: RA surveval index of genotype AA Ra surveval index of genotype aa R'A surveval index of genotype A R'a surveval index of genotype a 1 surveval index of genotype Aa The index R'A ande R'a were equalized to RA and Ra, respectively, for facilities in the conclusions. 2) Panmitic populations of Hymenoptera, barring mutations, migrations and selection, should follow the Hardy-Weinberg law, thus all gens will be present in the population in the inicial frequency (see Graphifc 1). 3) Heterotic genes: If mutation for heterotic gene ( 1 > RA > Ra) occurs, an equilibrium will be reached in a population when: P = R A + Ra - 2R²a _____________ (9) 2(R A + Ra - R²A - R²a q = R A + Ra - 2R²A _____________ (10) 2(R A + Ra - R²A - R²a A heterotic gene in an hymenopteran population may be maintained without the aid of new mutation only if the survival index of the most viable mutant (RA) does not exced the limiting value given by the formula: R A = 1 + √1+Ra _________ 4 If RA has a value higher thah the one permitted by the formula, then only the more viable gene will remain present in the population (see Graphic 10). The only direct proof for heterotic genes in Hymenoptera was given by Mackensen and Roberts, who obtained offspring from Apis mellefera L. queens fertilized by their own sons. Such inbreeding resulted in a rapid loss of vigor the colony; inbred lines intercrossed gave a high hybrid vigor. Other fats correlated with the "heterosis" problem are; a) In a colony M. quadrifasciata Lep., which suffered severely from heat, the percentage of deths omong males was greater .than among females; b) Casteel and Phillips had shown that in their samples (Apis melifera L). the males had 7 times more abnormalities tian the workers (see Quadros IV to VIII); c) just after emerging the males have great variation, but the older ones show a variation equal to that of workers; d) The tongue lenght of males of Apis mellifera L., of Bombus rubicundus Smith (Quadro X), of Melipona marginata Lep. (Quadro XI), and of Melipona quadrifasciata Lep. Quadro IX, show greater variationthan that of workers of the respective species. If such variation were only caused by subviables genes a rapid increasse of homozigoty for the most viable alleles should be expected; then, these .wild populations, supposed to be in equilibrium, could .not show such variability among males. Thus we conclude that heterotic genes have a grat importance in these cases. 4) By means of mathematical models, we came to the conclusion tht isolating genes (Ra ^ Ra > 1), even in the case of mutations with more adaptability, have only the opor-tunity of survival when the population number is very low (thus the frequency of the gene in the breeding population will be large just after its appearence). A pair of such alleles can only remain present in a population when in border regions of two races or subspecies. For more details see Graphics 5 to 8. 5) Sex-limited genes affecting only females, are of great importance toHymenoptera, being subject to the same limits and formulas as diploid panmitic populations (see formulas 12 and 13). The following examples of these genes were given: a) caste-determining genes in the genus Melipona; b) genes permiting an easy response of females to differences in feeding in almost all social Hymenoptera; c) two genes, found in wild populations, one in Trigona (Plebéia) mosquito F. SMITH (quadro XII) and other in Melipona marginata marginata LEP. (Quadro XIII, colonies 76 and 56) showing sex-limited effects. Sex-limited genes affecting only males do not contribute to the plasticity or genie reserve in hymenopteran populations (see formula 14). 6) The factor time (life span) in Hymenoptera has a particular importance for heterotic genes. Supposing one year to be the time unit and a pair of heterotic genes with respective survival indice equal to RA = 0, 90 and Ra = 0,70 to be present; then if the life time of a population is either one or two years, only the more viable gene will remain present (see formula 11). If the species has a life time of three years, then both alleles will be maintained. Thus we conclude that in specis with long lif-time, the heterotic genes have more importance, and should be found more easily. 7) The colonies of social Hymenoptera behave as units in competition, thus in the studies of populations one must determine the survival index, of these units which may be subdivided in indice for egg-laying, for adaptive value of the queen, for working capacity of workers, etc. 8) A study of endogamic hymenopteran populations, reproduced by sister x brother mating (fig. 2), lead us to the following conclusions: a) without selection, a population, heterozygous for one pair of alleles, will consist after some generations (theoretically after an infinite number of generation) of females AA fecundated with males A and females aa fecundated with males a (see Quadro I). b) Even in endogamic population there is the theoretical possibility of the presence of heterotic genes, at equilibrium without the aid of new mutations (see Graphics 11 and 12), but the following! conditions must be satisfied: I - surveval index of both homozygotes (RA e Ra) should be below 0,75 (see Graphic 13); II - The most viable allele must riot exced the less viable one by more than is permited by the following formula (Pimentel Gomes 1950) (see Gra-fic 14) : 4 R5A + 8 Ra R4A - 4 Ra R³A (Ra - 1) R²A - - R²a (4 R²a + 4 Ra - 1) R A + 2 R³a < o Considering these two conditions, the existance of heterotic genes in endogamic populations of Hymenoptera \>ecames very improbable though not - impossible. 9) Genie mutation offects more hymenopteran than diploid populations. Thus we have for lethal genes in diploid populations: u = q2, and in Hymenoptera: u = s, being u the mutation ratio and s the frequency of the mutant in the male population. 10) Three factors, important to competition among species of Meliponini were analysed: flying capacity of workers, food gathering capacity of workers, egg-laying of the queen. In this connection we refer to the variability of the tongue lenght observed in colonies from several localites, to the method of transporting the pollen in the stomach, from some pots (Melliponi-ni storage alveolus) to others (e. g. in cases of pillage), and to the observation that the species with the most populous hives are almost always the most frequent ones also. 11) Several defensive ways used for Meliponini to avoid predation are cited, but special references are made upon the camouflage of both hive (fig. 5) and hive entrance (fig. 4) and on the mimetism (see list in page ). Also under the same heading we described the method of Lestrimelitta for pillage. 12) As mechanisms important for promoting genetic plasticity of hymenopteran species we cited: a) cytological variations and b) genie reserve. As to the former, duplications and numerical variations of chromosomes were studied. Diprion simile ATC was cited as example for polyploidy. Apis mellife-ra L. (n •= 16) also sugests polyploid origen since: a) The genus Melipona, which belongs to a" related tribe, presents in all species so far studied n = 9 chromosomes and b) there occurs formation of dyads in the firt spermatocyte division. It is su-gested that the origin of the sex-chromosome of Apis mellifera It. may be related to the possible origin of diplo-tetraploidy in this species. With regards to the genie reserve, several possible types of mutants were discussed. They were classified according to their survival indices; the heterotic and neutral mutants must be considered as more important for the genie reserve. 13) The mean radius from a mother to a daghter colony was estimated as 100 meters. Since the Meliponini hives swarm only once a year we may take 100 meters a year as the average dispersion of female Meliponini in ocordance to data obtained from Trigona (tetragonisca) jaty F. SMITH and Melipona marginata LEP., while other species may give different values. For males the flying distance was roughly estimated to be 10 times that for females. A review of the bibliography on Meliponini swarm was made (pg. 43 to 47) and new facts added. The population desity (breeding population) corresponds in may species of Meliponini to one male and one female per 10.000 square meters. Apparently the males are more frequent than the females, because there are sometimes many thousands, of males in a swarm; but for the genie frequency the individuals which have descendants are the ones computed. In the case of Apini and Meliponini, only one queen per hive and the males represented by. the spermatozoos in its spermateca are computed. In Meliponini only one male mate with the queen, while queens of Apis mellijera L. are fecundated by an average of about 1, 5 males. (Roberts, 1944). From the date cited, one clearly sees that, on the whole, populations of wild social bees (Meliponini) are so small that the Sewall Wright effect may become of great importance. In fact applying the Wright's formula: f = ( 1/aN♂ + 1/aN♀) (1 - 1/aN♂ + 1/aN♀) which measures the fixation and loss of genes per generation, we see that the fixation or loss of genes is of about 7% in the more frequent species, and rarer species about 11%. The variation in size, tergite color, background color, etc, of Melipona marginata Lep. is atributed to this genetic drift. A detail, important to the survival of Meliponini species, is the Constance of their breeding population. This Constance is due to the social organization, i. e., to the care given to the reproductive individuals (the queen with its sperm pack), to the way of swarming, to the food storage intended to control variations of feeding supply, etc. 14) Some species of the Meliponini are adapted to various ecological conditions and inhabit large geographical areas (e. g. T. (Tetragonisca jaty F. SMITH), and Trigona (Nanno-trigona testaceicornis LEP.) while others are limited to narrow regions with special ecological conditions (e. g. M. fuscata me-lanoventer SCHWARZ). Other species still, within the same geographical region, profit different ecological conditions, as do M. marginata LEP. and M. quadrifasciata LEP. The geographical distribution of Melipona quadrifasciata LEP. is different according to the subspecies: a) subsp anthidio-des LEP. (represented in Fig. 7 by black squares) inhabits a region fron the North of the S. Paulo State to Northeastern Brazil, ,b) subspecies quadrifasciata LEP., (marked in Fig. 7 with black triangles) accurs from the South of S. Paulo State to the middle of the State of Rio Grande do Sul (South Brazil). In the margined region between these two areas of distribution, hi-brid colonies were found (Fig. 7, white circles); they are shown with more details in fig. 8, while the zone of hybridization is roughly indicated in fig. 9 (gray zone). The subspecies quadrifasciata LEP., has 4 complete yellow bands on the abdominal tergites while anthidioides LEP. has interrupted ones. This character is determined by one or two genes and gives different adaptative properties to the subspecies. Figs. 10 shows certains meteorological isoclines which have aproximately the same configuration as the limits of the hybrid zone, suggesting different climatic adaptabilities for both genotypes. The exis-tance of a border zone between the areas of both subspecies, where were found a high frequency of hybrids, is explained as follows: being each subspecies adapted to a special climatic zone, we may suppose a poor adaptation of either one in the border region, which is also a region of intermediate climatic conditions. Thus, the hybrids, having a combination of the parent qualities, will be best adapted to the transition zone. Thus, the hybrids will become heterotic and an equilibrium will be reached with all genotypes present in the population in the border region.

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New species described: Callia marginata from Peru, C. punctata from Colombia, C. annulata from Ecuador, C. tristis from Bolivia, C. paraguaya from Paraguay; from Brazil: C. divisa and C. tomentosa (Mato Grosso), and C. lissonota (Rondônia). A key to the species of Callia is added.

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Seeking the identification of Angiostrongylus cantonensis as a potential etiological agent of three clinical cases of eosinophilic meningitis, mollusc specimens were collected in the state of Espírito Santo, Brazil. The snails were identified as Sarasinula marginata (45 specimens), Subulina octona (157), Achatina fulica (45) and Bradybaena similaris (23). Larvae obtained were submitted to polymerase chain reaction and restriction fragment length polymorphism diagnosis. Their genetic profile were corresponded to A. cantonensis. Rattus norvegicus experimentally infected with third-stage larvae, developed menigoencephalitis, and parasites became sexually mature in the lungs. Additionally, larvae obtained from A. fulica snails, from São Vicente, state of São Paulo, also showed genetic profiles of this nematode. This is the first record of Brazilian molluscs infected with this nematode species.

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Angiostrongylus cantonensis is the most common aetiological agent of human eosinophilic meningoencephalitis. Following a report indicating the presence of this parasite in Brazil in 2007, the present study was undertaken to investigate the presence of A. cantonensis in the surrounding Brazilian port areas. In total, 30 ports were investigated and the following molluscs were identified: Achatina fulica, Belocaulus sp., Bradybaena similaris sp., Cyclodontina sp., Helix sp., Leptinaria sp., Melampus sp., Melanoides tuberculata, Phyllocaulis sp., Pomacea sp., Pseudoxychona sp., Rhinus sp., Sarasinula marginata, Streptaxis sp., Subulina octona, Succinea sp., Tomigerus sp., Wayampia sp. and specimens belonging to Limacidae and Orthalicinae. Digestion and sedimentation processes were performed and the sediments were examined. DNA was extracted from the obtained larvae and the internal transcribed spacer region 2 was analysed by polymerase chain reaction-restriction fragment length polymorphism after digestion with the endonuclease ClaI. Of the 30 ports investigated in this study, 11 contained molluscs infected with A. cantonensis larvae. The set of infected species consisted of S. octona, S. marginata, A. fulica and B. similaris. A total of 36.6% of the investigated ports were positive for A. cantonensis, indicating a wide distribution of this worm. It remains uncertain when and how A. cantonensis was introduced into South America.

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Aim We investigated the late Quaternary history of two closely related and partly sympatric species of Primula from the south-western European Alps, P. latifolia Lapeyr. and P. marginata Curtis, by combining phylogeographical and palaeodistribution modelling approaches. In particular, we were interested in whether the two approaches were congruent and identified the same glacial refugia. Location South-western European Alps. Methods For the phylogeographical analysis we included 353 individuals from 28 populations of P. marginata and 172 individuals from 15 populations of P. latifolia and used amplified fragment length polymorphisms (AFLPs). For palaeodistribution modelling, species distribution models (SDMs) were based on extant species occurrences and then projected to climate models (CCSM, MIROC) of the Last Glacial Maximum (LGM), approximately 21 ka. Results The locations of the modelled LGM refugia were confirmed by various indices of genetic variation. The refugia of the two species were largely geographically isolated, overlapping only 6% to 11% of the species' total LGM distribution. This overlap decreased when the position of the glacial ice sheet and the differential elevational and edaphic distributions of the two species were considered. Main conclusions The combination of phylogeography and palaeodistribution modelling proved useful in locating putative glacial refugia of two alpine species of Primula. The phylogeographical data allowed us to identify those parts of the modelled LGM refugial area that were likely source areas for recolonization. The use of SDMs predicted LGM refugial areas substantially larger and geographically more divergent than could have been predicted by phylogeographical data alone

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On the identity of Melipona torrida Friese (Hymenoptera, Apidae). Melipona marginata var. torrida Friese, 1916, described from three workers putatively collected in Costa Rica, never had its identity properly recognized. Since its original description, no additional specimens have ever been collected in Costa Rica. It is argued here that Melipona torrida was based on mislabeled specimens and corresponds to Melipona marginata obscurior Moure, 1971, a form known only from southern Brazil, Argentina and Paraguay. A lectotype is designated for Melipona torrida and notes on the type material of Melipona marginata obscurior are provided. Other known examples of species described from mislabeled specimens in Friese's Zur Bienenfauna von Costa Rica are discussed. It is pointed out that additional names proposed in this work, based on material from Costa Rica, might turn out to correspond to South American taxa. Also, the date of publication of this Friese's paper is discussed.

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ABSTRACTHere we describe seven new species of Limnophora from Ecuador: Limnophora bifasciatasp. nov. from Napo, Quito; Limnophora equatoriensissp. nov. from Zamora-Chinchipe, Zamora; Limnophora femurosetalissp. nov. from Zamora-Chinchipe, Zamora; Limnophora lamasisp. nov. from Zamora-Chinchipe, Zamora; Limnophora longivittatasp. nov. from Napo, Quito; Limnophora penaisp. nov. from Azuay, Cuenca and Limnophora polletisp. nov. from Napo, Quito. We provide an identification key for the ten recognized species of Limnophora from Ecuador, including L. marginata Stein, 1904, L. pica(Macquart, 1851) and L. saeva (Wiedemann, 1830). We also redescribed Limnophora marginata Stein, 1904, and designated designed lectotype male and paralectotypes males and females of the species.

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O objetivo deste trabalho foi avaliar o desempenho de 18 clones de seringueira resistentes ao Microcyclus ulei, usados como copas enxertadas. Foram utilizados oito clones híbridos de Hevea pauciflora x Hevea guianensis var. marginata, oito de H. pauciflora x H. rigidifolia e dois clones de H. pauciflora, enxertados sobre o painel de CNS AM 7905 - seleção primária de H. brasiliensis - e cultivados em Latossolo Amarelo distrófico, em Manaus, AM. Foram avaliados: perímetro do tronco, estado nutricional e produtividade de borracha seca. Copas enxertadas de híbridos H. pauciflora x H. guianensis var. marginata causam crescimento mais rápido do tronco, com redução do período de imaturidade da seringueira. O alto nível de resistência dos híbridos de H. rigidifolia ao percevejo-de-renda (Leptopharsa heveae) justifica a introdução de outros genótipos dessa espécie para novas hibridações. Os clones CPAA C 01, 06, 13, 15, 16 e 45 apresentam excelente potencial de produção de borracha seca, nas condições climáticas e de solos de terra firme da Amazônia Tropical Úmida.

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Este trabalho teve por objetivo avaliar algumas propriedades físicas e mecânicas da madeira de Eucalyptus urophylla S.T. Blake "Eucalipto" (Myrtaceae), Melia azedarach L. "Cinamomo" (Meliaceae), Lophantera lactescens Ducke, "lanterneira" (Malpighiaceae), Pinus elliottii Engelm. "Pinus" (Pinaceae) e Inga marginata Wild "Inga" (Mimosaceae), submetidas ao processo de degradação em razão da exposição à intempérie no período de 12 meses, as madeiras foram colocadas em dois ambientes com características edafoclimáticas diferenciadas, isto é, foram montados dois campos de apodrecimento, sendo um dentro de uma mata secundária e outro a céu aberto, em um pasto formado por gramíneas rasteiras. Na avaliação, adotou-se um índice de deterioração médio, para expressar a degradação causada pelos fatores bióticos, nos corpos-de-prova oriundos de toras expostas nos respectivos ambientes. As determinações da densidade aparente, bem como da resistência à flexão (módulo de elasticidade (MOE) e ruptura (MOR)) e compressão paralela às fibras da madeira, foram realizadas antes e depois da exposição à intempérie. Os resultados indicaram que ocorreram reduções diferenciadas nas propriedades avaliadas. As diminuições significativas da densidade ocorreram somente nos corpos-de-prova oriundos das madeiras expostas dentro da mata, bem como as reduções nos módulos de elasticidade e ruptura foram mais acentuadas nas madeiras procedentes desse ambiente. A resistência à compressão da madeira apresentou-se com reduções maiores, também nesse ambiente.

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O objetivo deste trabalho foi avaliar a viabilidade do uso de blocos prensados como recipientes na produção de mudas de Inga marginata, Jacaranda puberula e Zeyheria tuberculosa. O sistema de bloco prensado (440 cm³/muda) foi comparado com sacos plásticos (330 cm³) e tubetes de seção circular (280 cm³). O substrato utilizado foi uma mistura de composto orgânico, moinha de carvão e solo argiloso (6:2:2). Após a prensagem, os blocos prensados apresentaram dimensões de 60 x 40 x 12 cm (comprimento, largura e altura). Foram medidos a altura e o diâmetro das mudas mensalmente, dos 60 até 150 dias após a repicagem. Em seguida, determinou-se o peso de matéria seca da parte aérea e do sistema radicular. Para avaliar o comportamento das mudas produzidas nos diferentes tratamentos e em condições de campo, mediram-se a taxa de sobrevivência aos 2 meses e o crescimento em altura aos 10 meses após o plantio. As mudas produzidas no sistema de blocos prensados apresentaram crescimento superior ou similar àquelas produzidas nos sacos plásticos e tubetes. Em condições de campo, a taxa de sobrevivência e o crescimento das plantas oriundas do sistema de blocos prensados não apresentaram diferenças estatísticas em relação às plantas oriundas de sacos plásticos e tubetes. O sistema de blocos prensados mostrou-se tecnicamente viável para a produção de mudas das espécies florestais estudadas.

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O presente trabalho trata do levantamento florístico da família Selaginellaceae Willk. no Estado de São Paulo. De acordo com os dados obtidos, foi possível o reconhecimento de 14 espécies nativas, distribuídas em três subgêneros: Heterostachys Baker, Stachygynandrum (P. Beauv.) Baker e Tetragonostachys Jermy. Os subgêneros Heterostachys e Tetragonostachys estão representados no Estado por uma única espécie cada, Selaginella muscosa Spring e Selaginella sellowii Hieron., respectivamente. O subgênero Stachygynandrum está representado por 12 espécies: Selaginella contigua Baker, S. convoluta (Arn.) Spring, S. decomposita Spring, S. flexuosa Spring, S. macrostachya (Spring) Spring, S. marginata (Humb. & Bonpl. ex Willd.) Spring, S. mendoncae Hieron., S. microphylla (Kunth) Spring, S. suavis (Spring) Spring, S. sulcata (Desv. ex Poir.) Spring, S. tenuissima Fée e S. valida Alston. Selaginella mendoncae e Selaginella sellowii estão sendo citadas pela primeira vez para o Estado de São Paulo. Além dessas 14 espécies nativas, também foram encontradas quatro espécies introduzidas - Selaginella kraussiana (Kunze) A. Braun, S. pallescens (C. Presl) Spring, S. plana (Desv. ex Poir.) Hieron. e S. vogelii Spring. São apresentadas chaves de identificação e descrições para os subgêneros e espécies, bem como ilustrações, distribuição geográfica e comentários das espécies estudadas.

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Foi caracterizada a fisionomia e a estrutura do componente arbóreo de um fragmento de floresta estacional montana situado a 900 m de altitude. A área de estudo (8º11'144" -8º12'27" S e 36º23'730" -36º24'638" W) apresenta solos profundos e precipitação média anual de 948 mm ano-1. Foram amostrados todos os indivíduos vivos ou mortos, ainda em pé, com diâmetro a altura do peito > 5 cm, em 50 parcelas contíguas de 10 x 20 m, e tomadas as seguintes medidas: altura total, diâmetro do caule e área de cobertura da copa. As espécies foram classificadas quanto ao tamanho foliar, deciduidade e composição do limbo. Um total de 62 espécies (um taxon não identificado) foi amostrado. Densidade total, área basal total, altura e diâmetro médios e máximos dos indivíduos vivos foram 1.553 ind ha-1, 39 m² ha-1, 10,3 e 30 m e 14,2 e 105,0 cm, respectivamente. Cerca de 50% dos indivíduos vivos ocorreram abaixo de 10 m de altura. A distribuição das áreas basais e cobertura de copa por classe de altura indicou dois intervalos de concentração: 7-13 e 19-22 m. A área representa uma floresta estacional montana de transição entre as florestas ombrófilas e estacionais. A maioria das espécies é perenifólia e apresenta folhas simples e micrófilas (Casearia sylvestris Sw., Guapira nitida (Schmidt) Lundell, Marlierea clausseniana (O. Berg) Kiaersk., Ocotea aff. elegans Mez, Plinia sp., entre outras), ocupando o dossel da floresta juntamente com espécies notófilas (Amaioua cf. guianensis Aubl. e Roupala paulensis Sleumer) e mesófilas (Fabaceae sp. e Inga marginata Willd., entre outras). Entre as emergentes predominam espécies com folhas caducifólias e compostas, como Copaifera trapezifolia Hayne e Eriotheca crenulaticalyx A. Robyns.