Large-scale patterns in morphological diversity and species assemblages in Neotropical Triatominae (Heteroptera: Reduviidae)

We analysed the spatial variation in morphological diversity (MDiv) and species richness (SR) for 91 species of Neotropical Triatominae to determine the ecological relationships between SR and MDiv and to explore the roles that climate, productivity, environmental heterogeneity and the presence of biomes and rivers may play in the structuring of species assemblages. For each 110 km x 110 km-cell on a grid map of America, we determined the number of species (SR) and estimated the mean Gower index (MDiv) based on 12 morphological attributes. We performed bootstrapping analyses of species assemblages to identify whether those assemblages were more similar or dissimilar in their morphology than expected by chance. We applied a multi-model selection procedure and spatial explicit analyses to account for the association of diversity-environment relationships. MDiv and SR both showed a latitudinal gradient, although each peaked at different locations and were thus not strictly spatially congruent. SR decreased with temperature variability and MDiv increased with mean temperature, suggesting a predominant role for ambient energy in determining Triatominae diversity. Species that were more similar than expected by chance co-occurred near the limits of the Triatominae distribution in association with changes in environmental variables. Environmental filtering may underlie the structuring of species assemblages near their distributional limits.

The Simaba guianensis complex in northers South America

With additional data from specimens not studied by previous workers, the confusing Simaba guianensis compex was re-analized. Simaba polyphylla is recognized as a distinct species and two subspecies of S. guianensis are maintained. Simaba polyphylla, S. guianensis ssp. guianensis, and S. guianensis ssp. ecaudata are keyed, described, and illustrated and specimens examined are cited for each. Specimens of S. guianensis ssp. ecaudata show great morphological diversity but can be separeted into three groups. Further collecting may provide information that shows these groups to be worthy of separate taxonomic status.

Caste polymorphism of apterous line of the Neotropical termite Nasutitermes corniger (Motschulsky) (Isoptera, Termitidae)

Termite societies are structured by individuals that can be grouped into castes and instars. The development of these instars in most species occurs in irregular patterns and sometimes is distinguished subcastes in physical systems that originate polymorphic soldiers and workers. In this study, we characterized the morphological diversity of castes of apterous in Nasutitermes corniger. We collected four colonies of N. corniger, one every three months between May 2011 and February 2012. Individuals of the nest were separated into groups: larval stages, workers and presoldiers and soldiers. A morphometric analysis was performed on individuals from each group based on head width, metatibia, antenna, and thorax length. The data were submitted to discriminant analysis to confirm different morphological types inside these groups. The apterous line of N. corniger is composed of one first larval instar and two second larval instar. The workers caste has two lines of development with four instars in a larger line and three instars in a lower line. Two morphological types were identified in presoldiers and soldiers. The pattern of castes was similar to other species of the genus, in which bifurcation into two lines of workers, one smaller and one larger occurs after the first molt.

Worker morphology of the ant Gnamptogenys striatula Mayr (Formicidae, Ectatomminae) in different landscapes from the Atlantic Forest domain

Morphological traits, such as size and shape, may reflect a combination of ecological and evolutionary responses by organisms. Ants have been used to evaluate the relationship between the environment and species coexistence and morphology. In the present study, we analyzed the morphology of workers of Gnamptogenys striatula Mayr in different landscapes from the Atlantic Domain in southeastern Brazil, focusing on the variation in the morphological attributes of these populations compared to those from a dense ombrophilous forest. Eighteen morphological traits of functional importance for interactions between workers and the environment were measured to characterize the size and shape of the workers. In general, the results show that ants of urban areas possess some morphological attributes of smaller size, with highly overlapped morphological space between the populations in forested ecosystems. Further, some of the traits related to predation were relatively smaller in modified land areas than in the populations from preserved areas of dense ombrophilous forest. These results help broaden the knowledge regarding morphological diversity in G. striatula, suggesting that the characterization of the morphology may be important to quantify the effects of land use on morphological diversity, and presumably, to facilitate the use of ants as biological indicators.

Seed biometric parameters in oil palm accessions from a Brazilian germplasm bank

The objective of this work was to evaluate the morphological diversity of oil palm seeds and to cluster the accessions according to their morphological characteristics. Forty-one accessions from the oil palm germplasm bank of Embrapa Amazônia Ocidental were evaluated - 18 of Elaeis oleifera and 23 of E. guineensis. The groups were formed based on morphological characteristics, by principal component analysis. In E. oleifera, four groups were formed, tied to their region of origin, but with significant morphological differences between accessions from the same population. For tenera-type E. guineensis seeds, three widely divergent groups were formed, especially as to external parameters, which differentiated them from the other ones. The parameter endocarp thickness stood out in intra- and inter-population differentiation. For dura-type E. guineensis, three groups were formed, with larger seeds and thicker endocarps, which differed from all the other ones. The variability observed for seed characteristics in the analyzed accessions allows the establishment of different groups, to define strategies for genetic improvement.

Morphological and molecular diversity among cassava genotypes

The objective of this work was to characterize morphologically and molecularly the genetic diversity of cassava accessions, collected from different regions in Brazil. A descriptive analysis was made for 12 morphological traits in 419 accessions. Data was transformed into binary data for cluster analysis and analysis of molecular variance. A higher proportion of white or cream (71%) root cortex color was found, while flesh colors were predominantly white (49%) and cream (42%). Four accession groups were classified by the cluster analysis, but they were not grouped according to their origin, which indicates that diversity is not structured in space. The variation was greater within regions (95.6%). Sixty genotypes were also evaluated using 14 polymorphic microsatellite markers. Molecular results corroborated the morphological ones, showing the same random distribution of genotypes, with no grouping according to origin. Diversity indices were high for each region, and a greater diversity was found within regions, with: a mean number of alleles per locus of 3.530; observed and expected heterozygosity of 0.499 and 0.642, respectively; and Shannon index of 1.03. The absence of spatial structure among cassava genotypes according to their origins shows the anthropic influence in the distribution and movement of germplasm, both within and among regions.

Description of microsporidia in simulids: molecular and morphological characterization of microsporidia in the larvae of Simulium pertinax Kollar (Diptera: Simuliidae)

IntroductionMicrosporidia constitute the most common black fly pathogens, although the species' diversity, seasonal occurrence and transmission mechanisms remain poorly understood. Infections by this agent are often chronic and non-lethal, but they can cause reduced fecundity and decreased longevity. The objective of this study was to identify microsporidia infecting Simulium (Chirostilbia) pertinax (Kollar, 1832) larvae from Caraguatatuba, State of São Paulo, Brazil, by molecular and morphological characterization.MethodsLarvae were collected at a single point in a stream in a rural area of the city and were kept under artificial aeration until analysis. Polydispyrenia spp. infection was characterized by the presence of at least 32 mononuclear spores measuring 6.9 ± 1.0 × 5.0 ± 0.7µm in persistent sporophorous vesicles. Similarly, Amblyospora spp. were characterized by the presence of eight uninucleate spores measuring 4.5 × 3.5µm in sporophorous vesicles.ResultsThe molecular analysis confirmed the presence of microsporidian DNA in the 8 samples (prevalence of 0.51%). Six samples (Brazilian larvae) were related to Polydispyrenia simulii and Caudospora palustris reference sequences but in separate clusters. One sample was clustered with Amblyospora spp. Edhazardia aedis was the positive control taxon.ConclusionsSamples identified as Polydispyrenia spp. and Amblyospora spp. were grouped with P. simulii and Amblyospora spp., respectively, corroborating previous results. However, the 16S gene tree showed a considerable distance between the black fly-infecting Amblyospora spp. and the mosquito-infecting spp. This distance suggests that these two groups are not congeneric. Additional genomic region evaluation is necessary to obtain a coherent phylogeny for this group.

Should Trypanosoma cruzi be called "cruzi" complex? A review of the parasite diversity and the potential of selecting population after in Vitro culturing and mice infection

Morpho-biological diversity of Trypanosoma cruzi has been known since Chagas' first works in 1909. Several further studies confirmed the morphological differences among the parasite strains, which were isolated from different reservoirs and vectors, as well as from human beings. In the early sixties, antigenic differences were found in the parasite strains from various sources. These differences, coupled to the observation of regional variations of the disease, led to the proposal of the term cruzi complex to designate the taxon T. cruzi. Since then this protozoan has been typed in distinct biodemes, zymodemes and lineages which were consensually grouped into T. cruzi I, T. cruzi II and into non-grouped strains. T. cruzi genotypic characterization, initially carried out by schizodeme analysis and more recently by various other techniques, has shown a great diversity of the parasite strains. In fact, T. cruzi is formed by groups of heterogeneous sub-population, which present specific characteristics, including distinct histotropism. The interaction of the different infecting clones of the cruzi complex and the human host will determine the morbidity of the disease.

Diversity of Chromobacterium violaceum isolates from aquatic environments of state of Pará, Brazilian Amazon

The present study intended to characterize the phenotypic and genetic diversity of Brazilian isolates of Chromobacterium violaceum from aquatic environments within the Amazon region. Nineteen isolates showed morphological properties of C. violaceum and the majority grew at 44°C. Low temperatures, in contrast, showed to be inhibitory to their growth, as eleven isolates did not grow at 10ºC and nine did not produce pigmentation, clearly indicating an inhibition of their metabolism. The largest variation among isolates was observed in the citrate test (Simmons), in which 12 isolates were positive, and in the oxidation/fermentation of sucrose, with six positives isolates. Chloramphenicol, gentamicin and sulfonamides efficiently inhibited bacterial growth. Amplified products of the recA gene were digested with HindII or PstI, which produced three or four restriction fragments patterns, respectively. The combined analysis arranged the isolates into six genospecies. The higher diversity observed in Belém (genotypes C, D, E and F) may be a consequence of intense human occupation, pollution of the aquatic environment or due to the higher diversity of the environments sampled in that region. In conclusion, a high level of genetic and phenotypic diversity was observed, and four new genospecies were described.

Quantification of the diversity among common bean accessions using Ward-MLM strategy

The present work aimed at evaluating the divergence among common bean accessions by their agronomic, morphological and molecular traits, based on the Ward-MLM procedure. A collection of 57 accessions from the gene bank of Universidade Federal do Espírito Santo was used in this study, from which: 31 were landraces belonging to the community Fortaleza, in the municipality of Muqui, ES, Brazil; 20 accessions were provided by Embrapa Trigo; and 6 were commercial cultivars. Five agronomic traits (plant cycle, number of seeds per pod, number of pods per plant, weight of 100 seeds, and grain yield), five morphological traits (growth habit, plant size, seed shape, seed color, and commercial group) and 16 microsatellite primers were evaluated. High genetic variability was detected considering morphological, agronomic and molecular traits in the 57 common bean accessions studied. The Ward-MLM procedure showed that the ideal number of groups was five, according to the pseudo F and pseudo t² criteria. The accessions from Andean origin had heavier seeds than others and formed a cluster. The Ward-MLM statistical procedure is a useful technique to detect genetic divergence and to cluster genotypes by simultaneously using morphological, agronomic and molecular data.

Genetic diversity between improved banana diploids using canonical variables and the Ward-MLM method

The objective of this work was to estimate the genetic diversity of improved banana diploids using data from quantitative analysis and from simple sequence repeats (SSR) marker, simultaneously. The experiment was carried out with 33 diploids, in an augmented block design with 30 regular treatments and three common ones. Eighteen agronomic characteristics and 20 SSR primers were used. The agronomic characteristics and the SSR were analyzed simultaneously by the Ward-MLM, cluster, and IML procedures. The Ward clustering method considered the combined matrix obtained by the Gower algorithm. The Ward-MLM procedure identified three ideal groups (G1, G2, and G3) based on pseudo-F and pseudo-t² statistics. The dendrogram showed relative similarity between the G1 genotypes, justified by genealogy. In G2, 'Calcutta 4' appears in 62% of the genealogies. Similar behavior was observed in G3, in which the 028003-01 diploid is the male parent of the 086079-10 and 042079-06 genotypes. The method with canonical variables had greater discriminatory power than Ward-MLM. Although reduced, the genetic variability available is sufficient to be used in the development of new hybrids.

Diversity and nitrogen fixation efficiency of rhizobia isolated from nodules of Centrolobium paraense

The objective of this work was to isolate and characterize rhizobia from nodules of Centrolobium paraense and to evaluate their symbiotic efficiency. Soil samples collected from four sites of the Roraima Cerrado, Brazil, were used to cultivate C. paraense in order to obtain nodules. Isolates (178) were obtained from 334 nodules after cultivation on medium 79. Twenty-five isolates belonging to six morphological groups were authenticated using Vigna unguiculata and they were characterized by 16S rRNA. Isolates identified as Bradyrhizobium were further characterized using rpoB gene sequencing. A greenhouse experiment was carried out with C. paraense to test the 18 authenticated isolates. Approximately 90% of the isolates grew slowly in medium 79. The 16S rRNA analysis showed that 14 authenticated isolates belong to the genus Bradyrhizobium, and rpoB indicated they constitute different groups compared to previously described species. Only four of the 11 fast-growing isolates nodulated V. unguiculata, two of which belong to Rhizobium, and two to Pleomorphomonas, which was not previously reported as a nodulating genus. The Bradyrhizobium isolates ERR 326, ERR 399, and ERR 435 had the highest symbiotic efficiency on C. paraense and showed a contribution similar to the nitrogen treatment. Centrolobium paraense is able to nodulate with different rhizobium species, some of which have not yet been described.

Subgeneric diversity of Brasilonema (Cyanobacteria, Scytonemataceae)

The recently described scytonematoid cyanobacterial genus Brasilonema is known mainly from tropical and subtropical rain forests (Mata Atlântica) of southeastern Brazil, where it occurs in aerophytic wooden, stony and iron substrates. This genus was defined according to both molecular and morphological criteria. The type species B. bromeliae was described from the specialized habitat: it grows in phytothelmes, epiphytic on both living and died leaves within the rosettes of large bromeliad plants slightly above or in the zone of the water level. The genus Brasilonema is evidently widely distributed in coastal forests of São Paulo State, where it occurs also in remarkable diversity. According to our results, this genus currently comprises seven taxa, which are distinct by different morphology and ecological characteristics.

Morphological, physical and pedogenetic attributes related to water yield in small watersheds in Guarapari/ES, Brazil

Soil characteristics related to the genesis, land use and management are important factors in water dynamics in watersheds. This study evaluated physical, morphological and pedogenetic attributes related to water yield potential in small watersheds in Guarapari, ES, Brazil. The following representative profiles were selected, morphologically described and sampled in area of Atlantic Forest domain: Lithic Udifolists, Oxyaquic Udifluventes, Typic Paleudults, Typic Hapludults, Typic Hapludox, Oxic Dystrudepts and Typic Endoaquents. Samples were collected in the soil profiles for physical analysis. Measurements of field-saturated hydraulic conductivity and soil penetration resistance were perfomed in some profiles, which were under different uses. The Endoaquents of Limão Creek can be considered efficient as temporary water reservoirs. However, the use of artificial drainage tends to reduce this effect. Differential erosion was detected by the sand texture on the surface of the Typic Paleudults due to the low degree of clay flocculation, slope, high resistance to the penetration and low hydraulic conductivity of the Bt horizon, making it necessary to adopt soil management practices to increase the water infiltration. Under pasture, mainly in the cattle trails where the trampling is more intense, there was high resistance to penetration in the superficial layers of the Typic Hapludults. The Typic Hapludox have the greatest potential for water yield in the small watersheds because of its greater extent in the headwaters and their morphological and physical characteristics, which can result in increased aquifer recharge.

Genetic diversity in sugar apple (Annona squamosa L.) by using RAPD markers

Genetic diversity in a collection of 64 sugar apple accessions collected from different municipalities in northern Minas Gerais was assessed by RAPD analysis. Using 20 selected RAPD primers 167 fragments were generated, of which 48 were polymorphic (28.7%) producing an average of 2.4 polymorphic fragments per primer. Low percentage of polymorphism (< 29%) was observed by using the set of primers indicating low level of genetic variation among the 64 accessions evaluated. Genetic relationships were estimated using Jaccard's coefficient of similarity. Accessions from different municipalities clustered together indicating no correlation between molecular grouping and geographical origin. The dendrogram revealed five clusters. The first cluster grouped C19 and G29 accessions collected from the municipalities of Verdelândia and Monte Azul, respectively. The second cluster grouped G16 and B11 accessions collected from the municipalities of Monte Azul and Coração de Jesus, respectively. The remaining accessions were grouped in three clusters, with 8, 15 and 37 accessions, respectively. In summary, RAPD showed a low percentage of polymorphism in the germplasm collection.