Diversidade de abelhas (Hymenoptera, Apidae) ao longo de um gradiente latitudinal na Mata Atlântica

A Mata Atlântica é um dos ambientes mais ricos e ameaçados do mundo, o que deveria ter estimulado em muito o estudo e a conservação do Bioma, mas a fauna de Hymenoptera permanece ainda relativamente pouco conhecida. Em especial, a fauna de abelhas da floresta ombrófila densa é pouco estudada em comparação à fauna das áreas abertas brasileiras. O projeto temático "Biodiversidade de Hymenoptera e Isoptera: riqueza e diversidade ao longo de um gradiente latitudinal na Mata Atlântica - a floresta úmida do leste do Brasil", integrante do Programa Biota-Fapesp, foi idealizado com o objetivo de catalogar térmitas, formigas e famílias selecionadas de vespas ao longo da Mata Atlântica, disponibilizando dados que permitam melhor embasar a conservação deste bioma. O protocolo de amostragem aplicada para a coleta de himenópteros (excluindo as formigas) empregou armadilhas Malaise, pratos-armadilha de cor amarela e esforço similar na varredura de vegetação ao longo de 17 localidades selecionadas, representando um gradiente de quase 20° de latitude na Mata Atlântica, dos Estados da Paraíba até Santa Catarina. Este protocolo foi definido para otimizar a coleta de vespas, sendo as abelhas um produto secundário da amostragem (levantamentos de abelhas em geral utilizam captura em flores ao longo das estações do ano). No entanto, devido à escala regional do projeto e ao grande esforço de amostragem, uma expressiva quantidade de abelhas foi coletada durante o projeto, incluindo novos registros de abelhas para a Mata Atlântica. Foi amostrado um total de 797 espécimes distribuídos em 105 espécies de abelhas; o grupo de abelhas mais rico e abundante foi Meliponina. Uma análise de correspondência "destendenciada" ('detrended correspondence analysis') aplicada à uma matriz de presença ou ausência de Meliponina revela a relativamente fraca influência do gradiente latitudinal na composição das assembléias de abelhas de Mata Atlântica. Uma listagem das espécies amostradas por localidade, com suas freqüências relativas, é apresentada e discutida.

Age polyethism in Plebeia emerina (Friese) (Hymenoptera: Apidae) colonies related to propolis handling

Stingless bees collect plant resins and make it into propolis, although they have a wider range of use for this material than do honey bees (Apis spp.). Plebeia spp. workers employ propolis mixed with wax (cerumen) for constructing and sealing nest structures, while they use viscous (sticky) propolis for defense by applying it onto their enemies. Isolated viscous propolis deposits are permanently maintained at the interior of their colonies, as also seen in other Meliponini species. Newly-emerged Plebeia emerina (Friese) workers were observed stuck to and unable to escape these viscous propolis stores. We examined the division of labor involved in propolis manipulation, by observing marked bees of known age in four colonies of P. emerina from southern Brazil. Activities on brood combs, the nest involucrum and food pots were observed from the first day of life of the marked bees. However, work on viscous propolis deposits did not begin until the 13th day of age and continued until the 56th day (maximum lifespan in our sample). Although worker bees begin to manipulate cerumen early, they seem to be unable to handle viscous propolis till they become older.

Influence of spawning procedure on gametes fertilization success in Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae): Implications for the conservation of this species

Artificial reproduction and gamete fertilization were evaluated in Salminus hilarii wild and domesticated broodstocks. Wild and domesticated broodstocks were artificially induced to reproduction using a carp pituitary treatment. Four groups were considered: Group 1 (G1), fish caught in the wild maintained for three years in the same conditions as the domesticated broodstocks and spawned naturally; Group 2 (G2), broodstock born and raised in captivity and spawned naturally; Group 3 (G3), wild broodstocks, which were manually stripped for gamete collection and dry fertilization; and Group 4 (G4), domesticated males and females, also manually stripped. Oocytes, eggs, and larvae were sampled at different time intervals throughout embryonic development. Yolk sac absorption occurred approximately 24-29 h after hatching. Twenty-six h after hatching, the larvae mouths opened. Cannibalism was identified just 28-30 h after hatching. There was no morphological difference in embryonic development among all groups. The number of released eggs per gram of female was: G1: 83.3 ± 24.5 and G2: 103.8 ± 37.4; however, the fertilization success was lower in G2 (42.0 ± 6.37 %) compared with G1 (54.7 ± 3.02%) (P = 0.011). Hand-stripping of oocytes was not successful and the fertilization rate was zero. The reproduction of this species in captivity is viable, but it is necessary to improve broodstock management to enhance fertilization rates and obtain better fingerling production for restocking programs.

Mechanisms of pigmentation loss in subterranean fishes

Troglobitic (exclusively subterranean) organisms usually present, among their apomorphies related to the subterranean life (troglomorphisms), the regression of eyes and melanic pigmentation. The degree of regression varies among species, from a slight reduction to the complete loss of eyes and dark pigmentation, without a taxonomic correlation. While mechanisms of eye reduction have been intensively investigated in some troglobites such as the Mexican blind tetra characins, genus Astyanax, and the European salamander, Proteus anguinus, few studies have focused on pigmentation. The Brazilian subterranean ichthyofauna distinguishes not only by the species richness (23 troglobitic fishes so far known) but also by the variation in the degree of reduction of eyes and pigmentation. This study focused on Brazilian fishes completely devoid of melanic pigmentation: the characiform Stygichthys typhlops (Characidae) and the siluriforms Ancistrus formoso (Loricariidae), Rhamdiopsis sp.1 (Heptapteridae; from caves in the Chapada Diamantina, Bahia) and Rhamdiopsis sp. 2 (cave in Campo Formoso, Bahia). In order to investigate if such depigmentation is the result of blockage in some step in the melanogenesis, in vitro tests of administration of L-DOPA were done, using caudal-fin fragments extracted from living fish. Except for Rhamdiopsis sp. 2, all the studied species were DOPA(+), i.e., melanin was synthesized after L-DOPA administration. This indicates these fish do have melanophores but they are unable to convert L-tyrosine to L-DOPA. On the other hand, Rhamdiopsis sp. 2, like the albino specimens of Trichomycterus itacarambiensis previously studied (which correspond to one third of the population), are DOPA(-), either because the block of melanin synthesis occurs downstream in melanogenesis, which is probably the case with T. itacarambiensis (monogenic system in view of the phenotypic discontinuity), or because the so-called albinos do no possess melanophores. The physiological loss in the ability to synthesize melanin, apparently caused by different genetic processes in DOPA(+) and in DOPA(-) fishes, may co-exist in subterranean populations with a decrease in the density of melanophores, as observed in the pigmented two thirds of T. itacarambiensis population, a morphological reduction apparently controlled by polygenic systems producing a continuous phenotypic variation.

Localization of ribosomal genes in three Pimelodus species (Siluriformes, Pimelodidae) of the São Francisco River: 5S genes as species markers and conservation of the 18S rDNA sites

Pimelodidae is one of the most representative of Neotropical catfish families. However, these fish are still poorly studied in terms of cytogenetics, especially regarding the application of more accurate techniques such as the chromosomal localization of ribosomal genes. In the present work, fluorescent in situ hybridization with 5S and 18S rDNA probes was employed for rDNA site mapping in Pimelodus sp., P. fur and P. maculatus from the São Francisco River in the Três Marias municipality - MG. The results from the application of the 18S probe confirmed the previous data obtained by silver nitrate staining, identifying a simple nucleolar organizing region system for these species. However, the labeling results from the 5S rDNA probe demonstrated a difference in the number and localization of these sites between the analyzed species. The obtained data allowed inferences on the possible processes involved in the karyotypic evolution of this genus.

Variations in the sensitivity of different primers for detecting Wolbachia in Anastrepha (diptera: tephritidae)

Wolbachia are endosymbiont bacteria of the family Rickettsiacea that are widespread in invertebrates and occur between 20% and 60% of Neotropical insects. These bacteria are responsible for reproductive phenomena such as cytoplasmic incompatibility, male killing, feminization and parthenogenesis. Supergroups A and B of Wolbachia are common in insects and can be identified using primers for 16S rDNA, ftsZ and wsp; these primers vary in their ability to detect Wolbachia. The ftsZ primer was the first primer used to detect Wolbachia in Anastrepha fruit flies. The primers for 16S rDNA, ftsZ and wsp and the corresponding PCR conditions have been optimized to study the distribution of Wolbachia and their effect on the biology of Anastrepha in Brazil. In this work, we examined the ability of these primers to detect Wolbachia in Anastrepha populations from three regions in the State of São Paulo, southeastern Brazil. All of the samples were positive for Wolbachia supergroup A when screened with primers for 16S A rDNA and wsp A; the wsp B primer also gave a positive result, indicating cross-reactivity. The ftsZ primer showed a poor ability to detect Wolbachia in Anastrepha and generated false negatives in 44.9% of the samples. These findings indicate that reliable PCR detection of Wolbachia requires the use of primers for 16S rDNA and wsp to avoid cross-reactions and false negatives, and that the ftsZ primer needs to be redesigned to improve its selectivity.

Comparative analysis of microsatellite variability in five macaw species (Psittaciformes, Psittacidae): application for conservation

Cross-amplification was tested and variability in microsatellite primers (designed for Neotropical parrots) compared, in five macaw species, viz., three endangered blue macaws (Cyanopsitta spixii [extinct in the wild], Anodorhynchus leari [endangered] and Anodorhynchus hyacinthinus [vulnerable]), and two unthreatened red macaws (Ara chloropterus and Ara macao). Among the primers tested, 84.6% successfully amplified products in C. spixii, 83.3% in A. leari, 76.4% in A. hyacinthinus, 78.6% in A. chloropterus and 71.4% in A. macao. The mean expected heterozygosity estimated for each species, and based on loci analyzed in all the five, ranged from 0.33 (A. hyacinthinus) to 0.85 (A. macao). As expected, the results revealed lower levels of genetic variability in threatened macaw species than in unthreatened. The low combined probability of genetic identity and the moderate to high potential for paternity exclusion, indicate the utility of the microsatellite loci set selected for each macaw species in kinship and population studies, thus constituting an aid in planning in-situ and ex-situ conservation.

A new species of the genus Pimelerodius Vanin from the Amazon Region, with notes on the geografic distribution of Pimelerodius motacilla (Boheman) (Coleoptera, Curculionidae, Otidocephalini)

Pimelerodius punctiventris sp. nov. (type locality Brazil, Amazonas, Itacoatiara) is described and illustrated. The new taxon is compared with similar species, being distinguished from the other 12 known species of the genus by the presence of punctures in ventrite I. The available published key for identification of species of Pimelerodius is adapted to include the new species. A modification of the generic description of the aedeagus of Pimelerodius is provided, a necessity due to the differences observed in the aedeagus of the new species. The occurrence of P. motacilla (Boheman, 1843) in the Amazon Region, recorded in sympatry with P. punctiventris in Itacoatiara, AM, is discussed and confirmed, based on the study of 41 available specimens.

A systematic review of diapoma (teleostei: characiformes: characidae: stevardiinae: diapomini) with descriptions of two new species from southern Brazil

Diapoma is reviewed and four species are recognized: (1) Diapoma thauma, new species, from streams of the rio Jacuí basin, state of Rio Grande do Sul; (2) D. pyrrhopteryx, new species collected from the rio Canoas and streams flowing into this basin in the states of Rio Grande do Sul and Santa Catarina, Brazil; (3) Diapoma terofali, from streams flowing into rio Uruguay in Uruguay and Rio Grande do Sul, Brazil and streams flowing into rio de la Plata, Argentina; and (4) Diapoma speculiferum, from lowland coastal streams in Rio Grande do Sul, Brazil and Uruguay. Diapoma pyrrhopteryx possess the posteroventral opercular elongation typical of D. speculiferum, type species of the genus, but which is absent in D. thauma and D. terofali. Nonetheless, all the diapomin species have the caudal pouch organ about equally developed in both sexes and the dorsal portion of the pouch opening bordered by a series of 3 to 8 elongated scales, the two derived features that characterize the group. The two previously described species, D. speculiferum and D. terofali, are redescribed. Previous hypotheses of relationships among the diapomin genera Planaltina, Diapoma and Acrobrycon are discussed on the basis of preliminary morphological information. It is proposed that the Diapomini is a monophyletic group. An identification key, information on sexual dimorphism, gonad anatomy, reproductive mode and distribution of the species of Diapoma are provided.

A new species of Pacholenus Schoenherr from southeastern Brazil (Coleoptera, Curculionidae, Molytinae), and new occurrences of species of the genus

A new species of Pacholenus Schoenherr from southeastern Brazil (Coleoptera, Curculionidae, Molytinae), and new occurrences of species of the genus. Pacholenus monteiroi sp. nov. (type-locality Brazil, Rio de Janeiro state, Carapebus, Parque Nacional da Restinga de Jurubatiba) is described and illustrated. The weevil develops as a stem gall-former in Calyptranthes brasiliensis Spreng (Myrtaceae). The new species is easily distinguished from the other five known of the genus by the presence of a prominent supra-ocular ridge. An updated key for identification for all species of Pacholenus is provided. Three species of Pacholenus are presently recorded for the states of Rio de Janeiro and São Paulo; P. pelliceus and P. monteiroi occur in both states, while P. penicillus is only known from Rio de Janeiro; P. hispidus occurs in São Paulo, being the most widespread species of the genus, ranging from Minas Gerais south to Santa Catarina.

Trichomycterus dali: a new highly troglomorphic catfish (Silurifomes: Trichomycteridae) from Serra da Bodoquena, Mato Grosso do Sul State, Central Brazil

Trichomycterus dali, new species, is described from flooded limestone caves in Serra da Bodoquena karst area, State of Mato Grosso do Sul, Central Brazil. The new species is diagnosed by a unique character in the genus, the presence of conspicuous, ridge-like adipose folds lining dorsally throughout the body. Trichomycterus dali can be further distinguished readily from epigean congeners by the reduction of eyes and skin pigmentation (except for T. gorgona), and from remaining congeners (i.e., all hypogean plus T. gorgona) by the total loss of eyes, not visible externally (except for T. sandovali and T. spelaeus). Other diagnostic features includes very long barbels, especially the nasal (99.3-143.5% HL) and the maxillary (97.0-131.3% HL), pectoral-fin ray count reaching I,9 and a unique cranial fontanel with a conspicuous constriction on the meeting point of supraoccipital and the two frontal bones. The troglobitic status of the species is suggested by the presence of troglomorphisms on an advanced degree, especially the reduction of skin pigmentation, the total loss of eyes and the enlarged barbels. In addition, the presence of a well developed adipose fold in adults may indicate a distinctive adaptation acquired by neoteny to withstand the food scarce conditions of its hypogean habitat.

A new genus and two new species of Stevardiinae (Characiformes: Characidae) with a hypothesis on their relationships based on morphological and histological data

Lepidocharax, new genus, and Lepidocharax diamantina and L. burnsi new species from eastern Brazil are described herein. Lepidocharax is considered a monophyletic genus of the Stevardiinae and can be distinguished from the other members of this subfamily except Planaltina, Pseudocorynopoma, and Xenurobrycon by having the dorsal-fin origin vertically aligned with the anal-fin origin, vs. dorsal fin origin anterior or posterior to anal-fin origin. Additionally the new genus can be distinguished from those three genera by not having the scales extending over the ventral caudal-fin lobe modified to form the dorsal border of the pheromone pouch organ or to represent a pouch scale in sexually mature males. In this paper, we describe these two recently discovered species and the ultrastructure of their spermatozoa.

A taxonomic and morphological redescription of Potamotrygon falkneri Castex & Maciel, 1963 (Chondrichthyes: Myliobatiformes: Potamotrygonidae)

A taxonomic revision of two nominal species of freshwater stingrays of the genus Potamotrygon previously considered valid, Potamotrygon falkneri Castex & Maciel, 1963 and Potamotrygon castexi Castello & Yagolkowski, 1969, was conducted based on a detailed analysis of external and internal morphology, including a morphometric and meristic study of specimens from the recorded range of both species. The taxonomic status of the nominal species P. menchacai Achenbach, 1967, treated by previous authors as a junior synonym of P. falkneri, was also evaluated. These nominal species, which constitute what has been called the falkneri-castexi complex, were found to represent examples of chromatic variation present in a single species, given that intermediate patterns of coloration are common and the remaining characters analyzed are not consistent enough for separation at the specific level. Consequently, Potamotrygon falkneri is considered valid, whereas the nominal species Potamotrygon castexi and Potamotrygon menchacai are concluded to be junior synonyms of P. falkneri. Additionally, a putative new species is identified from the río Madre de Díos in Peru, which has some characters that do not correspond to P. falkneri. This species, known from few individuals, is here provisionally treated as Potamotrygon sp.

A new species of Pimelodus La Cépède, 1803 (Siluriformes: Pimelodidae) from rio Ribeira de Iguape basin, Brazil

Pimelodus multicratifer, a new species, is described from the rio Ribeira de Iguape basin. The new species differs from the other Pimelodus species by the following features: 26 to 30 gill rakers on the first branchial arch; a combination of three to six rows of dark spots regularly or irregularly scattered on the flanks and several small dark spots irregularly scattered on the dorsal surface of head, supraoccipital process, and sometimes on the dorsal and caudal fins; striated lips; maxillary barbels reaching between posterior tip of the pelvic-fin rays and posterior tip of the middle caudal-fin rays.

Intertidal life: field observations on the clingfish Gobiesox barbatulus in southeastern Brazil

The clingfish Gobiesox barbatulus shows nocturnal feeding activity, spending most part of the day stationary and adhered to the inferior part of stones. To feed, this species uses the sit-and-wait and particulate feeding tactics. It shows a carnivorous feeding habit mostly consuming small benthic crustaceans. It can move in two ways: (1) "stone-by-stone", sliding its ventral sucker disc across each stone and (2) "surf", when it takes advantage of the energy of the ebbing tide to quickly cross a distance up to four times its body length. Its reproductive season occurs between the end of spring and the beginning of summer, during which time it lays about 2,000 adhesive eggs of 1 mm each in a single layer under stones. It has more than one egg-laying session per reproductive season, therefore showing several different developmental stages. It performs fanning, mouthing and guarding of the eggs as forms of parental care. Data shown here also indicates that G. barbatulus has some shelter fidelity, being probably territorial.