Avaliação de quitosana, aplicada em pós-colheita, na proteção de uva 'Itália' contra Botrytis cinerea

Perdas significativas ocorrem durante o armazenamento e a comercialização de uvas de mesa devido, principalmente, à ocorrência do mofo cinzento (Botrytis cinerea Pers.:Fr.) e, para o controle de patógenos emprega-se, geralmente, o dióxido de enxofre (SO2). Diante da restrição crescente ao uso de produtos químicos em pós-colheita, tem ocorrido considerável interesse em métodos alternativos de controle. Este trabalho teve como principal objetivo avaliar os efeitos da quitosana, na proteção pós-colheita de uva 'Itália' contra B. cinerea. In vivo, avaliou-se o efeito direto e indireto da quitosana pelo tratamento dos cachos de uva, antes e após a inoculação com o patógeno. Utilizou-se quitosana nas concentrações de 0,00; 0,25; 0,50; 1,00; 1,50 e 2,00 % (v/v). Para inoculação, em 10 bagas de cada cacho de uva foram feitos ferimentos de ±2 mm de profundidade, procedendo-se em seguida, a aspersão da suspensão de conídios (±10(5) conídios.mL-1) de B. cinerea. Após os tratamentos, os cachos foram mantidos a 25±1 °C / 80-90 % UR e avaliados diariamente quanto à incidência e severidade da podridão. Avaliações in vitro do efeito do produto sobre o patógeno também foram realizadas analisando-se o crescimento micelial e a germinação dos conídios de B. cinerea. A solução de quitosana, nas concentrações de 1,5 e 2,0 % (v/v), quando empregada após a inoculação com B cinerea, reduziu significativamente o índice de doença no entanto, quando os cachos foram tratados antes da inoculação, não houve efeito significativo do tratamento sobre o desenvolvimento da doença. Nos ensaios in vitro, a solução de quitosana, nas maiores concentrações, suprimiu o crescimento micelial do patógeno e retardou a germinação dos conídios.

Unpalatability of Hyla semilineata tadpoles (Anura) to captive and free-ranging vertebrate predators

This study examines the unpalatability of Hyla semilineata tadpoles, relating this possible defence mechanism to their black, presumably aposematic, colouration. Bullfrog tadpoles (Rana catesbeiana), similar in size to the H. semilineata larvae, were used as controls in the experiments. The palatability of H. semilineata tadpoles was tested by offering the tadpoles to Fish (Hoplias malabaricus), free-ranging passerine birds (Pitangus sulphuratus) and hawks (Buteo magnirostris), and domestic chickens (Gallus domesticus). All predators showed a significant preference towards the control R. catesbeiana tadpoles. However, in experiments with fish, this preference was not significant for tadpole capture, only for their ingestion, suggesting that the fish could not distinguish between the two species before tasting them. Although great kiskadees (P. sulphuratus) preferred the control R. catesbeiana tadpoles, they promptly ingested more than half of the test H. semilineata tadpoles when these were offered alone. The chickens, used as naive predators, clearly learned to avoid the black H. semilineata tadpoles after a few trials. The conspicuous colouration and unpalatability of H. semilineata tadpoles may benefit the individual as well as the group, depending on the predator involved.

Evaluating the karyotypic diversity in species of Hyla (Anura; Hylidae) with 2n=30 chromosomes based on the analysis of ten species

Ten species of Hyla with 2n = 30 from Brazilian fauna were analysed cytogenetically. Hyla minuta is the unique presenting all bi-armed metacentric or submetacentric chromosomes in the karyotype, therefore, with the highest FN = 60. The remaining species have a variable number of uni-armed telocentric or subtelo-centric chromosomes: H. cruzi, H. elianeae, and H. rubicundula with three pairs (FN = 54), H. berthalutzae, H. elegans, H. microps, and H. nana with four pairs (FN = 52), and H. nahdereri and H. sanborni with five pairs (FN = 50). The uni-armed elements are among pairs 5, 6, 7, 11, 14, and 15, which also appeared with metacentric or submetacentric morphology. The remaining chromosome pairs 1, 2, 3, 4, 8, 9,10, 12, and 13 were never found to be telocentric or subtelocentric. AgNOR patterns are species-specific, the majority of the species exhibiting a single pair with AgNORs, with the exception of H. elegans and H. nana with more than one chromosome pair bearing this cytological marker. C banding was obtained in H. berthalutzae, H. cruzi, H. elegans, H. elianeae, H. microps, H. minuta, H. nahdereri, and H. nana, which showed positively stained centromeric heterochromatin. Our analysis confirms the great karyotypic diversity in the species of Hyla with 2n = 30, with no species sharing identical karyotypes.

On the identity of Hyla strigilata Spix, 1824 (Anura : Hylidae): redescription and neotype designation for a ghost taxon

Recent field work in Atlantic Rain Forest patches in the southern region of the State of Bahia, Brazil, resulted in the discovery of some populations of an unidentified species of the Scinax catharinae group. An extensive literature review, along with the examination of specimens and distribution patterns of all known species of this group, showed that Hyla strigilata Spix, 1824, a long confused species with lost type material, is an available name for the specimens from Bahia. In order to clarify the taxonomic problems surrounding this taxon, the nomenclatural history of Hyla strigilata is reviewed and a neotype is designated, described, and figured. The association of this name to extant populations from southern Bahia and its consequent stabilization is considered important since it is the type species of the genus Ololygon, a name available for the clade of Scinax catharinae. Data on habits, habitat, and geographic distribution are also presented.

The taxonomic status of Hyla pulchella joaquini (Anura : Hylidae) with description of its tadpole and vocalization

We redescribe Hyla pulchella joaquini and describe its tadpole and vocalization. The taxonomic status of this subspecies is reevaluated; and on the basis of morphology, geographic distribution, and vocalization, we propose the elevation of this subspecies to specific level with the name Hyla joaquini B. Lutz 1968. We also discuss the relationship of H, joaquini within the species groups of H. pulchella Dumeril and Bibron 1841 and H. circumdata (Cope 1871).

Conserved karyotypes in the Hyla pukhella species group (Anura, Hylidae)

Cytogenetic analyses were done on specimens of Hyla marginata and on three populations of H. semiguttata differing in morphology and in the physical parameters of their advertisement call, as well as in individuals of Hyla sp. (aff. semiguttata). All specimens had 2n = 24 chromosomes with a morphology very similar to that of other 24-chromosome Hyla species. Hyla semiguttata and H. marginata showed the same C-banding pattern but were distinguished by the location of the NOR on pair 1 in H. semiguttata (in the three populations) and Hyla sp. (aff. semiguttata), and on pair 10 in H. marginata. The H. semiguttata populations did not differ cytogenetically, despite variations in their morphology and advertisement calls. Similarly, H. semiguttata and H. p. joaquini studied previously had identical C-banding patterns and NOR locations, suggesting that they are very closely related.

Bioacoustic analysis of advertisement call in Hyla nana and Hyla sanborni (Anura, Hylidae) in Botucatu, São Paulo, Brazil

As características relacionadas à comunicação sonora em duas espécies aparentadas, Hyla nana e H. sanborni, pertencentes ao grupo nana de espécies, foram estudadas, entre agosto de 1997 e junho de 1999, em duas poças permanentes de grande porte em área aberta na região de Botucatu, Estado de São Paulo. Foram obtidas gravações de 131 exemplares, 71 indivíduos de H. nana e 58 de H. sanborni, durante início de atividade de vocalização e atividade de vocalização em coro. Houve diferença nos ritmos de emissão de notas dos cantos entre o início das atividades e durante os coros. O canto de anúncio das espécies consiste na emissão de séries consecutivas de notas simples, pulsadas, com taxa de repetição rápida. Hyla nana e H. sanborni apresentam dois tipos de notas em seu canto de anúncio, denominados aqui como tipos A e B. Notas do tipo A, introdutórias, apresentam maior duração e número de pulsos, e suas emissões foram mais freqüentes durante o início das atividades de vocalização. As notas introdutórias são as primeiras da série emitida em atividade de coro. As notas do tipo B, secundárias, são curtas e com menor número de pulsos, sendo emitidas durante as vocalizações em coro. Os dois tipos de notas encontrados diferem significativamente em sua estrutura temporal. As duas espécies apresentaram segregação acústica tanto na estrutura espectral como na temporal de seus cantos de anúncio.

Schooling and swimming behaviors of Hyla semilineata tadpoles (Anura, Hylidae)

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

O status taxonômico de Hyla cochranae Mertens e recaracterização de Aplastodiscus A. Lutz (Anura, Hylidae)

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

A molecular perspective on the phylogeny of the Hyla pulchella species group (Anura, Hylidae)

A molecular phylogenetic analysis of the Hyla pulchella species group was performed to test its monophyly, explore the interrelationships of its species, and evaluate the validity of the taxa that were considered subspecies of H. pulchella. Approximately 2.8 kb from the mitochondrial genes 12s, tRNA valine, 16s, and Cytochrome b were sequenced. The analysis included 50 terminals representing 10 of the 14-15 species currently recognized in the H. pulchella group, including samples from several localities for some taxa, several outgroups, as well as two species previously suspected to be related with the group (Hyla guentheri and Hyla hischoffi). The results show that the H. pulchella and Hyla circumdata groups are distantly related, and, therefore, should be recognized as separate groups. As currently defined, the H. pulchella group is paraphyletic with respect to the Hyla polytaenia group; therefore, we recognize the Hyla polytaenia clade in the H. pulchella group. Two subspecies of H. pulchella recognized by some authors are considered full species including Hyla pulchella riojana because it is only distantly related to H. pulchella, and Hyla pulchella cordobae because molecular and non-molecular evidence suggests that it is specifically distinct. With the inclusion of the H. polytaenia clade, H. guentheri, and H. bischoffi, and the recognition of the two former subspecies of H. pulchella as distinct species, the H. pulchella group now comprises 25 described species. All representatives of the H. pulchella group with an Andean distribution are monophyletic and nested within a clade from the Atlantic forest from south-southeastern Brazil/northeastern Argentina, and Cerrado gallery forest from central Brazil. (C) 2004 Elsevier B.V. All rights reserved.

CYTOGENETICS OF 4 BRAZILIAN HYLA SPECIES (AMPHIBIA-ANURA) AND DESCRIPTION OF A CASE WITH A SUPERNUMERARY CHROMOSOME

The chromosomes of Hyla fuscovaria, H. hayii and II. prasina, with 2n=24, and of Hyla sp. (aff. circumdata), a new species, with 2n=24 and 2n=25, were studied.The karyotypes with 2n=24 in the four species were very similar, with almost no differences in the size and morphology of the chromosomes. The numerical variability found in Hyla sp. (aff. circumdata) is due to the occurrence of a supernumerary chromosome in some specimens. NOR data obtained for the first time in the four species and C banding analysis of H. prasina indicate that such types of banding may be useful to differentiate species with very similar karyotypes, contributing to the understanding of chromosome evolution and the establishment of phylogenetic relationships among Brazilian Hyla species.

HYLA-LUCTUOSA, A NEW TREEFROG FROM SOUTHEASTERN BRAZIL (AMPHIBIA, HYLIDAE)

A new species of treefrog, Hyla luctuosa, is described from the Serra do Japi in southeastern Brazil. The new species is a member of the Hyla circumdata group characterized by large size, large tympanum, and rounded subarticular tubercles on the fingers. Descriptions of the tadpole and advertisement call and information on natural history are provided.