Stratification in French Guiana: Cerambycid Beetles Go Up When Rains Come Down

When tropical rain forest insect species are associated with a particular season or forest stratum, it can imply tolerance for heat and drought—or moisture dependence; attributes that may predict their responses to global climate change. In French Guiana (1995–1996), wood‐boring cerambycid beetles made a seasonal shift in stratum. During the dry season, ground stratum bait branches were densely colonized, but during the rainy season almost all cerambycids emerged from canopy stratum branches. Because the same substrate was available at both levels, abiotic factors probably influenced branch selection. In this study, cerambycids were reared at the same site (2007–2008) to determine if the seasonal shift recurred. Microclimate data (temperature, relative humidity, and wind speed) were collected with portable weather meters to test the hypothesis that microclimate would be similar at ground stratum during the dry season, and at canopy stratum during the rainy season. The seasonal shift in stratum did recur; many cerambycid individuals (56%) belonged to species classified as ‘seasonal shifters’. Temperatures in the preferred microhabitats were intermediate, but relative humidity remained high during the rainy season (regardless of stratum) and it was windier in the canopy (regardless of season). The shifters preferentially colonized branches at moderate mean temperatures (23.0–24.3°C) and high mean relative humidities (91.3–100%). Shifters were considered season and stratum generalists because they were reared at both strata and were present in both seasons, but they may actually track a narrow microclimate window. Should the regional climate become warmer and drier, it would probably favor species currently restricted to the dry season or canopy stratum.     

<Emphasis Type="Italic">Periconiella lecythidis</Emphasis> sp. nov., the causal agent of a zonate leaf spot disease of the Brazilian tree <Emphasis Type="Italic">Lecythis pisonis</Emphasis>

A new defoliating disease was observed on 20-year-old trees of Lecythis pisonis in Viçosa, Minas Gerais, Brazil. The disease is characterized by forming one or more large zonate epiphyllous leaf spots with a light brown to white center, followed by two to three zones gradually varying from brown to red-brown. On the corresponding abaxial leaf surface, the spots are lighter with a profuse greenish gray coloration caused by the fungal colonies. In PDA culture, the fungus is characterized by a slow growth of the colonies with brown-violet pigmentation at the reverse. Inoculation tests carried out on healthy plants of L. pisonis confirmed the pathogenicity of this fungus. Periconiella lecythidis sp. nov., the causal agent of the zonate leaf spot disease of L. pisonis is described, illustrated, discussed and compared with the other species of the genus Periconiella. The intricate generic affinity within a complex of morphologically similar hyphomycete genera consisting of Metulocladosporiella, Parapericoniella, Penidiella and Periconiella is discussed in detail.     

Flavan-3-ols from the barks of Barringtonia acutangula

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Cannibalistic Interactions Resulting from Indiscriminate Predatory Behavior in Tadpoles of Poison Frogs (Anura: Dendrobatidae)1

Poison frogs in the genus Dendrobates have very small clutch sizes (2–6 eggs among species for which there are data) and typically transport their tadpoles singly to small phytotelmata, such as bromeliad tanks, leaf axils, fallen fruit capsules, and treeholes. Tadpoles of many species are predaceous, consuming larvae of insects that use the same microhabitat for breeding, such as giant damselflies and mosquitoes. Previous studies and observations on the behavior of poison frog tadpoles led us to question whether tadpoles might be cannibalistic. We studied a population of Dendrobates castaneoticus in lowland rainforest in Pará, Brazil; additional data were collected on Dendrobates auratus in Nicaragua. At the study site in Brazil, we established a grid of 40 Brazil nut capsules, the microhabitat used by D. castaneoticus for tadpole deposition. Of 42 tadpoles deposited during the 55 days of the study, 20 were killed or died; 16 of these were presumably killed by conspecific tadpoles. Growth rate and time to metamorphosis was higher among tadpoles that consumed three or more tadpoles or relatively large larvae of the mosquito Trichoprosopon digitatum, a colonist of newly opened Brazil nut capsules. We propose that selection has favored the development of predatory behavior in poison frog tadpoles primarily as a mechanism to eliminate predators from the small phytotelmata in which they develop and that cannibalism is a secondary outcome of this behavior. Predatory behavior also provides tadpoles with a source of food, which is frequently limited in these microhabitats. Additional studies of the biology of tadpoles of other species of Dendrobates are needed to determine the evolution of predatory and cannibalistic behavior in the clade.     

Triterpenoid sapogenols from the leaves of Careya arborea: Structure of careyagenolide

The acid hydrolysate of the ethanol extract of Careya arborea leaves afforded a new triterpenoid lactone designated careyagenolide along with maslinic acid and 2α-hydroxy ursolic acid. The structure of careyagenolide has been established as 2α, 3β-dihydroxytaraxastan- 28, 20β-olide by a variety of spectroscopic evidence, chemical transformations and correlation with ψ-taraxasterol.     

Development and characterization of microsatellite markers for the Brazil nut tree Bertholletia excelsa Humb. & Bonpl. (Lecythidaceae)

Twelve polymorphic microsatellite markers were developed for the Brazil nut (Bertholletia excelsa), one of the most valuable non‐timber forest products from the Amazon, based on enrichment protocol. Six to 18 (mean 10.4) alleles per locus were identified and the expected heterozygosity ranged from 0.663 to 0.923 based on a screen of 40 individuals from one population of B. excelsa. The combined probabilities of genetic identity (8.39 × 10^?17) and paternity exclusion (0.999999) indicated that multilocus genotypes are likely to be unique allowing precise analyses of genetic structure, gene flow, and mating system of this economically important species.     

Flavonoid glycosides from Barringtonia acutangula

Using various chromatographic separation techniques, ten flavonoid glycosides, including six new compounds namely barringosides A?F (1–6), were isolated from a methanol extract of the Barringtonia acutangula leaves. The structure elucidation was confirmed by spectroscopic analyses, including 1D and 2D NMR, and HR ESI MS. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were also evaluated. Among the isolated compounds, quercetin 3-O-β-d-(6-p-hydroxybenzoyl)galactopyranoside (9) showed significant effect with an IC₅₀ of 20.00 ± 1.68 µM. This is the first report of these flavonoid glycosides from Barringtonia genus and their inhibition on LPS-induced NO production in RAW264.7 cells was reported here for the first time.