The Panama microplate, island studies and relictual species of Melipona (Melikerria) (Hymenoptera: Apidae: Meliponini)

The endemic stingless honey-making bee Melipona (Melikerria) insularissp.n. on Coiba and Rancheria Islands in Pacific Panama is described, together with the proposed sister species, M. ambigua sp.n. from northeast Colombia. The Coiba Island group and Panama mainland were surveyed, yielding one meliponine endemic (M. insularissp.n.) and six meliponine genera and species. The poor Coiba fauna of amphibians and birds corresponds to the poor social bee fauna and suggests habitat barriers generally precluded recolonization from the mainland during glacial periods. Many animals became extinct, yet some remain as relicts. Melipona insularissp.n. was isolated on accreted terranes of Coiba rainforest in the Panama microplate. Morphology suggests that M. insularissp.n. is not a direct descendant of the San Blas-E. Panama endemic Melikerria, M. triplaridis. A phylogenetic hypothesis corroborates disjunct distributions. Rainforest endemics such as Peltogyne purpurea (Fabaceae) and Ptilotrigona occidentalis (Apidae, Meliponini) also occur as relictual, disjunct populations in Central and South America. These may have been isolated before accelerated biotic exchange began 2.4 Ma. Our work supports the geological findings of both a volcanic arc and the San Blas massif providing a substantial bridge for Melikerria from Colombia and Panama in Eocene to Miocene times. We suggest there have been taxon cycles permitting recolonization during glaciations, whereby colonies of M. insularissp.n. were able to recolonize Rancheria, a 250 ha island, 2 km from Coiba. However, rafting colonies nesting in trees, carried on vegetation mats, may have produced founding populations of Melipona in Central America and on oceanic islands such as Coiba.

Natural regeneration in abandoned fields following intensive agricultural land use in an Atlantic Forest Island, Brazil

The time required to regrowth a forest in degraded areas depends on how the forest is removed and on the type of land use following removal. Natural regeneration was studied in abandoned old fields after intensive agricultural land use in areas originally covered by Brazilian Atlantic Forests of the Anchieta Island, Brazil in order to understand how plant communities reassemble following human disturbances as well as to determine suitable strategies of forest restoration. The fields were classified into three vegetation types according to the dominant plant species in: 1) Miconia albicans (Sw.) Triana (Melastomataceae) fields, 2) Dicranopteris flexuosa (Schrader) Underw. (Gleicheniaceae) thickets, and 3) Gleichenella pectinata (Willd.) Ching. (Gleicheniaceae) thickets. Both composition and structure of natural regeneration were compared among the three dominant vegetation types by establishing randomly three plots of 1 x 3 m in five sites of the island. A gradient in composition and abundance of species in natural regeneration could be observed along vegetation types from Dicranopteris fern thickets to Miconia fields. The gradient did not accurately follow the pattern of spatial distribution of the three dominant vegetation types in the island regarding their proximity of the remnant forests. A complex association of biotic and abiotic factors seems to be affecting the seedling recruitment and establishment in the study plots. The lowest plant regeneration found in Dicranopteris and Gleichenella thickets suggests that the ferns inhibit the recruitment of woody and herbaceous species. Otherwise, we could not distinguish different patterns of tree regeneration among the three vegetation types. Our results showed that forest recovery following severe anthropogenic disturbances is not direct, predictable or even achievable on its own. Appropriated actions and methods such as fern removal, planting ground covers, and enrichment planting with tree species were suggested in order to restore the natural forest regeneration process in the abandoned old fields.

Multiple Island Chains in Primary Resonances.

We analyse the dynamics of a relativistic particle moving in a uniform magnetic field and perturbed by a stationary electrostatic wave. We show that a pulsed wave produces an infinite number of perturbing terms with the same winding number. The perturbation coupling alters the number of island chains as a function of the parameters of the wave. We also observe that the number of chains in is always even if the number of islands in each chain is odd.

Heat island simulations in Londrina city, Brazil

This work aims to study the urban heat island on North region of Parana state, Brazil and the influence of land use and urban settlements on the intensity and frequency of occurrence of these events. Through atmospheric modeling whith WRF/Chem model two simulations were made with different land and use files, one with the original land use another obtained from a composition of MODIS-Landsat imagery. The simulations showed good skills compared to observed data. Urban areas presented higher temperatures. Landsat land use has represented better urban heat islands (UHI), the gradient between urban and rural areas was well demonstrated and the correlation coefficient was above 0.92. The model underestimated the maximum values and overestimated the minimum compared with observed data in both simulations.