Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

We used classical culture techniques to explore gut bacteria and changes associated with dietary change in the highly polyphagous, tropical caterpillar Automeris zugana (Saturniidae). Fifty-five third instar wild-caught sibs feeding on Annona purpurea (Annonaceae) in the Área de Conservación Guanacaste (ACG) in northwestern Costa Rica were divided into eight groups. Each of seven groups was reared to the ultimate instar on another species of food plant normally used by A. zugana. Some pupae were also analyzed for the presence of bacteria. Aerobic bacterial cultures were obtained from all 33 caterpillar guts and the eight pupae inventoried. There was no clear pattern in species composition of cultivated bacteria among the eight diets, and each caterpillar on a given food plant carried only a small fraction of the total set of species isolated from the set of caterpillars feeding on that food plant. Taken as a whole, the larvae and pupae contained 22 species of cultivable bacteria in 12 genera. Enterobacter, present in 81.8% of the samples, was the genus most frequently isolated from the caterpillars, followed by Micrococcus and Bacillus. Bacillus thuringiensis was isolated from 30.3% of the dissected caterpillars, but found in caterpillars feeding on only half of the species of food plants.

Previous electron microscope studies of ultrastructural events during hepatitis A virus replication in experimentally infected cells have used only ultrathin section techniques. Nevertheless, no important differences were observed between infected and uninfected cells. This study was carried out using scanning electron microscopy and negative staining of whole LLC-MK2 cells grown directly on grids covered with support membranes, and then infected with an hepatitis A virus strain. Thin sections of infected and unifected controls were also analyzed. An intricate web of projections forming a net between cell interfaces was observed only in infected cells. Some of these projections were more than 700 nm long and had ballooning tips. Nevertheless, HAV particles were not visualized in the infected cells.

Cecropia latiloba can be considered to be one of the most efficient colonizers of open areas in the nutrient-rich whitewater floodplains of the Amazon river. Its main strategy to be successful is the high tolerance towards waterlogging and submergence, and the fast vertical growth and reiteration capacity. This, and the tolerance of high irradiation and sediment deposition allow C. latiloba to form large monospecific stands on open sites, and thus the first closed canopy which represents the initial phase of a successional sequence which leads to highly diverse forests. This tree is extremely well adapted to the adverse growth conditions in Amazonian floodplains with prolongued periods of flooding and seedling submergence. The species occurs on the lowest levels in the flooding gradient. Although it belongs to the most often cited species under aspects of taxonomy, species distribution and general descriptions of the ecosystem, little has been published about its ecology. In the present paper the ecological, physiological and phenological characteristics of C. latiloba are described. It is an evergreen species which constantly produces new leaves. With flooding, leaf production is reduced but new leaves are flushed also with prolongued flooding. The peak of flowering and fruiting are in the flooded period. When mature, the fruits are dispersed mainly by water and fish. Seed germination occurs, without dormancy, within 5-13 days after water retreat. In the 7 months before the first flooded period seedlings reach 1 m of height, and height growth increases until a height of 15-20 m is achieved. Photosynthetic assimilation is high, with values of up to 21 mmol CO2 m-2s-1. C. latiloba is a very flood tolerant species, and waterlogged seedlings continuously produce new leaves and adventitiuos roots.

Logging, cattle raising, and agricultural activities have caused the destruction of most forested areas in Costa Rica. In some middle and highlands the abrupt topography delayed the complete destruction of montane forest. Consequently, some fragments of almost pristine forest remain along streams that run in deep canyons. Frequently, these remnants serve as corridors between larger forested areas and as routes for movement of frugivorous birds. Eighteen bird species, e.g., Turdus plebejus, Elaenia frantzii and Ptilogonys caudatus are common dwellers of forest patches throughout the Pacific slope of the Volcán Barva. These species fly frequently from forest fragments to adjacent pastures. They defecated and regurgitated seeds of 28 plant species on stumps scattered on pasture areas. Isolated trees and specially the stumps are suitable microhabitats for germination of seeds and establishment of seedlings.

The results of an experiment with two species of epiphytic angiosperms (Tillandsia caput-medusae and T. bulbosa) for monitoring polycyclic aromatic hydrocarbons (PAHs) in the air of Florence, Italy, are presented. PAHs are compounds known to be dangerous because of their carcinogenic potential, and among cormophytes, tillands (monocotyledons equipped with peculiar, specialised, epidermal trichomes) are considered promising for air pollution biomonitoring. PAHs data were obtained using GC/MS analysis of plant extracts. Analytical data indicated an increasing trend in time of PAHs bioaccumulation. This result was compared with instrumentally recorded parameters such as meteorological (rain) and environmental ones (PM10), indicating that trichome-operated physical capture of aerial particles was prominent in PAHs bioaccumulation on tillands. SEM (scanning electron microscope) observations confirmed the role of the trichomes. This work indicates that tillands are particularly useful, low-cost, biomonitoring organisms inside their area of distribution (all Latin American countries and southern USA) where these plants are easily available, but also wherever the climate allows them to survive.

The growth performance of Rhizophora apiculata Blume (mangrove) seedlings in the presence and absence of exogenous gibberellic acid (GA3) under different combinations of salinity and light was analyzed. Root and shoot growth responses of 75-day old seedlings in liquid-culture, were measured. It was concluded that light exhibited a significant inhibitory effect on all the growth parameters-number of primary roots, primary root length, shoot elongation, number of leaves, total leaf area; and, the GA3 treatment singly or in combinations with light, showed a significant influence on the total leaf area and primary root length

The fertility life table of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) preying either on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) caterpillars or on alternative prey Tenebrio molitor L. (Coleoptera: Tenebrionidae) under greenhouse conditions (30 ± 5ºC, 61 ± 23% RH) were studied. The life table was also determined for the pest T. absoluta under the same conditions. The net reproductive rate (Ro) and the intrinsic rate of natural increase (rm) were higher 14.13 and 46.32 times for predators fed on T. molitor prey, however, the generation time (T) was similar between prey. The pest T. absoluta showed Ro and rm higher 2.15 and 32.10 times than those achieved for predators fed on this pest. However, females fed on a suitable prey T. molitor showed higher Ro and rm than those yielded for the pest. The survival curves were similar for P. nigrispinus females fed on both prey and classified as being type II by Weibull analysis. The results suggest that P. nigrispinus is able to maintain its population preying only on T. absoluta caterpillars; however, the life table parameters determined individually for both showed that the pest produces more generations per year and faster population natural growth than the predator.

Nests of Sceliphron fistularium were obtained in Colombia and Moji Guaçu, São Paulo, Brazil. Complete nests consisted of 1 to 54 sausage-shaped cells, arranged side by side along a horizontal axis, and found attached to electrical wires (Colombia, n = 7) and walls (Colombia, n = 4 and Moji Guaçu, n = 4). The number of cells per nest ranged from 1 to 54, their length varying from 20.8 to 29.7 mm, and their diameter from 7.6 to 11.7 mm. Brood cells were provisioned with spiders of the family Araneidae. Only Alpaida veniliae was collected in Colombia, whereas the most frequent species found in Moji Guaçu was Micrathena swainsoni (62.0%) followed by M. acuta (23.3%). Adults emerged from June to October. The length and diameter of female and male cells were similar. Nevertheless, females were significantly larger than males. The sex ratio of individuals obtained from nests was 1.16 females : 1 male. A life table was constructed, and details of the life cycle of the wasps and parasitoids are presented. The most common mortality factors were either unknown or due to the parasitoid wasp Melittobia sp.

Coelomera lanio (Coleoptera: Chrysomelidae) is the most important defoliator of Cecropia trees. Natural enemies of C. lanio collected in the region of Viçosa, State of Minas Gerais, Brazil were identified on field observations in a forest fragment and on laboratory analyses. Individuals of C. lanio were not found on Cecropia pachystachya trees colonized by Azteca mülleri (Hymenoptera: Formicidae). The majority of the egg masses of C. lanio collected in the field were found to be parasitised by a species of the family Eulophidae (Hymenoptera), while larvae of this pest were attacked by a parasitoid of the family Tachinidae (Diptera). Individuals of Oplomus catena (Heteroptera: Pentatomidae) were observed preying on C. lanio larvae. The fungus Beauveria bassiana was found growing on larvae, pupae and adults of C. lanio while the fungus Metarhizium anisopliae only affected pupae of this insect in laboratory conditions

A new and morphologically very distinct species of Pediobius from Costa Rica is described. The new species (P. nishidai) is unique among New World species of Pediobius in having the propodeum elongated and extended backwards (i.e. with an elongated nucha). The entire type series (15 females, two males) was reared from a single prepupa of Epilachna mexicana and it has been concluded that the new Pediobius species is a gregarious endoparasitoid that pupates inside its host. The possible use of this new species as a biological control agent against “the Mexican bean beetle” (E. varivestis) should be tested.