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

During a 3 weeks' visit to Costa Rica in January/February, 1982, 9 new species of Agromyzidae were discovered and are described in the genera Melanagromyza, Ophiomyia, Japanagromyza, Liriomyza and Phytoliriomyza. Eighteen species new to Costa Rica were also found, including the three important pests, Liriomyza huidobrensis, L. sativae and L. trifolii. In addition, leaf mines were collected on 10 plants, 2 certainly and 6 probably representing further undescribed species. Keys to the 13 genera and 53 species now known in Costa Rica are provided. Phytomyza centralis Frost is synonymised with Phytomyza loewii Hendel.

Eighteen species of nematophagous fungi, representing ten genera, were found in thirty-eight samples of soil collected in El Salvador. Eleven of the species were predators and seven were endozoic parasites. The numbers of nematophagous fungi found in cultivated and uncultivated soils were not significantly different. Stylopage hadra was the dominant species in the sampling. The ability to capture nematodes was previously unknown for Helicosporina veronae. One predatory species of Dactylella with conidial appendages was observed.

Some aspects on the biology of the mud shrimp. Upogebia dawsoni from the Requeson mangrove area, whithin Bahia Concepcion, and Mulege river estuary, Mulege (Baja California Sur, México) are described. Collections of U. dawsoni were done in January (winter), March (Spring) and July (Summer) in 1986 at Requeson, and in October (Fall) of 1985 and June (summer) of 1986, at Mulege. A total of 280 individuals were collected between 0.40 and 1.0 m in depth. Size, sex ratio, spawning period, egg number, stomach contents and external morphology were recorded. A seasonal comparative analysis between the two localities showed that the specimens from Requeson had greater lengths. In Summer, females represented 6.67% and juveniles 93.33% while in Fall, females represented 93.27%, males 3.58%, juveniles 2.25%, and ovigerous females, stage II 0.90% at Mulege. In Winter, females comprised 30.76%, at Requeson. Two spawning periods were detected, one in Fall (Mulege), and other in Summer (Requeson). The largest female (total length= 28.0 mm) carried out 2133 eggs and the shortest one (total length = 11.0 mm) had 119 eggs. Sediment, leaves and roots of mangrove, insect wings, diatoms, dinoflagellates bacteria, and sponge spicules were found in the stomachs. 

A pilot study of the mangrove oyster (Crassostrea rhizophorae), cultured in a raft system in Estero Viscaya, Limón, Costa Rica, between January and June, 1982 showed that the condition index reached the highest percentage at age V (for dry weight) and age IV (for wet weight). Strong correlations were observed between meat weight, shell weight (dry and wet), shell cavity fluid weight and yield of meat.The minimum commercial size for the fresh market oyster was determined by the analysis of relationships obtained between shell cavity fluid weight, meat and shell weight (dry and wet) and yield of meat to size, and age. The size of 60 mm total length and 23 g weight was reached in five months.

Zooplankton samples were collected in 1977-78 in the Estero El Verde, Sinaloa, a small coastal lagoon located on the mainland coast of the Gulf of California, México. Nine species of Copepoda and a single species of Cladocera were recognized, of which four were found to be the dominant species in the system (Acartia tonsa, A. lilljeborgii, Diaptomus amatitlanensis and Moina micrura). Two species of Pseudodiaptomus (P. cf. culebrensis and Pseudodiaptomus sp.) were also present at different periods of the year. The holoplanktonic community of the system is basically formed by freshwater species that are present only during the rainy season, by marine species that occasionally enter the lagoon and by species with an affinity for estuarine waters (Acartia and Pseudodiaptomus).

Phonological characteristics and reproductive efficiency of the aroid Dieffenbachia oerstedii were studied in two populations in the Central Valley, Costa Rica (along streams on the Pacific drainage). Most inflorescences were produced in May and June, and ripe fruits (exposed by dehiscence of the spathe) were observed a year later in June. Most (90 %) of reproductive plants produced one or two inflorescences, a few produced three per season and only one produced four (out of 151 inflorescences observed). Production of new leaves dropped considerably during the blooming period. Number of fruit per infructescense varied from 13 to 43; each fruit containing one green seed. Seed color was different (red or pink) in those producing nonviable albino plants (129 out of 728 seeds used in germination observations, i.e., 17.7%). Some seedless fruits were also observed, which might function as a reinforcement for the well-established ornithocory in this species, since these and the fruits with nonviable seeds would be an extra reward for frugivory. Emphasizing this idea, seeds seem to require some kind of abrasive action (like passing through the digestive tract of a bird) to germinate, since seeds covered by intact pericarp failed to germinate in all trials, whereas naked seeds germinated in nearly 100% of the experiments.

A study of mangrove oysters (Crassostrea rhizophorae) cultured in a raft system between January and June 1982 in the Vizcaya Tideland, Limón, Costa Rica showed that the rates of growth were higher for the first three months of culture, decreasing gradually in the next three months. An average length of 65.83 mm with a maximum of 85.50 mm was reached at the sixth month. Strong correlation was observed between total live weight and total length.The minimal sexual maturity size was 13 mm with an approximate age between 15 and 22 days; spawning was not observed in individuals smaller than 21 mm.

Signs of malnutrition were observed in mice fed raw pejibaye (Bactris gasipaes) meal as a substitute of corn in the feed. No problems appeared when the animals were fed the same mixtures previously autoclaved. An aqueous extract of pejibaye meal inhibited the caseinolytic action of porcine pancreatine. The inhibiting effect disappeared when boiling the extract for one hour upon dialysis. ApparentIy a relatively low molecular weight pro tease inhibitor is present in raw pejibaye meal.

The population structure of the mollusc Donax dentifer in a colonizable area of approximately 100 000 m2 in the upper band of the intertidal zone at Garza Beach, Puntarenas, Costa Rica showed aggregate distribution with a mean density of 48 individuals/m2. The biomass estimated was 65.4 g/m2 for a total of 6.54 metric tons. A growth rate of 6.14 mm/month was estimated for the first 7 age groups.

Lacteous fat globules with their membranes from human milk and calostrum were studied by scanning and transmission electron microscopy. The first appear as spheroidal structures with some irregularities on the surface. Under the transmission electron microscope these irregularities are composed of islets from a material morphologically similar to cytoplasm, and with structures that resemble a fragment of rugose endoplasmic reticulum. The membranes in specimens fixed immediately after secretion are tri-layered, similar in appearance to those of a single membrane, but in samples fixed between two and four hours after secretion the details are unclear. Through freeze-etching, the laminar aspect of the fat globules is observed.