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

Sceloporus malachiticus is a diurnal iguanid lizard occupying upland and montane areas through much of Mexico and Central America. In Costa Rica, where field observations were made, this species utilizes various habitats between elevations from about 600 to more than 3,000 meters. In response to the diel march of temperature, activity usually demonstrated a unimodal peak in the late morning hours, prior to the onset of cloud caver. Body temperatures generally exceed those of both ambient air and substratum; active animals exhibit a greater differential than inactive ones. Body temperatures range from 8.4 °C to 34.4 °C, of which the voluntary activity range is 22.0 to 34.4 °C (X28.6 °C). No significant differences were found among different size or sex groupings. Basking behavior is common throughout the range of activity in all groups. Neither hibernation nor acclimation is exhibited in montane S. malachiticus.In comparing these thermal responses with other sceloporines, the most conspicuous feature of this population of S. malachiticus is its low thermal preferendum. Among the collective voluntary activity ranges and preferenda reported for other members of the genus there is an obvious contrast with the results obtained. Further evidence acquired during this study indicates that thermal preferenda among sceloporines are more characteristic of their autecology than their phylogeny.

A comparative study between two Acanthina brevidentata (Woods, 1828) populations from July to September, 1982 in Playa Panamá, Bahía Culebra, Guanacaste, Costa Rica, showed different regression and correlation values in total weight, aperture length, total width and totallength between the two populations. The horizontal distribution along the surface transect in the intertidal zone showed a gradual increase in the number of individuals for one population, whereas it was irregular in the other; spatial dispersion was regular in one and contagious in the other.

Information on the growth and mortality of the freshwater clam, Glabaris luteolus is provided, for the first time. The rapid growth and low mortality observed during the study demonstrate the importance of this species as an alternative in polyculture activities. The work also showed the effect of monthly handling of the individuals, with regard to the growth and mortality. It appears that G. luteolus exhibits a yearlong reproductive period with at least one maximum peak.

The reproductive cycle of 1094 specimens of the mangrove cockle, Anadara tuberculosa, was studied by a smear method and macroscopic observation of the gonads at Punta Morales, Costa Rica from May 1980 to April 1981. The percentage of males and females was approximately 1 : 1, the mean of individuals of undtermined sex was 13.84% raging from 42% in June of 1980 to 0 in December 1980. Ripening and fully ripe individuals were observed throughout the year. There was no evidence of sexual reversal in any specimen. The period of greatest _ spawning activity was from May to September, the percentage of spent individuals ranged from 70 to 50%, respectively. Active gametogenesis was observed with a decrease in the water temperature and salinity. The spawning peak coincided with high salinity and water temperature.

Acanthemblemaria aspera is a shallow water species that has not been found in the Santa Marta region (Colombia). Acantina betinensis is an endemic of the southern Caribbean which inhabits empty worm holes in dead corals. Acantina rivasi is a shallow water form that inhabits empty barnacle shells. Ekemblemaria nigra is rare in the Colombian Carribbean. Lucayablennius zingaro is common below 20 m at Islas del Rosario (Colombia), but is absent from the Santa Marta region.

Approximately eight species of the Phorid fly, Melaloncha, were seen parasitizing honey bees, especially during the rainy season in various parts of Costa Rica. Copulation of these flies takes place in the vicinity of the beehives and around flowers visited by both species. Melaloncha apparently introduces the ovipositor through the intersegmental membranes of the abdomen of the bee, where the first larval stages develop. After the bee dies, the larva migrates to the thorax where it completes its development and pupates. Melaloncha also parasitizes Bombus Mexicanus and Melipona fasciata. Parasitism of honey bees by this Phorid has serious economic implications.

Nutritive assesment of pejibaye (Bactris gasipaes) meals included proximal composition of the lipid and nitrogenous fractions. Caloric values obtained as true metabolizable energy (TME) indicate that the pejibaye has a higher content of energy than corn and that it is not necessary to separate the seeds from the fruits in animal feeds; the level of indispensable aminoacids is considerably low, especially methionine, which is lower than in corn; thin layer chromatography shows that most of the free fatty acids are present in a ratio of 2 : 1 in unsaturated to Saturated acids. The predominant fatty acids in whole pejibaye meal are oleic and palmitic acids with adequate levels of linoleic acid. Saturated fatty acids are predominant in the seed, with a very high content of lauric and myristic acids.

A preliminary inventory of the composition of zooplanktonic species found in Bayano Lake, between February and September 1981, revealed that there are seven species of RotifeIa, five Cladocera, two Copepoda, one Ostracada and larvae of Macrobrachium (Decapoda) and Chaoborus (Diptera). The composition, abundance and horizontal and monthly distribution of the most important zooplanktonic groups found in Bayano Lake are here presented.

Sample of commercial species of mollusks were collected by trawl during seasonal cruises at stations located along three transects on the coastal shelf of southern Sinaloa. México (SIPCO Cruises). Samples were obtained from 27 la 117 m and included 5 species of Anadara, Chione kellettii and Solenosteira gatesi among the most abundant species. For these species, fresh weight per hour of trawl was of 2.4 kg/hour for the shallowest stations and maximum abundance was found off Teacapán. Most of the specimens were obtained between 27 and 78 m. although Anadara spp. and C. kellettii were found at 109 and 114 m. Environmental conditions (temperature. salinity. dissolved oxygen and sediments) at the sampling localities are discussed, noting that S. gatesi was found on almost every type of substrate and tolerates very low levels of oxygen. Chione kellettii was predominantly found in clayish substrates and also tolerates very low levels of oxygen. Catch per unit area for C. kellettii is estimated as 12 kg/ha and would certainly increase if dredges were used.

A biological study of a tropical chiton, Chiton stockesii, including aspects of its distribution, density, reproduction and biometry, was carried out at Punta Pochote, Bahía Ballena, Costa Rica, from August 1981 to July 1912. C. stockessi showed an aggregate-type distribution with a relative density of 0.2 ind./m2, 0.5 ¡nd./m2 and 6.3 ind./m2. In the upper, middle and lower littoral zones, respectively. The calculated correlation coefficients among all the measured variables were significant (P ≤ 0.01). It was not possible to determine sexual dimorphism (P ≤ 0.01) with respect to total length, height and weight. The lowest values for the coefficient of variation corresponded to the first two of these three variables (13.99% and 12.49%, respectively). The ratio of males to females was 1.54: 1, there was no evidence of hermaphroditism. The correlation between gonadal index and gonadal stage showed a similar seasonal variation (P ≤ 0.05). The periods of greatest gametogenesis and accumulation of mature gametes were from August-September 1981, and April-May 1982. The spawning seasons were between September-October 1981, November- February 1982 and June-July 1982. All of these periods were characterized by a decrease in the weight and length of the gonads.