Showing papers in "Revista De Biologia Tropical in 2003"

Polythene and Plastics-degrading microbes from the mangrove soil

Abstract: Biodegradation of polythene bags and plastic cups was analyzed after 2, 4, 6, and 9 months of incubation in the mangrove soil. The biodegradation of polythene bags was significantly higher (up to 4.21% in 9 months) than that of plastic cups (up to 0.25% in 9 months). Microbial counts in the degrading materials were recorded up to 79.67 x 10(4) per gram for total heterotrophic bacteria, and up to 55.33 x 10(2) per gram for fungi. The microbial species found associated with the degrading materials were identified as five Gram positive and two Gram negative bacteria, and eight fungal species of Aspergillus. The species that were predominant were Streptococcus, Staphylococcus, Micrococcus (Gram +ve), Moraxella, and Pseudomonas (Gram -ve) and two species of fungi (Aspergillus glaucus and A. niger). Efficacy of the microbial species in degradation of plastics and polythene was analyzed in shaker cultures. Among the bacteria, Pseudomonas species degraded 20.54% of polythene and 8.16% of plastics in one-month period. Among the fungal species, Aspergillus glaucus degraded 28.80% of polythene and 7.26% of plastics in one-month period. This work reveals that the mangrove soil is a good source of microbes capable of degrading polythene and plastics.

How do mangrove forests induce sedimentation

Abstract: The mangrove forests play a significant role as sediment traps. They reduce tidal flows and induce sedimentation of soil particles at low tide. However, there are no such processes taking place in the non-mangrove areas. Site of Avicennia–Rhizophora interphase is more efficient than Avicennia and or Rhizophora zones, in trapping the sediment by 30, 25 and 20% respectively at low tide as compared to high tide

Introduction to Physidae (Gastropoda: Hygrophila); biogeography, classification, morphology.

Abstract: Physidae, a world-wide family of freshwater snails with about 80 species, are reclassified by progressive characters of the penial complex (the terminal male reproductive system): form and composition of penial sheath and preputium, proportions and structure of penis, presence or absence of penial stylet, site of pore of penial canal, and number and insertions of penial retractor muscles. Observation of these characters, many not recognized previously, has been possible only by the technique used in anesthetizing, fixing, and preserving. These progressive characters are the principal basis of 23 genera, four grades and four clades within the family. The two established subfamilies are divided into seven new tribes including 11 new genera, with diagnoses and lists of species referred to each. Proposed as new are: in Aplexinae, Austrinautini, with Austrinauta g.n. and Caribnautu harryi g.n., nom.nov.; Aplexini; Amecanautini with Amecanauta jaliscoensis g.n., sp.n., Mexinauta g.n., and Mayabina g.n., with M. petenensis, polita, sanctijohannis, tempisquensis spp.nn., Tropinauta sinusdulcensis g.n., sp.n.; and Stenophysini, with Stenophysa spathidophallus sp.n.; in Physinae, Haitiini, with Haitia moreleti sp.n.; Physini, with Laurentiphysa chippevarum g.n., sp.n., Physa mirollii nom.nou.; and Physellini, with Chiapaphysa g.n., and C. grijalvae, C. pacifica spp.nn., Utahphysa g.n., Archiphysa g.n., with A. ashmuni, A. sonomae spp.nn., Physella hemphilli sp.n., and Ultraphysella sinaloae g.n., sp.n. The simplest reproductive system is found in Austrinauta of the Aplexinae; its penial complex approaches that in the related family Lymnaeidae. Within Physinae a close approximation is found in Haitia. By these two genera the two subfamilies are drawn close together. Four grades of progressive complexity are recognized: (I) penial sheath entirely muscular; (II) penial sheath with both glandular and muscular tissue; (III) penis with penial stylet or other specialization of the tip of the penis; and (IV) pore of penial canal lateral rather than terminal as in the lower grades. In both subfamilies there are clades with glandular tissue in the penial sheath, a penial sheath subdivided into two parts, and tip of penis specialized in various ways. These clades are formalized as new tribes. Of 23 genera of Physidae, 17 occur in Pacific drainages of North and Central America, eight of these restricted to the region. Concentration of primitive genera along the Pacific coast from Mexico to Costa Rica conforms to previous observations that primitive pulmonate families are concentrated within, or along the continental margins of, the Pacific Ocean. An ancestral origin of Physidae along an ancient eastern Pacific coast is probable. From this region the several lineages have spread north, south and east in the Americas, and through Siberia to Europe. Although Physinae have fewer genera than Aplexinae (11 v. 12), they have more species (47 v. 34). Greater land area in the temperate zone has provided more opportunity for speciation of Physinae, in contrast to the generally tropical and warm-temperate range of Aplexinae. Furthermore, 10 species of Physinae are localized in individual lakes, whereas Aplexinae are not lake-dwellers. Both well-developed egg strings and capsular strings are found in the spawn of Sibirenauta elongatus. These structures have been known in Lymnaeidae, but not hitherto in Physidae; they are a link with some marine groups, such as Siphonariidae. Spiral color bands and white streaks in the shell of Mexinauta recall those in Lancidae (Lymnaeacea), whereas the radula of Physidae is like that of Chilinidae. Physidae thus show affinities to various basal stocks of aquatic pulmonates; no clear-cut sister-group can be recognized. Most species have a restricted range; out of 55 with sufficiently detailed information for analysis, 25 are limited to a single 1 degrees x 1 degrees quadrangle. Only a few species are widespread, on one or even two continents. Accordingly, more species of Physidae are threatened by habitat destruction than in other families of Hygrophila with generally wider distributions. Other features are a key to genera; catalog of more than 430 names applied to living Physidae, with original reference, type locality, and location of type specimens; summary of museums with types; and glossary.

Moluscos del Perú

Abstract: Peru es un pais muy diverso, tanto en especies como en habitats. Segun el sistema de Holdridge 84 de 103 zonas de vida estan representadas en el pais. En este trabajo se reconocen 18 zonas ecologicas de los cuales dos ecosistemas son marinos. La malacofauna peruana cuenta con 1910 especies registradas. La mayor diversidad esta en el mar con 1018 especies de las cuales 570 son gasteropodos, 370 son bivalvos, 36 son cefalopodos, 34 son poliplacoforos, 3 son monoplacoforos, 3 escafopodos y 2 son aplacoforos. Las familias con mayor cantidad de especies son Veneridae (57spp.), Muricidae (47spp.), Collumbellidae (40 spp.) y Tellinidae (37 spp.). El 56% de las especies marinas se presentan en la provincia Panamena, el 11 % estan presentes solo en la provincia Peruana y el porcentaje restante estan presentes en ambas provincias. Ademas hay que destacar que 73 especies marinas son endemicas de Peru. El ambiente terrestre tambien posee una impresionante diversidad malacologica. Hasta la fecha hay 763 especies reconocidas que representa un 2.54% del total mundial estimado para los moluscos terrestres y el 38% de las especies esperadas para America del Sur. Las familias con mayor cantidad de especies son Bulimulidae con 424 spp., Clausiliidae con 75 spp y Systrophiidae con 55 spp. El grupo de moluscos menos diverso es el de las especies dulceacuicolas, hasta la fecha se han reportado 129 especies. En este grupo se han registrado 35 especies endemicas siendo los hidrobidos los que brindan el mayor aporte (14 spp.). Tanto para moluscos marinos como continentales se analiza los factores que afectan la distribucion de las especies, su ecologia y su conservacion. Ademas, se establece cuales son las regiones menos estudiades y los grupos que requieren de mas atencion. Adicionalmente, se comenta sobre la historia del estudio de cada uno de los grupos y su utilizacion.

Food niche overlap among neotropical frugivorous bats in Costa Rica.

Abstract: Food habits of 15 species of frugivorous bats were studied at La Selva Biological Station, Costa Rica. Eight hundred and fifty-four (854) fecal samples and 169 samples from fruit parts and seeds discarded by bats beneath feeding roosts were analyzed. During eight months of study, 47 fruit species consumed by bats were identified. Five plant genera (Cecropia, Ficus, Piper, Solanum, and Vismia) constituted 85% of all plants found in fecal samples. Feeding niche breadth differed significantly among the six most common species of frugivorous bats (Artibeus jamaicensis, Carollia sowelli, C. castanea, C. perspicillata, Dermanura sp., and Glossophaga commissarisi). All species, except for Dermanura sp., showed a diet dominated by one or two plant species. This suggests a pattern of resource partitioning at a generic level, in which Carollia consumed mainly Piper, Artibeus consumed Ficus and Cecropia, and Glossophaga consumed Vismia. Cluster analysis revealed higher values of food niche overlap in congeneric species than among species of different genera. Results show that if food is a limiting factor, mechanisms other than trophic selection must reduce interspecific interference or competition for food in this frugivorous bat guild.

Invasion by Ligustrum lucidum (Oleaceae) in NW Argentina: early stage characteristics in different habitat types

Abstract: Currently biological invasions are considered one of the world's most serious conservation problems. Ligustrum lucidum is the most abundant exotic tree in secondary forest patches of montane forests of NW Argentina. We studied the determinants of success of the early stages of its life cycle in distinct habitat types, with the hope of identifying vulnerabilities that could be exploited to control the invasion. Seed arrival, germination, seedling recruitment and survival, and sapling growth were studied in edges, gaps and forest interior. Seed arrival was also assessed under perches and in open fields. Germination was studied in forest and grassland patches. L. lucidum seedling survival and sapling growth were compared with the most abundant native species survival and growth. Seed arrival was strongly seasonal with a peak in mid-August. Seed rain did not differ significantly among habitat types, however there was a tendency for edges to receive more seeds when only dispersed seeds were considered. Perches strongly enhanced seed arrival; more than 40 times the number of seeds were dispersed beneath citrus plants (i.e. perches) than found in paired open areas. In the forest, seeds in gaps and edges had higher germination rates, but there was no difference in seedling survival. Fruits under closed canopy exhibited the lowest germination. Germination and survival were low in open areas. Neither seedling recruitment nor sapling growth differed between gaps and forest interior. L. lucidum saplings grew significantly more than saplings of the most common native species, and also showed higher seedling survival. L. lucidum is a prolific fruit producer, is capable of germinating and surviving in a broad range of forest environments, it is relatively shade tolerant and has higher survival and faster growth rate in comparison to the most common native species. All these characteristics highlight its potency as a successful invader, and point to few vulnerabilities that could be targets of control measures.

Reproductive aspects of Oreochromis niloticus (Perciformes: Cichlidae) at Coatetelco Lake, Morelos, Mexico

Abstract: Sex ratio, size at maturity, maturity stages, fecundity and egg diameter of Oreochromis niloticus from Coatetelco Lake, Morelos State, Mexico, were studied from January to December 1993. Sex ratio (male:female) was approximately 1:1.02. Length at maturity was 117 mm (males) and 120 mm (females). The fecundity ranged between 104 and 709 eggs, with egg diameter from 1 000 to 3 000 μm. The gonadosomatic and hepatosomatic index indicate that the species breeds during summer and winter.

Moluscos terrestres do Brasil (Gastrópodes operculados ou não, exclusive Veronicellidae, Milacidae e Limacidae)

Abstract: Studies on terrestrial prosobranchs (streptoneureans) and shelled pulmonates (euthyneureans) show the significant diversity of the Brazilian malacofauna These mollusks are still poorly known, despite the increasing interest in the group that started in the XVIII century when land mollusks began to be collected and deposited in scientific collections The species are arranged in alphabetical order; the taxonomic combination is updated when possible with the original and other bibliographic references This checklist includes original study of specimens deposited in Brazilian, American and European collections, as well as names and additional data of important early naturalists and current researchers of the group Species are here associated to their original references; geographical distribution and other taxonomic references were added to each A total of 590 species were found (27 families and 95 genera) The systematic arrangement of suprageneric and generic taxa was based on Taylor & Sohl (1962), Thiele (1929-1931), Wenz (1938-1944) and Zilch (1959-1960) Breure (1973-1985) was especially useful regarding Bulimuloidea because the characteristics of some subgenera justified a raise to generic level The consistent characteristics found in some controversial subspecies justify a species rank for them

Zooplankton associations and environmental factors in Ogunpa and Ona rivers, Nigeria.

Abstract: Zooplankton abundance, composition and environmental parameters were monitored in two tropical rivers over a twenty month period. The data was subjected to cluster, factor and correlation analysis to determine the grouping pattern of zooplankton and their relationship to environmental parameters. Environmental factors in Ogunpa and Ona rivers -included buffering capacity, trace metal ions, pH-temperature/ transparency- were primarily influenced by rainfall. The dominance of the Rotifera in both rivers was attributed to their short developmental rate and fish predation on larger zooplankton. Two groups of associations were identified in each river – a commonly occurring species group exhibiting strong homogenous correlation with environmental factors and a predominant group exhibiting weak correlation with environmental factors and whose abundance / composition may be defined by biotic factors.

On the phytoplankton of Awba reservoir, Ibadan, Nigeria.

Abstract: The physico-chemical characteristics and phytoplankton of Awba reservoir in the University of Ibadan, Nigeria, were monitored to determine the impact of eutrophication on phytoplankton composition. The principal component analysis identified three major components influencing the physicochemistry of the water, namely trace metals, dissolved oxygen and ionic composition. Comparative analysis with a previous study showed a phenomenal increase in zinc, copper and iron levels over a 10-year period. Furthermore, the ferruginous nature of the soil contributed to the high levels of iron which exceeded the World Health Organization Standards for drinking water quality. The most abundant phytoplankton species was Microcystis aeruginosa which has been implicated in toxic blooms in freshwaters. The conditions favouring cyanophyte blooms and their implications are discussed.

Monitoring the coral disease, plague type II, on coral reefs in St. John, U.S. Virgin Islands.

Abstract: I n July 1997, conspicuous white patches of necrotic tissue and bare skeleton began to appear on scler- actinian corals in several bays around St John, US Virgin Islands Analysis of diseased coral tissue from five differ- ent species confirmed the presence of a Sphingomonas-like bacterium, the pathogen for plague type II To date, 14 species of hard corals have been affected by plague type II around St John This disease was monitored at Haulover and Tektite Reefs at depths of 7-12 meters The study site at Tektite Reef has >50% cover by scleractinian corals with 90% of hard corals being composed of Montastraea annularis Monthly surveys at Tektite Reef from December 1997 to May 2001 documented new incidence of disease (bare white patches of skeleton) every month with associ- ated loss of living coral and 905% of all disease patches occurred on M annularis The frequency of disease within transects ranged from 3 to 58%, and the area of disease patches ranged from 025 to 9000 cm 2 The average percent cover by the disease within 1 m 2

Phytomedicinal potential of tropical cloudforest plants from Monteverde, Costa Rica

Abstract: A pharmacological survey of plants from Monteverde, Costa Rica, including 165 species representing 61 families has been carried out. Crude plant extracts have been tested for in-vitro bactericidal and fungicidal activity as well as cytotoxic and anti-herpes activity. Of these, 123 extracts exhibited notable cytotoxicity, 62 showed antibacterial activity, 4 showed antifungal activity, and 8 showed promising antiviral activity. Thus, 101 of the plant species examined in this work, or 62%, showed marked bioactivity in one or more bioassays. These results underscore the phytomedicinal potential of Neotropical cloud forests.

Three scleractinian coral diseases in Dominica, West Indies: distribution, infection patterns and contribution to coral tissue mortality

Abstract: Coral diseases have been documented in many areas of the Caribbean, but studies in the eastern Caribbean region have been lacking. The prevalence, distribution patterns and contribution to the mortality of coral tissue by black band disease (BBD), white plague (WP) and dark spots disease (DSD) were examined at five reef sites along the west coast of Dominica. 185 of the 325 diseased colonies recorded between March and August 2000, in a survey area of 5884 m2, were WP. This disease contributed to 89% of the total 4.08 m2 of tissue mortality caused by diseases during the survey period. WP also affected the largest average tissue surface area (relative to colony size) per colony and exhibited the largest average tissue loss per infection when compared to BBD and DSD. The species most susceptible to WP and BBD in Dominica differed from most other described Caribbean locations with Siderastrea siderea being most susceptible. S. siderea was also the only species noted to be susceptible to DSD. Measurements of colony size revealed that each disease affected the larger colonies of some coral species. Comparisons between disease prevalence at each site and various physical parameters, including temperature, wave height, depth, and current patterns, did not exhibit significant correlations. The lack of a direct correlation between temperature and disease prevalence indicates that there are other seasonal factors contributing to the higher prevalence of diseases recorded during the summer months in Dominica. WP prevalence at each site was positively correlated to the relative species abundances of the species most susceptible to WP. This was the dominant factor in determining sitespecific disease densities of this disease and may therefore be a valuable predictive and management tool. There were no correlations between BBD or DSD and the relative abundances of susceptible species. The spatial distribution patterns of WP, BBD and DSD were clustered, which is a distribution pattern that suggests an infectious disease.

White plague disease outbreak in a coral reef at Los Roques National Park, Venezuela.

Abstract: Cor al diseases have been reported as a major problem affecting Caribbean coral reefs. During August 2000, a coral mortality event of White Plague Disease-II (WPD-II) was observed at Madrizqui Reef in Los Roques National Park, Venezuela. This disease was identified as the major cause of coral mortality, affecting 24% of all colonies surveyed (n = 1 439). Other diseases such as Black Band Disease (BBD), Yellow Blotch Disease (YBD), Dark Spots Disease (DSD) and White Band Disease (WBD) were also recorded, but showed a lower incidence (0.14- 0.97%). Two depth intervals, D1 (5.5-6.5 m) and D2 (9-9.5 m) were surveyed with two sets of three band transects 50 x 2 m long, placed parallel to the long axis of the reef. All healthy and injured corals, along each band transect, were counted and identified to species level. Additionally, all diseases and recent mortality that were still identifiable on each colony also were recorded. The incidence of colonies affected by WPD-II ranged from 12.8 to 33% among transects, where thirteen species of scleractinian corals showed several degrees of mortality. The species most affected were Montastraea annularis (39.13%), M. faveolata (26.67%), M. franksi (9.86%), Stephanocoenia intersepta (7.25%), Colpophyllia natans (6.96%), Diploria labyrinthiformis (2.99%), Mycetophyllia aliciae (2.03%), M. cavernosa (1.74%), and D. strigosa (1.45%). WPD-II was more common in the deeper strata (9-9.5 m), where 63% of the surveyed colonies were affected, although the disease was present along the entire reef. Presently, it is imperative to determine how fast the disease is spreading across the reef, how the disease spreads across the affected colonies and what the long-term effects on the reef will be.

The effect of elevated temperature on the toxicity of the laboratory cultured dinoflagellate Ostreopsis lenticularis (Dinophyceae)

Abstract: Ostreopsis lenticularis Fukuyo 1981, is the major benthic dinoflagellate vector implicated in ciguatera fish poisoning in finfish on the southwest coast of Puerto Rico. Clonal laboratory cultures of O. lenticularis (clone 301) exposed to elevated temperatures (30-31°C) for 33 and 54 days showed significant increases in the quantity of ex-tractable toxin they produced as compared to their toxicities versus cells grown at temperatures of 25-26°C. O. lenticularis samples collected directly from the field following exposure to elevated temperatures for comparable pe-riods of time also showed significant increases in extractable toxin. The increased toxicity of both field sampled and laboratory grown O. lenticularis exposed to elevated temperatures may result from the effects of elevated tempera-tures on their metabolism and/or the bacterial symbionts found associated with these microalgae. The number of bacteria associated with cultured O. lenticularis exposed to elevated temperatures was significantly reduced. In-creased toxin recovery from O. lenticularis exposed to elevated temperatures may have resulted from the direct effect of temperature on toxin production and/or the reduction of Ostreopsis associated bacterial flora that consume toxin in the process of their growth. This reduction in the quantity of associated bacterial flora in temperature treated cultures may result in increased toxin recovery from O. lenticularis due to a reduction in the consumption of toxin by these symbiont bacteria.

Basic limnology of fifty-one lakes in Costa Rica.

Abstract: We visited 51 lakes in Costa Rica as part of a broad-based survey to document their physical and chemical characteristics and how these relate to the mode of formation and geographical distribution of the lakes. The four oxbow lakes were low in elevation and tended to be turbid, high in conductivity and CO2, but low in dissolved O2; one of these, L. Gandoca, had a hypolimnion essentially composed of sea water. These were similar to the four wetland lakes, but the latter instead had low conductivities and pH, and turbidity was often due to tannins rather than suspended sediments. The thirteen artificial lakes formed a very heterogenous group, whose features varied depending on local factors. The thirteen lakes dammed by landslides, lava flows, or lahars occurred in areas with steep slopes, and were more likely to be stratified than most other types of lakes. The eight lakes that occupy volcanic craters tended to be deep, stratified, clear, and cool; two of these, L. Hule and L. Rio Cuarto, appeared to be oligomictic (tending toward meromictic). The nine glacial lakes, all located above 3440 m elevation near Cerro Chirripo, were clear, cold, dilute, and are probably polymictic. Cluster analysis resulted in three significant groups of lakes. Cluster 1 included four calcium-rich lakes (average 48 mg l-1), Cluster 2 included fourteen lakes with more Si than Ca+2 and higher Cl- than the other clusters, and Cluster 3 included the remaining thirty-three lakes that were generally less concentrated. Each cluster included lakes of various origins located in different geographical regions; these data indicate that, apart from the high-altitude glacial lakes and lakes in the Miravalles area, similarity in lake chemistry is independent of lake distribution.

La comunidad de peces de la Laguna de Términos: estructura actual comparada

Abstract: Se presentan los resultados de investigacion sobre la ecologia de la comunidad de peces de la Laguna de Terminos. Se describe la estructura y se discute de manera comparada con la informacion publicada. Se realizaron 19 campanas mensuales de campo en 23 sitios de muestreo durante el periodo de septiembre de 1997 a marzo de 1999. Se identificaron 107 especies de peces que se agruparon en 76 generos y 37 familias. Se capturaron 25588 organismos con un peso total de 601.5 kg. La abundancia de la comunidad en escala temporal oscilo de 0.395 a 0.895 ind/m2; 8.638 a 18.316 g/m2 y 18.358 a 34.837 g/ind. La diversidad de la comunidad, estimada por el indice de Shannon y Weaver oscilo entre 1.875 y 3.995. El valor de los indices de equitatividad y riqueza de especies presentaron una variacion entre 0.519 y 0.993 y 4.94 y 7.88 respectivamente. Se identificaron 18 especies dominantes con base en el analisis de los valores de numero de individuos, peso y porcentaje de aparicion. La especie mas importante tanto por su abundancia numerica como por su frecuencia de aparicion es Arius melanopus que representa el 26.5% de la captura total seguida de Diapterus rhombeus con el 18.9%. Tambien como especies dominantes cabe destacar la presencia de aquellas de interes pesquero tanto local como regional y son Bairdiella chrysura , B. ronchus , Archosargus rhomboidalis , Eugerres plumieri , Cynoscion arenarius y Chaetodipterus faber .

The fish fauna in tropical rivers: The case of the Sorocaba river basin, SP, Brazil

Abstract: A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tiete River, located in the State of Sao Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twen- ty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In rela- tion to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representa- tive species in relation to average weight. Largest standard length were recorded for Sternopygus macrurus, Steindachnerina insculpta, Eigenmannia aff. virescens and Cyprinus carpio.

Estructura de tallas y crecimiento de los cangrejos Callinectes arcuatus y C. bellicosus (Decapoda: Portunidae) en la laguna costera Las Guásimas, México

Abstract: Presentamos informacion sobre la estructura de tallas, la relacion ancho-peso y los parametros de crecimiento de las jaibas Callinectes arcuatus y C. bellicosus. Las muestras fueron recolectadas mensualmente con una red de arrastre tipo camaronera durante el dia y la noche desde marzo 1998 hasta febrero 2000 en una laguna costera del Golfo de California. C. bellicosus (n= 878) fue mas abundante que C. arcuatus (n= 357) y su intervalo de talla de 8.4-166 mm ancho del caparazon (AC) y 9-130 mm AC, respectivamente. Ambas poblaciones son representadas principalmente por jovenes (75 mm AC) entre 37-75 mm AC y adultos entre 76-90 mm AC. La relacion ancho-peso mostro que los machos crecen mas que las hembras en ambas especies y se observo una tendencia de crecimiento isometrico. Los parametros de crecimiento para C. arcuatus estimados con el modelo von Bertalanffy fueron: K= 0.84 ano-1, L∞= 140 a -0.12 mm para C. arcuatus, y K= 0.9 ano -1, L∞= 169 a -0.11 mm para C. bellicosus. Estos resultados mostraron que la edad relativa a la cual se alcanza el crecimiento maximo es entre los tres y cuatro anos de edad para ambas especies.

Pollination of Anthurium (Araceae) by derelomine flower weevils(Coleoptera: Curculionidae)

Abstract: Cyclanthura flower weevils (Coleoptera: Curculionidae: Derelomini) are identified for the first time as pollinators of multiple species of Anthurium (Araceae) in Costa Rica. The weevils are present on the inflorescences in small numbers during the pistillate and staminate phase of anthesis, and consume plant tissues and pollen. The individuals of one species of Cyclanthura can visit several Anthurium species within the same locality. They also engage in reproductive activities and are likely to oviposit into the flowers. The mating strate- gies suggest that sperm precedence selects males that are able to secure their position as the last partner prior to oviposition. Rev. Biol. Trop. 55 (1): 269-277. Epub 2007 March. 31.

Patrones en la biología poblacional de moluscos de importancia comercial en México

Abstract: The need to propose recommendations for the management of over 80 species of bivalves and gastropod mollusks exploited commercially in Mexico, led to look for trends on the population and reproductive biology in re-lation to prevailing environmental conditions of the habitats where they are exploited. The reproductive cycle, growth parameters for the von Bertalanffy equation, mortality and recruitment of 18 populations of 14 species from 13 localities are compared and related to ambient temperature, precipitation, evaporation, geomorphology, tides, and water salinity and temperature. Localities were classified as influenced by landmasses or with marine influence, with a de-sert or tropical humid climate. With restricted or continuous communication to oceanic waters and with or without freshwater runoff. The reproductive cycles were classified in four groups in relation to intensity and duration of the spawning season: 1) limited to one annual spawning, 2) two or more defined spawning periods, 3) two or more ex-tended spawning periods, and 4) continuous low intensity spawning. And three groups in relation to gonad recovery, and duration and intensity of gametogenesis: 1) post spawn and rest stages absent or restricted, 2) fast gametogenesis and a clear mature stage, and 3) extended gametogenesis and limited maturity stages. The population parameters were classified in relation to age structure and number of cohorts, intensity and duration of recruitment, and growth rates as expressed by L∞ and K. In relation to their life cycle four types were found: 1) population represented by only one cohort, at least during part of the year, 2) with two or more cohorts at any time, 3) longevity under five years, and 4) longevity over five years. In relation to recruitment: 1) one recruitment period restricted to a short sea-son, 2) two or more recruitment periods, 3) constant recruitment with one or more peaks, and 4) constant recruitment without periods of dominance.

Pharmacological activity of the essential oil of Satureja viminea (Lamiaceae).

Abstract: The aqueous extract and the essential oil of Satureja viminea (Lamiaceae) were tested. General physiologic effects were assessed through the Hippocratic screening test. Non fasted female Sprague Dawley rats were utilized and 250, 500, 750 and 1000 mg/kg doses were used. Two animals were used for each dosage level and for the vehicle alone. Exploratory behavior and curiosity were measured using a hole board apparatus and placing non-trained mice on the board and recording the number of holes explored in a 5 minute period. The Boissier chimney test was used to evaluate motor coordination. Muscle strength was assessed through a grasping test where mice were hung by their fore-limbs 40 cm above the base on a horizontal metal stainless bar. In all these tests, 3 groups of 6 albino mice, were treated with 1000 mg/kg of each the essential oil of S. viminea, the vehicle and diazepan (1 mg/kg) as a positive control. Analgesic activity was explored in Sprague-Dawley rats. The tail flick method described by D'Amour and Smith (1941) modified by CYTED was implemented on three groups (6 rats each) of animals treated with, each the essential oil of S. viminea (1000 mg/kg), the vehicle and indomethacine. The test was carried out just before and 30, 60 and 120 min after oral treatment. Peristaltic activity was measured in albino mice, three groups of 6 animals each, treated orally with each the essential oil of S. viminea (1000 mg/kg), the aqueous extract (1000 mg/kg), and the vehicle. The marker used was activated carbon. Animals were sacrificed 30 min after the marker was given and the percent of total small intestine traversed by it was calculated. Also a lethal dose 50 (LD 50) was determined with the Spearman-Karber method. A dose-related spontaneous motor activity reduction was observed. Exploratory behavior and curiosity were diminished. The grasping strength of mice was reduced. A very clear and significant analgesic effect was observed with the oral administration of the essential oil of S. viminea (1000 mg/kg). This effect is compared to that of indomethacine. Intestinal transit and gastric emptying were inhibited by the essential oil. The LD50 of the essential oil of S. viminea is 556.8 mg/kg.

Combined effect of concentrations of algal food (Chlorella vulgaris) and salt (sodium chloride) on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera)

Abstract: Salinity is an important variable influencing the density and diversity of rotifers. Studies on salt tolerance of rotifers have so far concentrated on euryhaline species while very little information is available on noneuryhaline taxa. In the present work, we have evaluated the combined effects of Chlorella vulgaris and sodium chloride on the population growth of two freshwater rotifers B. calyciflorus and B. patulus. A 24 hr acute tolerance test using NaCl revealed that B. calyciflorus was more resistant (LC50 = 3.75 ± 0.04 g l-1) than B. patulus (2.14 ± 0.09 g l-1). The maximal population density (mean±standard error) for B. calyciflorus in the control at 4.5 X106 cells ml-1 (algal level) was 80 ±5 ind. ml-1, which was nearly a fifth of the one for B. patulus (397 ± 7 ind. ml-1) under comparable conditions. Data on population growth revealed that regardless of salt concentration, the density of B. calyciflorus increased with increasing food levels, while for B. patulus, this trend was evident only in the controls. Regardless of salt concentration and algal food level, the day of maximal population density was lower (4 ± 0.5 days) for B. calyciflorus than for B. patulus (11 ±1 day). The highest rates of population increase (r values) for B. calyciflorus and B. patulus were 0.429 ± 0.012 and 0.367 ± 0.004, respectively, recorded at 4.5 X106 cells ml-1 of Chlorella in the controls. The protective role of algae in reducing the effect of salt stress was more evident in B. calyciflorus than B. patulus.

Caterpillars of Eumaeus childrenae (Lepidoptera; Lycaenidae) feeding on two species of cycads (Zamiaceae) in the Huasteca region, Mexico

Abstract: There are few genera of butterflies that feed on cycads. Among them the genus Eumaeus (Lycaenidae) presents aposematic coloration in all its life stages. In this work we report for the first time the herbivory of young leaflets of Ceratozamia mexicana and Zamia fischeri (Zamiaceae) by caterpillars of E. childrenae in their natural habitat in the Huasteca region, Mexico.

Moluscos continentales de México: Dulceacuícolas

Abstract: There are 16 freshwater mollusc families reported from Mexico, but besides a few studies of habitat and distribution, only Pomacea flagellata, Pomacea patula catemacensis and Helisoma trivolvis has been studied in some detail, mainly regarding reproduction. In Mexico, the parasite Fasciola hepatica is transmitted by Lymnaea obrussa, L. humilis and L. cubense ). Larval trematodes have been found in Planorbidae, Physidae, Lymnaeidae, Ancylidae and Pisidiidae. Diet and growth have been studied for Lymnaea bulimoides, L. cubensis and L. humilis . Piquerol A extracted from Piqueria trinervia acts as molluscicide. There are reports about freshwater molluscs as pollution bioindicators and as source of food, foreing currency and lime. Mexican freshwater molluscs are an endangered resource.

A survey of the epibiota of Eretmochelys imbricata (Testudines: Cheloniidae) of Mona Island, Puerto Rico

Abstract: Epibiotic organisms inhabiting non-nesting hawksbill sea turtles, Eretmochelys imbricata (Linnaeus, 1766), are described from Mona and Monito Islands, Puerto Rico. Epibiont samples from 105 turtles of shallow (< 40 m) water foraging habitats were collected and identified to the lowest possible taxon. This epibiotic assemblage consisting of at least 4 algal functional groups and 12 animal phyla represents the greatest phylogenetic diversity for marine turtle epibiota. Six groups are considered new reports for marine turtles. Most epibiont colonization was found on posterior marginal scutes and under overlapping scutes. Ecological attributes of epibiota and their symbiosis with E. imbricata provide a tool to understand basi and epibiont populations.

Demografía y ecología de anidación de la iguana verde, Iguana iguana (Squamata: Iguanidae), en dos poblaciones explotadas en la Depresión Momposina, Colombia

Abstract: Se estudio la demografia y ecologia de anidacion de dos poblaciones de Iguana iguana que enfrentan explotacion severa y alteracion del habitat, en la Depresion Momposina, Colombia. Los datos de transectos lineales fueron analizados con el modelo de Fourier para estimar la densidad de grupos sociales. El tamano promedio de grupo y la densidad general de iguanas vario dentro y entre poblaciones (1.05 - 6.0 grupos/ha, y 1.5 - 13.7 iguanas/ha respectivamente). Las estimaciones de densidad fueron mucho menores que las reportadas en areas mas protegidas en Panama y Venezuela. Las densidades de las iguanas fueron considerablemente mayores en sitios localizados a lo largo de los rios (2.5 iguanas/grupo) que en sitios en el margen de las cienagas (1.5 iguanas/grupo), probablemente debido a diferencias en la vegetacion. No hubo correlacion entre las estimaciones de densidad y la de abundancia relativa (numero de iguanas vistas/hora/persona), debido a diferencias en detectabilidad de los grupos de iguanas entre los sitios. La proporcion sexual hallada (1:2.5 machos: hembras), es probablemente el resultado del sistema de apareamiento poligamo de esta especie, en vez de indicar un verdadero sesgo demografico. Se monitoreo 34 nidos los cuales sufrieron poca depredacion por vertebrados. Sin embargo si fueron afectados por inundaciones, pisoteo por ganado e infestacion por larvas de mosca Phoridae. El tamano de huevos por nidada en estas poblaciones fue de 29.4 menor que cualquier otro reporte de la literatura, con la excepcion de las poblaciones de Iguana que habitan la isla altamente xerica de Curacao, implicando que las hembras adultas en nuestra area son inusualmente pequenas. Probablemente este es el resultado de la explotacion prolongada y excesiva de estas poblaciones en vez de ser una respuesta adaptativa a condiciones ambientales extremas.

Base de datos del Museo Nacional de Historia Natural: moluscos de Chile

Abstract: The collection of moluscos, Chile and other parts of the world, deposited in the present dependencies of the Laboratory of Malacologia of the National Museum of Historia Natural (MNHN) of Chile, is the result of a process of harvesting that began with the founders of the natural history of Chile from 1782, with Juan I. Molina, Claudio Gay in 1854 and R. A. Philippi as of 1853, among other naturalists. Important it was the contribution made by D’Orbigny that made descriptions of malacofauna of Chile, observed in his expeditions Latin America, between 1826 and 1833. At the moment, the collection is in a stage of organization, cataloguing and recovery of pieces originally described by Rudolfo A. Philippi, as well as of numerous donations and exchanges that the naturalist received being director of the Museum. The study and documentation of the collections of moluscos have been a slow process and have obeyed, preferredly, to the development of works in those groups of greater interest of the investigators who are been in charge of the Phylum. As of year 1997, a new process began, with the rating of rooms of work and deposit (Room Collection Philippi and Chilena). Also its location in the present taxonomy is had boarded and their conditions of conservation are improving. Many of the present lots of terrestrial, marine moluscos and of continental waters and insulares must be reviewed. Numerous specimens of other latitudes exist that have been entered the data base. Therefore, according to the bibliography consulted and data on collections in the country, they are registered for Chile, six classes, 34 orders, 254 families, 596 sorts and 1492 species. Key words: Moluscos, Chile, data base, collection.

Factors affecting growth of the spiny lobsters Panulirus gracilis and Panulirus inflatus (Decapoda: Palinuridae) in Guerrero, México

Abstract: The effects of sex, injuries, season and site on the growth of the spiny lobsters Panulirus gracilis, and P. inflatus, were studied through mark-recapture techniques in two sites with different ecological characteristics on the coast of Guerrero, Mexico. Panulirus gracilis occurred in both sites, whereas P. inflatus occurred only in one site. All recaptured individuals were adults. Both species had similar intermolt periods, but P. gracilis had significantly higher growth rates (mm carapace length week-1) than P. inflatus as a result of a larger molt increment. Growth rates of males were higher than those of females in both species owing to larger molt increments and shorter intermolt periods in males. Injuries had no effect on growth rates in either species. Individuals of P. gracilis grew faster in site 1 than in site 2. Therefore, the effect of season on growth of P. gracilis was analyzed separately in each site. In site 2, growth rates of P. gracilis were similar in summer and in winter, whereas in site 1 both species had higher growth rates in winter than in summer. This could be due to spatial differences in processes related to changes in population density and food resources, which were documented in previous works. The overall results show that P. gracilis grows faster than P. inflatus, and that growth rates of both species are highly variable and are affected by environmental factors such as site and season, which should be taken into account when attempting to produce population growth curves for each species.

Effect of Echinacea purpurea (Asteraceae) aqueous extract on antibody response to Bothrops asper venom and immune cell response

Abstract: The effect of aqueous extract of Echinacea purpurea roots on the murine antibody response to Bothrops asper snake venom in vivo was studied. Three groups were used. Group #1, baseline control, was treated with snake venom plus PBS. Group #2 was treated with snake venom plus sodium alginate as adjuvant (routine method used at Instituto Clodomiro Picado), and group #3 or experimental group, was treated with snake venom plus aqueous extract of E. purpurea root as adjuvant. In all groups, the first inoculation was done with Freund's complete adjuvant (FCA). By the time of the second bleeding, mice in group #3 showed a remarkable increment in the level of anti-venom antibodies compared with those in groups #1 or #2. In vitro immune cell proliferation as a response to aqueous extract of E. purpurea root was studied using human lymphocytes activated with different lectins (Con A, PHA and PWM). In all cases, increase in percentage of lymphoproliferation was greater when E. purpurea root extract was used in addition to individual lectins.