[Intake of processed meats by Costa Rican women: effect of socioeconomic status]
Intake of processed meats has been associated with serious health problems that are common among women. In 2015, the International Agency for Research on Cancer classified processed meats as human carcinogens, associated specifically with colon cancer. The increase in intake of processed meats, which are a low-cost source of dietary protein, varies by socioeconomic status (SES) and can impact chronic disease incidence.
Reproductive cycle of the endemic and threatened fish Puntius shalynius (Cypriniformes: Cyprinidae) in Meghalaya, India
Puntius shalynius is a highly endemic freshwater minor carp that is economically important and is threatened because of its ornamental value. The present investigation evaluated this barb gonadal maturation, based on morphology and spawning of this species in the Umiam river, Meghalaya, India. The population of this indigenous fish has declined due to its fragmented distribution and exploitation as an ornamental fish. The reproductive cycle of P. shalynius was studied for the first time. A total of 609 fish samples were randomly collected from the river for a period of two years during January 2010 and December 2011. Five maturity phases (rest, primary growth, secondary growth, ripe and spent) were observed on the basis of ovarian and testicular macroscopic evaluation throughout the annual cycle. Peak spawning activity was observed in the month of June/ July and it coincided with the start of the monsoon season. The study showed that the fish spawns once in a year with single spawning peak and that the species is a low fecund fish. It is important to conserve this species for its unique ecological value and urgent management policies should promote its sustainable utilization.
Divergent predation environment between two sister species of livebearing fishes (Cyprinodontiformes: Poeciliidae) predicts boldness, activity, and exploration behavior
Predators can influence a variety of prey traits, including behavior. Traits such as boldness, activity rate, and tendency to explore can all be shaped by predation risk. Our study examines the effects of predation on these behaviors by considering a natural system in which two sister species of livebearing fishes, Brachyrhaphis roseni and B. terrabensis, experience divergent predation environments. In February of 2013, we collected fish in the Río Chiriquí Nuevo drainage, Chiriquí, Panama, and conducted behavioral assays. Using open-field behavioral assays, we evaluated both juveniles and adults, and males and females, to determine if there were differences in behavior between ontogenetic stages or between sexes. We assessed boldness as ‘time to emerge’ from a shelter into a novel environment, and subsequently measured activity and exploration within that novel environment. We predicted that B. roseni (a species that co-occurs with predators) would be more bold, more active, and more prone to explore, than B. terrabensis (a species that does not co-occur with predators). In total, we tested 17 juveniles, 21 adult males, and 20 adult females of B. roseni, and 19 juveniles, 19 adult males, and 18 adult females of B. terrabensis. We collected all animals from streams in Chiriquí, Panama in February 2013, and tested them following a short acclimation period to laboratory conditions. As predicted, we found that predation environment was associated with several differences in behavior. Both adult and juvenile B. roseni were more active and more prone to explore than B. terrabensis. However, we found no differences in boldness in either adults or juveniles. We also found a significant interaction between ‘sex’ and ‘species’ as predictors of boldness and exploration, indicating that predation environment can affect behaviors of males and females differently in each species. Our work demonstrates the importance of considering sex and life history stage when evaluating the evolution of behavior.
[Ants’ higher taxa as surrogates of species richness in a chronosequence of fallows, old-grown forests and agroforestry systems in the Eastern Amazon, Brazil]
Deforestation in Amazon forests is one of the main causes for biodiversity loss worldwide. Ants are key into the ecosystem because act like engineers; hence, the loss of ants’ biodiversity may be a guide to measure the loss of essential functions into the ecosystems. The aim of this study was to evaluate soil ant’s richness and to estimate whether higher taxa levels (Subfamily and Genus) can be used as surrogates of species richness in different vegetation types (fallows, old-growth forests and agroforestry systems) in Eastern Amazon. The samples were taken in 65 areas in the Maranhão and Pará States in the period 2011-2014. The sampling scheme followed the procedure of Tropical Soil Biology and Fertility (TSBF). Initially, the vegetation types were characterized according to their age and estimated species richness. Linear and exponential functions were applied to evaluate if higher taxa can be used as surrogates and correlated with the Pearson coefficient. In total, 180 species distributed in 60 genera were identified. The results showed that ant species richness was higher in intermediate fallows (88) and old secondary forest (76), and was lower in agroforestry systems (38) and mature riparian forest (35). The genus level was the best surrogate to estimate the ant’s species richness across the different vegetation types, and explained 72-97 % (P < 0.001) of the total species variability. The results confirmed that the genus level is an excellent surrogate to estimate the ant’s species richness in the region and that both fallows and agroforestry systems may contribute in the conservation of Eastern Amazon ant community.
Oocyte distribution within and between ovary lobes is largely homogeneous in Lachnolaimus maximus (Perciformes: Labridae)
Studies of fish reproductive biology often involve quantitative estimates based on histological sections of the ovaries. Prior characterization of gonad oocyte distribution patterns in females is fundamental to these studies. Heterogeneous distribution requires a standardized sampling protocol to prevent bias in data such as fecundity estimations. In contrast, homogeneous distribution allows sampling of any portion of the gonads with no risk of bias. A preliminary study was done of gonad oocyte distribution mode in a hogfish Lachnolaimus maximus population in the southern Gulf of Mexico. A total of 23 sexually-active females were selected and classified by reproductive stage. Six histological sections were taken from the anterior, middle and posterior regions of the left and right ovary lobes of each individual. Digital image processing (AxioVision and Image ProPlus programs) was used to estimate oocyte density per unit area in different development stages. Contingency tables were used to analyze oocyte distribution frequencies between the regions of each lobe and between the lobes of each ovary. This was supported with a Pearson’s χ2 test for goodness-of-fit and a replicated G test to confirm distribution heterogeneity. Oocyte type distribution was homogeneous in almost all the females regardless of ovary region or lobe. This was particularly the case for females in the actively spawning reproductive subphase. Females in this subphase are normally used to estimate batch fecundity in fish species such as L. maximus, which have asynchronous oocyte development and batch spawning. However, heterogeneity was present in tertiary vitellogenesis oocytes in the right lobe of females in the spawning capable reproductive phase. In these cases, it is preferable to take histological sections from any region of the left ovary lobe to ensure unbiased estimation of fecundity and adequate characterization of this species’ sexual cycle.
[Reproduction of Centropomus undecimalis and C. ensiferus (Perciformes: Centropomidae) in a tropical coastal lagoon]
Snooks C. undecimalis and C. ensiferus are important fishery resources in their distribution area. In Venezuela they are caught by artisanal fisheries along the entire coast. However, studies on their biology that would help establish fishing regulations are scarce. To study reproduction aspects of these species, we analyzed 1 325 individuals of C. undecimalis and 2 025 of C. ensiferus caught by artisanal fishing in the Laguna de Tacarigua in Northern Venezuela, from July 2009 to September 2010. Total length, total weight, sex and stage of gonadal development were recorded. The sex ratio varied throughout the year: there was a significant difference in favor of C. undecimalis males (1.5:1), and C. ensiferus females (1:3.3). Differences were also evident in the sexual proportion at each size group. For both species, males dominated in the lower size ranges while females dominated in the larger size ranges. These results suggested sequential hermaphroditism (protrandry) in both species. Size at sexual maturity (Lm50) for C. undecimalis was ♀= 73.6 and ♂= 59.3 cm, and ♀= 26 and ♂= 21.5 cm for C. ensiferus. C. ensiferus reproduced throughout the year with two periods of higher intensity (August to September and February to April). Although we found very few mature individuals for C. undecimalis, February showed an important reproduction peak. Growth differences were found between males and females of C. undecimalis: positive allometry for females (P= 0.0022*L3.353) and negative allometry for males (P= 0.0108*L2.945). Both males and females of C. ensiferus showed a positive allometric relationship (P= 0.0049*L3.235). Lack of fishing regulations and controls, evidenced in this study by significant volumes of immature individuals in the catches, and the particular reproductive biology of these species, strongly indicates the need to establish regulations to ensure their responsible use. We recommend establishing a closed season during the first quarter of the year and minimum catch sizes for both species.
Preclinical efficacy against toxic activities of medically relevant Bothrops sp. (Serpentes: Viperidae) snake venoms by a polyspecific antivenom produced in Mexico
The assessment of the preclinical neutralizing ability of antivenoms in Latin America is necessary to determine their scope of efficacy. This study was aimed at analyzing the neutralizing efficacy of a polyspecific bothropic-crotalic antivenom manufactured by BIRMEX in Mexico against lethal, hemorrhagic, defibrinogenating and in vitro coagulant activities of the venoms of Bothrops jararaca (Brazil), B. atrox (Perú and Colombia), B. diporus (Argentina), B. mattogrossensis (Bolivia), and B. asper (Costa Rica). Standard laboratory tests to determine these activities were used. In agreement with previous studies with bothropic antivenoms in Latin America, a pattern of cross-neutralization of heterologous venoms was observed. However, the antivenom had low neutralizing potency against defibrinogenating effect of the venoms of B. atrox (Colombia) and B. asper (Costa Rica), and failed to neutralize the in vitro coagulant activity of the venom of B. asper (Costa Rica) at the highest antivenom/venom ratio tested. It is concluded that, with the exception of coagulant and defibrinogenating activities of B. asper (Costa Rica) venom, this antivenom neutralizes toxic effects of various Bothrops sp venoms. Future studies are necessary to assess the efficacy of this antivenom against other viperid venoms.
[Nesting ecology of Crocodylus acutus (Reptilia: Crocodylidae) in Bahia Portete, La Guajira, Colombia]
C. acutus is cataloged in critical danger in Colombia. We studied its population at Bahia Portete, in order to survey the nesting activities and to obtain valuable information for a conservation management program. This study was undertaken with the participation of the Wayuü community using the Agreement Conservation Model, and took place during July 2007, August 2008, June and August 2009, and March to August 2010 and 2011. Sampling surveys were made by the use of transects along the coast, in order to find nests. For each nesting area found, we recorded the nests biometrics, eggs and hatchlings, fertility of the eggs and reproductive events. We explored a total of 55.12 km, and determined four nesting areas. Colonial nesting and the environmental variables were factors that affected the hatchling success. From the total of nests found, 37 % were oriented towards North, and 48 % were built next to Stenocereus griseus. Juyi island substrate was mostly constituted by sand (71.9 %, 71.44 %). The average number of eggs by nest was 28.42 ± 6.63, the largest egg diameter was 71.84 ± 3.54 mm, the average nest weight was 81.54 ± 9.99 g, and the hatchlings presented an average length of 25.47 ± 1.16 cm. For this specific site in Colombia, the reproductive period begins in March and ends in August. The few areas of nesting and the 95 % fertility suggest the performance of a conservation management program for this species at Bahía Portete.
Reproductive biology of Sodhiana iranica (Brachyura: Gecarcinucidae) from Southern Iran
Freshwater crab, Sodhiana iranica, is an endemic gecarcinucid crab that has been recently reported from Southern Iran. This research examined some reproductive aspects of S. iranica from Eelood freshwater spring, Southern Iran. Crabs were haphazardly sampled from April 2012 to April 2013, on a bimonthly basis. Measurements of Gonado-Somatic Index (GSI), Hepato-Somatic Index (HSI), oocyte diameter, and other aspects such as carapace width (CW) and total body weight (TW) were made in the captured specimens. Results showed a single seasonal reproductive cycle. Maturation and spawning occurred from December 2012 to April 2013 during the study period. The peaks of HSI were observed in April 2012 and February 2013. The oocyte diameter showed its most significant increase between August 2012 and February 2013. Considering the single seasonal breeding of S. iranica, a correct management, during the reproductive cycle, is necessary to support a healthy stock of this crab.
[Comparison between Phyllophaga (Coleoptera: Melolonthidae) assemblages in Western Cuba]
The Cuban archipelago has 79 Phyllophaga species with a 98.6 % of endemism, which makes the group ecologically and economically important, as some species are classified as crop pests. The aim of this study was to determine the relationship between the composition and structure of the Phyllophaga assemblages with their habitat type, considering both plant structure and level of human habitat disturbance. A total of 17 locations were sampled in Western Cuba during the rainy seasons of the period from 2011 to 2015; these differed in habitat types (forests and agroecosystems). Samplings followed standard methods and were made once with a light trap screen in each locality. A total of 1153 individuals of 24 Phyllophaga species were collected. The total abundance of collected individuals varied between 10 and 306, and species richness between two and nine species. The most abundant species was Phyllophaga dissimilis (Chevrolat) which also had the highest frequency of occurrence. Generally, less anthropized sites reflected richer and equitative communities; although these characteristics appeared in two sites that showed intermediate degree of disturbance. The non-metric multidimensional scaling showed that the most similar samples were those of the very anthropized sites; this similarity was given mainly by the abundance of Phyllophaga dissimilis, P. insualepinorum and P. puberula. Besides, the geographical distance was not related to the similarity of these assemblages.
Galápagos macroalgae: A review of the state of ecological knowledge
Previous work has highlighted the critical role of macroalgal productivity and dynamics in supporting and structuring marine food webs. Spatio-temporal variability in macroalgae can alter coastal ecosystems, a relationship particularly visible along upwelling-influenced coastlines. As a result of its equatorial location and nutrient rich, upwelling-influenced waters, the Galápagos Archipelago in the East Pacific, hosts a productive and biodiverse marine ecosystem. Reports and collections of macroalgae date back to the Beagle voyage, and since then, more than three hundred species have been reported. However, their ecology and functional role in the ecosystem is not well understood. According to various disparate and in part anecdotal sources of information, abundant and diverse communities exist in the Western regions of the archipelago, the North is essentially barren, and in the central/South abundance and distribution is variable and less well defined. Both oceanographic conditions and herbivore influence have been theorized to cause this pattern. Extensive changes in macroalgal productivity and community composition have occurred during strong ENSO events, and subsequent declines in marine iguana (an endemic and iconic grazer) populations have been linked to these changes. Iguanas are only one species of a diverse and abundant group of marine grazers in the system, highlighting the potentially important role of macroalgal productivity in the marine food web. This review represents a first compilation and discussion of the available literature and presents topics for future research.
[Soil seed bank formation during early revegetation of areas affected by mining in a tropical rain forest of Chocó, Colombia]
Mining is one of the main economic activities in many tropical regions and is the cause of devastation of large areas of natural tropical forests. The knowledge of the regenerative potential of mining disturbed areas provides valuable information for their ecological restoration. The aim of this study was to evaluate the effect of age of abandonment of mines and their distance from the adjacent forest, on the formation of soil seed bank in abandoned mines in the San Juan, Chocó, Colombia. To do this, we determined the abundance and species composition of the soil seed bank, and the dynamics of seed rain in mines of different cessation period of mining activity (6 and 15 years), and at different distances from the adjacent forest matrix (50 and 100 m). Seed rain was composed by five species of plants with anemocorous dispersion, and was more abundant in the mine of 6 years than in the mine of 15 years. There were no significant differences in the number of seeds collected at 50 m and 100 m from the adjacent forest. The soil seed bank was represented by eight species: two with anemocorous dispersion (common among the seed rain species) and the rest with zoochorous dispersion. The abundance of seeds in the soil did not vary with the age of the mine, but was higher at close distances to the forest edge than far away. During the early revegetation, the formation of the soil seed bank in the mines seems to be related to their proximity to other disturbed areas, rather than their proximity to the adjacent forest or the cessation activity period of mines. Therefore, the establishment of artificial perches or the maintenance of isolated trees in the abandoned mines could favour the arrival of bird-dispersed seeds at mines. However, since the soil seed bank can be significantly affected by the high rainfall in the study area, more studies are needed to evaluate management actions to encourage soil seed bank formation in mines of high-rainfall environments in the Chocó region.
[Genotoxic evaluation of Río Grande (Antioquia, Colombia) water using micronucleus frequency in erythrocytes of Brycon henni (Characiformes: Characidae)]
The permanent monoculture of bananas and plantains farming in the middle of Río Grande (Turbo - Antioquia) requires the application of a variety of pesticides. Inappropriate banana production practices in this region, have often led to waterbody pollution by agrochemicals from leachate and runoff processes. Currently, fish are the most common vertebrates used as bioindicators of water quality, because they are very sensitive to the presence of contaminants. Our main goal with this study was to compare the frequency of micronucleated erythrocytes (MNE) in peripheral blood specimens of fish Brycon henni, from two locations (polluted and unpolluted) in the Rio Grande. We evaluated the frequency of MNE in peripheral blood samples of fish B. henni from each location during two rainy seasons in 2010 and two dry seasons in 2011. Blood samples were collected, fixed for 24 h, and then were stained with Giemsa. Among results, we found that the median frequency of MNE was higher in the polluted site by agrochemical discharges (0.15±0.18), than in the unimpacted site (0.06±0.08). Furthermore, the frequency of MNE in B. henni during the dry season was highly significant for both locations. The results of this study indicated that the analysis of MNE in B. henni could be recommended as a suitable method for in situ detection of environmental genotoxins.
[Basic biological parameters for Pseudocurimata lineopunctata (Characiformes, Curimatidae) conservation in the Anchicayá River of the Cauca Valley, Colombia]
Pseudocurimata lineopunctata represents an important nutritional source for local human communities in Colombia and Ecuador. Although the yearly catch of this fish is low (590 kg/year), there are no restrictions on minimum size, and this species is categorized as vulnerable with moderate extinction risk by the Regional Autonomous Corporation of the Cauca Valley (Colombia). To support conservation programs, biological data of the target species are required. Therefore, the aims of this study were to describe the sex ratio, distribution, size to weight ratio, macroscopic stages of reproductive maturity, fecundity, and size at first sexual maturity for P. lineopunctata. For this, fish samples were captured with nets over nine months (February-October) in 2007. The total length (Lt) of the captured fish ranged between 10.7 and 16.5 cm, with total weight (Pt) between 25.0 and 67.5 g. Females represented 52.6 % of the sample group while males represented 47.4 %, and differences in sex ratio were observed in relation to fish size. For all sampled months, the fish captured showed an advanced maturity state. Based on analyses of the gonadosomatic index (IGS), gonadic index (IG), and Fulton’s condition factor (K), and two spawning peaks were determined, one in June-July, and the other in September-October. The size at first sexual maturity was 9.2 cm for females and 10.1 cm for males. Absolute fecundity was estimated as 3 598 oocytes/g♀. It is necessary to carry out additional investigations on the reproduction of this species, to support future repopulation programs.
Reproductive pattern of the large fruit-eating bat, Artibeus amplus (Chiroptera: Phyllostomidae) in the Venezuelan Andes
Bimodal polyestry is the most common reproductive pattern in tropical bats, and it consists in producing one offspring per female twice a year. Reproductive patterns are closely related to rainfall regimes, frequently occurring twice a year in tropical regions. The goal of our study was to determine the reproductive pattern of the large fruit-eating bat, Artibeus amplus Handley, 1987 in a cave in the Venezuelan Andes inhabited by a large, stable colony. Thus, in this study we describe for the first time this important biological aspect of this unknown Neotropical bat species through the examination of external reproductive characteristics of males (inguinal or scrotal testes) and females (pregnant, lactating, post-lactating), based on 211 individuals (120 males and 91 females) captured between September 2008 and August 2009, in Cueva del Parque Las Escaleras, Estado Táchira, Venezuela. During this period of monthly sampling for a full year, most males displayed large scrotal testes, averaging 10 mm maximum length. The examination of females indicated that although pregnancy was first observed in November 2008, it reached a maximum during January and February 2009. Although adult males with scrotal testes throughout the year could imply that females have more than one pregnancy, our results suggested a seasonally monoestrous reproductive pattern for A. amplus. This study represents the first report of reproductive pattern for this poorly-known Neotropical frugivorous species. The observed monoestrous reproductive pattern supports the existence of synchronization between precipitation and reproduction. This synchronization has been frequently observed in most species of fruit bats. In this study, Artibeus amplus presumably adjust the parturition to anticipate the rainy season, as a strategy that allows maintenance of offspring during high availability of fruits.
Trypanosoma evansi (Kinetoplastida: Trypanosomatidae) in capybaras (Hydrochoerus hydrochaeris, Rodentia: Hydrochoeridae): prevalence, effect and sexual selection
Parasites play a crucial role in the ecology of animals. They also appear to be important in mechanisms underlying sexual selection processes. In this article we study the prevalence, effect and potential role in sexual selection of the protozoon Trypanosoma evansi in capybaras, Hydrochoerus hydrochaeris. We collected our samples from the annual capybara cull of a ranch in Venezuela, using the volume of the snout scent gland as an indicator of dominance; the residuals of body weight as indicators of condition; and the residuals of the spleen mass as indicators of immune function. Overall prevalence was 30.9% (N=97) with no difference between males and females and no relation between infection with T. evansi and condition. However, we found that infected animals had larger spleens (residuals), indicating an immunological cost of the infection. Further, males with larger snout scent glands (more dominant) were less likely to be infected than males with smaller glands (less dominant) suggesting that by choosing males with a large gland, females may be using the gland as an indicator of health, which is consistent with the “good genes” view of sexual selection.
[Leaf-litter breakdown as a tool to assess the functional integrity of high Andean streams of Southern Ecuador]
The ecological condition of tropical Andean rivers are threatened by many human activities including changes in land use and cover in watersheds. Current protocols diagnose the structural condition of streams but not their function. In this study we proposed an assessment tool using the leaf-litter breakdown as a measure of the functional condition and health of high Andean streams in Southern Ecuador, including methodology and threshold values adapted to local conditions. We selected 15 streams in three micro-basins (Mazán, Llaviuco and Matadero) within or in the vicinity of Cajas National Park where we deployed litterbags for 15, 28 and 64 days. We used two types of mesh (coarse and fine) for the litterbags in order to separate the contribution of macro-invertebrates and microorganisms in the decomposition process and also tested two different leaf substrates: Alder (Alnus acuminata) and Miconia (Miconia bracteolata). In each collection period we determined physical and chemical parameters, applied the riparian quality index (QBR-And) and river habitat index (IHF). Decomposition rates (-k) were determined from the time period at which approximately 50 % ash-free mass would have been lost. We used Ktotal and the ratio of the rate of decomposition between coarse and fine mesh (Kg/Kf) to define the functional condition thresholds. To test the metrics sensitivity we used graphical methods, one-way ANOVA and discriminative efficiency (ED). The analysis of watershed land-use and cover showed a gradient of intervention: Matadero ≥ Llaviuco > Mazán. The composition of the environmental variables of Mazán streams were different with respect to Llaviuco and Matadero, whose values were similar to each other. The QBR-And index showed a significant gradient from very low levels in Matadero (27.5), moderately high values in Llaviuco (66.5) to high values in Mazán (87). Alder leaf-litter breakdown rates were significantly faster in Mazán than in Matadero and Llaviuco streams, while breakdown rates of Miconia were not significantly different among watersheds. The Kg/Kf ratio was significantly higher in Mazán compared to Llaviuco and Matadero, which did not differ. We consider the Kg/Kf metric sensitive enough to discriminate impacts in the studied areas. Our results support the use of the leaf-litter breakdown as an appropriate tool to assess functional ecological condition, complementing the structural assessments of these Andean rivers.
[Economic potential of ornamental fish catching under federal protection in Mexico.]
Ornamental fisheries are economically viable activities in developing countries due to the fact that aquaria have become a worldwide hobby. In Mexico, the fishery has been conducted since the 1980s, especially in the Baja California Peninsula, but nevertheless, there are no adequate records of commercial production, or about the economic gain due to the exploitation of the resource. The objective of this paper was to calculate the maximum allowable catch for the five ornamental fishes included in the NOM-059-SEMARNAT (protected by federal mandate), and the net monetary gain that the resource might generate. Censuses (N=1 610) were conducted in 21 reef sites of the Mexican Pacific and Gulf of California in order to estimate population density of each taxon; also, natural mortality rate (M) was calculated from maximum size (L∞), individual growth rate (k) and temperature (C), and the total allowable catch was estimated on the basis of M. Finally, considering the prices of the species paid to fishermen at the beach, an estimation of the economic value of a single fishing season for an area of 220 hectares (representative of the catch area assigned in average to a cooperative in Mexico) was produced. The results indicated that the areas with the best economic potential were Encantadas Islands, Los Angeles Bay, and San Lorenzo Archipelago (all in the state of Baja California). Outside of the gulf (where no legal ornamental fisheries exist) the potentially more rentable locations were Marietas Islands (Jalisco), and the Revillagigedo Islands. Aquarium fisheries may be a viable activity in several of the analyzed areas of the country, however, the potential gain that harvest represents is not enough to fully sustain an organized group that would perform it; for that reason the ornamental fishery should be seen as an alternative commercial activity. Finally, to guarantee this activity to be a rentable and sustainable fishery, we recommended that, the existing rules defined by the Mexican federal government should be applied to control the catch quotas.
Estimation of genetic variation in closely related cycad species in Ceratozamia (Zamiaceae: Cycadales) using RAPDs markers
The Ceratozamia norstogii complex from Southern Mexico is made up of four closely related taxa and occurs in similar habitats (Quercus forest). All have linear-lanceolate leaflets with great similarity between them, especially in juvenile stages, but differentiate with age. There has been debate regarding delimitation of species due to character loss in herbarium specimens. The aim of this study was to determine the genetic variation, and to measure genetic similarity between the four taxa. We studied populations in Cintalapa (Chiapas) for C. alvarezii and C. norstogii; the Sierra Atravesada (Oaxaca) for C. chimalapensis, and Villa Flores (Chiapas) for C. mirandae. One population for each taxon was sampled (only one population is known for C. alvarezii) 11-15 randomly chosen adult individuals were sampled. Twenty-eight primers were tested of which five were polymorphic using the RAPD’S technique. The data were analyzed using Bayesian methods. Results revealed low genetic diversity, and a differentiation was found between species, suggesting a recent divergence. A previous morphological and anatomical study on the complex has found the taxa to be distinct. However, the results of this study have shown that the C. norstogii species complex is in a divergence process, probably through genetic drift and founder effects.
[Spatial and temporal abundance and distribution of Stomolophus meleagris (Rhizostomae: Stomolophidae) in a lagoon system southern Gulf of Mexico]
The scyphomedusae feed mainly on microscopic crustaceans, eggs and fish larvae, molluscs and some other jellyfishes. The distribution and abundance of the scyphomedusae has an economic and ecological impact as they are predators that have an influence on the population dynamics of other fisheries. This investigation took place in the lagoon system ‘Arrastradero-Redonda’, Tabasco, from September 2013 to August 2014, with the purpose to provide information on the distribution, and spatial and temporal abundance of Stomolophus meleagris; along with its relation to environmental parameters. A total of 10 stations were defined and biological samples were taken on a monthly basis during this annual cycle. For this purpose, three pulls with a beach seine monofilament (20m long by 3m height, mesh opening 1.5 cm, 5 to 10 minutes) per station were made within a 1 km2 area. Information obtained was used to calculate the fishing efficiency analysis (CPUE con org./Evaluated Area Unit) and to determine the relationship with the environmental parameters. Our results showed that the abundance in the stations 1 to 3 was from 7 to 19 org./km2 from April to August 2014; less organisms were observed in stations 6 to 10 (an average of 1 org./km2) from October 2013 to March 2014. The multiple correlation steps analysis indicated that there is a strong association between the CPUE and some environmental investigated variables, and a 70.9 % variability of the data was observed. The salinity resulted the most important variable because it determined a 64.3 % of variation; it was followed by the temperature with a 3.6 %; meanwhile, dissolved oxygen explained only the 2.9 %, this was mainly because within the area there are several geological, oceanographic and biological factors that favor the distribution of this species due to seawater contribution through the Tupilco bar. With the provided data with this investigation we were able to determine the fishery potential of this resource for Tabasco state. However, additional research is required to allow an extended quantification of this resource, to determine the commercial exploitation areas, and drive studies about reproductive and feeding habits, that may provide the necessary information to establish plans for sustainable use.
Assessment of populations in a transect of in Punta Galeta, Panamá: culture-dependent analyses reveal biotechnological applications
is considered an ecological niche for microorganisms with potentially novel and complex degrading enzymes.