Revista de Biología Tropical

The role of neophobia in a pioneer olfactory enrichment for amazons, macaws, and toucans

Carmen Hernández — 2024-01-23

Introduction: Despite sensory enrichment being critical for ensuring the well–being of captive wild animals, smells are not being included in enrichment protocols for birds. For this group, neophobia can be a problem when it comes to implementing new enrichment devices. Objective: To explore how participation in an olfactory enrichment and latency times varies between bird taxonomic groups (Amazona spp. / Ara spp. / Ramphastos spp.). Methods: We exposed 257 birds to a scent enrichment, and we recorded which individuals engaged with it and the time they took to interact with it. Results: We discovered that participation by toucans in the enrichment was higher compared to amazons and macaws. Furthermore, latency time to interact with the enrichment was higher in amazons that in the other species. Our findings could suggest that toucans are neophilic species which could benefit from higher exploration rates. Amazons on the contrary seem to be particularly neophobic, possibly because of their less opportunistic feeding habits compared to toucans and their higher vulnerability to predation compared to macaws. Conclusion: These results point out that toucans would be more inclined to engage in environmental enrichments, while a more natural design using smells inside familiar objects could be a more successful enrichment for psittacids

Digestive proteases of Morelet’s crocodile (Crocodylus moreletii) in three life stages

Manuel Alejandro Castillo-Rodríguez — 2024-04-16

Introduction: Morelet’s crocodile (Crocodylus moreletii) is a species distributed in the Mexican southeast and threatened due to multiple pressures. Objective: To characterize the digestive proteases in the acid phase (stomach) and alkaline phase (intestine) of three life stages of C. moreletii in captivity (hatchling, juvenile, and adult). Methods: Total alkaline and acid protease activities were quantified using casein and haemoglobin as substrates. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were quantified using synthetic substrates. Protease profiles were analysed by SDS-PAGE and Native-PAGE. Results: The specific activity of acid and alkaline proteases showed differences between the three stages, finding the highest activity in the juveniles. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were higher in hatchlings. There were differences in optimum pH and temperature of acid and alkaline proteases, trypsin, and leucine aminopeptidase between the three stages, demonstrating the diversification of the enzymes according to different stages, as well as the presence of specific isoforms in each stage of C. moreletii. The acid phase zymogram showed four bands with pepsin-like acid activity in the hatchling and juvenile crocodile, while in the adult only two of the four bands were detected. The alkaline zymogram showed that the hatchling had the highest number of activity bands compared to the other stages, corresponding to the high specific activity reported in the alkaline phase. Conclusions: Digestive proteases of Morelet’s crocodile differ in their biochemical characteristics and the number of proteases between hatchling, juvenile, and adult. This could help in the future design of balanced diets as well to the sustainable management and production of this species.

Phylogenetic relationships of the Mangrove Hummingbird, “Amazilia” boucardi (Apodiformes: Trochilidae) of Costa Rica

Federico J. Albertazzi — 2024-01-29

Introduction: A recent revision of the generic classification of the Trochilidae based on DNA sequences revealed many inconsistencies with the current generic classification, largely based on plumage characters subject to homoplasy, especially in the Trochilini, the largest tribe. A thorough generic reorganization brought the classification into accord with the phylogeny, but due to lack of genetic data, two species remained unclassified. One of these was the Mangrove Hummingbird, “Amazilia” boucardi, endemic to Costa Rica and included in the IUCN red list of threatened species. Objective: To obtain molecular evidence to clarify the generic relationships of “A.” boucardi. Methods: We isolated DNA from tissues of this species and amplified 4 nuclear and 4 mitochondrial fragments and compared these with homologous fragments from 56 species in the Trochilini, constructing phylogenetic trees with maximum likelihood and Bayesian methods. Results: Our phylogenetic analyses confirmed the placement of boucardi in the Trochilini and definitely excluded it from Amazilia but placed it with high confidence in the genus Chrysuronia Bonaparte, 1850, within which its closest relative is C. coeruleogularis, which also inhabits mangroves. Conclusions: Our genetic data based on nuclear and mitochondrial regions clearly indicate the relationship of A. boucardi and L. coeruleogularis. Moreover, it is also support by their habitat distribution in the mangroves of the Pacific coast of Costa Rica and Western Panama. Therefore, we suggested to exclude A. boucardi as "incertae sedis".

Species distribution models and conservation status of threatened bats in the Tumbesian region of Ecuador and Perú

Carlos Avila — 2024-01-29

Introduction: Biodiversity is being lost at an accelerating rate because of global change. Tools such as species distribution models (SDMs) have been widely used to improve knowledge about species’ conservation status and help develop management strategies to mitigate biodiversity loss. SDMs are especially important for species with restricted distributions, such as endemic species. Objective: To determine how potential distribution predicted by SDMs for eight threatened bat species differed from the distribution maps reported by the IUCN. Also, to infer the area of distribution and state of endemism of each specie, and to evaluate the importance of the Tumbesian region for their conservation. Methods: Based on presence records across the species' entire ranges, we used SDMs to assess the conservation status of these eight species in the Tumbesian region of Ecuador and Peru. Results: The areas estimated by SDMs were 35-78 % smaller for four species (Eptesicus innoxius, Lophostoma occidentale, Platalina genovensium and Lonchophylla hesperia) and 26-1 600 % larger for three species (Amorphochilus schnablii, Promops davisoni and Rhogeessa velilla) than those reported by the IUCN. For Tomopeas ravus, the area estimated by the SDM and IUCN was similar but differed in spatial distribution. SDMs coincided with areas of endemism reported by previous authors for E. innoxius, R. velilla, and T. ravus, but were different for A. schnablii, P. genovensium, P. davisoni, and L. hesperia, due in part to projected distributions for these latter species in dry inter-Andean valleys according to the SDMs. Conclusions: The region represents a significant portion (40-96 %) of the predicted distribution of seven of the eight species studied, underscoring the importance of this region for bat conservation. Our results show likely distributions for these species and provide an important basis for identifying research gaps and developing conservation measures for threatened bats in the Tumbes biodiversity hotspot.

Environmental sympatry through time: spatio-temporal distribution and conservation status of two sympatric anuran species (Leptodactylidae) in South America

Rebeca Acosta — 2024-01-29

Introduction: Leptodactylus latinasus and Physalaemus cuqui are sympatric anuran species with similar environmental requirements and contrasting reproductive modes. Climatic configuration determines distribution patterns and promotes sympatry of environmental niches, but specificity/selectivity determines the success of reproductive modes. Species distribution models (SDM) are a valuable tool to predict spatio-temporal distributions based on the extrapolation of environmental predictors. Objectives: To determine the spatio-temporal distribution of environmental niches and assess whether the protected areas of the World Database of Protected Areas (WDPA) allow the conservation of these species in the current scenario and future. Methods: We applied different algorithms to predict the distribution and spatio-temporal overlap of environmental niches of L. latinasus and P. cuqui within South America in the last glacial maximum (LGM), middle-Holocene, current and future scenarios. We assess the conservation status of both species with the WDPA conservation units. Results: All applied algorithms showed high performance for both species (X̅_TSS = 0.87, X̅_AUC = 0.95). The L. latinasus predictions showed wide environmental niches from LGM to the current scenario (49 % stable niches, 37 % gained niches, and 13 % lost niches), suggesting historical fidelity to stable climatic-environmental regions. In the current-future transition, L. latinasus would increase the number of stable (70 %) and lost (20 %) niches, suggesting fidelity to lowland regions and a possible trend toward microendemism. P. cuqui loses environmental niches from the LGM to the current scenario (25 %) and in the current-future transition (63 %), increasing the environmental sympathy between both species; 31 % spatial overlap in the current scenario and 70 % in the future. Conclusion: Extreme drought events and rainfall variations, derived from climate change, suggest the loss of environmental niches for these species that are not currently threatened but are not adequately protected by conservation units. The loss of environmental niches increases spatial sympatry which represents a new challenge for anurans and the conservation of their populations.

Spatial and temporal dynamics of the primate community in a regenerating forest of the Manu Biosphere Reserve, Peru

Jackeline Aida Mendoza-Soto — 2024-04-16

Introduction: Amazonian forests with varying degrees of anthropogenic disturbance in the process of natural regeneration harbour many sympatric primate species. However, studies on their usage by primates are still lacking. Objective: To comprehensively study the spatial and temporal dynamics within the primate community in a regenerating forest within the Manu Biosphere Reserve. Methods: Two sets of historical data from Crees Foundation for Manu were analyzed, comprising records from January 2011 to February 2023 and corresponding to data obtained through incidental data and Terrestrial In-line Transects in three types of forest with different degrees of historical disturbance. Results: Lagothrix lagothricha and Ateles chamek showed a preference for less disturbed forests; Plecturocebus toppini, for more disturbed forests; and the other species did not show a clear preference. Regarding vertical stratification, A. chamek, L. lagothricha and Alouatta sara showed a preference for the upper stratum, P. toppini, Saimiri boliviensis and Sapajus macrocephalus showed a preference for the middle and upper strata and Leontocebus weddelli and Aotus nigriceps, for the middle stratum. According to the temporal activity of each species, seven species (A. chamek, S. macrocephalus, S. boliviensis, P. toppini, L. lagothricha, L. weddelli, and A. sara) were observed during the day, four were similar. Conclusions: The primate community varies according to disturbance gradient due to the preferences of some species. The recorded primates make a differentiated use of the vertical strata and most of them show diurnal activity.

Sustainability of dual exploitation (fry and adults) of the fish Semaprochilodus laticeps (Characiformes: Prochilodontidae) in Colombia

Joan Stiven Bocanegra-Mora — 2024-04-16

Introduction: Semaprochilodus laticeps is a freshwater fish species native to the Orinoco Basin that is exploited in Colombia at two different stages of its life cycle: fry (for the ornamental trade) and adults (for the consumer market). This double exploitation of juveniles and adults raises concerns about the population stability of the species. Objective: To evaluate the sustainability of the exploitation of the species in these two life stages. Methods: 1 277 specimens of S. laticeps were sampled between June and December 2017. Population parameters were estimated from length-frequency data using ELEFAN 1 routine of the FISAT II package. Length at first maturity (Lm) and length at maximum yield (Lopt) were determined using the Froese and Binohlan equations. Virtual population analysis was performed based on Jones length cohort analysis. Results: Population parameters were as follows: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 yr-1, M = 1.24 yr-1 and F = 1.68. Lm was estimated to be 29.6 cm SL and Lopt at 33.4 cm SL. Of note, 96.3 % of the fish caught in the consumer fishery exceeded Lm and 80 % exceeded Lopt. The results of the virtual population analysis suggested that a very low proportion (0.85 %) of the population was caught as fry, possibly due to natural mortality. Conclusions: Based on the results, as no indicators of overexploitation were identified, it is recommended to continue with the dual use of S. laticeps. It is recommended to maintain the existing conservation measures, such as the closed season during the reproductive period, to ensure sustainable fishery exploitation. The results obtained can serve as a reference to analyze the situation of other species currently fished for both the ornamental (fry) and food (adult) markets.

Spatio-temporal variation in the diversity of Geadephaga beetles (Coleoptera: Carabidae, Cicindelidae), in the tropical dry forest of the Colombian Caribbean

José Daniel Sarmiento-Roa — 2024-01-23

Introduction: The use of arthropods in ecological studies in the tropical dry forest (TDF) of Colombia focused mainly on spiders, butterflies, ants, and dung beetles; therefore, it is necessary to understand the seasonal dynamics of the other groups such as Geadephaga in this ecosystem. Objective: To evaluate the spatiotemporal variations and the effect of environmental conditions on the diversity of the Geadephaga communities in two TDF fragments in the Colombian Caribbean. Methods: This study was conducted during four sampling events between February and June 2018, each lasting four days, and four nights. Four sampling stations were selected in each locality (Reserva Campesina La Montaña = RCM and Reserva La Flecha = RLF), separated 350 m one from another, with square plots of 50 × 50 m. A light trap was installed in the center of each square, while pitfall traps were installed in the four vertices, and manual capture, beating sheets and leaf litter sieve were carried out. Results: A total of 348 Carabidae and 114 of Cicindelidae were captured. In both fragments, the richness and abundance presented the lowest values in dry season, while the highest values were observed during the rainy season. Tetracha affinis (Dejean, 1825) was the most abundant species in RCM during rainy season. Conclusions: The richness variation and abundance of Geadephaga corresponds to a seasonal pattern at both locations. A high dissimilarity between the communities of Geadephaga from the two fragments was found, despite having similar environmental conditions.

Precipitation explains Wood Thrush (Hylocichla mustelina) occupancy patterns in Northern Costa Rica

Natalie Viviana Sánchez — 2024-02-29

Introduction: The Wood Thrush is a migratory bird that has experienced dramatic declines in its populations in recent decades. This species overwinters in forest fragments with intermediate levels of habitat modification in Central America. However, more studies detailing the use of remnant forests through time are needed to elucidate the threats this species faces in the wintering grounds.

Objective: To understand the effects of environmental and forest structure variables on the occupancy of Wood Thrush in Northern Costa Rica.

Methods: The study area was the Área de Conservación Guanacaste (ACG), located in Northern Costa Rica, in December 2016, and during the 2018-2019 migration season. We estimated Wood Thrush occupancy and detection probability in four locations of ACG (dry forest, cloud forest, and two locations in the wet forest) using single-season occupancy models. We also estimated Wood Thrush occupancy and probability of persistence in different months in three vegetation types (open area, secondary forest, and old-growth forest) in the wet forest of ACG using a multi-season occupancy model approach.

Results: Wood Thrush occupancy was best described by precipitation in the four locations of the ACG; the probability of occupancy increased with precipitation. The average occupancy of Wood Thrushes varied with vegetation type: open area with shrubs and forest edge (0.69 ± 0.09), secondary forest (0.46 ± 0.1), and old-growth forest (0.61 ± 0.1). Wood Thrush probability of persistence responded partially to changes in precipitation, with an unexpected increase in persistence when the rainfall continued decreasing in the season.

Conclusion: Wood Thrush occupancy was best predicted by changes in precipitation considering a larger spatial scale. Its probability of persistence partially varied with precipitation. An increase in persistence closer to Spring migration might be explained by the start of the breeding season of resident birds, potentially reducing territorial conflicts and conserving energy before migration. The long-term protection of wet forests in Northern Costa Rica is of paramount importance for the conservation of Wood Thrushes in their wintering grounds.

Methanogenesis in sediments of a tropical coastal wetland: a culture-dependent method

María del Rocío Torres-Alvarado — 2024-04-16

Introduction: Methanogenic archaea (MA), participate in the anaerobic mineralization of organic matter in mangrove sediments, their activity is related to atmospheric warming due to the production of methane; several environmental variables can influence the presence of MA and methane production in these sediments. Objective: To analyze, through culture-dependent techniques, viable methanogenic archaea (VMA) in the sediments, and the production of methane from acetate in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico. Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (N = 9). VMA in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates. The influence of sulfate on methane production was analyzed from acetate in microcosm by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content, and carbonates in the sediments were evaluated. Results: The abundance of VMA was 10² to 10⁸ MPN/g of wet sediment, higher than that reported in other studies, this abundance was higher when methanol (10⁴-10⁸ MPN/g sediment) was used as substrate, compared to acetate (10²-10⁵ MPN/g sediment); methane production in the microcosms increased in sulfate-free conditions (29.78-929.75 nmol CH₄/month) and in the sediments of the rainy season. Conclusion: The influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics is highlighted, determining that in the rainy season, the decrease in salinity, more electronegative Eh, and the increase in organic fractions favored the methanogenesis.

Objetive: To analyze, through culture-dependent techniques, the abundance of MA and the production of methane in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico.

Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three sampling locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (n=9). The methanogenic abundance in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates; methane production was analyzed from acetate by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content and carbonates in the sediments were evaluated.

Results: The abundance of MA was 10² to 10⁸ cells/g of wet sediment, higher to that reported in other studies, this abundance was higher when methanol (10⁴ - 10⁸ cells/g sediment) was used as substrate, compared to acetate (10² - 10⁵ cells/sediment); methane production increased in rains with 13% compared to dry.

Conclusion: Highlighted the influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics, determining that in the rainy season, the decrease in salinity, Eh more electronegative and the increase in organic fractions favored both methanogenic abundance as methane production.

Spatio-temporal composition of aquatic birds community in Juluapan Lagoon, Colima, Mexican Central Pacific

Yareni Saharai Pablo-López — 2024-01-23

Introduction: Aquatic birds (AB) are usually associated with wetlands, which provide refuge, food, and/or nesting sites for resident and migratory species. Despite their ecological importance, there is little knowledge on AB in some tropical environments, such as those found on the Colima coast. Objective: To investigate the spatial and temporal composition of the AB community in Juluapan Lagoon, Colima, Central Mexican Pacific. Methods: Monthly counts were conducted between June 2017 and May 2018 during low-tide conditions to record habitat use by AB. Species richness and bird counts were obtained to compare sampling areas; mean richness and number of individuals were compared between seasons. Results: We detected 53 species and 5 750 individuals. The highest species richness and relative abundance values were obtained in winter at the lagoon area farthest from the connection with the marine system, where anthropogenic activity is lower. Diversity was greater in zones 2 and 3 in spring, summer, and fall. Muddy flats were the most used environment, and the most frequent activity was resting. Nesting activity was only recorded in the middle of the lagoon at the mangrove during spring. Shorebirds and waders were the most dominant groups in the bird community of the Juluapan lagoon. Conclusions: This coastal wetland is a site of great biological importance for aquatic birds; thus, conservation measures should be implemented, and there should be a continuous study of the effects of anthropogenic pressure.

Correlation Abundance Networks for analyzing biological interactions during cyanobacterial blooms

Verónica Laura Lozano — 2024-04-03

Introduction: Cyanobacterial blooms are becoming increasingly common, and understanding their dynamics can be crucial for proposing appropriate management strategies. While the physical and chemical parameters influence on blooms have been extensively studied, less attention has been put on the susceptibility of the biological communities. Objective: The purpose of this study was to analyze the phytoplankton abundance networks during blooms at different levels of intensity and how bloom-forming cyanobacteria interact with and/or impact phytoplankton community. Methods: We used 22 samplings conducted in the same reservoir located in northern Argentina, which is known for recurrent cyanobacterial blooms. Each sampling was classified into four levels based on the abundance of cyanobacteria. For each level, abundances correlation networks were constructed considering all species. Results: A pattern of decreasing statistically significant abundance correlations was observed as the intensity of the blooms increased: 219 correlations at level 1; 144 at level 2; 80 at level 3, and only 33 at level 4. Bloom-forming cyanobacteria showed to be little correlated with others species in all the levels, which could be associated to certain independence with the community. Increased bloom seems to disconnect the phytoplanktonic correlation abundances network. Conclusion: Analyzing correlation abundances networks should be a valuable tool for understanding the dynamics and development of cyanobacterial blooms, as well as identifying key species in this process.

Diversity of Leptohyphidae (Ephemeroptera) nymphs in the Quenane-Quenanito river, Colombian plain foothills

Sara Velásquez-López — 2024-02-06

Introduction: Various anthropic pressures affect the aquatic ecosystems of the foothills of Colombia. The response to environmental stressors is still unknown in bioindicator organisms such as Leptohyphidae. Objective: To determine the diversity of Leptohyphidae nymphs of the Quenane-Quenanito river, in two contrasting hydrological periods and its relationship with some physicochemical variables. Methods: In December (2014) and February (2015), organisms were collected with a Surber net at six stations along the current. Alpha and beta diversity was analyzed and redundancy analysis and generalized linear model were applied to establish the relationship between taxa and environmental variables. Results: Were identified 369 organisms belonging to four genera (Amanahyphes, Traverhyphes, Tricorythopsis, and Tricorythodes), two species, and eight morphospecies. Amanahyphes saguassu is reported for the first time for the Meta department. High diversity of Leptohyphidae nymphs was recorded in the transition to drought season and greater abundance in drought. Beta diversity indicated that the configuration of the assemblage changes spatially and temporally. Conclusions: Leptohyphidae organisms prefer fast habitats, particularly in the dry period where they find food (leaf litter, detritus) and shelter to establish themselves successfully; anthropic activities such as urbanization notably affect diversity. The high diversity recorded in this small stream in the foothills of the plains reflects the need to increase this type of works and collection efforts of study material in the region.

Geographical distribution model of the fish Coryphaena hippurus (Perciformes: Coryphaenidae) according to climate change in the Pacific Oriental Tropical

Estefania Isaza-Toro — 2024-04-16

Introduction: Coryphaena hippurus is a species of commercial interest with a high migratory capacity, a characteristic that places it in tropical and subtropical environments, preferring areas with a temperature range between 21 and 30 °C and salinity close to 31 ppt. Although the population trend of C. hippurus is stable, the fishing of this resource is increasing and occupies important positions in the economy of the Eastern Tropical Pacific coastal countries, which demonstrates the need to design and strengthen conservation strategies for the adequate use of this resource. Given its location in tropical and subtropical environments, its availability and distribution could be affected by climate change. Objective: To analyze the current and future potential distribution of C. hippurus under climate change scenarios. Methods: Ten algorithms were used to model the potential distribution and current habitat suitability index of C. hippurus as a function of sea surface temperature, current salinity and velocity, and these results were then projected under the most extreme climate change scenario. Results: There were good performances with all the algorithms used, but the model generated with BIOCLIM (AUC: 0.89) was chosen because it also solves the problem of spatial and temporal bias found in the records of the species. The region of greatest habitat suitability for C. hippurus matches the oceanic fronts of the Eastern Tropical Pacific. Under future conditions of extreme climate change, the species distribution pattern indicates a contraction, relocation, and expansion of habitat south of the equator. Conclusions: Under conditions of extreme climate change, the distribution model for C. hippurus suggests a process of topicalization of marine ecosystems in the Eastern Tropical Pacific by 2100.

Impact of Collared Peccaries Dycotiles tajacu (Artiodactyla: Tayassuidae) on understory vegetation in the tropical rainforest of the Nogal-La Selva Biological Corridor, Costa Rica

Marco Herminio Osorto Nuñez — 2024-02-29

Introduction: Evidence suggests that herbivores, such as peccaries, shape vegetation structure and diversity through predation, trampling, dispersal, and rooting behavior. Objective: To evaluate the impact of peccaries (Dycotiles tajacu) on the understory vegetation of the tropical rainforest in the Nogal-La Selva Local Biological Corridor, Costa Rica, comparing a site with the absence of peccaries to another with the presence of these animals. Methodology: From June to November 2021, 20 experimental exclusions and 20 free access plots, each measuring 2 m² were used to quantify herbivory, the number of leaf blades, damaged leaves, healthy leaves, sapling height, and fallen biomass at both sites. Results: A higher sapling density was found in the Nogal Reserve, but a lower sapling diversity, while in La Selva there was a higher sapling diversity, but a lower density of seedlings. Herbivory and sapling height in La Selva exceeded those in Nogal. The exclusion of peccaries reduced seedling damage but did not affect the dynamics of fallen biomass. Conclusion: For the design, implementation, and evaluation of the effectiveness of biological corridors, it is crucial to consider plant-animal interactions to enhance the flow of ecological processes through functional and structural connectivity, analyzed from interactions such as those presented in this paper.

Unveiling activity patterns of the deer Odocoileus virginianus (Artiodactyla: Cervidae) and its predators in Mexico's Arid Region

Fernando Plata Pérez — 2024-04-09

Introduction: Size, predator presence, and habitat nutritional quality influence herbivorous species' activity patterns and resource utilization. Objectives: This study aims to determine the relative abundance and activity patterns of white-tailed deer (Odocoileus virginianus) and their main predators.

Methods: The study was conducted in the WMU "Bienes Comunales Santa Cruz Nuevo" in Totoltepec de Guerrero, Puebla, Mexico. Twenty-two quadrants were randomly selected, and camera traps were installed. Over a two-year period (2018-2020), wildlife visits were recorded to estimate the relative abundance index (RAI), activity patterns, and overlap coefficient (Dhat1) of white-tailed deer and their predators based on their activity schedule.

Results: The estimated RAI for deer was 7.2%, while it was 3.4% for coyotes (Canis latrans), 2.3% for bobcats (Lynx rufus), and 0.14% for pumas (Puma concolor). White-tailed deer were observed in 31% of the camera traps, while coyotes were captured in 68% of them. The overlap of the activity schedule, Dhat1, between deer and coyotes was 0.18. In contrast, the activity overlap between foxes and deer was higher (Dhat1: 0.2979; EE 0.037) based on the analysis of variance. The activity pattern of coyotes indicated they were crepuscular, with increased activity during the afternoon and night. However, an increase in activity synchronized with deer's patterns was also observed. The bobcat coincided with deer in 10% of the cameras, but due to the limited number of observations, it was not possible to estimate the activity overlap between these species.

Conclusions: The activity overlap between white-tailed deer and foxes is more significant than that of deer and coyotes in this region. The activity overlap between deer and coyotes is lower compared to other parts of the world.

Production and germination of acorns from the Andean oak Quercus humboldtii (Fagaceae) affected by recurrent fires

Maurico Aguilar-Garavito — 2024-04-16

In recent decades, changes in use and increased wildfires have led to the disappearance of 60% of the surface area of Colombia's Andean forests and their increasing fragmentation. Among these forests are Quercus humboldtii oak forests, the only South American Fagaceae species of high socioeconomic and biodiversity interest. The reproductive response of this species will condition its regeneration capacity and the persistence of the oak forests. However, our knowledge of the effect of fire on the production and germination of acorns in Q. humboldtii is incipient. Objective: To evaluate the production and germination of Q. humboldtii acorns in oak forests affected by recurrent wildfires. Methods: We monitored acorn production and germination in Q. humboldtii trees from fire and non-fire-affected forests (central Colombia Andes, Boyacá, Iguaque massif) for fourteen months. We also evaluated fire incidence, tree size, precipitation, temperature and other site characteristics. Results: Acorn production began 34 months after the fire. In burned oaks, the production of incompletely developed acorns (abortions) was almost nine times higher than that of mature acorns. In addition, Oaks with larger scar areas or many scars were more likely to produce aborts. Conversely, oaks of larger size, especially in the crown, tend to produce more acorns. The few mature acorns from burned trees had smaller sizes and lower germination rates than unburned trees and the literature. The unburned trees in this study did not produce mature acorns, but abortion production is ten times lower than in the burned trees. Therefore, it is feasible that Q. humboldtii presents masting, and the unburned trees are in a low production cycle. Conclusions: Fire, tree size, and masting control acorn production in Iguaque oak forests, , which could affect the recruitment of the species due to a possible limitation in the source.

Elaeis guineensis (Arecaceae) residue as a fuel sorbent for passive application in fire-fighting engineering

Hazel Aragón — 2024-02-14

Introduction: Spills of flammable liquids can lead to serious accidents, mainly in industrial plants and on roads. To prevent the spread of spills, various forms of collection are used, such as absorption with porous solids. Agroindustrial waste can be used as sorbent materials for flammable liquids. Objective: To determine the sorption capacity of the residual empty-fruit bunch of oil-palm (Elaeis guineensis) and the macaw palm (Acrocomia sp.) nutshell for four organic flammable liquids. Methods: The residual biomasses of E. guineensis and Acrocomia sp. were assessed as sorbents for spilled fuels (diesel, jet fuel, commercial kerosene, and gasoline). Volumetric measurement of liquid-fuel absorption at 24 ºC was taken during a week. Desorption was measured at 50 ºC as the drying kinetics, by using moisture scales. Results: The sorption capacity of the Acrocomia sp. material was not satisfactory, compared to the E. guineensis residual material, due to differences in the residual architecture of the organic material. This last can absorb 2.4 ± 0.2 cm³ g^-1 at 24 ºC, during a one-week period. Diatomite absorbs greater quantities of the organic liquids but, the fluids diffusion at 50 ºC is 0.26 ± 0.09 times more slowly in the mineral matrix, because of the greater pore tortuosity in this mineral matrix. Conclusions: The oil-palm empty fruit bunch of E. guineensis, showed lesser but adequate performance than the sorbing behavior for fire hazard mitigation of diatomite. The nutshell of macaw palm (Acrocomia sp.) did not prove to be useful for this recovery operation.

Genotypic dynamics and dispersion in Colombian biomes of kdr mutations associated with resistance to pyrethroids in the Aedes aegypti mosquito (Diptera: Culicidae)

Oscar Alexander Aguirre-Obando — 2024-04-16

Introduction: In Colombia, Aedes aegypti is present in 80 % of the country and little is known about the kdr mutations related to pyrethroids (PY) resistance, as well as the influence of different biomes (mainly temperature) and passive ground delivery transport on maintaining and disseminating populations with these mutations. Objective: To model the behavior of genotypic frequencies associated with the kdr Val1016Ile + Phe1534Cys mutation in A. aegypti populations, considering vector population movement between Colombian biomes through passive ground delivery transport. Method: We obtained data from the literature regarding population dynamics, mosquito life cycle parameters associated with temperatures for each Colombian biome, and ground cargo transportation, including truck transport. We also evaluated the impact of the evolutionary cost for the kdr Val1016Ile and Phe1534Cys mutations on oviposition and death rates. Results: Population behavior is influenced by the evolutionary cost of resistant genotypes and passive cargo transport. Once resistant genotypes arrive in a biome through truck-mediated mosquito transport, they persist. Conclusion: Passive migration through land cargo transport is essential for the dissemination of individual resistance carriers between different regions or biomes. Evolutionary cost plays a critical role in the dynamics of kdr mutations in A. aegypti populations.

A new vector emerges? Aedes vittatus mosquito (Diptera: Culicidae): habitat and current and future potential global geographic invasion

Oscar Alexander Aguirre Obando — 2024-01-04

Introduction: The Aedes vittatus mosquito is an important vector of yellow fever in Africa, with vectorial competence for dengue, chikungunya and Zika. Its presence has been reported in some places in Africa, Asia, Europe and – recently – America. However, such information is scattered and with little description of the characteristics of the areas where it inhabits. Objective: Therefore, the aim was to compile records of its occurrence, describe the ecological characteristics of its habitat and estimate its current and future potential global invasion. Methods: A dataset was formed with the first records and global records of the mosquito, which were the basis for describing the habitat of the areas where it is found and together with layers of bioclimatic variables were implemented to estimate, through an ecological niche model (ENM), the areas of potential invasion using the MaxEnt algorithm. Since the native range of A. vittatus is unknown, two hypotheses were proposed for the calibration of accessible áreas, Africa and Asia, based on the genetic information available so far. Results: It is suggested that, regardless of its native area, A. vittatus is currently distributed in all continents in both tropical and subtropical zones, where at higher emissions and high time periods, it could expand into subtropical climates colonizing colder climates. Conclusions: It is estimated that the mosquito can be found on all continents at altitudes between 0 – 2500 m and at temperatures between 15 – 30 °C, being found mainly in tropical coverages and in urban areas being favored probably by transcontinental and terrestrial passive transport networks allowing the invasion of new locations.

The influence of age on the phenolic contents and lignins of Gmelina arborea (Lamiaceae)

Jose Bernal Azofeifa Bolaños — 2024-01-19

Introduction: Melina (Gmelina arborea) is a tree species of great interest for its wood and medicinal properties. In Costa Rica, there are genetically superior clones that are propagated without knowledge of the ontogenic and physiological age of the materials.

Objective: To evaluate how age influences the content of phenols and lignins in leaves, petioles, stems, and roots of melina plants.

Methods: The total phenolic and lignins contents were determined using Folin-Ciocalteu colorimetric method and alkaline extraction method, respectively. Plants of five different ages were chosen for the investigation (in vitro plants “year 0” and trees of a year and a half, four, seven and 20 years). Sampling was done in March and April 2021.

Results: All parts of the plant analyzed contain phenolic compounds and lignins, regardless of their age. There was no positive correlation between age and phenol and lignin content for any development condition, since the highest values were not obtained in the oldest trees. Leaf extracts from in vitro plants and seven-year-old trees showed, respectively, the highest phenol and lignin contents for all conditions (P < 0.05). The lowest average values of phenolic compounds for all conditions were obtained in four-year-old trees. Regarding lignins, the lowest content occurred in the oldest roots, although the trend was not maintained for the rest of the plant parts.

Conclusions: This study provides the first results of the content of phenolic compounds and lignins present in different tissues of a forest species of different ages. Therefore, they are the first reference values about the biochemical commitment for phenolic synthesis according to the age and the specific developmental stage of a woody plant.

Microsporogenesis and ultrastructure of pollen grains of the Andean blackberry Rubus glaucus (Rosaceae)

Edgar Javier Rincón-Barón — 2024-04-10

Introduction: Studies on the microsporogenesis of Rubus glaucus are non-existent and little is known about the ultrastructure of the pollen grains. Objectives: To describe the microsporogenesis process, and ultrastructural aspects of the pollen grains in Rubus glaucus. Methods: Flowers at different developmental stages were embedded in paraffin. Sections were stained with Safranin-Alcian Blue, PAS-Amidoblack and Lacmoid or included in resin and stained with toluidine blue. Ultrathin sections were examined by transmission electron microscopy (TEM). For scanning electron microscopy (SEM) observation, the material was fixed and dehydrated in 2.2 dimethoxypropane, then with Hexamethyldisilazane (HMDS), and the samples were coated with gold. Results: Anthers are differentiated by a cellular mass at the ends distal to the staminal filaments. During development, the anther wall presents several cellular layers and at maturity, they are reduced to the epidermis and the endothecium. Microsporocytes undergo simultaneous meiosis and form tetrahedral tetrads. The tapetum develops secretory activity until pollen grains are released, then the cellular content undergoes autolysis. During sporodermis formation, the exine is first deposited and then the intine in a centripetal form. The pollen grains are tricolporate, isopolar, oblate to peroblate, with radial simetry, circular in outline with blunt apices in polar view, ellipsoidal in equatorial view. The exine is thick, tectated, striate perforate. The sporodermis presents an ectexine formed by a tectum interrupted by perforations and thick columellae. Colpus membrane presents small exine granules and orbicules on the surface. The intine develops known structural patterns. Pollenkitt is inconspicuous. Conclusion: Anthers structure and development follows the known patterns of angiosperms. Simultaneous microsporogenesis and centripetal deposition of the sporodermis, as well as ornamentation patterns, have been previously described for the Rosaceae Family.

La Planta: estructura y función, un hito en la literatura científica tropical. Flores-Vindas, E. (2024). La planta: estructura y función (5a ed.). Editorial Tecnológica de Costa Rica

Gerardo Avalos — 2024-04-03

El análisis de la anatomía y morfología vegetal resulta esencial para comprender la diversidad de estrategias adaptativas de las plantas frente a la variación ambiental. El conocimiento de la variabilidad en la estructura y función de las células, tejidos, órganos, sistemas y organismos vegetales implica explorar la anatomía interna de la planta, así como analizar su diversidad morfológica a lo largo del desarrollo mediante procesos de morfogénesis y diferenciación.

Biomass and bioethanol production of the shrub Ulex europaeus (Fabaceae) estimated with remote sensor imagery in the Andean paramos

Diego F. Osorio-Castiblanco — 2024-04-16

Introduction: Gorse (Ulex europaeus, family Fabaceae) is an evergreen shrub native to Europe and invasive in the Andean high-mountain tropical paramos. Objective: To quantify the extent of a biological invasion within a paramo near Los Nevados National Natural Park in Tolima, Colombia, and evaluate bioeconomic solutions to encourage shrub eradication while promoting the local economy and industry. Methods: An object-based supervised classification approach was conducted using UAS (Uncrewed Aircraft Systems)-based RGB imagery and a Planet-derived NDVI (Normalized Difference Vegetation Index) layer, both from 2022, to quantify the area invaded. This value, the height obtained from a UAS-derived nDSM (Normalized Digital Surface Model), and a pair of allometric equations found in the literature were employed to estimate the gorse aboveground biomass (AGB) and aboveground available fuel, also known as fuel load. Then, documented bioethanol production estimations were applied to calculate its potential extraction based on the AGB values. Results: The invaded area was quantified to be 66 465 m², with an overall accuracy rate of 85.3 %. Furthermore, the fuel load was found to be approximately half of the AGB, which poses a high risk of fire in the ecosystem. The findings also suggest that up to USD 88 933.7 could be generated if all gorse in the study area is exploited to produce bioethanol. Conclusions: This study underscores the urgency of managing the biological invasion of gorse in the Andean paramo and suggests the potential for bioeconomic solutions to mitigate the impact of these invasions.