Search Results (695)

The Sierra Madre Occidental (SMO) is a vital biological corridor in Mexico, yet its floristic knowledge remains fragmented. This study inventories and analyzes the vascular flora of Cerro Mohinora, the highest peak in Chihuahua and a protected area critical for mountain biodiversity. Through the collection of 1200 specimens, we identified 350 taxa across 205 genera and 76 families. Asteraceae (57 taxa) and Poaceae (32) are the most species-rich, with hemicryptophytes dominating the life forms (55.7%). The native flora exhibits a predominantly Nearctic affinity (56.6%), followed by Neotropical (37.2%). Notably, 33.7% of species are endemic to Mexico, including 11.4% to the SMO and 2.9% related to microendemics. Cerro Mohinora serves as the type locality for 18 species, including Salvia reginae, which was discovered during the fieldwork of this study and formally described in 2019. It should be noted that not all of these taxa were recorded in the present survey. Regarding conservation, eight species are listed nationally and 54 internationally. Low exotic species representation (2.6%) contrasts with the vulnerability of the endemic flora. Our findings characterize Cerro Mohinora as a critical boreal refuge and an active evolutionary center, underscoring the need to strengthen conservation frameworks and management strategies to mitigate climate change impacts. Full article

The neotropical genus Inga (Fabaceae) is a fast-growing tree component of tropical forests which plays crucial ecological and functional roles. However, its diversity patterns and the specific environmental drivers that structure its distribution in Andean landscapes remain insufficiently documented. This study aimed to quantify the diversity and distribution of Inga species in the province of Imbabura (4785 km²), northern Ecuador, while evaluating the influence of key environmental determinants. By integrating 52 field records along 321 km of exploration and 22 herbarium records (QCNE, MO, AAU, F, HUTN), the study analyzes the role of topographic variables (12.5 m resolution) and climate data (1 km² resolution). Seventeen species were recorded, almost tripling previous regional findings. The results demonstrate that species richness and occurrence are strongly structured by altitude, temperature, and soil properties as primary environmental drivers. Ten species showed narrow altitudinal ranges and limited thermal tolerance (<2 °C), indicating high habitat specialization, while I. densiflora and I. insignis exhibited broader niches. Edaphically, most species were associated with sandy loam soils, particularly Mollisols and Inceptisols developed from volcanic material. These findings indicate that climatic gradients and edaphic conditions act as the main environmental filters shaping Inga assemblages in heterogeneous montane landscapes. The observed high level of specialization suggests significant vulnerability to land-use change and highlights the need for habitat-specific conservation strategies in Andean forests. Full article

Tropical forests differ widely in floristic composition, stand structure, standing volume, and carbon storage, yet comparative evidence across contrasting tropical forest types remains limited. This study examined whether variation in standing volume and carbon stocks among contrasting tropical forests was more closely associated with structural attributes or with diversity-related patterns. Two tropical wet forests in Colombia and one tropical semi-deciduous forest in Mexico were evaluated using 40 circular plots of 500 m² established within a 100 ha reference area in each forest, where all trees with DBH > 10 cm were measured. Floristic composition, ecological dominance, diversity, dendrometric attributes, standing volume, biomass, and carbon stocks were estimated using a common analytical framework. The two wet forests showed higher effective diversity, broader taxonomic dominance, greater basal area, mean height, standing volume, biomass, and carbon stocks than the tropical semi-deciduous forest. In contrast, the semi-deciduous forest showed stronger dominance concentrated in fewer taxa, especially Euphorbiaceae, a pattern that may reflect the ecological suitability of this family under more seasonal and water-limited conditions. At the family level, standing volume, biomass, and carbon were distributed more evenly among dominant families in the wet forests, whereas they were more concentrated in fewer lineages in the semi-deciduous forest. Basal area showed the strongest association with standing volume, total biomass, and total carbon, followed by mean height and mean DBH. Overall, the results indicate that, under the conditions evaluated, structural organization was more closely associated with standing volume and carbon storage than diversity alone, while diversity acted as a complementary correlate. Full article

Dryopidae (Insecta: Coleoptera) comprise 37 genera and about 280 species, occurring on all continents except Antarctica. The Neotropical fauna of the family has been neglected for decades, despite a few recent contributions. So far, seven genera and 29 species have been recorded from Brazil. Based on 369 adults collected in the Brazilian states of Bahia, Paraná, and Rio de Janeiro, we describe Dryops antonioi sp. nov., D. nelsimarae sp. nov., and D. simoneae sp. nov. Furthermore, we herein redescribe and provide new records for D. ovatus (Grouvelle, 1890), an updated key to the species recorded from the country and a checklist of Neotropical representatives of the genus. Full article

The Atlantic Forest is a highly diverse biome that is under constant pressure due to human action, resulting in habitat fragmentation and intensifying edge effects, affecting biodiversity. The aim was to study the edge effect and influence of biotic and abiotic parameters on Calliphoridae and Mesembrinellidae communities in Três Picos State Park. Two traps baited using beef liver were placed at each site (n = 5) across 1000 m from the edge toward the interior of the forest, with vegetal characterization at each point. Collections occurred between June 2021 and May 2023, encompassing each season twice. The dipterans were identified taxonomically using a stereoscope microscope with the aid of taxonomic keys, totaling 5476 specimens. Dipteran abundance and species composition were primarily influenced by seasonal variation, while the distance from the forest edge or vegetation structure showed no effect. Abundance peaked during warmer periods, and temperature showed a positive effect on overall dipteran abundance. No species showed a strong association with specific seasons or distance along the edge–interior gradient. These results indicate that, in a relatively continuous and well-preserved forest remnant, edge effects do not lead to significant species loss, and climatic seasonality shapes patterns of dominance and abundance. Our findings highlight the ecological stability of the studied conservation unit and support the use of Calliphoridae and Mesembrinellidae as effective bioindicators. Understanding how dipteran assemblages respond to seasonal and edge-related gradients contributes to the development of cost-effective biomonitoring tools for tropical forest conservation. Full article

The Neotropical cichlid genus Apistogramma represents one of the most taxonomically diverse and ecologically significant groups of South American freshwater fishes, yet its evolutionary history and species boundaries remain poorly understood due to a lack of comprehensive genomic resources. To address this gap, this study investigated the complete mitogenomic characteristics of six representative Apistogramma species (A. agassizii, A. allpahuayo, A. baenschi, A. nijsseni, A. resticulosa, and A. cacatuoides) to establish a robust molecular framework for species identification and phylogenetic reconstruction. The results showed that Apistogramma mitogenomes are highly conserved. All six Apistogramma species exhibited significant AT bias. Selection pressure analysis revealed that the Ka/Ks ratios for all 13 protein-coding genes were between 0 and 1, indicating that these genes were under purifying selection. Differential site analysis identified nad5, cox1, and nad4 as ideal molecular markers for rapid Apistogramma species identification owing to higher proportions of variable sites. Phylogenetic analysis recovered Apistogramma as a strongly supported monophyletic clade (BP = 100, PP = 1.00), within which A. nijsseni clustered with A. baenschi and A. cacatuoides with A. agassizii. These internal phylogenetic relationships are consistent with the calculated genetic distances and previous morphological groupings. These findings provide an important theoretical basis and data support for rapid species identification, genetic evolutionary research, and divergence time estimation within Apistogramma. Full article

Anomalopsychidae Flint, 1981, is a small family of caddisflies comprising two genera: the monotypic Anomalopsyche Flint, 1967, and Contulma Flint, 1969, including 31 described species grouped into the cranifer and spinosa species groups. The genus Contulma is distributed across Costa Rica, the Andes, and the mountainous areas of Brazil and Chile, with six species recorded in Brazil, primarily from the Atlantic Forest biome in the southeastern region. In this study, we describe and illustrate a new species of Contulma from the Cerrado biome of São Paulo State, representing the first record of the genus in this biome. Male specimens were collected using Malaise traps in a stream within a protected area. The new species is distinguished by the presence of both a strongly sclerotized dorsomesal process and a strongly dorsolateral process on tergum IX and by an extremely deep cleft in the posteromesal process of sternum IX, dividing it into two narrow, digitated lobes. Based on its unique combination of characters, the new species cannot be placed unambiguously in either of the species groups. Consequently, C. assisensis sp. nov. is here treated as incertae sedis within Contulma. With this addition, seven species of Contulma are now known from Brazil, most of which are recorded from the Atlantic Forest (6 spp.), especially in the mountainous areas of southeastern Brazil. The discovery of this new species in the Cerrado highlights the underestimated diversity of the genus in Brazil and underscores the importance of regional taxonomic studies for addressing biogeographic and diversity knowledge gaps. The identification key provided enables the differentiation of the seven Contulma species now known from Brazil. Full article

Yellow fever (YF) remains a re-emerging vector-borne zoonotic disease in tropical regions of the Americas despite the availability of an effective vaccine. In South America, the virus is maintained through a jungle transmission cycle involving Haemagogus and Sabethes mosquitoes and non-human primates (NHPs), which act as amplifying hosts and key epidemiological sentinels. This narrative review examines the current status of YF epizootics in South America, with a focus on the role of NHPs in viral circulation, early detection, and spillover risk to human populations. We synthesize recent evidence on epizootic patterns across endemic countries, the differential susceptibility of neotropical primates, and the ecological and environmental drivers influencing transmission, including deforestation, habitat fragmentation, and human encroachment into forested areas. In addition, we analyze current surveillance strategies, including wildlife monitoring, entomological and genomic surveillance, and their integration within a One Health framework. This review highlights that YF epizootics are expanding geographically and are closely linked to environmental change and human–ecosystem interactions. Strengthening integrated, multidisciplinary surveillance systems is essential to improve early detection, guide vaccination strategies, and prevent human outbreaks. These findings underscore the critical importance of operationalizing the One Health approach to enhance preparedness and response to YF in South America. Full article

Brazil hosts the world’s greatest stingless bee diversity but remains a leading pesticide consumer. This study evaluated the effects of thiamethoxam on Melipona scutellaris (Apidae) and Scaptotrigona postica (Apidae) larvae using standardized in vitro protocols and patented biomimetic technologies. Larvae were exposed to a field-realistic dose (RD) of 0.02292 ng a.i./larva—calculated using the BeeRex model for citrus crops—and two lower doses: RD/10 and RD/100. Thiamethoxam exposure resulted in significant mortality and developmental alterations, even at 100-fold dilutions. In M. scutellaris, mortality was dose-dependent; RD and RD/10 induced body malformation and reduced food consumption, resulting in >98% mortality. At RD/100, surviving individuals showed significant reductions in body size. In S. postica, all tested doses induced larval darkening and accelerated fungal growth, leading to 100% mortality during the feeding period, including at RD/100. This pattern contrasts with the greater tolerance reported for the adult stage of this species. Overall, the results suggest that larval stages may be more sensitive to thiamethoxam exposure than adults, highlighting the importance of considering different life stages in pesticide risk assessment. These findings also emphasize the need for validated experimental approaches to support environmental risk evaluation for Neotropical pollinators. Full article

This study evaluated the susceptibility of common bean (Phaseolus vulgaris L.) cultivars to Euschistus heros feeding across various phenological stages. Three cultivars (IPR Curió, IPR Sabiá, and IPR Urutau) were infested with 0.5 insects per plant for eight days starting at anthesis and 8, 16, 24, 32, and 40 days after flowering (DAF) using a randomized block design with five replicates. E. heros did not significantly impact grain yield or reproductive abscission, except for the IPR Curió cultivar during flowering, which demonstrated substantial qualitative damage. Feeding injury resulted in increased grain punctures and the grading of commercial classification to Type 2. The most critical susceptibility period occurred during the grain-filling stages (16–24 DAF). IPR Curió was the most sensitive cultivar, exhibiting Type 2 status at both 16 and 24 DAF. These findings demonstrate that although common beans exhibit quantitative tolerance to E. heros at the tested density, qualitative damage during grain development significantly compromises marketability and value. Integrated Pest Management (IPM) should prioritize protecting the crop during mid-to-late reproductive stages to ensure that grain quality standards are met. Full article

Anaerobic digesters operating under neotropical conditions face significant technological constraints. High humidity, intense solar radiation, and pronounced diurnal temperature variations increase conductive, convective, and radiative heat losses. These factors reduce internal thermal stability and directly affect methane production rates and overall energy efficiency. As a result, thermal instability becomes a recurrent operational bottleneck in biogas plants without active temperature control. This review examines the thermal and dynamic behavior of anaerobic reactors from a process-engineering perspective. It integrates energy balances, heat-transfer mechanisms, and computational fluid dynamics (CFD) modeling. The combined effects of temperature gradients, hydrodynamic mixing patterns, and structural material properties are analyzed to determine their influence on thermal homogeneity, microbial stability, and methane yield consistency under mesophilic conditions. Technological strategies to mitigate thermal losses are evaluated. These include passive insulation using low-conductivity materials, geometry optimization supported by numerical modeling, and thermal recirculation schemes, as these factors govern temperature distribution and process resilience. Current limitations are also discussed, particularly the frequent decoupling between ADM1-based kinetic models and transient heat-transfer analysis. This separation restricts predictive capability under real-scale diurnal temperature oscillations. The development and validation of coupled hydrodynamic–thermal–biokinetic models under fluctuating neotropical boundary conditions are proposed as critical steps. Such integrated approaches can enhance operational stability, ensure consistent methane production, and improve energy self-sufficiency in organic waste valorization systems. Full article

The Veracruzan biogeographic province is a central part of the Gulf of Mexico slope and serves as an interface between the Neotropical Region, the Mexican Transition Zone, and the Nearctic Region. We provide an overview of amphibian and reptile diversity in the province, focusing on species richness, endemism, conservation status, and faunal similarity to neighboring biogeographic provinces. In the Veracruzan biogeographic province there are 343 native species of amphibians and reptiles, encompassing nearly one quarter of the Mexican herpetofauna, with over 85% of the families and over 90% of the genera found in Mexico represented. The province therefore possesses exceptional taxonomic richness. It has the fifth highest richness among Mexican biogeographic provinces. The herpetofauna comprises several Neotropical taxa and locally endemic species found among amphibians of montane and cloud forest fauna. Richness of amphibians and reptiles generally increases with province area. Regions of the Mexican Transition Zone exhibit a relatively higher species richness than their Neotropical neighbors. Analyses of faunal similarities between the Veracruzan province and its neighboring provinces and highlight the importance of geographic proximity, environmental continuity, and historical processes for assemblage composition. Amphibians are more threatened than reptiles, with high levels of endemism and vulnerability to habitat loss and emerging diseases, whereas reptiles are more threatened by habitat degradation, exploitation, and invasive species. Our findings show that the Veracruzan biogeographic province is an important reservoir of herpetofaunal diversity and a priority region for conservation in Mexico. Full article

Anostomidae is one of the most diverse families within the order Characiformes and is widely distributed across the river basins of the Neotropical region. Anostomids are known to host a rich diversity of metazoan parasites, including ectoparasites, such as monopisthocotylans, and endoparasites, such as nematodes, cestodes, and digeneans. The present study aims to develop an inventory of metazoan parasites recorded in fish of the Anostomidae family. A bibliographic review of metazoan parasite species in anostomids was conducted, using searches in different databases. This bibliographic review was complemented with information from books and book chapters on ictioparasitology. The data were compiled until January 2025. Based on the review, 191 taxa (126 are described at the species level and 65 were identified only to the genus level or higher taxonomic categories) of metazoan parasites associated with anostomid fishes were found. Monopisthocotyla and Nematoda were the taxonomic groups with the most parasitic associations at the species level, with 31 and 30 species, respectively. This study presents a comprehensive and updated inventory of metazoan parasites associated with fish from the family Anostomidae, covering over 170 years of research (1850–2025). This survey highlights the importance of anostomids as hosts for a rich parasitic fauna. Full article

Rhipicephalus microplus infestations are a major concern for cattle production in neotropical regions. Anti-tick vaccines represent a sustainable alternative to chemical acaricides; however, improving vaccine efficacy remains challenging. This study evaluated the protective efficacy of polypeptide-based formulations of pBm86 and pSubolesin administered as co-immunization or as a cocktail in naturally infested cattle. Twelve calves were assigned to three groups: G1: 100 μg pBm86 + 50 μg pSubolesin co-immunized; G2: same formulation in cocktail; and G3: control. The cocktail significantly reduced adult female tick numbers, oviposition, and larvae hatching (p < 0.05), achieving a vaccine efficacy of 75%. In contrast, co-immunization achieved 50% efficacy. Vaccinated cattle developed significantly increased antigen-specific IgG levels against Subolesin than Bm86. IgG antibodies recognized native tick proteins by Western blot, and their efficacy was confirmed in vitro using blood-feeding assays. These results indicate that the cocktail formulation showed improved efficacy compared with co-immunization in this study, possibly by affecting complementary biological processes in ticks. Finally, this study supports the development of multi-antigen, polypeptide-based vaccines as a promising and sustainable approach for the control of R. microplus under natural field conditions. Full article

Piper aduncum L. (Piperaceae) is a neotropical species widely recognized for its bioactive essential oils (EOs), which exhibit antifungal, insecticidal, larvicidal, and antimicrobial properties. This study investigates the influence of circadian rhythms on the chemical composition and yield of P. aduncum EOs cultivated under agroecological conditions in the Rio de Janeiro Botanical Garden. Fresh leaves were collected every three hours over a 24 h cycle during both dry (July 2023) and rainy (February 2024) seasons. EOs were extracted by hydrodistillation and analyzed using GC-MS and GC-FID. A total of 20 compounds were identified in the dry season, while 10 were detected in the rainy season. Dillapiole was the predominant constituent in both periods, ranging from 75.78% to 88.27% (dry) and 75.90% to 90.86% (rainy). The highest EO yield was observed at 3:00 p.m. (0.73%) in the dry season and at 12:00 p.m. (0.61%) in the rainy season. Despite seasonal variations in chemical diversity, dillapiole content remained stable, reinforcing its biotechnological potential. The results highlight the importance of optimized harvesting times to maximize EO yield and composition, contributing to the sustainable exploitation of P. aduncum for medicinal and agricultural applications. Full article