Brazilian Journal of Biology最新文献

{"title":"Moon phases influence encounters of anurans in the Brazilian semi-arid region of Piauí.","authors":"M S C S Lima, J S Andrade, J Pederassi","doi":"10.1590/1519-6984.300375","DOIUrl":"10.1590/1519-6984.300375","url":null,"abstract":"<p><p>The lunar cycle is associated with the behaviour of amphibians, influencing vocalization, reproductive behaviours, and environmental choices. In the present work, we aimed to answer some questions regarding the influence of lunar phases and their interference with the behaviours of semiarid anuran species in Piauí, Northeastern Brazil. The work was carried out in the municipality of Floriano (S 6°30'; W 43°42'), and an active search was carried out for the inventory, with weekly campaigns from June 2018 to June 2019. The days were transformed into Julian days, and the sampling corresponding to 365.25 Julian days (JDN) were transformed into degrees (JDN*360/365). The absolute occurrence by species was classified as constant, accessory, and accidental. In the circular statistics the Rayleigh test (Z) was applied to verify that there is no randomness, with the sample being considered unidirectional if the calculated interval corresponds to z ≥ z (α) and P=0.01. Sample sufficiency was estimated using the RAO'S (U) spacing test, with the value considered random when U<U (α) and P= 0.01. During the 13 months of sampling, 1,921 individuals were recorded in 12 species. Rhinella diptycha was the species with the highest record (constant species), and Physalaemus albifrons was the one with the lowest record of occurrence (accidental species). It was possible to deduce that most of the species (60%=6 of 10 species evaluated) present a greater occurrence between 270°-0°-90°, that is, the lunar albedo with less clarity. A similar pattern was observed in the Atlantic Forest in a previous study. Four species were considered constant; two were considered accessory species and six, species with accidental occurrence. Studies with the lunar synodic cycle are important, as they help to understand the mechanisms of interaction between anuran species and the environment.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e300375"},"PeriodicalIF":0.0,"publicationDate":"2026-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148310384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Psyllaephagus brachiatus and Psyllaephagus sp. HH (Hymenoptera: Encyrtidae) in infestations of Glycaspis brimblecombei (Hemiptera: Aphalaridae) in Brazil.","authors":"M M Domingues, E P Soliman, L B Silva, A L Favoreto, V R Carvalho, V A Costa, F Nanini, H S Dallapiccola, J C Zanuncio, C F Wilcken","doi":"10.1590/1519-6984.300346","DOIUrl":"https://doi.org/10.1590/1519-6984.300346","url":null,"abstract":"<p><p>Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), a pest of Australian origin, has spread to many countries where it damages plants of the Eucalyptus genus. The parasitoid Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is the most widely employed biological control strategy to manage this pest. The identification of Psyllaephagus species present in Brazil is essential, as they may compromise the effectiveness of the biological control of G. brimblecombei. The objective of this study was to report species of Psyllaephagus (Hymenoptera: Encyrtidae) in infestations of G. brimblecombei in Brazil. Psyllaephagus spp. adults were collected, identified, stored in 90% ethanol at -20°C, and identification verified by molecular methods. The DNA of the adult insects was extracted and amplified using the primers CP1 and CB2. The phylogenetic analysis confirmed the association of the parasitoid lineage found to Psyllaephagus brachiatus Riek and Psyllaephagus sp. HH (Hymenoptera: Encyrtidae) reported in Australia as heteronomous hyperparasitoids (autoparasitoids) with females developing in unparasitized psyllids and males in those parasitized by conspecific females or heterospecific parasitoids. The biology of these Psyllaephagus lineages and its impact as hyperparasitoids in their hosts in Brazil requires further studies. Psyllaephagus brachiatus and Psyllaephagus sp. HH, were identified for the first time in Brazil, and their detection in infestations of G. brimblecombei highlights the need to better understand their relationship with this pest and its parasitoid P. bliteus.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e300346"},"PeriodicalIF":0.0,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Larvicidal and oviposition deterrent activities of Pongamia pinnata (L.) Pierre and Vitex trifolia (L.) leaves extracts against mosquito (Aedes aegypti Linnaeus 1762).","authors":"N L Arpiwi, I M S Wijaya, N K Ekawati, Sutomo","doi":"10.1590/1519-6984.303159","DOIUrl":"https://doi.org/10.1590/1519-6984.303159","url":null,"abstract":"<p><p>The Aedes aegypti mosquito is the main vector of several dangerous diseases, including dengue fever (DF), chikungunya, Japanese encephalitis, West Nile fever, and yellow fever. Pongamia pinnata and Vitex trifolia are two multipurpose plant species that can be used for mosquito control. The present research aims to analyze the larvicidal and oviposition deterrent activities of P. pinnata and V. trifolia leaf extracts against Ae. aegypti. Pongamia pinnata and V. trifolia leaves were extracted using methanol, and the extracts were screened for phytochemical compounds. The extracts were tested for larvicidal and oviposition deterrent activities against Ae. aegypti at concentrations of 300, 400, 500, 800, 1000, 1500, and 2000 ppm with triplicates. Positive control (0.02% temephos) and negative control (0.01% Tween-80 in 0.5% aqueous acetone) were included. For larvicidal activity, 25 third-instar larvae were exposed to each test solution, and mortality was recorded after 24 and 48 hours. Lethal concentration 50% and 90% (LC50 and LC90) were calculated using Probit analysis. For oviposition-deterrent activity, 25 gravid female mosquitoes were placed in test cages. Eight ovitraps were placed in each cage, one for P. pinnata and another for V. trifolia test solutions. The number of eggs was counted under a dissecting microscope at 3 and 6 days. Results showed that both P. pinnata and V. trifolia leaf extracts contained phenols, tannins, flavonoids, steroids, alkaloids, and saponins. Terpenoids were only found in V. trifolia leaf extract. Larval mortality increased with increasing extract concentration. The highest larval mortality of 88% and 92% was achieved with concentrations of 2000 ppm and 1500 ppm for P. pinnata and V. trifolia extracts, respectively. The LC50 and LC90 after 24 hours of P. pinnata leaf extract were 891.41 ppm and 1252.25 ppm respectively while for V. trifolia leaf extract were 648.67 ppm and 1627.19 ppm respectively. Oviposition deterrent activity of P. pinnata leaf extract ranged from 7.02% - 19.33% at 300 - 2000 ppm, whereas V. trifolia leaf extract was 91.16 - 95.81% at 1500 - 2000 ppm. In conclusion, both P. pinnata and V. trifolia methanol leaf extracts exhibited dose-dependent larvicidal activity. Pongamia pinnata leaf extract showed low oviposition deterrent activity, with a mean of 11.59% at 300 - 2000 ppm. Vitex trifolia leaf extract showed high oviposition deterrent activity of 91.16 - 95.81% at 1500-2000 ppm.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e303159"},"PeriodicalIF":0.0,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of tuberous roots and yield of cassava in response to potassium topdressing rates in Northwestern Paraná, Brazil.","authors":"J B Silva, T R B Silva, C Z Alves, B S Colares","doi":"10.1590/1519-6984.306439","DOIUrl":"https://doi.org/10.1590/1519-6984.306439","url":null,"abstract":"<p><p>Potassium fertilization is essential for cassava cultivation, especially in sandy soils with low nutrient availability. This study aimed to evaluate the growth, development, and yield of cassava in response to increasing rates of potassium chloride (60% K2O), as well as to assess the feasibility of applying higher rates. The experiment was carried out in a randomized block design with four replications and five treatments: T1 - no potassium fertilization; T2 - 200 kg ha-1 of KCl applied 45 days after planting; T3 - 200 kg ha-1 of KCl at 45 days plus 200 kg ha-1 at 90 days after planting; T4 - 267 kg ha-1 of KCl at 45 days; and T5 - 267 kg ha-1 of KCl at 45 days plus 267 kg ha-1 at 90 days after planting. Five plants were harvested per plot to determine the number and mass (kg) of tuberous roots, allowing estimation of the total number of roots per hectare and yield (kg ha-1). From each harvested plant, one root was randomly selected for measuring length (cm) and diameter (cm). Starch content (g kg-1) was determined using the hydrostatic balance method. No significant differences among treatments were observed for root length, diameter, or starch content. However, treatments with 200 kg ha-1 of KCl (T2 and T3) showed higher root numbers per hectare and yield compared with the others. The management with doubled potassium rates was not economically feasible, since the productivity gain did not offset the increased fertilizer cost.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e306439"},"PeriodicalIF":0.0,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperparasitoids of Xenostigmus bifasciatus (Hymenoptera: Braconidae), parasitoid of Cinara spp. (Hemiptera: Aphididae), in Pinus plantations in Brazil.","authors":"N C Oliveira, R S Camargo, C F Wilcken, J Cola Zanuncio, M T Tavares, M B de Camargo, P B Vandresen, J J Lima, M S Dos Santos, M Dos Santos","doi":"10.1590/1519-6984.305862","DOIUrl":"https://doi.org/10.1590/1519-6984.305862","url":null,"abstract":"<p><p>Hyperparasitoidism can reduce the biological control of Cinara spp. (Hemiptera: Aphididae) in Pinus (Gymnospermae: Pinaceae) plantations in Brazil. Cinara atlantica (Wilson, 1919) and Cinara pinivora (Wilson, 1919), introduced into Brazil in the 1990s, damage young Pinus plants. The primary parasitoid Xenostigmus bifasciatus (Ashmead, 1891) (Hymenoptera: Braconidae) was introduced and released between 2002 and 2004 in the states of Paraná, Santa Catarina, and São Paulo, Brazil. The dispersion of this biological control agent was extensive, with parasitoidism near 100%, stabilizing Cinara spp. populations for years, however, the population increase of these aphids in Pinus taeda (Linnaeus, 1753) plantations up to 2.5 years old between 2022 and 2025 suggests a reduction in the efficiency of biological control. Eight hundred and eighty-four mummies of Cinara spp. were collected from commercial plantations in Santa Catarina and reared in laboratory, from which 203 Hymenoptera specimens emerged, including 24 (11.82% of the total mummies collected) of X. bifasciatus and 179 (88.18%) of the hyperparasitoids Asaphes californicus Girault, 1917 (Hymenoptera: Chalcidoidea: incertae sedis) (55.17%); Dendrocerus carpenteri (Curtis, 1829) (Hymenoptera: Megaspilidae) (10.80%); D. ramicornis (Boheman, 1832) (Hymenoptera: Megaspilidae) (9.90%); and Euneura sopolis (Walker, 1844) (Hymenoptera: Pteromalidae) (12.31%). This is the first record of D. ramicornis and the four species associated with Cinara spp. in P. taeda in Brazil. The high incidence of hyperparasitoidism may be the main cause of the reduced efficiency of Cinara spp. biological control in Pinus plantations in southern Brazil by X. bifasciatus.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e305862"},"PeriodicalIF":0.0,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probiotic Bacillus spp. modulate biofilm microbial assembly in Litopenaeus vannamei culture water.","authors":"Khibar Syiar Moehammad, Ilham Misbakudin Al Zamzami, Zulkisam Pramudia, Yogita Ayu Dwi Susanti, Abd Rahem Faqih, Yahya, Andi Kurniawan","doi":"10.1590/1519-6984.303812","DOIUrl":"https://doi.org/10.1590/1519-6984.303812","url":null,"abstract":"<p><p>Shrimp aquaculture faces persistent challenges arising from microbial imbalances and pathogenic dominance, often linked to biofilm-forming bacterial communities. Probiotics, particularly Bacillus spp., offer a sustainable alternative to antibiotic and chemical management; however, their structural and ecological roles in biofilm modulation remain insufficiently understood. This study applied an integrative approach combining Scanning Electron Microscopy (SEM), 16S rRNA amplicon sequencing, and nutrient monitoring to evaluate the influence of Bacillus-based probiotic supplementation on biofilm communities in Litopenaeus vannamei culture water. Amplicon-based analysis revealed a distinct reconfiguration of bacterial assemblages: untreated biofilms were dominated by Vibrio spp., whereas probiotic supplementation reduced their relative abundance and transiently increased marine-associated genera such as Marivita, Pseudoalteromonas, and Marinobacter during early succession. Bacillus exhibited increased relative abundance under probiotic treatment, coinciding with a shift toward a more compositionally balanced community structure. SEM observations corroborated these findings, showing that probiotic application was associated with less compact and more heterogeneous biofilm architecture. Nutrient analyses demonstrated moderately lower concentrations of ammonia, nitrite, and nitrate in probiotic-treated systems, whereas phosphate concentrations remained consistently low across treatments. Although Bacillus abundance was negatively associated with inorganic nitrogen parameters, functional mechanisms were not directly measured. These findings therefore represent ecological associations rather than mechanistic confirmation of enhanced nutrient turnover. Overall, the results highlight the potential of Bacillus-based probiotics as environmentally compatible biofilm modulators in shrimp aquaculture systems.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e303812"},"PeriodicalIF":0.0,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization of surfactin biosynthetic gene in Bacillus cereus BT1.8 and its antifungal efficacy against Fusarium oxysporum.","authors":"F A Nafidiastri, Salamun, H S Riqina, M Izzuddin, Ni'matuzahroh, Fatimah, A Geraldi, N A Rumandani","doi":"10.1590/1519-6984.302463","DOIUrl":"https://doi.org/10.1590/1519-6984.302463","url":null,"abstract":"<p><p>Bacillus sp. is a genus of bacteria that can produce active biosurfactant compounds and has potential as an antimicrobial agent. The Bacillus bacteria used in this study were isolated from the soil of Bekol Baluran National Park, which is predicted to contain various types of bacteria that can inhibit soil-borne pathogenic fungi such as Fusarium oxysporum, considering that this pathogen causes root rot in plants. This study aims to identify the potential of Bacillus spp. isolates BT1.8, BT9.1, and SM2.3 in producing biosurfactants as antifungal agents. The methods used ranged from macroscopic, microscopic, and molecular characterization of bacteria, in-vitro antifungal activity testing using the swab method and creating a F. oxysporum block, to biosurfactant activity testing through hemolytic activity using Blood Agar medium. Molecular analysis of the biosurfactant biosynthesis gene was performed using PCR with specific primers for the srfAD gene. The results showed that the Bacillus sp. BT1.8 isolate exhibited the best antifungal activity with a 69% inhibition zone against the growth of F. oxysporum. Isolate BT1.8 was identified as having 99.11% similarity to B. cereus ATCC1457 and possesses the srfAD gene, which shows a high level of homology with a similar gene in Bacillus halotolerans with accession number WP_105955226.1. Hemolytic activity results also show that all three bacterial isolates can destroy blood cells through beta hemolysis. This indicates that the presence of the surfactin biosynthesis gene can produce biosurfactant compounds that are capable of significantly inhibiting the growth of F. oxysporum. These results show that B. cereus BT1.8 has potential as a biological biocontrol agent in the form of seed coating that can be used in the formulation of environmentally friendly biocidal products.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e302463"},"PeriodicalIF":0.0,"publicationDate":"2026-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ectomycorrhizal compatibility of Lactarius quieticolor and Tuber floridanum with Pinus elliottii and Pinus taeda.","authors":"L C Dias, R F Ramos, J B Magalhães, V G Handte, G V Ferreira, P H Santiago, D L Scheid, L A Tabaldi, E Gasparin, T Grebenc, Z I Antoniolli","doi":"10.1590/1519-6984.305139","DOIUrl":"https://doi.org/10.1590/1519-6984.305139","url":null,"abstract":"<p><p>This study evaluated ectomycorrhizal compatibility, functional effects, and the inoculum-dose response of Lactarius quieticolor and Tuber floridanum in Pinus elliottii and Pinus taeda, aiming to understand the role of fungus-host specificity in the expression of growth and physiological responses. Basidiomes of Lactarius spp. used as the inoculum source were identified through morphological and molecular analyses, confirming the identity as L. quieticolor. The symbiont L. quieticolor formed ectomycorrhizae on both Pinus species, whereas T. floridanum established an association only with P. elliottii, representing the first experimental record of this interaction. In P. elliottii, both fungi elicited integrated responses regardless of dose, with increases in growth, root biomass and electron transport rate, while L. quieticolor also increased root length, phosphorus content and modulated initial chlorophyll fluorescence. In P. taeda, effects were more limited and dose-dependent: increases in shoot nitrogen content, electron transport rate and root colonization were observed only at the highest inoculum concentrations. Multivariate analyses revealed a clear separation between control and inoculated plants even as the fungal treatments, indicating specific functional signatures. Altogether, the results demonstrate that ectomycorrhizal compatibility is not universal among congeneric Pinus species and highlight the potential of L. quieticolor and T. floridanum as functional ectomycorrhizal symbionts, with implications for seedling production and the ecology of forest systems.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e305139"},"PeriodicalIF":0.0,"publicationDate":"2026-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive mitochondrial genome profile of New Zealand white rabbit (Oryctolagus cuniculus) using Nanopore sequencing technology.","authors":"D A Lestari, S Sutopo, E T Setiatin, F Mustofa, E Kurnianto, A Setiaji","doi":"10.1590/1519-6984.298644","DOIUrl":"https://doi.org/10.1590/1519-6984.298644","url":null,"abstract":"<p><p>This study was aimed to discover, identify, and comprehensively explore the characteristics of the complete mitochondrial DNA genomes of the NZW rabbit (Oryctolagus cuniculus). This study utilized genomic DNA (gDNA) which was extracted from New Zealand White (NZW) rabbit's liver tissue. The extracted gDNA was rigorously evaluated for both quality and quantity to ensure optimal suitability for mitochondrial DNA enrichment. The sequencing process was carried out using whole genome sequencing (WGS) analysis with Nanopore technology, employing the Oxford Nanopore Technologies GridION platform and bioinformatic tools. Data analysis was carried out using the MEGA11 software to uncover potential mutations, assess genetic diversity, genetic distance and visualize the phylogenetic relationships. The NZW rabbit mtDNA genome spans 17,374 bp, with adenine (31.5%) and thymine (28.3%) as the dominant nucleotides. Leucine is the most abundant amino acid (15.82%), while cysteine is the least abundant (0.61%). The s-rRNA and l-rRNA genes are 957 bp and 1,581 bp long, respectively. The 2,000 bp D-loop region contains two repetitive elements: a 20-bp sequence repeated 14 times and a 153-bp sequence repeated 5 times, which differs from that previously reported in other rabbit mtDNA genomes, thus becoming a specific characteristic and a novel finding of this study.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e298644"},"PeriodicalIF":0.0,"publicationDate":"2026-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hematological parameters of freshwater stingrays from the lower river negro, Amazonas, Brazil.","authors":"R M Paixão, A R S Liebl, M F S Gomes, M W S Ribeiro, A N A Santos, J P F Rufino, A C N Alves, A T Oliveira","doi":"10.1590/1519-6984.297982","DOIUrl":"https://doi.org/10.1590/1519-6984.297982","url":null,"abstract":"<p><p>Freshwater stingrays of the subfamily Potamotrygoninae represent a unique group of elasmobranchs exclusively adapted to freshwater environments in South America. Despite their ecological and socioeconomic importance, significant gaps remain in our understanding of their biology and distribution, information essential for effective conservation strategies. In this context, investigating blood physiology is a valuable tool for assessing the health status, well-being, and adaptive capacity of free-living individuals. This study aimed to determine blood parameters (erythrogram, leukogram, thrombogram, and plasma biochemistry) in freshwater stingrays from the lower Rio Negro, Amazonas. Three species were captured: Potamotrygon motoro, Potamotrygon wallacei, and Paratrygon spp., totaling 27 specimens. The animals were anesthetized with eugenol, and 1 to 2 mL of blood was collected by gill puncture. The morphological, hematological, and biochemical analysis of these three stingray species revealed significant differences among species and sexes. Paratrygon spp. stood out for its larger body size and higher thrombocyte counts, suggesting greater robustness and immune response. Females generally exhibited larger dimensions and higher physiological values, indicating sexual dimorphism and greater reproductive demand. P. wallacei showed a smaller size and a distinct hematological profile, possibly reflecting adaptations to more restricted environments. Variations in glucose, protein, and leukocyte levels underscore the influence of ecological and reproductive factors on species physiology, highlighting distinct adaptive strategies in response to the Amazonian environment. In this context, as the first information on freshwater stingrays from the lower Rio Negro region, the hematological parameters reveal specific aspects of the species, sex, and habitat.</p>","PeriodicalId":55326,"journal":{"name":"Brazilian Journal of Biology","volume":"86 ","pages":"e297982"},"PeriodicalIF":0.0,"publicationDate":"2026-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148267277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}