Lipid composition of the Amazonian 'Mountain Sacha Inchis' including Plukenetia carolis-vegae Bussmann, Paniagua & C.Téllez.

Several Amazonian species of Plukenetia are remarkably rich sources of polyunsaturated fatty acids, in particular α-linolenic acid. The lipid composition of the large-seeded, recently described 'Mountain Sacha Inchi' Plukenetia carolis-vegae is reported here for the first time, and compared with Plukenetia huayllabambana, two cultivars of Plukenetia volubilis, and a newly developed hybrid between P. volubilis and P. carolis-vegae. All species and cultivars had a very high content of polyunsaturated fatty acids, 82.6-86.7% of total fatty acids, and at least 46.6% α-linolenic acid of total fatty acids. The highest content was found in P. carolis-vegae which had 57.4%. The exceptionally high α-linolenic acid content suggests that P. carolis-vegae may be an important plant-derived dietary source of this essential fatty acid and that the species has considerable potential for further domestication and commercialisation of its seeds and seed oil. A TAG analysis was carried out for the two P. volubilis cultivars, in which LLnLn and LnLL were most prevalent, and for P. huayllabambana, in which LLnLn constituted the largest fraction, followed by LnLnLn, indicating that this large-seeded species also has interesting dietary properties.

Unveiling biogeographical patterns of the ichthyofauna in the Tuichi basin, a biodiversity hotspot in the Bolivian Amazon, using environmental DNA.

To date, more than 2400 valid fish species have been recorded in the Amazon basin. However, some regions remain poorly documented. This is the case in the Beni basin and in particular in one of its main sub-basins, the Tuichi, an Andean foothills rivers flowing through the Madidi National Park in the Bolivian Amazonia. The knowledge of its ichthyological diversity is, however, essential for the management and protection of aquatic ecosystems, which are threatened by the development of infrastructures (dams, factories and cities), mining and deforestation. Environmental DNA (eDNA) has been relatively little used so far in the Amazon basin. We sampled eDNA from water in 34 sites in lakes and rivers in the Beni basin including 22 sites in the Tuichi sub-basin, during the dry season. To assess the biogeographical patterns of the amazonian ichthyofauna, we implemented a metabarcoding approach using two pairs of specific primers designed and developed in our laboratory to amplify two partially overlapping CO1 fragments, one of 185bp and another of 285bp. We detected 252 fish taxa (207 at species level) among which 57 are newly identified for the Beni watershed. Species compositions are significantly different between lakes and rivers but also between rivers according to their hydrographic rank and altitude. Furthermore, the diversity patterns are related to the different hydro-ecoregions through which the Tuichi flows. The eDNA approach makes it possible to identify and complete the inventory of the ichthyofauna in this still poorly documented Amazon basin. However, taxonomic identification remains constrained by the lack of reference barcodes in public databases and does not allow the assignment of all OTUs. Our results can be taken into account in conservation and management strategies and could serve as a baseline for future studies, including on other Andean tributaries.

Age validation and contrasted growth performances of Pseudoplatystoma punctifer (Siluriformes: Pimelodidae) in two river systems of the Western Amazon

The doncella Pseudoplatystoma punctifer is an economically and ecologically important catfish in the Amazon basin. However, little is known about its age, growth and population dynamics parameters. This study aims to validate the formation of growth marks in vertebrae of individuals collected from two rivers systems of the Peruvian Amazon (Amazon-Marañón-Ucayali and Putumayo) and compare growth parameters using the von Bertalanffy growth function between sexes and systems. A total of 372 individuals from the Amazon-Marañón-Ucayali (AMU) system and 93 from the Putumayo River were analyzed. The formation of one growth ring per year was validated and the individual ages ranged from zero to nine years old. Females grew significantly larger than males in both systems. Both females and males grew significantly better in the AMU system than in the Putumayo River. Maximum observed length and size at maturity in the AMU system were lower than those reported in previous studies in the area, and together with an important proportion of juveniles in the catches, suggest that the species is heavily exploited. Further studies on the reproductive biology and population dynamics of the doncella are needed in order to implement management measures more in line with the current situation.(AU)

La doncella Pseudoplatystoma punctifer es un bagre de importancia económica y ecológica en la cuenca Amazonica. Pese a ello, poco se conoce acerca de parámetros de edad, crecimiento y dinámica poblacional. Este estudio tuvo como objetivo validar la formación de marcas de crecimiento en vértebras de individuos colectados en dos sistemas fluviales de la Amazonia Peruana (Amazonas-Marañón-Ucayali y Putumayo) y comparar los parámetros de crecimiento usando la función de von Bertalanffy entre sexos y sistemas. Fueron analizados 372 individuos del sistema Amazonas-Marañón-Ucayali (AMU) y 93 del Putumayo. Se validó la formación de un anillo de crecimiento por año, la edad osciló entre cero y nueve años. Las hembras fueron significativamente más grandes que los machos en ambos sistemas. Para ambos sexos el crecimiento fue significativamente mayor en el sistema AMU que en el Putumayo. Las máximas tallas y edades de primera madurez observadas en el sistema AMU fueron menores a las reportadas en estudios previos en el área, y junto con un considerable porcentaje de juveniles presentes en las capturas, se sugiere que la especie está siendo fuertemente explotada. Son necesarios estudios de biología reproductiva y dinámica poblacional de doncella para implementar medidas de manejo acordes a la situación actual.(AU)

The Digestive Function of Pseudoplatystoma punctifer Early Juveniles Is Differentially Modulated by Dietary Protein, Lipid and Carbohydrate Content and Their Ratios.

Pseudoplatystoma punctifer is an Amazonian catfish highly appreciated for its high flesh quality, size, and commercial value. Its aquaculture is pursued to satisfy the demands of an increasing population in the region. However, knowledge of the nutritional needs during the early life stages is necessary for improving growth and reducing the incidence of cannibalism, factors that limit the success of its commercial farming. This study aimed at evaluating the influence of four diets containing different protein and lipid levels (30:15, 30:10, 45:15, or 45:10 in %) in the digestive physiology and performance of early juveniles. The results showed that the dietary protein:lipid as well as carbohydrate levels and ratios influenced differently the whole-body proximate composition, the digestive physiology and development, and hence growth and survival. The 45:15 diet promoted the best growth, survival, and the most rapid development of the digestive system, as shown at histological (higher number of hepatocytes, goblet cells in the anterior intestine and enterocytes in all intestinal portions, and longer folds in the posterior intestine), molecular (highest amylase, lipoprotein lipase, phospholipase, trypsinogen, and pepsinogen gene expression), and biochemical (highest lipase and pepsin activities and higher alkaline phosphatase:leucine alanine peptidase activity ratio) levels. Lipids were favored over carbohydrates as source of energy, with lipids promoting a protein-sparing effect at adequate energy:protein ratio. Carbohydrate content higher than 25% was excessive for this species, leading to unbalanced lipid metabolism and fat deposition in the liver.

SNP Markers as a Successful Molecular Tool for Assessing Species Identity and Geographic Origin of Trees in the Economically Important South American Legume Genus Dipteryx.

Dipteryx timber has been heavily exploited in South America since 2000s due to the increasing international demand for hardwood. Developing tools for the genetic identification of Dipteryx species and their geographical origin can help to promote legal trading of timber. A collection of 800 individual trees, belonging to 6 different Dipteryx species, was genotyped based on 171 molecular markers. After the exclusion of markers out of Hardy-Weinberg equilibrium or with no polymorphism or low amplification, 83 nuclear, 29 chloroplast, 13 mitochondrial single nucleotide polymorphisms (SNPs), and 2 chloroplast and 5 mitochondrial INDELS remained. Six genetic groups were identified using Bayesian Structure analyses of the nuclear SNPs, which corresponded to the different Dipteryx species collected in the field. Seventeen highly informative markers were identified as suitable for species identification and obtained self-assignment success rates to species level of 78-96%. An additional set of 15 molecular markers was selected to determine the different genetic clusters found in Dipteryx odorata and Dipteryx ferrea, obtaining self-assignment success rates of 91-100%. The success to assign samples to the correct country of origin using all or only the informative markers improved when using the nearest neighbor approach (69-92%) compared to the Bayesian approach (33-80%). While nuclear and chloroplast SNPs were more suitable for differentiating the different Dipteryx species, mitochondrial SNPs were ideal for determining the genetic clusters of D. odorata and D. ferrea. These 32 selected SNPs will be invaluable genetic tools for the accurate identification of species and country of origin of Dipteryx timber.

Molecular evidence for three genetic species of Dipteryx in the Peruvian Amazon.

There is a high international demand for timber from the genus Dipteryx, or "shihuahuaco" as it is known in Peru. Developing tools that allow the identification and discrimination of Dipteryx species is therefore important for supporting management of natural populations and to underpin legal trade of its timber. The objective of this study was the molecular characterization of Dipteryx species in the Peruvian Amazonia. Two plastid regions (cpDNA: trnH-psbA and matK) were sequenced and 11 microsatellite markers (nDNA) were genotyped for 32 individuals identified as Dipteryx charapilla, D. micrantha morphotype 1 and D. micrantha morphotype 2. Using the concatenated sequences of the plastid genes, we identified ten haplotypes that were not shared between the species or between the D. micrantha morphotypes. Haplotypic diversity was greater in D. micrantha morphotype 2 and D. charapilla than in D. micrantha morphotype 1, which presented only one haplotype with a wide distribution in Peru. The microsatellites allowed the discrimination of the same three clades and identified diagnostic alleles for each clade. These results allowed us to demonstrate that the two morphotypes of D. micrantha are different at both the plastid and nuclear markers, which supports the existence of three genetically distinct species in Peru. This study provides information for the genetic discrimination of Dipteryx species and emphasises the importance of conserving the genetic variability of this genus in the Peruvian Amazonia.

Tempo and rates of diversification in the South American cichlid genus Apistogramma (Teleostei: Perciformes: Cichlidae).

Evaluating biodiversity and understanding the processes involved in diversification are noticeable conservation issues in fishes subject to large, sometimes illegal, ornamental trade purposes. Here, the diversity and evolutionary history of the Neotropical dwarf cichlid genus Apistogramma from several South American countries are investigated. Mitochondrial and nuclear markers are used to infer phylogenetic relationships between 31 genetically identified species. The monophyly of Apistogramma is suggested, and Apistogramma species are distributed into four clades, corresponding to three morphological lineages. Divergence times estimated with the Yule process and an uncorrelated lognormal clock dated the Apistogramma origin to the beginning of the Eocene (≈ 50 Myr) suggesting that diversification might be related to marine incursions. Our molecular dating also suggests that the Quaternary glacial cycles coincide with the phases leading to Apistogramma speciation. These past events did not influence diversification rates in the speciose genus Apistogramma, since diversification appeared low and constant through time. Further characterization of processes involved in recent Apistogramma diversity will be necessary.

Revision of hemoproteid genera and description and redescription of two species of chelonian hemoproteid parasites.

Pigmented hemosporidian parasites that do not exhibit erthyrocytic schizogony, and infect birds, chelonians, and squamates, have been classified in various genera over time. These classifications have reflected vertebrate hosts, insect vectors, and variations in morphology and life history observed in representative species. Side-necked turtles ( Podocnemis spp.) from the Peruvian Amazon were screened for hemoparasites and 2 species of hemosporid parasites infecting these hosts were observed. Molecular phylogenetic analysis of these new isolates, along with parasites from lizards, a snake, and a variety of Haemoproteus species from birds from both the Haemoproteus and Parahaemoproteus subgenera, strongly support the separation of the non-avian parasites into a separate genus. The name with precedent for this group is Haemocystidium Castellani and Willey 1909, and we propose that subgeneric classification of Haemocystidium and Simondia be applied to parasites of squamates and chelonians, respectively. We offer a description of Haemocystidium (Simondia) pacayae n. sp. and a redescription of Haemocystidium (Simondia) peltocephali ( Lainson and Naiff 1998 , n. comb.) Morphologically, the parasites are quite similar, with H. pacayae slightly more elongated than H. peltocephali. The discovery and identification of parasite species is urgent, especially in endangered species and wildlife inhabiting rapidly declining ecosystems such as the Amazon.

Molecular identification of a cryptic species in the Amazonian predatory catfish genus Pseudoplatystoma (Bleeker, 1962) from Peru.

Pseudoplatystoma species are highly prized South American Pimelodid migratory catfishes. Until recently, their taxonomy was not clearly established, with discrepancies between morphological and molecular analyses. Here, Pseudoplatystoma species from the Peruvian Amazon were characterized at the molecular level from a sample representing the observed range of their color pattern variations in the study area. Analyses were performed using seven microsatellite loci for 103 specimens and, for part of them (52), using sequences of two regions of their mitochondrial genome [Cytochrome Oxidase subunit I (COI) and Control Region (CR)]. Factorial correspondence analysis and assignment tests based on microsatellite polymorphism showed that the specimens originally identified as P. punctifer belonged to two different gene pools highly differentiated from P. tigrinum. Morphological examination identified two different morphotypes (with and without black stripes), suggesting the existence of two distinct taxa within P. punctifer. This result was corroborated by the ML tree based on CR sequences, where all individuals but four clustered in a similar way as in the FCA and Bayesian assignment tests. For these four individuals, mitochondrial introgression or retention of ancestral polymorphism was likely. In contrast, the ML tree based on COI sequences showed that reciprocal monophyly was not yet achieved for this marker for the two P. punctifer taxa. The existence of three sympatric species of Pseudoplatystoma in the Peruvian Amazon is discussed in relation to their molecular characteristics, color patterns and ecology. Evolutionary scenarios regarding their divergence are hypothesized.

DETECTION OF INFECTION WITH Toxoplasma gondii IN MANATEES (Trichechus inunguis) OF THE PERUVIAN AMAZON / Detección de infección por Toxoplasma gondii en manatíes (Trichechus inunguis) de la Amazonía peruana

The Amazonian manatee (Trichechus inunguis) is an aquatic mammal that inhabits freshwater environments and is endemic to the Amazon Basin. The presence of Toxoplasma gondii antibodies was investigated in 19 manatees in one rescue unit in the northern region of Peru. Antibodies to T. gondii were detected in 12 (63.2 %) of 19 animals by using the modified agglutination test (titer, 1:25), and no association between sex and age of the animals and the presence of T. gondii antibodies was observed (p < 0.05). The results suggest a contamination by T. gondii oocysts in the aquatic environment where these animals live.

El manatí amazónico (Trichechus inunguis) es un mamífero acuático que habita en ambientes de agua dulce y es endémico de la cuenca del Amazonas. La presencia de Toxoplasma gondii se investigó en 19 manatíes, en una unidad de rescate en la región norte del Perú. Los anticuerpos contra T. gondii fueron detectados en 12 (63,2 %), de 19 animales mediante el uso de la prueba de aglutinación modificada (título, 1:25). No fue observada asociación entre el sexo y edad de los animales con la presencia de anticuerpos de T. gondii (p < 0,05). Los resultados sugieren la contaminación por ooquistes de T. gondii en el medio acuático donde viven estos animales.

Conservation genetics of harvested river turtles, Podocnemis expansa and Podocnemis unifilis, in the Peruvian Amazon: all roads lead to Iquitos.

We present a mtDNA analysis of Podocnemis expansa (n = 81) and Podocnemis unifilis (n = 228) turtles traded in Peru to evaluate the potential origin of these animals. In particular, we were interested in the relationship between samples reported in the Iquitos markets (IMs) and a Pacaya Samiria Natural Reserve (PSNR) where illegal hunting is presumed. Our mtDNA data showed that, for both species, all haplotypes found within the PSNR were observed in the IM, and that these markets also displayed haplotypes not documented in the reserve. This suggests that the IMs are recipients of Podocnemis turtles from within and outside the PSNR. The fact that most of the haplotype diversity observed in the markets was not found within the PSNR strongly suggests that Podocnemis genetic diversity is exploited in areas where conservation actions are limited. Hence, we recommend expanding Podocnemis conservation efforts outside of protected areas.

Phylogeography and sex-biased dispersal across riverine manatee populations (Trichechus inunguis and Trichechus manatus) in South America.

Phylogeographic patterns and sex-biased dispersal were studied in riverine populations of West Indian (Trichechus manatus) and Amazonian manatees (T. inunguis) in South America, using 410bp D-loop (Control Region, Mitochondrial DNA) sequences and 15 nuclear microsatellite loci. This multi-locus approach was key to disentangle complex patterns of gene flow among populations. D-loop analyses revealed population structuring among all Colombian rivers for T. manatus, while microsatellite data suggested no structure. Two main populations of T. inunguis separating the Colombian and Peruvian Amazon were supported by analysis of the D-loop and microsatellite data. Overall, we provide molecular evidence for differences in dispersal patterns between sexes, demonstrating male-biased gene flow dispersal in riverine manatees. These results are in contrast with previously reported levels of population structure shown by microsatellite data in marine manatee populations, revealing low habitat restrictions to gene flow in riverine habitats, and more significant dispersal limitations for males in marine environments.

Diferenciación morfológica y por ISSR (inter simple sequence repeats) de especies del género plukenetia (euphorbiaceae) de la Amazonía peruana: propuesta de una nueva especie / Morphological and differentiation by ISSR (inter simple sequence repeats) of species of the genus plukenetia (euphorbiaceae) in the Peruvian Amazon: proposal of a new species

En el presente trabajo se estudian cinco especies del género Plukenetia de la Amazonía peruana: P. brachybotrya, P. loretensis, P. polyadenia, P. huayllabambana, P. volubilis (procedencia San Martín); y de un supuesto morfotipo (P. volubilis, procedencia Cusco). Los 126 especímenes estudiados fueron identificados mediante claves de caracteres morfológicos (formas de hojas, tallos y semilla; posición de glándulas basilaminares) y posteriormente mediante marcadores moleculares ISSR (CAA, CAG, GACA). Los análisis morfológicos permitieron separar las cinco especies descritas: P. brachybotrya, P. loretensis, P. polyadenia, P. volubilis y P. huayllabambana. Los dos supuestos morfotipos de P. volubilis fueron discriminados por la posición de las glándulas, tamaño de semillas y forma del tallo. Los resultados proporcionados por el Análisis Factorial de Correspondencia (AFC) y corroborados por el Índice de fijación (FST), distancia genética y el dendograma estimado por el método UPGMA, evidencian una fuerte diferenciación entre los seis taxa, corroborando la identidad taxonómica molecular de las cinco especies ya descritas morfológicamente. Además, los resultados (Fst y la distancia genética) indicarian que P. volubilis (del Cusco) podría ser una nueva especie de Sacha Inchi, aún no descrita para la ciencia.

Are rapids a barrier for floodplain fishes of the Amazon basin? A demographic study of the keystone floodplain species Colossomamacropomum (Teleostei: Characiformes).

We investigated demographic history and population structuring of Colossoma macropomum sampled from 14 localities in the Amazon basin and the Bolivian sub-basin; the two basins are separated by a series of 16 rapids. Although genetically differentiated, IMa analyses suggest non-zero bi-directional migration rates, and inter-basin divergence of approximately 17 thousand years ago. Analyses in BEAST indicated that Bolivian C. macropomum has been demographically stable except for a moderate population increase in the last 12 thousand years, while Amazonian C. macropomum has been experiencing demographic growth over the last 350 thousand years, resulting in approximately one order of magnitude increase in coalescent N(e).

Phylogeography of the piranha genera Serrasalmus and Pygocentrus: implications for the diversification of the Neotropical ichthyofauna.

The phylogenetic relationships within the piranhas were assessed using mitochondrial sequences with the aim of testing several hypotheses proposed to explain the origin of Neotropical diversity (palaeogeography, hydrogeology and museum hypotheses). Sequences of the ribosomal 16S gene (510 bp) and control region (980 bp) were obtained from 15 localities throughout the main South American rivers for 21 of the 28 extant piranha species. The results indicate that the genus Serrasalmus is monophyletic and comprises three major clades. The phylogeographical analyses of these clades allowed the identification of five vicariant events, extensive dispersal and four lineage duplications suggesting the occurrence of sympatric speciation. Biogeographical patterns are consistent with the prediction made by the museum hypothesis that lineages from the Precambrian shields are older than those from the lowlands of the Amazon. The vicariant events inferred here match the distribution of the palaeoarches and several postdispersal speciation events are identified, thereby matching the predictions of the palaeogeography and hydrogeology hypotheses, respectively. Molecular clock calibration of the control region sequences indicates that the main lineages differentiated from their most recent common ancestor at 9 million years ago in the proto Amazon-Orinoco and the present rate of diversification is the highest reported to date for large carnivorous Characiformes. The present results emphasize that an interaction among geology, sea-level changes, and hydrography created opportunities for cladogenesis in the piranhas at different temporal and geographical scales.

Revisão taxonômica dos camarões de água doce (Crustacea: Decapoda: Palaemonidae, Sergestidae) da Amazônia Peruana

A taxonomic revision of eight species of freshwater shrimps of the family Palaemonidae and one of the family Sergestidae from the Peruvian Amazonia was made. Two new species of the genus Pseudopalaemon are described, and Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 are recorded from Peru for the first time. Key, distributional data and ilustrations for the species are presented

Foi realizada uma revisão taxonômica das espécies de camarões de água doce da Amazônia peruana que abrangeu oito espécies da família Palaemonidae e uma espécie da família Sergestidae. São descritas duas novas espécies do gênero Pseudopalaemon e feitos os primeiros registros de Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 para o Peru. São fornecidos chave de identificação, dados distribucionais e ilustrações para as espécies estudadas.

Revisão taxonômica dos camarões de água doce (Crustacea: Decapoda: Palaemonidae, Sergestidae) da Amazônia Peruana / Taxonomic revision of the freshwater shrimps (Crustacea: Decapoda: Palaemonidae, Sergestidae) from the Peruvian Amazonia

Foi realizada uma revisão taxonômica das espécies de camarões de água doce da Amazônia peruana que abrangeu oito espécies da família Palaemonidae e uma espécie da família Sergestidae. São descritas duas novas espécies do gênero Pseudopalaemon e feitos os primeiros registros de Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 para o Peru. São fornecidos chave de identificação, dados distribucionais e ilustrações para as espécies estudadas.

A taxonomic revision of eight species of freshwater shrimps of the family Palaemonidae and one of the family Sergestidae from the Peruvian Amazonia was made. Two new species of the genus Pseudopalaemon are described, and Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 are recorded from Peru for the first time. Key, distributional data and ilustrations for the species are presented.

Composição do Zooplâncton em diferentes ambientes do lago Camaleão, na ilha da Marchantaria, Amazonas, Brasil

This study aims to verify occurrence and distribution of the major zooplankton groups in three different sub-habitats at Lago Camaleão: channel, aquatic macrophytes and flooded forest, during the high water period (August, 1996). Cladocera, Copepoda and Rotifera occurred with different relative abundances within the three studied environments. In the channel, Cladocera occurred with a high number of species and individuals, Bosminopsis deitersi being the dominant species (89%). Cladocera and Copepoda were equally dominant in the flooded forest, even thought only copepods, nauplius and copepodites immature forms were found. On the macrophytes, Rotifera was the group with the largest occurrence, with the dominance of Lecane quadridentata, Keratella Americana and Brachionus patulus followed by copepods (immature forms) and cladoceres, the latter mostly of the Chydoridae family (21.4%).

Este trabalho teve o objetivo de verificar a ocorrência e a distribuição dos principais grupos de zooplâncton em três diferentes sub-habitats do lago Camaleão: canal, macrófitas aquáticas e floresta alagada, no período de cheia (agosto de 1996). Nos três ambientes estudados, Cladocera, Copepoda e Rotifera ocorreram com abundância relativa diferentes. No canal, Cladocera ocorreu com maior número de espécies e de indivíduos, sendo dominante a espécie Bosminopsis deitersi (89%). Na floresta alagada Cladocera e Copepoda foram igualmente dominantes, ressaltando-se que somente ocorreram as formas imaturas de copépodes, náuplios e copepoditos. Nas macrófitas, o grupo de maior ocorrência foi Rotifera, com a dominância de Lecane quadrídentata, Keratella americana e Brachionus patulus seguido de copépodes (formas imaturas) e de cladóceros, estes na maioria da família Chydoridae (21.4%).

Biologia reprodutiva do Camarão Macrobrachium brasiliense (Heller, 1862) (Crustacea: Decapoda: Palaemonidae) em Igarapés de terra firme da Amazônia Peruana

The reproductive biology of Macrobrachium brasiliense (Decapoda: Palaemonidae) was studied based on 2,604 specimens collected from October 1994 to August 1995, in two forest streams along the Iquitos-Nauta, highway in Loreto (Peruvian Amazon).The female: male sex ratio was 1.7:1. M. brasiliense showed sexual dimorphism in the cephalotorax length, females being slighthly smaller than males. Reproduction was contínuos with a reproductive peak between April and June. Fecundity ranged from 15 to 168 eggs per female. A significant relationship was observed between fecundity and cephalotoraxic length and the weight. Egg volume presented no significant relationship with cephalotoraxic length or fecundity.

Foi estudada a biologia reprodutiva de Macrobrachium brasiliense (Decapoda: Palaemonidae) com base em 2604 indivíduos coletados entre outubro de 1994 e agosto de 1995, em dois igarapés de terra firme da estrada Iquitos-Nauta, Loreto (Amazônia peruana). A proporção sexual fêmea: macho foi de 1,7:1 sendo que as fêmeas foram um pouco mais abundantes que os machos durante todo o período de coleta. M. brasiliense apresentou dimorfismo sexual no comprimento cefalotorácico, sendo as fêmeas ligeiramente menores que os machos. A reprodução foi contínua, com o pico reprodutivo entre abril e julho. A fecundidade variou de 15 a 168 ovos por fêmea, observando-se uma relação significativa entre a fecundidade e o comprimento cefalotorácico e o peso. O volume do ovo não apresentou relação significativa com o comprimento cefalotorácico e a fecundidade.