Artigos Científicos - ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2152

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Acesso aberto (Open Access)
Composition of shrimp populations (Crustacea: Decapoda) in non-vegetated areas of two river islands in a Brazilian Amazon estuary
(Universidade Federal do Pará, 2013-12) NÓBREGA, Priscila Sousa Vilela da; SILVA, Bianca Bentes da; MARTINELLI-LEMOS, Jussara Moretto
This study investigates the shrimp found in non-vegetated areas of an estuary of the Amazon River. We ascertained the input of juveniles, species' biometrics and the influence of environmental factors on the abundance of species. The samples were collected monthly, from August 2006 to July 2007, in two places in the estuary, each next to an island. For collecting, we used a manual trawl to perform three hauls per month, totaling 36 samples per site. The abundance of shrimps was estimated as a function of the density of specimens per unit area. We used the Spearman's correlation to test the hypothesis that there is significant correlation between the average of the environmental variables measured and variations in shrimp density. The Kruskal-Wallis and the Mann-Whitney tests showed that there were significant differences in environment factors (temperature and salinity) among the months and sites. We obtained 6,091 shrimps, from which 5,231 (85.88%) were caught off the Arapiranga Island and 860 (14.12%) off the Mosqueiro Island, Palaemonidae and Penaeidae were the only families recorded. Five species were collected: Macrobrachium amazonicum (Heller, 1862), Macrobrachium surinamicum Holthuis, 1948, Macrobrachium carcinus (Linnaeus, 1758), Macrobrachium rosenbergii (De Man, 1879), and Farfantepenaeus subtilis (Pérez-Farfante, 1967). The latter (pink shrimp) was found for the first time in oligohaline environments (0-8). Macrobrachium amazonicum was the most abundant species. The recruitment of M. amazonicum juveniles was continuous throughout the year. The population of M. surinamicum was composed by juveniles and adults and that of F. subtilis exclusively by juveniles. The environmental factors analyzed were variable throughout the year and seem to explain the patterns of shrimp species occurrence in the region, the variation in their abundance and juvenile recruitment.
Acesso aberto (Open Access)
Larval and adult density of the porcellanid crab Petrolisthes armatus (Anomura: Porcellanidae) in an Amazon estuary, northern Brazil
(Universidade Federal do Pará, 2013-12) OLIVEIRA, Danielly Brito de; SILVA, Dalila Costa; MARTINELLI-LEMOS, Jussara Moretto
Petrolisthes armatus (Gibbes, 1850) is a porcellanid crab with a wide geographical distribution. In the present study we analyzed variations in the abundance of P. armatus adults and larvae over an annual cycle in the Marapanim estuary of the Amazon coastal zone, in the northeastern portion of the state of Pará, Brazil. Particularly, we focused on the presence of ovigerous females and timing of larval release, with the aim of elucidating reproductive patterns in a tropical estuarine system. The mean density of P. armatus larvae (zoea I and II) correlated positively with the salinity of the shallow waters of the estuary, whereas the abundance of adults correlated with the salinity registered in water samples collected from the benthic environment. There was also a significant positive correlation between larval density (zoea I and II) and water temperature. Ovigerous females were captured throughout the study period, from August 2006 to July 2007, but were more abundant in June and less abundant during the rainy months, between February and May. Larvae were only present during the dry season and transition months (June to January), and were absent during the rainy season (February to May). Petrolisthes armatus reproduces throughout the year in the Marapanim estuary and all developmental stages of this species (zoeal stages I and II, megalopae and adults) are found in the estuary. The results indicate that the study area is an important environment for the reproduction of this decapod.
Acesso aberto (Open Access)
New evidences supporting trophobiosis between populations of Edessa rufomarginata (Heteroptera: Pentatomidae) and Camponotus (Hymenoptera: Formicidae) ants
(Universidade Federal do Pará, 2016-06) SILVA, Daniel Paiva; FERNANDES, José Antônio Marin
Despite its important effect on the maintenance of tritrophic interactions among plants, insect herbivores, and ants, there is still a paucity of natural history and basic biology information involving trophobiosis among Heteroptera stink bugs. Here, based on previous observations of a new trophobiotic interaction between Edessa rufomarginata (De Geer, 1773) and Camponotus rufipes (Fabricius, 1775) ants, we describe the chemical profile of the honeydew obtained by Gas Chromatography–Mass Spectrometry. There were mainly three different sugars (trehalose, glucose, and sorbose) within our samples. The extrafloral nectaries of Caryocar brasiliense Camb., the host plant of E. rufomarginata, attracts a wide assemblage of Cerrado ants with varying aggressiveness toward herbivores. Therefore, this facultative trophobiotic interaction may allow the survival of the stink bug while feeding on the risky, highly ant-visited plant. Given the rarity of trophobiotic interactions between Pentatomidae species and ants and considering a zoological perspective within this family, here we discuss the ecological and evolutionary routes that may allow the rise of these interactions.
Acesso aberto (Open Access)
Reproductive ecology of the catfish, Hassar affinis (ACTINOPTERYGII: DORADIDAE), in three lakes of the Pindaré- Mearim lake system, Maranhão
(Universidade Federal do Pará, 2017-09) CANTANHÊDE, Lorrane Gabrielle; CARVALHO, Irayana Fernanda da Silva; NUNES, Karla Bittencourt; ALMEIDA, Zafira da Silva de; SANTOS, Nayara Barbosa
Reproductive biology affords fundamental features for the establishment of protective measures for fish. The aim of the present work therefore was to determine the reproductive features of the catfish, Hassar affinis, known locally as bico-deflor, in three lakes of the Pindaré-Mearim Lake System, in the state of Maranhão, with the aim of subsidising the closed season. Monthly collections were carried out between July 2014 and July 2015, when 206 individuals were sampled from Lake Aquiri (LA), 247 from Lake Cajari (LC), and 126 from Lake Viana (LV). In the laboratory, each individual was weighed and measured; a ventral longitudinal incision was then made in order to observe the gonads macroscopically. They were then fixed in Bouin’s solution for microscopic analysis and in Gilson’s solution for an analysis of fecundity. Positive allometry was recorded at the three study sites. The sex ratio for the total period was 3.29F:1M (LA), 2.43F:1M (LC) and 2.15F:1M (LV). Mean length at first sexual maturity was estimated at 10.60 cm (LA), 10.84 cm (LC) and 11.12 cm (LV). The period from March to May was defined as the breeding season for this species in the three lakes. Mean absolute fecundity was 21,634 oocytes (LA), 16,357 oocytes (LC) and 25,898 oocytes (LV). The information obtained through this study indicates that, in addition to being important spawning areas, the three lakes are interconnected in relation to the migratory dynamics of H. affinis, so it is necessary to arrive at a model that would satisfactorily cover the three lakes, considering that the dam has a negative effect on Lake Viana.

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