The açaí fruit depulping produces large amounts of long lignocellulosic fiber bundles that are disposed in the environment. Chemical pretreatments may improve açaí fibers favoring their usage in ...advanced materials. This work aimed to define optimal alkali reaction parameters to improve the properties of açaí fibers. Two NaOH concentrations (5 % and 10 %) and two reaction temperatures (80 °C and 100 °C) were tested. The raw and treated fibers were analyzed by scanning electron microscopy, Fourier transformed infrared spectroscopy, X‐ray diffraction, and thermal analyses. All the alkali pretreatments separated fibers from the bundles, unblocked pit channels by removing silicon structures, exposed the inner lignin, partially removed non‐cellulosic compounds, and raised the cellulose crystalline index. The highest temperature and NaOH content resulted in better cleaning and isolation of the fibers, while milder conditions better preserved the cellulose crystalline structure and thermal stability.
There is evidence that climate change may worsen the ecological conditions needed by many pollinator species for their survival; however, little is known about how the rise in ambient temperature ...might affect the survival of large bee species in tropical regions of the planet. This study investigated the thermoregulation mechanisms of the large carpenter bee
Xylocopa frontalis
when nesting spontaneously in nests designed to allow direct measurement of the bees’ temperature while carrying out different activities. It was seen that the species divides its activities throughout the day according to the amount of body heat generated and the ambient temperature, performing activities that generate more body heat at cooler times of the day. The bees also use strategies of thermoregulation, such as heat loss by air convection, evaporative cooling by nectar dehydration, and not foraging during the hottest times of the day to avoid overheating. The study shows that
X. frontalis
is well adjusted to the ecological conditions of the areas in which it lives but suggests that future rises in the ambient temperature could pose a serious threat to the survival and pollination services provided by this bee and other similar tropical species.
In hot climates, foraging bees risk overheating during food collection. Here, we investigated influence of ambient temperature on the foraging activity in
Melipona subnitida
, a stingless bee species ...that naturally occurs in the hottest and driest regions of the Brazilian tropical dry forest. We observed a decrease in round-trip duration of pollen foragers with increasing ambient temperature. Foraging duration of nectar collectors, however, was not affected by the thermal conditions of the environment. When exposed to heat stress in incubators, the upper thermal limits of foragers decreased with increasing exposure time. Moreover, individuals with previous access to liquid food showed higher critical and lethal temperatures than unfed bees. Our study revealed plastic changes in the upper thermal limit of
M. subnitida
, which help to understand the foraging activity pattern of this stingless bee species.
Polyarthritis has been associated with canine visceral leishmaniasis (CanVL), and co-infection with Ehrlichia canis is common and may alter clinical manifestations. A total of 89 dogs presenting ...CanVL were subdivided into two groups: (1) G1, consisting of 46 dogs seronegative to Ehrlichia spp., and (ii) G2, consisting of 43 dogs seropositive to Ehrlichia spp. Eight joints (carpal, tarsal, stifles and elbows) from each dog were evaluated by radiography and synovial fluid (SF) cytologic analysis. Overall, 74 of the 89 (83.1%) dogs presented joint abnormalities suggestive of osteoarthritis by radiography (G1: 40/46 86.9%; G2: 34/43 79.0%), with no statistically significant between-group difference. All dogs with abnormal joint X-ray images presented radiographic lesions bilaterally, independent of the characteristics of the lesion. Soft tissue swelling around the joint and joint space narrowing were more commonly observed in G1 than in G2 dogs. There was no significant between-group difference in terms of other radiographic abnormalities suggestive of osteoarthritis (evident trabecular pattern, subchondral bone sclerosis, osteolysis, osteolytic-proliferative lesions or bone proliferation). SF from 174/315 (55.2%) and 152/307 (49.5%) joints from G1 and G2 dogs, respectively, presented an inflammatory infiltrate, but there was no significant association between the presence of inflammatory infiltrate and group. There was also no statistical difference between groups in either of the evaluated joints in terms of the percentage of neutrophils or mononuclear cells. Leishmania spp. amastigotes were found in 69/315 (21.9%) joints from G1 dogs and in 100/307 (32.5%) joints from G2 dogs (Fisherʼs exact test, P = 0.002, odds ratio = 0.5, 95% confidence interval = 0.4-0.8). The neutrophilic infiltrate was significantly higher in joints with amastigote forms in both G1 (Mann-Whitney U-test, U.sub.(18) = 817, Z = -3.76, P = 0.0001) and G2 dogs (Mann-Whitney U-test, U.sub.(18) = 6543, Z = - 5.06, P < 0.0001). A high prevalence of arthritis in dogs with CanVL was found, and all dogs presented involvement in multiple joints. Although no difference was observed between groups in terms of the number of dogs with polyarthritis and the presence of an inflammatory infiltrate in SF, Leishmania spp. amastigotes were found more frequently in joints from G2 dogs. Further studies evaluating SF in dogs co-infected with L. infantum and E. canis should be performed to evaluate this finding.
The geographical distribution of sand flies in Brazil has been the subject of some studies, yet there is no information about the phlebotomine fauna in João Pessoa, State of Paraíba, Brazil. The aim ...of this work is to evaluate the occurrence and distribution of sand flies in the Atlantic forest fragments and to evaluate a possible dispersion in 06 nearby districts. Light traps were used during three consecutive nights, supplemented by an aspirator during the dry period and rainy season. A total of 222 sand flies were found, 143 (130 males and 13 females) in the Atlantic forest, and 79 in urban areas. During the entire dry season, three species of phlebotomine sand flies were recorded in 11 forest fragments, Lutzomyia longipalpis, Lu. migonei and Lu. whitmani. During the rainy season, only Lu. longipalpis was found. This was the only species identified in the studied neighborhoods during both seasons. The differences in diversity of sand flies encountered between natural habitats and urban areas may thus be correlated mostly with adaptations to particular habitats and availability of food. One species (Lu. longipalpis) appears to be rapidly adapting to urban areas because of deforestation.
Although the importance of bees as the pollinators responsible for maintaining gene flow for many native and cultivated plants in ecosystems around the world is recognized, much of their biodiversity ...and behavior remains to be discovered. Stingless bees are considered key pollinators for several plant species in tropical and subtropical ecosystems and they also provide pollination services for economically important agricultural crops. Many countries are using the honey bee (Apis mellifera Linnaeus, 1758, Hymenoptera: Apidae) as a surrogate to evaluate the risk of pesticides to all species of bees. However, there is uncertainty regarding the extent to which honey bees can serve as surrogates for non-Apis bee species in the risk assessment for pesticides. This paper provides a short overview of the life history traits relevant in risk assessment of stingless bees. It summarizes what is known about stingless bee exposure to pesticides compared to that of honey bees and presents criteria for potential candidate species from Brazil for use in pesticide risk assessment in tropical environments. This paper also identifies gaps in knowledge of bee biology and pesticide exposure routes not covered by the current honey bee exposure assessment paradigm. Based on these gaps, research is needed on life history traits, estimates of nectar and pollen consumption, mud, resin, and water collection and available protocols to adequately assess toxic effects of pesticides to stingless bees. This review is part of a series of papers on the risk of exposure of non-Apis bees to pesticides.
Orchid bee species are important pollinators in the Neotropics. While male orchid bees are known to have a close interaction with odor-rewarding flowers, orchid bee females are often pollen ...generalists. In the current study, we investigated differences in the pollen diet diversity of orchid bees in various vegetation types and across sites with varying levels of forest cover by means of an analysis of the frass pellets of the orchid bee,
Euglossa cordata
(Linnaeus, 1758), and multiple species based on a literature review. The pollen grains found in the inner part of brood cells were used to assess the plant composition making up the diet of
E. cordata
in various areas of the state of São Paulo in Brazil. We found that this plant composition differed among vegetation types, and that diet specialization was lower in forested areas. Forest cover appeared to be the factor mostly associated with pollen richness in nests of
E. cordata
. Number of brood cells per nest were also associated with forest cover. The model used to assess the effect of forest cover on plant richness as part of brood diet of
E. cordata
was tested with the inclusion of published data and a newly generated data for
E. annectans
. This new data set allowed to understand the influence of forest in the pollen diet of multiple species in a more extensive geographic scale. Forest cover appeared to be important for a diversified pollen diet in several orchid bee species.
Implications for insect conservation
Since a diversified pollen diet offered to larva bees is associated with bee survival and health, our results indicate that orchid bees relying on areas with higher forest cover have a more resilient population. Such findings emphasize the importance of conservation of forests, especially in the Neotropical region where many pollinator species are adapted to continuous forest environments.
In recent years, species richness and diversity in aquatic ecosystems has declined as environments are increasingly impacted by anthropic actions. Freshwater prawns are well adapted to survive in a ...disturbed and heterogeneous environment. For instance, Amazon river prawn (Macrobrachium amazonicum) populations vary in migratory behavior between rivers and estuaries, depending on factors such as dams. However, there is limited information on the influence of environmental conditions on life‐history traits of this species, which we investigate here using two distinct and unconnected aquatic systems, a dammed river and an estuary, in the eastern Brazilian Amazon. The biological characteristics of M. amazonicum populations in the two environments were compared and related to environmental parameters, which differed significant differences between the two environments and between seasons. Dissolved oxygen, precipitation, and temperature varied most significantly with the seasons in both the estuary and river. M. amazonicum prawns in the estuary were larger and heavier than those in the river during rainy periods. The mass–length ratios and condition factor varied significantly between the M. amazonicum populations in the estuary and river, with negative allometric growth (grows faster in length than in weight) predominating in both populations, and condition factor was better in the estuary for males and in the river for females. The relative frequencies of occurrence of the different female maturation stages and the male morphotypes were related to precipitation and turbidity in both environments and also to salinity in the estuary. In these two distinct aquatic systems, the abiotic parameters determined by the seasonal precipitation cycle profoundly influenced the development of this crustacean, despite its ecological plasticity. Overall, the study showed that river damming triggered environmental changes in the freshwater river ecosystem and played a key role in determining the life‐history characteristics of M. amazonicum in these contrasting aquatic systems.
Macrobrachium amazonicum is endemic of South America with a large geographical distribution and both biological and economical importance to Amazon. It shows variations in the ecological characteristics, behavior, and life‐history traits between populations.
The study investigated native solitary bee species that nest in pre-existing cavities in the Baturité Massif, State of Ceará, Brazil, their preference for nest substrates and aspects of these bee ...communities. Samples were taken in four distinct areas of the Baturité Massif using three types of trap-nests: dried bamboo internodes, cardboard tubes and rational boxes. Out of the 185 nests offered, 34 were colonized and 24 of them produced 131 bees, belonging to two families (Apidae and Megachilidae) and five genera (Centris, Mesocheira, Euglossa, Megachile and Coelioxys) from six species, including parasitic ones. Nesting preference was observed to certain types of substrates (χ²=17.89, p<0.001), with bamboo internodes being preferred by bee to build their nests, while monthly variation in temperature and humidity did not affect bee emergency. Spite of few nests foundations and the few species sampled, this work contributed to an unprecedented knowledge about the species that use pre-existing cavities in the Baturité Massif that may contribute to assist in the maintenance and conservation of this mountainous area and can be useful for pollination services of native and agricultural plants.
BACKGROUND: In Brazil, dengue epidemics erupt sporadically throughout the country and it is unclear if outbreaks may initiate a sustainable transmission cycle. There are few studies evaluating the ...ability of Brazilian Aedes aegypti populations to transmit dengue virus (DENV). The aim of this study was to compare DENV susceptibility of field-captured Ae. aegypti populations from nine distinct geographic areas of the city of Belo Horizonte in 2009 and 2011. Infection Rate (IR), Vector Competence (VC) and Disseminated Infection Rate (DIR) were determined. METHODS: Aedes aegypti eggs from each region were collected and reared separately in an insectary. Adult females were experimentally infected with DENV-2 and the virus was detected by qPCR in body and head samples. Data were analyzed with the Statistical Package for the Social Sciences version 17. RESULTS: IR varied from 40.0% to 82.5% in 2009 and 60.0% to 100.0% in 2011. VC ranged from 25.0% to 77.5% in 2009 and 25.0% to 80.0% in 2011. DIR oscillated from 68.7% to 100.0% in 2009 and 38.4% to 86.8 in 2011. When the results were evaluated by a logistic model using IR as covariate, North, Barreiro, South-Central and Venda Nova showed the strongest association in 2009. In 2011, a similar association was observed for South-Central, Venda Nova, West and Northeast regions. Using VC as covariate, South-Central and Venda Nova showed the most relevant association in 2009. In 2011, South-Central, Venda Nova and Barreiro presented the greatest revelation associations. When DIR data were analyzed by logistic regression models, Pampulha, South-Central, Venda Nova, West, Northeast and East (2009) as well as South-Central, Venda Nova and West (2011) were the districts showing the strongest associations. CONCLUSIONS: We conclude that Ae. aegypti populations from Belo Horizonte exhibit wide variation in vector competence to transmit dengue. Therefore, vector control strategies should be adapted to the available data for each region. Further analysis should be conducted to better understand the reasons for this large variability in vector competence and how these parameters correlate with epidemiological findings in subsequent years.
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