Bruno Spacek Godoy

Managing mosquito populations remains the most effective approach to mitigating arbovirus transmission. However, stressor-induced mortality under determined conditions can trigger compensatory or overcompensatory effects in adult mosquito characteristics (total biomass, individual size). In this study, we evaluated the role of Eucalyptus benthamii essential oil as a stressor on Aedes aegypti larvae, investigating its effects on larval development, adult size, longevity, and overall adult emergence. First-instar A. aegypti larvae were subjected to essential oil concentrations of 8.5 (LD50) and 18.5 ppm (LD90) in controlled laboratory conditions. We assessed pupal mortality, the proportion of pupae that successfully transitioned to adulthood, adult longevity (in days), larval growth rates, wing length, and overall larval mortality. The results revealed that the interaction between time and treatment had a significant effect on larval mortality. Although the essential oil concentration did not affect the number of larvae reaching adulthood, adult longevity and larval development time were notably extended under LD90 and LD50 concentration, respectively. Larval mortality rates were highest during the first week of exposure to the LD90 treatment. Furthermore, males and females produced in microcosms with LD50 and LD90 had significantly larger wings than in the control. These findings suggest that sublethal doses of E. benthamii essential oil may enhance certain adult A. aegypti population characteristics through overcompensatory mortality.

Lotic ecosystems are structured by factors operating at multiple spatial scales. We investigated how local and regional environmental variables influence the composition, richness, and abundance of Ephemeroptera, Plecoptera and Trichoptera (EPT) assemblages in streams of the Tocantins–Araguaia basin in the Cerrado (Brazilian savanna) biome, Goiás, Brazil. We sampled aquatic insects and environmental variables in 19 streams. We employed multiple regression analyses to evaluate the impact of spatial and environmental factors on taxonomic richness and abundance. We applied multiscale multivariate codependence analysis (MMCA) to examine the environmental and spatial effects on assemblage composition. Our results revealed that taxonomic richness increased with the percentage of agriculture in the watershed at finer scales, reflecting colonisation by tolerant taxa. Total abundance, in turn, responded to local factors (conductivity and temperature) and watershed areas. The assemblage composition of EPT was primarily structured by broad‐scale spatial gradients (~192 and ~128 km), associated with altitude and pH, respectively. These findings demonstrate that spatial processes (limited dispersal) act together with specific environmental filters to shape assemblages. We conclude that conservation strategies for aquatic biodiversity in the Cerrado must adopt a multiscale perspective that considers both local factors and watershed integrity.

The composition of aquatic macroinvertebrates in Amazonian streams is related with the physical and chemical characteristics of the water, and the integrity of the surrounding habitat. The partitioning of diversity into additive components is a well-established and validated approach, but studies employing temporal additive partitioning have relatively limited representation in the Ecology field. We aimed to analyze spatio-temporal patterns in the diversity of aquatic macroinvertebrates in 11 streams in the Serra dos Carajás region, Eastern Amazonia. We used three distinct sampling periods, in which the macroinvertebrate communities and environmental variables were sampled, to evaluate the contribution of spatial and temporal effects on community. We separated the diversity into local, regional, and temporal components, and we used a permutational multivariate analysis of variance to identify the variations of environmental conditions between different streams and between sampling periods. The results showed a greater accumulation of taxa between different sampling periods than expected at random. Samples collected at the end of the rainy season exhibited notable differences in environmental conditions from the others. Our findings indicate that environmental change is a relevant driver to spatial and temporal dynamics of macroinvertebrate communities. Additionally, our results highlight the significance of temporal beta diversity in understanding total diversity of streams, and we conclude that it is essential to conduct more prolonged studies to understand the effect of environment in stream ecology. This will help distinguish between stochastic factors, seasonal variations, and the impact of long-term anthropogenic influences. Graphical abstract

Background: The Amazon biome exhibits complex arboviral transmission dynamics influenced by accelerating deforestation, climate change, and socioeconomic inequities. Objectives/Methods: This study integrates official epidemiological records with socioeconomic, environmental, and climate variables by applying advanced geostatistical methods (Moran’s I, SaTScan, kernel density estimation) combined with principal component analysis and negative binomial regression to assess the spatiotemporal dynamics of dengue incidence and its association with socio-environmental determinants across municipalities in Pará state (eastern Brazilian Amazon) from 2010 to 2024. Results: Dengue incidence showed an overall decline but with marked epidemic peaks in 2010–2012, 2016, and 2024. The spatial analysis revealed significant clustering (Moran’s I = 0.221, p < 0.01), with persistent high-risk hotspots across most of Pará. Of 144 municipalities, 104 exhibited significant dengue risk, while 58 maintained sustained transmission. Negative binomial regression model identified key determinants: illiteracy, low urbanization, reduced GDP, and climate variables. Conclusions: Dengue transmission in the Amazon is driven by synergistic socio-environmental disruptions, necessitating intersectoral policies that bridge public health surveillance, sustainable land-use governance, and poverty alleviation. Priority actions include targeted vector control in high-risk clusters, coupled with integrated deforestation and climate monitoring to predict outbreak risks. The findings emphasize the urgency of implementing multisectoral interventions tailored to the territorial and socio-environmental complexities of vulnerable Amazonian regions for effective dengue control.

Aim: The relationships between environmental variables and macroinvertebrate assemblages depend on spatial extent, but the relative importance of local and regional factors remains unclear. Understanding these scale‐dependent relationships is crucial for improving biodiversity assessments and ecosystem management. We hypothesise that climate variables drive macroinvertebrate composition at broad spatial extents, whereas local water quality and habitat conditions are more influential at smaller spatial extents.Location: A total of 5,788 streams across nine ecoregions in the conterminous United States, sampled by the United States Environmental Protection Agency (EPA).Time Period: Samples collected in the years 2008, 2009, 2013, 2014, 2018, and 2019.Major Taxa Studied: Freshwater macroinvertebrates, including 992 genera.Methods: We analysed macroinvertebrate abundance data alongside 25 environmental variables categorised into four types: physical‐habitat structure, water quality, watershed characteristics, and climate. We applied Multivariate Multiscale Codependency Analysis (MMCA) at both national and ecoregion‐specific scales to determine which environmental variables were most strongly associated with assemblage composition at different spatial extents.Results: Assemblage‐environment relationships varied with spatial extents. Climate and watershed variables were the dominant drivers at broader spatial extents, whereas local water quality and physical habitat structure were more influential at smaller inter‐site distances. Additionally, the environmental variables most strongly associated with macroinvertebrate composition varied across ecoregions, suggesting that regional factors such as land use and historical environmental conditions shape biotic responses.Main Conclusions: Our findings underscore the importance of spatial scale in ecological studies and conservation planning. Recognising how key environmental predictors change with spatial extent enhances biodiversity assessments, informs targeted conservation strategies, and improves ecosystem management. The observed regional variation in assemblage‐environment relationships highlights the need for regionally tailored management approaches to maintain and restore aquatic biodiversity.

Background: The Amazon region possesses vast natural and anthropogenic ecosystems within a hydroclimatic environment conducive to the proliferation of arboviruses associated with infectious diseases in the human population, notably dengue fever, which poses a recurrent and significant public health challenge. Objective and Methods: We wished to update the dengue mapping for the state of Pará (eastern Amazon) using municipality-level secondary data between 2010 and 2024, including epidemiological information. Furthermore, the seasonal effects of soil and atmospheric meteorological variables (ERA5 reanalysis) on the annual municipal incidence of dengue were statistically analyzed through correlation and cluster-based regression methods. Results: Dengue mapping identified key areas over the central, southwest, and southeast parts of Pará, with eleven municipalities exhibiting extreme dengue counts exceeding 300 cases per 100,000 inhabitants. The epidemiological profile in these cities with worsening transmission showed a higher incidence in adults aged 20–39 years old (39%) and a predominance among women (54%). The majority of dengue cases occur during the rainy season (January to May), accounting for 69% of annual cases, when the climate conditions maximize vector proliferation. The statistical analyses highlighted the significant and spatially heterogeneous influence of regional climate variables on the dengue transmission cycle. Conclusions: This study advances our understanding of climatic drivers of dengue in the Amazon and provides relevant evidence to support region-specific surveillance and control strategies.

As atividades antrópicas na região Amazônica geram impactos ao ambiente aquático e, por consequência, aos organismos que vivem nesses locais. O pouco conhecimento sobre as relações ecológicas da comunidade de peixes na região, assim como sua relação com as variáveis ambientais determinando sua sobrevivência e distribuição, geram essas perdas de dados para estudos ecológicos e biomonitoramento. O objetivo do nosso estudo foi avaliar como as variáveis ambientais influenciam na riqueza e abundância de espécies de peixes de igarapés de afluentes do rio Itacaiúnas, Pará, Brasil. Por tanto, testamos a hipótese de que a riqueza e a abundância dessas comunidades se alteram de acordo com a variação dos parâmetros físico e químicos nesses igarapés. O estudo foi realizado em 16 igarapés da Floresta Nacional de Carajás, com coletas da comunidade de peixes, mensuração de variáveis físico e químico da água e de morfologia do canal. Para sintetizar as variáveis ambientais usamos uma Análise de Componentes Principais. Relacionamos as variáveis ambientais usando uma forward selection de regressão com distribuição de Poisson com a riqueza de espécies e abundância de indivíduos. Os resultados mostram que as variáveis ambientais influenciaram na riqueza e abundância da comunidade de peixes, pois estão relacionadas à disponibilidade de habitat, de alimentos, no ciclo de vida, nas relações tróficas e nas condições da água. Esses achados ressaltam a importância da qualidade da água, particularmente a turbidez, que foi a que mais influenciou o estado das comunidades aquáticas, fornecendo informações valiosas para futuras estratégias de conservação e monitoramento.

Mosquitoes, particularly Aedes aegypti, pose significant public health risks by transmitting diseases like dengue, zika and chikungunya. Bacillus thuringiensis var. israelensis (BTI) is a crucial larvicide targeting mosquitoes while sparing other organisms and the environment. This study evaluated the effects of sublethal BTI doses on Ae. aegypti larvae regarding mortality, development, adult emergence and size, using a wide-area spray application in an urban neighbourhood. Laboratory experiments with four BTI concentrations (0, 0.008, 0.02 and 0.04 ppm) assessed compensatory and over compensatory responses. The spray achieved over 90% larval mortality within 48 h, but accumulating sublethal doses could trigger compensatory and over compensatory effects, enhancing the fitness of survivors. A dose–response relationship was evident, with higher BTI concentrations leading to increased mortality, reduced longevity and fewer pupae. BTI exposure also skewed the sex ratio towards males and altered adult sizes, potentially affecting population dynamics and vectorial capacity. These findings highlight the effectiveness of BTI in Ae. aegypti control and the importance of understanding compensation, overcompensation and density-dependent effects. While wide-area BTI applications can reach inaccessible breeding sites and offer potent mosquito control, careful consideration of ecological and evolutionary consequences is crucial.