A new virus, named Mutum virus, related to members of the family Tymoviridae, was isolated from mosquitoes (Mansonia spp.) in clone C6/36 cells, and its complete genome was sequenced. Its genome is 6494 nt in size with an organization resembling that of tymovirids. The isolated virus is phylogenetically related to two viruses isolated from Culex spp. mosquitoes: Ek Balam virus, reported in Mexico, and Culex-originated Tymoviridae-like virus, isolated in China. The results of this study suggest that this virus is a new member of the family Tymoviridae.
Mansonia amazonensis (Theobald, 1901) is one of 15 species of the subgenus Mansonia Blanchard, 1901. It is essentially a Neotropical species, recorded in Bolivia, Peru and Brazil. In the highly seasonal Amazon region, Mansonia species find ideal environmental conditions for reproduction, development and establishment. Considering that climate significantly influences the size and behavior of mosquitoes, and insects in general, we analyzed the influence of seasonality on wing morphological variability in populations of Ma. amazonensis. Captures were carried out near the banks of the Madeira River in Rondônia State, Brazil during the dry, rainy and transition periods between seasons during 2018 and 2019. Morphometric characters of 181 wings were analyzed using morphological methods. The results show that wing size of Ma. amazonensis increases following a relatively gradual trend, from smaller wings during the dry period to larger ones in the rainy season. This study provides the first evidence, detected using geometric morphometry, of seasonally associated phenotypic variability in the wing conformation of Ma. amazonensis.
Long-distance dispersal plays a critical role in population dynamics, particularly in species that occupy fragmented habitats, but it is seldom detected and investigated. The pelagic seabird Swinhoe's Storm-petrel, Oceanodroma monorhis, breeds exclusively in the NW Pacific. Individuals have been regularly observed in the Atlantic Ocean since the 1980s, but breeding has never been confirmed. In this study, we searched for evidence of breeding of Swinhoe's Storm-petrels on Selvagem Grande Island, NE Atlantic, between 2007 and 2013. During this period, six individuals were captured, sexed and characterized molecularly for two mitochondrial loci, cytochrome oxydase I and the control region, to confirm species identity, survey genetic diversity and estimate evolutionary relationships within the Hydrobatinae. These individuals were confirmed to be Swinhoe's Storm-petrels, and all except one are females. Phylogenetic analyses suggest sister relationship with Matsudaira's Storm-petrel and dismiss misidentifications with other dark rump species.Patterns of genetic variation suggest that dispersal occurred likely by more than a single female. Despite the record of a pair duetting in a burrow, breeding could not be confirmed. Swinhoe's Storm-petrels are regularly occurring at Selvagem Grande, but capture/recapture patterns suggest that a possible breeding population is small and likely not selfsustaining. In seabirds, long-distance dispersal events may facilitate colonization of new habitats created in the context of predicted climate change impacts on the marine ecosystems.
This work aimed to evaluate the spatial distribution of mosquitoes in different seasonal periods and the interaction between climatic factors and the abundance of mosquitoes, especially those belonging to the tribe Mansoniini in the area surrounding the Amazon hydroelectric production region (Jirau-HP) of Rondônia state, Brazil. Mosquito specimens were collected in May, July, October, and December 2018, and April, July, September, and November 2019, over periods of three alternating days during the hours of 6:00 p.m. to 8:00 p.m. Mosquito sampling was performed using automatic CDC and Shannon light traps. Canonical correspondence analysis (CCA), combined with Monte Carlo permutations, was used to evaluate the correlation between climatic variables and species distribution. In addition, non-metric multidimensional scaling (NMDS) was used to verify the similarity among the sampled communities from the different collections. After analyzing the total mosquito fauna at all sampling points, 46,564 specimens were identified, with Mansonia dyari showing the highest relative abundance in 2018 (35.9%). In contrast, Mansonia titillans had the highest relative abundance in 2019 (25.34%), followed by Mansonia iguassuensis (24.26%). The CCA showed that maximum temperature significantly influenced the distribution of mosquito populations in the study area (p = 0.0406). The NMDS showed that sampling carried out in the rainy and dry seasons formed two distinct groups. There was a significant correlation between species richness and cumulative precipitation 15 days before the sampling period (R2 = 58.39%; p = 0.0272). Thus, both temperature and precipitation affected mosquito population dynamics. The effect of rainfall on mosquito communities may be due to variations in habitat availability for immature forms.
Background:
Mansonia
mosquitoes transmit arboviruses to humans. This study describes the karyotypes and C-banding of
Mansonia humeralis
,
Mansonia titillans, Mansonia pseudotitillans
, and
Mansonia indubitans.
Methods:
From the 202 larvae, the brain ganglia were dissected (n=120) for the preparation of slides. Twenty slides with well-distended chromosomes for each species (10 for karyotyping and 10 for C-banding) were selected for further study.
Results:
The haploid genome and the average lengths of the chromosomal arms differed in relation to the centromere between species, and intraspecific differences also occurred in the distribution of the C-bands.
Conclusions:
These results are useful for better understanding of the chromosomal variability of
Mansonia
mosquitoes.
The objective of this study was to evaluate the effect of the construction of the Jirau hydroelectric plant on the anopheline species, in Porto Velho, Rondônia, Brazil. For this, sampling was carried out in 23 locations in the pre ( 2004) and 23 after construction (2018) phases in the hydroelectric dam's coverage area, performed by human landing catch between 6:00 pm and 10:00 pm. We found 14 anopheline species. In the pre-construction phase, An. darlingi (73%) was the most abundant and after construction An. braziliensis (31.5%) was the most abundant. The T test indicated that there were no differences in the indexes -diversity (H '), richness (Sjack 1), equitability (J') and dominance (d) of anophelines species -evaluated between the phases (p > 0.05). The spatio-temporal distribution of An. darlingi proved to be wide, with the highest density values observed in March (x w = 27.1) in the pre-construction phase and in the months of May ( x w = 4) and July (x w = 3.1), post-construction. Differences in hematophagic activity peaks were observed between species and between phases. According to the data obtained in this study, the construction of the hydroelectric plant had little influence on the composition of anopheline species, however changes were observed in the spatio-temporal distribution of the An. darlingi and in the pattern of hematophagic activity of the species, which directly influenced the dynamics of malaria in the region.
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