Biology subjects

Ribolla, P. E. M.

Publications and source records attributed to Ribolla, P. E. M..

3 recordsLinked to original sources

bioRxiv2021

Population dynamics of the primary malaria vector Nyssorhynchus darlingi in a high transmission setting dominated by fish farming in western Amazonian Brazil

Vale do Rio Jurua in western Acre, Brazil, has reported highest malaria numbers since 2005, and is considered persistent transmission hotspot. Fish farming development was encouraged to improve standard of living, resulting in productive breeding sites for Amazonian malaria vector species, including Nyssorhynchus darlingi that, combined with the high human density and mobility, adds to the local malaria burden. This study reports entomological profile of immature and adult Ny. darlingi at three sites in Mancio Lima, Acre, during the rainy and dry season (February to September, 2017). From 63 fishponds, 10,859 larvae were collected, including 5,512 first-instar Anophelinae larvae and 4,927 second, third and fourth-instars, of which 8.5% (n = 420) were Ny. darlingi. This species was most abundant in not-abandoned fishponds and in the presence of emerging aquatic vegetation. Seasonal analysis of immatures in urban landscapes found no significant difference in the numbers of Ny. darlingi, corresponding to equivalent population density during the rainy to dry transition period. However, in the rural landscape, significantly higher numbers of Ny. darlingi larvae were collected in August (IRR = 5.80, p = 0.037) and September (IRR = 6.62, p = 0.023) (dry season), compared to February (rainy season), suggesting important role of fishponds for vector population maintenance during the seasonal transition in this landscape type. Adult sampling detected mainly Ny. darlingi (~93%), with similar outdoor feeding behavior, but different abundance according to landscape profile: urban site 1 showed higher peaks of human biting rate in May (46 bites/person/hour), than February (4) and September (15), while rural site 3 shows similar HBR during the same sampling period (22, 24 and 21, respectively). This study contributes to a better understanding of the larvae biology of the main malaria vector in the Vale do Rio Jurua region and, ultimately will support vector control efforts.

ecology↗

bioRxiv2019

Different energetic diets affect the maintenance of Apis mellifera L. colonies during off-season

The aim of this study wasto evaluate the best energetic foodforuse in the maintenance of honey bee colonies during the off-season. To do this, 20Apis mellifera beehives were used(with five beehives per treatment): CTL,control (without feeding); SJ,sugarcane juice; SS,sugar syrup; and IS,inverted sugar. We evaluated the food consumption, population development, and physiological state (expression of vitellogenin and hexamerin 70agenes)of eachcolony.The results showed that the supplementation of colonieswith sugar syrup resulted in an intermediateconsumption and thebetter development of the colony.In addition, this diet ensured that the colonies were in a good physiological state,as beesfed this diet presentedthe highest relative expression levels of vitellogenin and hexamerin 70ameasuredamong all thediets tested.Therefore, sugar syrup was concluded to be the best artificial energetic food for use in thesupplementation of honey bee colonies during the off-season.

genetics↗

bioRxiv2018

Genetic heterogeneity in Anopheles darlingi related to biting behavior in western Amazon

In the Amazon Basin, Anopheles (Nyssorhynchus) darlingi is the most aggressive and effective malaria vector. In endemic areas, behavioral aspects of anopheline species such as host preference, biting time and resting location after a blood meal have a key impact on malaria transmission dynamics and transmission control strategies. An. darlingi present a variety in behavior throughout its broad distribution including blood feeding related. To investigate the genetic basis of its biting behaviors, host-seeking An. darlingi were collected in two settlements (Granada and Remansinho) in Acre, Brazil. Mosquitoes were classified by captured location (indoors or outdoors) and time (dusk or dawn). Genome-wide SNPs were used to assess the degree of genetic diversity and structure in these groups. There was evidence of genetic component of biting behavior regarding both location and time in this species. This study supports that An. darlingi blood-feeding behavior has a genetic component. Additional ecological and genomic studies may help to understand the genetic basis of mosquito behavior and address appropriate surveillance and vector control.\n\nAuthor SummaryMalaria is a disease caused by parasite of the genus Plasmodium and is transmitted by mosquitoes of the genus Anopheles. In the Amazon Basin, the main malaria vector is Anopheles darlingi, which is present in high densities in this region. Egg development requires that females of this mosquito seek hosts for blood meals. Anopheles females blood feeding may occur indoor or outdoor the houses and typically from the sunset to dawn. Anopheles darlingi in particular present great variability regarding its behaviour, presenting variety of peak biting times and patterns. This work shows that there is a genetic component that partially explains these two behaviors: location of the blood meal (inside or outside the houses) and time of feeding. Single nucleotide polymorphisms (SNPs) scattered throughout the genome of Anopheles darlingi showed genetic diversity and structure in these groups. A comprehensive understanding of the genetic basis for mosquito behaviour may support innovative vector surveillance and control strategies.

epidemiology↗