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Aedes aegypti and Aedes albopictus are responsible for transmitting major human arboviruses such as Dengue, Zika, and Chikungunya, posing a global threat to public health. The lack of etiological treatments and efficient vaccines makes vector control strategies essential for reducing vector population density and interrupting the pathogen transmission cycle. This study evaluated the impact of long-term pyriproxyfen exposure on the genetic structure and diversity of Ae. aegypti and Ae. albopictus mosquito populations. The study was conducted in Manaus, Amazonas, Brazil, where pyriproxyfen dissemination stations have been monitored since 2014 up to the present day. Double digest restriction-site associated DNA sequencing was performed, revealing that despite significant local population reductions by dissemination stations with pyriproxyfen in various locations in Brazil, focal intervention has no significant impact on the population stratification of these vectors in urban scenarios. The genetic structuring level of Ae. aegypti suggests it is more stratified and directly affected by pyriproxyfen intervention, while for Ae. albopictus exhibits a more homogeneous and less structured population. The results suggest that although slight differences are observed among mosquito subpopulations, intervention focused on neighborhoods in a capital city is not efficient in terms of genetic structuring, indicating that larger-scale pyriproxyfen interventions should be considered for more effective urban mosquito control. [ABSTRACT FROM AUTHOR]

Context: There are pre-hatch factors that can influence performance during the growing phase, such as the egg size and breeder age. Aims: Investigate the influence of egg weight and flock age separately on egg characteristics, hatching traits, hatchling weight, and initial offspring performance. Methods: Treatments consisted of eggs laid by 28-week-old (Y), 42-week-old (M), or 61-week-old (O) broiler breeder hens and different egg-weight classes, light (L, 56.6–62.2 g), average (A, 62.3–67.9 g), or heavy (H, 68–73.6 g). Eggs of a similar weight from hens of different ages (treatments YA/ML, YH/MA/OL, and MA/OA) were selected, which allowed us to assess specifically the effect of maternal flock age on the following variables: egg characteristics (eggshell, yolk, and albumen), incubation traits (egg weight loss (EWL), and hatchability), hatchling weight, and live performance of the progeny (7, 14 and 21 days). When data satisfied homogeneity of variance, they were submitted to the one-way ANOVA, and means were compared by Tukey's test at 5% probability level. Key results: Eggshell thickness and albumen height were lower, but albumen weight, yolk weight, and percentage of yolk were higher in eggs produced by older flocks. When eggs of the same weight were evaluated, the variables were also affected by flock ages. EWL increased with the hen age. The age of the hen and egg weight significantly affect the hatchability and hatchling weight. The maximum hatchability was recorded in eggs from broiler breeders at the age of 42 weeks (90.53%). In the average egg-size group (62.3–67.9 g), the young hens produced the lightest chick, and the old flock had the worst hatchability. Broiler's performance was influenced both by flock age and egg weight. Conclusions: The eggshell thickness is mainly influenced by the egg size. However, other egg features are affected by flock age. EWL and chick weight are reduced in young flocks. The oldest flocks produced heavier chicks and the positive effect on feed intake and bodyweight remained until 14 days of age. Implications: Egg size and broiler breeder age can influence the egg traits and performance of broilers. The purpose of this study was to investigate the effects of flock age and egg weight on egg characteristics, incubation traits, hatchling weight, and initial offspring performance. Eggshell thickness and albumen height were lower, but albumen weight, yolk weight, and percentage of yolk were higher in eggs laid by older broiler breeders. Feed intake, bodyweight, and feed consumption rate were affected by the age of the hens and egg size. [ABSTRACT FROM AUTHOR]