Bottom-up regulation and competition of Aedes aegypti (Diptera: Culicidae) larvae along an
urbanization gradient in Puerto Rico: Effects on population performance and vector competence
Aedes aegypti, is the primary vector of emerging arboviruses causing serious human illnesses including
yellow fever, dengue, Zika, and chikungunya. Species population dynamics are related to urbanization and
human density as larvae develop in man-made habitats and bloodfeed on humans. Previous studies have
independently related urbanization parameters, detrital inputs, and larval competition to some aspects of Ae.
aegypti life history (e.g., development time, biomass, fecundity) and vector competence. However, no study
has determined how urbanization can influence these ecological interactions in larval habitats, the effect that
this can have on Ae. aegypti performance across life stages, generations, and vector competence, nor have
used a nutrient stoichiometry approach to do so. Urbanization changes could translate to changes in detritus
availability and species competition in larval habitats along a gradient of urbanization which could in turn,
influence the susceptibility of Ae. aegypti to dengue infection. The first objective of this proposal is to determine
the influence of urbanization on Ae. aegypti larval bottom-up effects and competition in Puerto Rico. The
second and third objectives are to assess the influence of urbanization related-detrital inputs and Aedes sp.
competition on the species life history across generations and vector competence, respectively. Preliminary
data suggests that plant detritus biomass and composition have a significant effect on Ae. aegypti larval and
adult biomass. In addition, container water nitrogen (%N) significantly increases with urbanization, that water
Carbon:Nitrogen (C:N) is significantly higher in suburban containers, and C:N exhibits a significant relationship
with Ae. aegypti larval biomass. The overall hypothesis of this proposal is that urbanization influences
detrital inputs and competition in Ae. aegypti larval habitats and that this variation will affect species
performance (survival, development rate, and biomass) and dengue vector competence. A combination
of field sampling and laboratory experiments will be used to answer the objectives. Sixty larval containers will
be sampled across a gradient of urbanization in San Juan, Puerto Rico following a stratified random sampling
method with three strata (urban density): low, medium, and high. Incubated containers will simulate larval
conditions of each strata with combinations of detrital inputs and species intraspecific and interspecific
competition. Aedes aegypti females will be infected with a dengue blood meal to determine virus dissemination
and transmission rates. Nutrient analysis (i.e., %C %N, C:N) will be performed on container water, detritus,
larvae, and adults from field and laboratory experiments. The results of this research have relevance to vector
ecology, vector control strategies, arbovirus diseases, and public health.
