Carry-over effects of larval microclimate on the transmission potential of a mosquito-borne pathogen

Abstract

Climate shapes the transmission of mosquito-borne pathogens through impacts on both the vector and the pathogen. In addition to direct effects of the environment, carry-over effects from previous life history stages can influence mosquito traits relevant to disease transmission.While this has been explored in a laboratory setting, the net effect of temperature-mediated carryover effects due to relevant environmental variation in the larval stage is ambiguous. Here, we use data collected from a semi-field experiment investigating dengue dynamics in Aedes albopictus across a natural environmental gradient to parameterize a dengue transmission model. We reared Ae. albopictus across three different land classes characterized by their proportion of impervious surface. Emerged females were offered a dengue infectious bloodmeal, kept at a constant 27°C, and assayed for infection, dissemination, and infectiousness 21 days post infection. Incorporating carryover effects of larval environment on measures of vector competence resulted in lower predicted dengue transmission potential across land class and season, however a strong positive relationship with larval environmental temperature remained. Given the significant impact of carry-over effects, future mechanistic models of disease transmission should include both direct and carry-over effects of environmental temperature.