Abstract
How wild organisms are responding to climate change is one of the most pressing issues of the 21st century. As ectotherms, insects are particularly vulnerable to increases in temperature and extreme weather events because their fitness and survival are directly linked to abiotic conditions. For holometabolous insects with a wide geographic range, it is important to quantify upper thermal and lower hydric limits for multiple populations and life stages that differ in habitat usage and mobility. Population differences in egg survival are understudied despite the importance this life stage plays in population dynamics. As a sessile life stage, eggs likely experience strong selection pressures in response to extreme heat and drought. In this paper, we tested for population and phenotypic differences in egg survival for multiple USA populations of the invasive mosquito vector, Aedes albopictus . We found evidence of interpopulation differences in egg survival in response to high temperature and low humidity as well as plasticity in survival depending on experimental conditions. Some populations consistently had low survivorship across experiments. We found that field-collected eggs have low survivorship under field conditions, suggesting that egg survivorship may be low in nature. Finally, we showed that eggs experiencing high temperatures produced larvae that were unable to develop to the fourth instar during a simulated heatwave. Combined, our results reveal phenotypic plasticity and suggest a heritable component to thermal and hydric tolerance in this globally invasive species.