Eco-physiological mechanisms and adaptive value of egg diapause in the invasive mosquito Aedes albopictus (Diptera : Culicidae)
Year: 2016
Type: dissertation
Abstract: The success of widespread invasive species depends of their ability to support the selection pressures of the colonized environments. The climatic determinant is a key barrier for naturalization and spread of invasive species, especially climate seasonality in temperate area. Diapause is the prime component of the winter response in insects, and a convenient model of phenotypic plasticity. The role of diapause in the adaptive capacity of an invasive species was investigated in the Asian tiger mosquito Aedes albopictus in French Mediterranean area. We show phenotypic differentiations between tropical and temperate strains (in embryogenesis kinetics, egg width and volume, and wing length) likely linked to genotypes. The diapause preparation phase per se increased the timing of embryogenesis, while photoperiod is responsible of egg volume variability, both findings of importance for molecular research. The role plays by diapause on the Ae. albopictus temperate population dynamics was demonstrated through an integrated approach. Life history traits (egg and larval survival, adult wing length and shape) of non-diapausing individuals were not differently affected by winter than diapausing individuals, likely due to the cold acclimation capacity. Diapause initiation and termination in field occurred at constant timing despite different winter conditions. The modeling of diapause shutdown demonstrated that diapause is not strictly obligatory to the species persistence, although it procured serious temporal and abundance advantages in the Southern margins of the temperate area. It highlights that the prime role of diapause is the seasonal synchronization and the prevention of egg hatching under fluctuating winter conditions. The suitability of the Mediterranean area to the establishment of diapausing or tropical invasive mosquito species is confirmed. Diapause is a plastic response with rapid evolution, which has implications for Northward spread of Ae. albopictus, and the future expansion of its active period in the Mediterranean basin.
Source: Digital Access to Libraries
Author: Guillaume Lacour
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2611217545