title: When mothers anticipate: effects of the prediapause stage on embryo development time and of maternal photoperiod on eggs of a temperate and a tropical strains of Aedes albopictus (Diptera: Culicidae).
abstract: BACKGROUND
  The diapause of Aedes albopictus is maternally induced by photoperiod and initiates at the pharate larvae stage in eggs. This pre-diapause results in enhanced survival eggs during the winter. This study aims to disentangle the effects of photoperiod and diapause on embryonic developmental time and egg size in A. albopictus. A temperate strain capable to perform diapause and a tropical strain unable of diapause were reared at 21°C with long-(LD) and short-day (SD) lengths. Four distinct traits were studied on embryos and eggs were measured at the end of embryogenesis.
  
  
  RESULTS
  The chronologies of embryo development for both strains were influenced by maternal photoperiod, especially in the temperate strain in which the development of SD eggs took longer than LD eggs. The delay increased gradually in the temperate strain, and reached up to 38 h at the end of embryogenesis. The kinetics of embryogenesis differed among the temperate and the tropical strains, each one of the 4 studied traits showing differences. For example the serosal cuticle was secreted precociously in the tropical strain. Egg width and volume are influenced by the maternal photoperiod and the strain×photoperiod interaction. For both strains, larger eggs were laid by female reared under SD when compared to LD.
  
  
  CONCLUSIONS
  The influence of several maternal effects was demonstrated in this study. The diapause process modifies greatly the length of embryogenesis in the temperate strain, whereas the maternal photoperiod has a direct influence on egg size and embryogenesis regardless of the strain considered. These findings provide useful data on chronology of embryonic development for integrative biology studies of egg pre-diapause stages.
authors.affiliation: EID Méditerranée, 165 Avenue Paul-Rimbaud, 34184 Montpellier, France; Earth and Life Institute, Biodiversity Research Centre, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium. Electronic address: glacour@eid-med.org.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lacour
authors.affiliation: EID Méditerranée, 165 Avenue Paul-Rimbaud, 34184 Montpellier, France. Electronic address: florian.vernichon@gmail.com.
authors.forename: Florian
authors.initials: F
authors.lastname: Vernichon
authors.affiliation: EID Méditerranée, 165 Avenue Paul-Rimbaud, 34184 Montpellier, France. Electronic address: cadilhac.nicolas@hotmail.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cadilhac
authors.affiliation: UMR-MIVEGEC, Institut de Recherche pour le Développement, 34394 Montpellier, France. Electronic address: sebastien.boyer@ird.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boyer
authors.affiliation: EID Méditerranée, 165 Avenue Paul-Rimbaud, 34184 Montpellier, France. Electronic address: clagneau@eid-med.org.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lagneau
authors.affiliation: Earth and Life Institute, Biodiversity Research Centre, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium. Electronic address: thierry.hance@uclouvain.be.
authors.forename: Thierry
authors.initials: T
authors.lastname: Hance
mesh_terms: D000330:Aedes / Q000196:embryology* / Q000502:physiology; D000818:Animals; D064666:Diapause, Insect; D004625:Embryo, Nonmammalian / Q000502:physiology; D047108:Embryonic Development; D005260:Female; D010063:Ovum / Q000254:growth & development / Q000502:physiology; D017440:Photoperiod
keywords: Day length; Diapause; Embryo development; Phenotypic plasticity