title: Decrease of fluctuating asymmetry among larval instars in an aquatic, holometabolous insect.
abstract: The use of fluctuating asymmetry (FA) to reveal environmental stress in natural populations has been investigated extensively over the past decade. In aquatic ecosystems, many investigations involve amphibiotic insects with larval development stages in freshwater. To explain the important variability in study results, we investigated the FA level of a natural Hydropsyche exocellata (Insecta: Trichoptera) population at four different stages, from first larval instar to adult. The level of FA decreased between larval stages, but remained constant between the last larval instar and the adult. The presence of a compensational growth mechanism and the elimination of asymmetric individuals by natural selection are two hypotheses that could explain this observation.
authors.affiliation: UMR CNRS EcoBio, Université Rennes-1, Campus de Beaulieu, 263, Av. du Général-Leclerc, 35042 Rennes cedex, France. christophe.piscart@univ-rennes1.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Piscart
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Moreteau
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Beisel
mesh_terms: D000465:Algorithms; D000818:Animals; D004777:Environment; D005121:Extremities / Q000254:growth & development; D005260:Female; D005618:Fresh Water; D007313:Insecta / Q000033:anatomy & histology* / Q000254:growth & development; D007814:Larva / Q000033:anatomy & histology* / Q000254:growth & development; D008297:Male