title: On the fate of seasonally plastic traits in a rainforest butterfly under relaxed selection.
abstract: Many organisms display phenotypic plasticity as adaptation to seasonal environmental fluctuations. Often, such seasonal responses entails plasticity of a whole suite of morphological and life-history traits that together contribute to the adaptive phenotypes in the alternative environments. While phenotypic plasticity in general is a well-studied phenomenon, little is known about the evolutionary fate of plastic responses if natural selection on plasticity is relaxed. Here, we study whether the presumed ancestral seasonal plasticity of the rainforest butterfly Bicyclus sanaos (Fabricius, 1793) is still retained despite the fact that this species inhabits an environmentally stable habitat. Being exposed to an atypical range of temperatures in the laboratory revealed hidden reaction norms for several traits, including wing pattern. In contrast, reproductive body allocation has lost the plastic response. In the savannah butterfly, B. anynana (Butler, 1879), these traits show strong developmental plasticity as an adaptation to the contrasting environments of its seasonal habitat and they are coordinated via a common developmental hormonal system. Our results for B. sanaos indicate that such integration of plastic traits - as a result of past selection on expressing a coordinated environmental response - can be broken when the optimal reaction norms for those traits diverge in a new environment.
authors: Institute of Biology, Leiden University PO Box 9505, 2300 RA, Leiden, the Netherlands ; Laboratory of Genetics, Wageningen University and Research Centre P.O. Box 309, 6700 AH, Wageningen, the Netherlands ; Department of Zoology, University of Cambridge Downing Street, Cambridge, CB2 3EJ, UK.
authors: Vicencio
authors: V
authors: Oostra
authors: Institute of Biology, Leiden University PO Box 9505, 2300 RA, Leiden, the Netherlands ; Department of Zoology, University of Cambridge Downing Street, Cambridge, CB2 3EJ, UK.
authors: Paul M
authors: PM
authors: Brakefield
authors: Institute of Biology, Leiden University PO Box 9505, 2300 RA, Leiden, the Netherlands.
authors: Yvonne
authors: Y
authors: Hiltemann
authors: Institute of Biology, Leiden University PO Box 9505, 2300 RA, Leiden, the Netherlands ; Laboratory of Genetics, Wageningen University and Research Centre P.O. Box 309, 6700 AH, Wageningen, the Netherlands.
authors: Bas J
authors: BJ
authors: Zwaan
authors: Institute of Biology, Leiden University PO Box 9505, 2300 RA, Leiden, the Netherlands ; Department of Zoology, University of Cambridge Downing Street, Cambridge, CB2 3EJ, UK.
authors: Oskar
authors: O
authors: Brattström
keywords: Bicyclus anynana; Bicyclus martius; Bicyclus sanaos; constraints; life-history evolution; phenotypic plasticity; reproductive investment; seasonality