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SUMMARY:Butterflies on steroids: hormones\, gene expression and how to dea
 l with fluctuating environments - Vicencio Oostra - Leiden University\, Th
 e Netherlands
DTSTART:20111004T150000Z
DTEND:20111004T160000Z
UID:TALK32175@talks.cam.ac.uk
CONTACT:Oskar Brattstrom
DESCRIPTION:Virtually all organisms face some level of heterogeneity in th
 e quality of their environment. When such fluctuations are seasonal and th
 us predictable\, there is scope for anticipating them and adjusting life h
 istory strategies well in time. Such plasticity is a common feature of ani
 mal life\, and may include such diverse adaptations as migration\, diapaus
 e or plumage molt. \n\n\nAs part of my PhD\, I study mechanisms by which t
 he afrotropical butterfly Bicyclus anynana copes with its habitat's contra
 sting seasonal environments. In the warm wet season\, when food is abundan
 t\, butterflies reproduce fast and live relatively short lives. In contras
 t\, in the cold dry season food is limited and butterflies bridge this har
 sh period as cryptic adults\, postponing reproduction until the start of t
 he next wet season. \n\nWe studied how conditions during larval developmen
 t induce these two alternate phenotypes. In particular\, we found how Ecdy
 steroid hormones play an important role in interpreting the environment du
 ring development by responding in a threshold-like manner to an environmen
 tal gradient\, acting like a switch mechanism between alternate developmen
 tal trajectories. Subsequently\, these hormones  induce the changes in the
  adult traits involved in the seasonal adaptation\, such as wing pattern a
 nd fecundity\, in a time- and temperature dependent manner. This suggests 
 that rather than constraining environmental responses\, the hormone system
  allows for both flexibility and integration of traits underlying adaptati
 ons to divergent environments.\n\nEnvironmentally induced phenotypic diffe
 rences between seasonal morphs ultimately depend on transcriptional regula
 tion\, since both morphs develop from the same genetic background. Transcr
 ipts of innate immunite genes were expressed at much higher level in the w
 et season\, possibly related to the higher reproductive activity. In contr
 ast\, lipid metabolic and transport genes showed higher activity in dry se
 ason conditions\, reflecting increased storage of acquired resources.\n
LOCATION:Part II Lecture Theatre\, Department of Zoology
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