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SUMMARY:Balancing selection in Müllerian mimicry: causes and consequences
  - Dr Violaine Llaurens\, Muséum National d’Histoire Naturelle Institut
  de Systématique\, Evolution\, Biodiversité 
DTSTART:20150310T160000Z
DTEND:20150310T170000Z
UID:TALK55208@talks.cam.ac.uk
CONTACT:Dr Hannah Rowland
DESCRIPTION:Mimicry among toxic species is a textbook example of natural s
 election driving evolutionary convergence of complex traits. Most toxic sp
 ecies involved in such Müllerian mimicry display a single warning signal 
 within population because of selection exerted by predators\, fixing the m
 ost common signal. Surprisingly\, in the toxic butterfly Heliconius numata
 \, several warning patterns are maintained within localities\, and each di
 splay high resemblance with distasteful species from different communities
 . During this talk\, I will first explore several hypotheses on the origin
  of balancing selection in this species. First\, weak toxicity of H. numat
 a might favour disruptive selection on warning patterns\, because each war
 ning pattern will mimic a different group of toxic species\, thus limiting
  the impact of lack of toxicity on the efficiency of the warning signal. I
  will thus present empirical estimation on toxicity variations in H. numat
 a and its effect on birds’ predation behaviour. Then I will present some
  theoretical results on the role of disassortative mating as a selective p
 ressure promoting local polymorphism of warning pattern. Finally\, I will 
 investigate the consequences of this balanced polymorphism on the underlyi
 ng genetic architecture. Variations in warning pattern in H. numata are co
 ntrolled by a supergene P in which each allele encodes for a different mim
 etic pattern. As a consequence of this polymorphism\, a high number of het
 erozygote are present in natural population and promote strict dominance b
 etween mimetic allele as a response to selection exerted against intermedi
 ate non-mimetic of heterozygotes. I will show results from RNAseq investig
 ating the molecular basis of such dominance at the supergene P.
LOCATION:Part II Lecture Theatre\, Department of Zoology
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