[HELICONIUS] Ithomiinae interspecific hybridization, something I didn't know about

[James Mallet]

Vasconcellos-Neto, J. 1982. Interspecific hybridization in Mechanitis 
butterflies (Ithomiinae): a novel pathway for the breakdown of 
isolating mechanisms. Biotropica 14:288-294.
http://www.jstor.org/stable/info/2388088
A novel pathway is proposed to explain the occasional breakdown of 
prezygotic (chemical-courtship) isolating mechanisms in mimetic 
ithomiine butterflies (Mechanitis polymnia and M. lysimma) In dense 
dry-season populations, mixed groups of males have been observed to 
court a single female. She becomes receptive through recognition of 
the pheromone produced by the conspecific majority males, but may be 
mated by a transpecific minority male in the courting group, leading 
to accidental interspecific hybridization. All five interspecific 
matings observed in Sumare, Sao Paulo, Brazil, were between a female 
of the more-abundant species, M. polymnia casabranca, and a male of 
the less-abundant M. lysimnia lysimnia. The F1 hybrid can probably 
backcross to both parental types, as many recombinant phenotypes are 
represented in the 48 presumed hybrids known from six localities, 
among over 36,500 parental types sampled or marked during seven 
years. The small interspecific introgression may occasionally be 
important in the evolution of these mimetic butterflies.
best, j

________________________________

James Mallet
UCL
www.ucl.ac.uk/taxome/jim  
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