New Publication: Disentangling local adaptation and phenotypic plasticity in traits associated with altitude and temperature in widespread tropical butterflies

In our new paper in Journal of Evolutionary Biology we report the results of several large experiments rearing butterflies from different altitudes under common conditions at Ikiam university in Ecuador. Through these we identified genetically controlled traits that differ between populations at different altitudes and tested how populations from different altitude responded to being reared at different temperatures. We found that in both species tested (Heliconius erato and Heliconius melpomene) the amount of black on the wing increased with increasing altitude. This may help the butterflies at cooler higher altitudes to heat up faster. 

In one species (H. erato) we found differences between populations in how rearing temperature affected thermal tolerance as an adult (a gene-by-environment interaction): butterflies from low altitudes when reared at higher temperatures were more heat resistant, whereas in high altitude populations rearing temperature had no effect. This may be because the lower altitude populations are more likely to experience higher temperatures. In the other species (H. melpomene) we found the butterflies from higher altitude could develop faster at colder temperatures compared to their low altitude counterparts (but there was no difference in developmental rate at warmer temperatures). 

This huge undertaking was led by postdoc Patricio Salazar-Carrion and PhD student Tien Nguyen, with most of the experimental work done by research assistants Sophie Smith, Kimberly Gavilanes and Michelle Guachamin-Rosero. Dr Caroline Bacquet led the work at Ikiam.