What's in a day? A lot. The butterflies live between two and three weeks after emerging from the pupa, so they have to produce eggs quickly. In the fragile world of a butterfly, a day can make all the difference between reproducing and not.
The physiological difference
The researchers delved into what was behind these differences in egg production and development. They obtained blood samples from butterflies from old populations and new populations. Compared to females in the established patches, the females in these newly colonized patches had more
Juvenile hormone appears to be a key. It plays an important role in regulating egg and larval development and also regulates reproduction, particularly egg maturation, in adults, Fescemyer said. Vitellogenin is the protein precursor to egg yolk, which the embryo uses for food. Total protein is the most important nutrient for egg maturation, he said.
Adds to previous study
Previous studies had found other physiological differences between these more robust butterflies and their status quo sisters and brothers. They found that individuals that established new populations mate sooner, lay more eggs and have a different form of an enzyme important to flying, phosphoglucose isomerase. They also found they have a higher metabolic rate.
Future research will try to further uncover more physiological and molecular differences that account for the differences in reproduction and in flight, Fescemyer said. The researchers also hope to see what part host plant nutrition plays in these differences.