Studying Royal Migration

Monarch butterflies—famous for their royal wingspan and bold orange and black stripes—may be unconventional animals to study, but they have been the center of attention for Jeremy L. Hsu ’11 for the past year and a half.

Butterflies first piqued Hsu’s interest when he conducted summer research through a FAS Center for Systems Biology program, and he has stayed with the same lab ever since.

“Butterflies are very charismatic and gregarious, and they’re very cool to work with,” said Hsu, an Organismic and Evolutionary Biology concentrator.

He said that butterflies make “a great model system” to study because of their small size, short lifespan, low-maintenance, and “because everyone’s fascinated by them.”

Of the two existing subspecies of Monarch butterflies, one is notable for its annual mass migration from Northern America to Mexico and then northward again. The other subspecies does not migrate and lives yearlong in equatorial regions.

“I’m trying to figure out, why?” said Hsu.

The journey of the migratory butterflies lasts longer than the normal life span of one monarch; in fact, the generation that finally returns to the original site may be three to four generations removed from the original butterflies.

Previous studies, according to Hsu, have examined the factors that allow the first generation to live the longest. Other studies have focused on the neurological aspects of migration or the levels of gene expression in the different butterfly generations.

His study, Hsu said, investigates the genetic basis that distinguishes the two subspecies’ migratory behavior.

Most of the time he spends in lab is spent on genotyping, which involves extracting DNA, usually from the thorax of the insect, finding out the exact nucleotide sequence, and then comparing the sequences between the migratory and non-migratory subspecies.

The monarchs have been collected from all over the Americas, including Boston, California, Hawaii, and Ecuador, to ensure the robustness of the data.

Hsu recalled his interesting trip to Costa Rica to obtain more butterflies samples.

“You just swing, hope you get them. Then, many curses,” said Hsu, of catching butterflies using a large net.

“I really enjoyed the field work. It was a great experience,” he added.

Hsu has already found some promising results, and some of the gene sequences have indeed shown differences between the two subspecies. The genes of interest found so far control energy production, sun-compass orientation, and the juvenile hormone pathway, which regulates development and reproduction.

Having already presented his results at two biology conferences over the summer, Hsu is working to develop his current project into a senior thesis.

Marcus R. Kronforst, the lab’s principal investigator, said the results “may be zeroing in some spots in the genome that are very significant and lead to an explanation of migration behavior differences.”

“[Hsu] is a very self-motivated scientist, and he has been tackling this project in a very comprehensive way,” said Kronforst, who is a Bauer Fellow at the Center for Systems Biology. “His project may be for a senior thesis, but the level of work that he is doing is on the level of that of a [graduate student.]”

—Staff writer Helen X. Yang can be reached at hxyang@fas.harvard.edu.