A monarch butterfly tethered in our monarch flight simulator.
The monarch butterfly, Danaus plexippus
, is famous for its spectacular annual migration across North America, recent worldwide dispersal, and orange warning coloration. Despite decades of study and broad public interest, we know little about the genetic basis of these hallmark traits. Recently, by sequencing and analyzing 101 Danaus
genomes from around the globe, we uncovered the history of the monarch’s evolutionary origin and global dispersal, characterized the genes and pathways associated with migratory behavior, and identified the discrete genetic basis of warning coloration. The results substantially changed our understanding of this classic system, showing, for instance, that D. plexippus
was ancestrally migratory and dispersed out of North America to occupy its broad distribution. We found striking signatures of selection associated with suites of genes involved in neurogenesis, development, and metabolism but the strongest signatures of selection centered on flight muscle function, resulting in greater flight efficiency among migratory monarchs, and that variation in monarch warning coloration was controlled by a gene not previously implicated in insect pigmentation. We are now working to determine the precise environmental cues that trigger migratory behavior and genetically dissect the migratory syndrome – including behavior, physiology and morphology. This research is of particular importance now because monarch migration is currently experiencing a notable decline. Our work is documenting the evolutionary, genetic, and behavioral distinctiveness of North American monarchs and identifying the functional molecular basis of this amazing natural phenomenon.
Tenger-Trolander, A., C. R. Julick, W. Lu, D. A. Green, K. L. Montooth and M. R. Kronforst. 2023. Seasonal plasticity in morphology and metabolism differs between migratory North American and resident Costa Rican monarch butterflies. Ecology and Evolution 13: e9796. bioRxiv preprint
Tenger-Trolander, A. and M. R. Kronforst. 2020. Migration behaviour of commercial monarchs reared outdoors and wild-derived monarchs reared indoors. Proc. R. Soc. B 287: 20201326. UChicago Medicine News Phys.org
Talla, V., A. A. Pierce, K. L. Adams, T. J. B. de Man, S. Nallu, F. X. Villablanca, M. R. Kronforst and J. C. de Roode. 2020. Genomic evidence for gene flow between monarchs with divergent migratory phenotypes and flight performance. Molecular Ecology 29: 2567– 2582. ScienceDaily YouTube
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Green, D. A. and M. R. Kronforst. 2019. Monarch butterflies use an environmentally sensitive, internal timer to control overwintering dynamics. Molecular Ecology 28: 3642-3655. Dryad Data ScienceDaily EarthSky
Zhan, S., W. Zhang, K. Niitepold, J. Hsu, J. F. Haeger, M. P. Zalucki, S. Altizer, J. C. de Roode, S. M. Reppert and M. R. Kronforst. 2014. The genetics of monarch butterfly migration and warning colouration. Nature 514: 317-321. Nature News & Views Science Magazine NY Times National Geographic Washington Post NBC News
Pierce, A. A., M. P. Zalucki, M. Bangura, M. Udawatta, M. R. Kronforst, S. Altizer, J. F. Haeger and J. C. de Roode. 2014. Serial founder effects and genetic differentiation during worldwide range expansion of monarch butterflies. Proc. R. Soc. B 281: 20142230.