Lack of evidence for a fine-scale magnetic map sense for fall migratory Eastern North American monarch butterflies (Danaus plexippus)
Guerra PA, Parlin AF, Matter SF. Ecology and evolution, November 2022.
Read the paper Free to read · doi:10.1002/ece3.9498
What this paper is about
A monarch flying to Mexico has never been there. Sea turtles solve the same problem with an inherited magnetic map, and monarchs do have a magnetic sense.
The authors tested whether overwintering locations shift as the Earth's magnetic field drifts. They found no evidence that monarchs use a fine-scale magnetic map to find the sites.
Summarised here from the abstract below. Not the authors’ words.
Abstract
How first-time animal migrants find specific destinations remains an intriguing ecological question. Migratory marine species use geomagnetic map cues acquired as juveniles to aide long-distance migration, but less is known for long-distance migrants in other taxa. We test the hypothesis that naïve Eastern North American fall migratory monarch butterflies (Danaus plexippus), a species that possesses a magnetic sense, locate their overwintering sites in Central Mexico using inherited geomagnetic map cues. We examined whether overwintering locations and the abundance of monarchs changed with the natural shift of Earth's magnetic field from 2004 to 2018. We found that migratory monarchs continued to overwinter at established sites in similar abundance despite significant shifts in the geomagnetic field, which is inconsistent with monarchs using fine-scale geomagnetic map cues to find overwintering sites. It is more likely that monarchs use geomagnetic cues to assess migratory direction rather than location and use other cues to locate overwintering sites.
Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.
Key terms
Find the paper
Cite this page
This page is licensed CC BY 4.0. Quote it, adapt it and reuse it, including commercially, as long as you credit Milkweed USA and link back.
Milkweed USA. (2026). Lack of evidence for a fine-scale magnetic map sense for fall migratory Eastern North American monarch butterflies (Danaus plexippus) (listing). Retrieved DATE, from https://milkweedusa.com/research/lack-of-evidence-for-a-fine-scale-magnetic-map-2022/
"Lack of evidence for a fine-scale magnetic map sense for fall migratory Eastern North American monarch butterflies (Danaus plexippus) (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/lack-of-evidence-for-a-fine-scale-magnetic-map-2022/. Accessed DATE.
Milkweed USA. "Lack of evidence for a fine-scale magnetic map sense for fall migratory Eastern North American monarch butterflies (Danaus plexippus) (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/lack-of-evidence-for-a-fine-scale-magnetic-map-2022/.
@misc{milkweedusa_researchlackofevidenceforafi,
title = {Lack of evidence for a fine-scale magnetic map sense for fall migratory Eastern North American monarch butterflies (Danaus plexippus) (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/lack-of-evidence-for-a-fine-scale-magnetic-map-2022/},
note = {Accessed DATE}
}