A long-term survey of spring monarch butterflies in north-central Florida

Lincoln P. Brower, Ernest H. Williams*, Kelly Sims Dunford, James C. Dunford, Amy L. Knight, Jaret Daniels, James A. Cohen, Tonya Van Hook, Emily Saarinen, Matthew J. Standridge, Samantha W. Epstein, Myron P. Zalucki, Stephen B. Malcolm

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Long-term springtime counts of immature and adult monarch butterflies and their Asclepias humistrata host plants in north-central Florida reveal a close relationship between the milkweed’s phenology and the butterfly’s spring remigration from Mexico. Remigrant adults arrive after most frosts occur and as the milkweeds are flourishing but before the plants begin to senesce. The peak of adult arrival is during the first few days in April; the eggs that are laid during this peak develop through April, leading to a second peak in adult abundance in early May. These newly emerged adults continue the migration northward. In addition to assessing the phenology of annual events, our long-term survey, with regular monitoring from 1994–2017, has enabled us to evaluate long-term trends. Both adults and immatures have declined in abundance from1985 to 2017; since 2005, both have declined by around 80%. This decline has occurred concurrently with the decline in the number of monarchs at their Mexican overwintering sites.

Original languageEnglish
Pages (from-to)2025-2046
Number of pages22
JournalJournal of Natural History
Issue number31-32
StatePublished - 26 Aug 2018
Externally publishedYes


  • Milkweeds
  • Monitoring
  • Phenology
  • Population decline
  • Spring remigration


Dive into the research topics of 'A long-term survey of spring monarch butterflies in north-central Florida'. Together they form a unique fingerprint.

Cite this