Synonyms and other taxonomic changes
Danaus plexippus (Linnaeus, 1758)
Papilio plexippus Linnaeus 1758
ADULT: large, with conspicuous black veins on orange wings.
Monarchs often show a distinctive gliding flight with their wings held tilted upward in a dihedral (V shape).
Males have scent-scale patches on hindwings, prominent when wings are open, and just possible to see when wings are folded.
LARVA: entire length has alternating black, white, and yellow bands; front and hind ends have a pair of long black filaments projecting diagonally upward
Much of temperate North America into tropics and much of South America. Also some islands in Pacific, Australia (introduced?). Highly migratory.
Open areas with flowers, hostplants
March through fall in North America; all year in tropics.
Adults take nectar from a variety of flowers.
The caterpillars feed on plants in the Milkweed family (Asclepiadaceae [or Apocynaceae in part]), primarily Milkweeds (Asclepias), but also other genera including Calotropis, Cynanchum, Gonolobus, Sarcostemma, etc.
The adults make mass migrations from August-October, flying to hibernate along the California coast and in central Mexico.
At the wintering sites in Mexico, the butterflies roost in trees and form huge aggregations that may have millions of individuals.
They leave for the north in the spring, and females lay eggs along the way.
The females lay eggs singly on the leaves of the milkweeds (Asclepias); caterpillars eat the leaves and flowers.
and one that won't make it:
The chrysalis is light green, except for when the butterfly is about to emerge
female vs male:
Chrysalis just before emergence
Freshly emerged butterfly
There are extensive accounts of Monarch migration and ecology in technical and popular literature.
Members of the public often mistake the unrelated Viceroy
(below) for a Monarch, but the Viceroy is much smaller and has a black band across the hindwing.
See comparison of Monarch (1) and Viceroy (2) hindwings here:
The related Queen
lacks black veins on the forewing and has darker/browner wings, and the Soldier
has darker/browner wings.
Koch, R.L., R.C. Venette, and W.D. Hutchison. 2005. Influence of alternate prey on predation of monarch butterfly (Lepidoptera: Nymphalidae) larvae by the multicolored Asian lady beetle (Coleoptera: Coccinellidae) Environmental Entomology. 34(2): 410-416.
Southwest Monarch Study
(map & data for some AZ recoveries)
Texas Monarch Watch
- Mike Quinn, 2015