|scientific name Danaus plexippus |
common name Monarch
Most likely to be encountered in the southern prairie grasslands.
Migrants reach southern Alberta in late May to June, offspring emerging in Aug. to Sep.
The black-veined, orange upperside with a white-spotted black border is unique. The Viceroy (Limenitis archippus) though similar, has a black hindwing median line. Monarchs are easy to recognize by their distinctive leisurely, floating flight, holding their wings V-shaped above the body when gliding; Viceroys hold their wings in a flat plane when gliding, a behaviour characteristic of the genus Limenitis.
Migrants from the southern US appear in the spring, and lay eggs on a number of milkweed species, particularly along prairie river valleys. Larvae are like no other in Alberta, boldly banded with alternating black, white and yellow stripes. There are two long, black fleshy 'horns' near the front and rear. Pupae are bright blue-green with golden spots. This is undoubtedly one of the most familiar butterflies in North America, and much research has been carried out on its ecology and remarkble migration. Surprisingly, the Monarch's wintering grounds in Mexico were not discovered until 1975, largely as a result of the research efforts of Fred Urquhart (Layberry et al. 1998). Almost all of the North American Monarchs overwinter in a handful of sites in the Mexican highlands, and conservation efforts for this species are largely dependent on the welfare of these sites. For more detailed accounts of the Monarch's ecology, see Brower (1995) and references therein.
The Monarch is of special concern in Canada (COSEWIC 2002).
The main larval host in Alberta is Showy Milkweed (Asclepias speciosa), and larvae have also been recorded on A. ovalifolia in Edmonton (Bird et al. 1995). Adults prefer nectaring at milkweed flowers and composites (Klassen et al. 1989).
Globally widespread, with the centre of the range in North America from BC east to Newfoundland, north to the southern NWT south to Argentina (Layberry et al 1998).
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