Wildlife

Fritillaries and Orange Patterned Butterflies

Monarch
Danaus plexippus

Description

3 1/2-4" (89-102 mm). Very large, with FW long and drawn out. Above, bright, burnt-orange with black veins and black margins sprinkled with white dots; FW tip broadly black interrupted by larger white and orange spots. Below, paler, duskier orange. 1 black spot appears between HW cell and margin on male above and below. Female darker with black veins smudged.

Similar Species

Viceroy smaller, has shorter wings and black line across HW. Queen and Tropic Queen are browner and smaller. Female Mimic has large white patch across black FW tips.

Life Cycle

Egg, 3/64" h x 9/256" w(1.2 x 0.9 mm), pale green, ribbed, and pitted, is shaped like lemon with flat base. Caterpillar, to 2" (51 mm), is off-white with black and yellow stripes; 1 pair of fine black filaments extends from front and rear. Chrysalis, to 7/8" (28 mm), pale jade-green, studded with glistening gold; plump, rounded, appears lidded, with lid opening along abdominal suture. Host plants are milkweeds (Asclepias) and dogbane (Apocynum).

Flight Successive broods; April-June migrating northward, July-August resident in North, September-October migrating southward, rest of year in overwintering locales. Year-round resident in S. California and Hawaii.

Habitat

On migration, anywhere from alpine summits to cities; when breeding, habitats with milkweeds, especially meadows, weedy fields and watercourses. Overwinters in coastal Monterey pine, Monterey cypress, eucalyptus groves in California, and fir forests in Mexican mountains.

Range

Nearly all of North America from south of Hudson Bay through South America; absent from Alaska and Pacific Northwest Coast. Established in the Hawaiian Islands and Australia.

Discussion

 One of the best known butterflies, the Monarch is the only butterfly that annually migrates both north and south as birds do, on a regular basis. But no single individual makes the entire round-trip journey. In the fall, Monarchs in the North begin to congregate and to move southward. Midwestern and eastern Monarchs continue south all the way to the Sierra Madre of middle Mexico, where they spend the winter among fir forests at high altitudes. Far western and Sierra Nevada Monarchs fly to the central and southern coast of California, where they cluster in groves of pine, cypress, and eucalyptus in Pacific Grove and elsewhere. Winter butterflies are sluggish and do not reproduce; they venture out to take nectar on warm days. In spring they head north, breed along the way, and their offspring return to the starting point. Both Mexican and international efforts are underway to protect the millions of Monarchs that come to Mexico. In California, nearly all of the roosting sites face threatening development.