Mating (16 hours)
• Monarch mate for the first time when they are 3 to 8 days old
• Mated pairs remain together for up to 16 hours (early afternoon to the next morning)
• Both sexes mate several times during their lives

Egg (3-4 days)
• Female monarchs lay eggs on young milkweed plants, generally on the underside of leaves
• The egg will hatch in 3-4 days; the caterpillar will eat its eggshell for its first meal

Larva (10 -14 days)
• After eating its eggshell, the caterpillar will feed on the milkweed leaves
• The caterpillar will shed its skin (molt) 4 times as it grows
• The caterpillar will eat almost constantly for about two weeks
• Once fully grown, approximately 2 inches in length, the caterpillar will seek out a place to pupate

Pupation (several hours)
• The caterpillar hangs upside down and forms a pre-pupal “J”
• It shed its skin for the last time – the exoskeleton is split and discarded; the new skin (cuticle) is exposed and the chrysalis stage begins
• Generally form between 9-11 am or 5-7 pm

Chrysalis (10-14 days)
• This stage lasts for about two weeks
• When the mature butterfly can be seen through the pupal cuticle (chrysalis) the butterfly will emerge within 24 hours
• The butterfly releases a fluid and splits the pupal cuticle just before emerging
• The abdomen of the emerging butterfly will be enlarged and will pulsate as fluid is pumped into the wings, until the wings are fully expanded and stiff. It takes another 1-2 hours for the monarch’s wings to harden sufficiently for flight.

Adult Monarch
• During the first 24 hours the wings will harden and the sensory mechanisms (eyes, odor receptors on the antennae, and taste receptors on the ends of the legs will become fully functional
• Adult butterflies can live up to 6 weeks
• Monarchs that reach adulthood in the Autumn are the butterflies that will migrate to Mexico
• Peak migration in southern Maine is September 1-12