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The eggs are laid by the females during spring and summer breeding months. The eggs are laid onto the leaves of milkweed plants.& hatch (after 4 days), revealing worm-like larvae, the caterpillars. The caterpillars consume their egg cases, then feed on milkweed, and sequester substances called cardenolides, a type of cardiac glycoside. During the caterpillar stage, monarchs store energy in the form of fat and nutrients to carry them through the non-feeding pupa stage. The caterpillar stage lasts around 2 weeks. In the pupa or chrysalis stage, the caterpillar spins a silk pad on a twig, leaf, etc., and hangs from this pad by its last pair of prolegs. It hangs upside down in the shape of a 'J', and then molts, leaving itself encased in an articulated green exoskeleton. At this point, hormonal changes occur, leading to the development of a butterfly (metamorphosis). The chrysalis darkens (the exoskeleton becomes transparent) a day before it emerges, and its orange and black wings can be seen. The mature butterfly emerges after about two pupal weeks and hangs from the split chrysalis for several hours until its wings are dry (often in the morning). Meanwhile fluids are pumped into the crinkled wings until they become full and stiff. Some of this orangey fluid (called meconium) drips from the wings. Finally (usually in the afternoon) the monarch spreads its wings, quivers them to be sure they are stiff, and then flies away, to feed on a variety of flowers, including milkweed flowers, red clover, and goldenrod. Monarchs can live a life of two to eight weeks in a garden having their host Asclepias plants and sufficient flowers for nectar. This is especially true if the flower garden happens to be surrounded by native forest that seems to be lacking in flowers.
On butterfly weed (Asclepias tuberosa)
Lat: 35.90, Long: -86.96
Spotted on Oct 9, 2011
Submitted on Oct 9, 2011