Annual Life Cycle - Generation 1
Generation 1 | Generation 2 | Generations
3 & 4
Overview
Monarchs in Generation 1 are the offspring of the monarchs that overwinter. They
are laid from late March through April in the southern United States and northern
Mexico, and fly north as adults. They do not undergo reproductive diapause.
Life Cycle Summary
The first monarch generation of the year begins when females that have spent the
winter in Mexico lay eggs in northern Mexico and the southern United States beginning
in late March. The last eggs are laid in late April or early May, farther north.
Since it is often cool when Generation 1 larvae are developing, it may take them
up to 40 or 50 days, or even more, to develop from eggs to adults.
Generation 1 adults emerge from late April to early June. They mate and begin to
lay eggs about four days after emerging, and continue the journey north that their
parents began, laying eggs along the way. They begin to arrive in the northern US
and southern Canada in late May.
Like all monarchs, this generation begins life on plants in the milkweed family.
The most important host plants for Generation 1 monarchs in the southern US are
Asclepias oenotheroides, A. viridis and A. asperula.