Female monarchs often lay their eggs on the underside of milkweed leaves. They are not clustered, but laid individually, and ideally, on separate leaves to avoid competition among developing caterpillars.
Monarch eggs are so tiny it can be difficult to see them clearly without a hand lens. The longitudinal lines help differentiate them from other insect eggs, which can be very helpful.
This monarch egg is 1 mm across and approximately 2 mm long.
Monarch Egg on Milkweed Leaf
Monarchs often lay eggs on the underside of milkweed leaves, which provides protection while they are developing. They can also be found on the tops of leaves, but that exposes them more to the elements as well as predation from above.
Monarch Eggs on Common Milkweed Leaf
This photo shows a newly laid monarch egg on the underside of a common milkweed leaf.
Egg Loading on Common Milkweed Leaf
These eggs were laid on the same leaf and very close together. This is called egg loading and is a problem for emerging caterpillars, since they will be faced with competition as soon as they hatch. Females typically lay eggs on separate leaves and plants, but may lay many at once due to lack of suitable milkweed in the area or the need to quickly lay her eggs for another reason. Eggs are often laid on young leaves near the top of the plant and can be found on plants less than 6" tall.
Hatching Gallery & Video
Head Capsule Becoming Visible (1 of 9)
Head Capsule Darkening (2 of 9)
Head Capsule Darkening (3 of 9)
Egg Ready to Hatch (4 of 9)
Chewing Egg Shell (5 of 9)
Hatching (6 of 9)
Hatching (7 of 9)
Hatching (8 of 9)
Hatched and Eating Shell (9 of 9)
Video: Monarch Egg Hatching
Monarch eggs are about 1 millimeter in size. When the tiny caterpillar hatches, it is approximately 2 millimeters long, creamy white with few markings. Once they hatch, they will often feed on milkweed hairs and their egg shell.