Egg identification sheet

In the wild, a female monarch can lay 300 to 400 eggs in the space of a few weeks. Females usually lay one egg per milkweed plant, gluing it to the underside of a leaf to protect it from nasty weather. Don’t be surprised, though, if you find several eggs on the same plant or even on the same leaf.A monarch egg is barely 1 mm in size, so you need to look carefully!


Height: 1.2 mm
Width: 0.9 mm
Duration: 3 to 8 days

  • Usually a single egg per milkweed plant, but sometimes several.
  • Creme-coloured or yellowish, oval and slightly conical, covered in longitudinal raised ridges.


Watch out for false eggs!

Milkweed produces a sticky whitish sap that sometimes forms small bubbles on the leaves. Be careful not to confuse these droplets with monarch eggs! To distinguish between them, look carefully (with a magnifying glass): a monarch egg is covered in vertical lines.

  • Small whitish bubbles, rather spherical.
  • Different sizes, may resemble a monarch egg.
Photo: André Sarrazin
Photo: André Sarrazin