Date: 09/19/2006

Number: 1

We pondered all summer about the constant presence of monarch larvae on milkweed but the absence of pupae on milkweed. I have rarely seen monarch pupae on milkweed over many years of observations, and I have often wondered why the larvae seek tree branches, barbed wire, shrubs, and even thistles as pupation sites. But recently we observed a monarch pupa on a milkweed leaf. Two days ago and before the pupa matured, the milkweed leaf yellowed, withered, and dropped from the milkweed stem. The monarch pupa disappeared into the litter below the plant. Perhaps milkweed does not provide adequate longterm stability for pupae and successful butterflies have hatched from pupae on other supports. Thus natural selection for pupation away from the host food plant?

Unity, ME

Latitude: 44.6 Longitude: -69.3

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