Monarch butterflies are in trouble. Their numbers have plummeted 97 % since the 1980s for several reasons:
- They lay their eggs on only one host plant, milkweed. Unfortunately, milkweed often grows along roadsides or farm fields where extensive pesticide sprayings occur. Milkweed is an innocent victim of man’s obsession with pesticides and insecticides.
- Extensive logging has occurred in Mexico, where the Eastern population overwinters. The habitat fragmentation endangers monarchs so much that a winter storm can decimate their numbers very rapidly. Even more alarming is the news from California, where the western population is facing a decimation of 86 % last year.
We were therefore thrilled that our Pennsylvania yard was a thriving monarch nursery last summer. Their pupa were usually so well concealed that we never found them until a freshly hatched butterfly perched nearby to unfold its wings. There is nothing like seeing a butterfly go through the life stages of egg, caterpillar, pupa and finally, adult.
While the caterpillars only feast on milkweed plants, the adults are not so limited in their choices. Any nectar-producing flower will do, whether it is spearmint, lobelia, goldenrod or zinnia. Zinnias were especially popular once monarchs began passing through our yard during their fall migration. That’s why it is so important to provide nectar sources for insects well into fall.