The latest decrease in monarch butterflies is likely due to a decrease in the milkweed plant (Asclepias) – a primary food for monarchs – from herbicide use in the butterfly’s reproductive and feeding grounds in the U.S., as well as extreme climate variations during the fall and summer affecting butterfly reproduction.
Omar Vidal, director of the WWF in Mexico said:
Extreme climate fluctuations in the U.S. and Canada affect the survival and reproduction of butterflies. The monarch’s life cycle depends on the climatic conditions in the places where they develop. Eggs, larvae and pupae develop more quickly in milder conditions. Temperatures above 95°F can be lethal for larvae, and eggs dry out in hot, arid conditions, causing a drastic decrease in hatch rate.
The Monarch specialists are urging all of us to plant milkweed this year. Even though Colorado is not on a direct migration path for the Monarch, we do get strays here, and having a milkweed plant for them would not be a bad idea. This year we’ll have two types of milkweed plants available, Asclepias tuberosa, AKA butterfly weed, a Colorado native and Asclepias curassavica, a beautiful milkweed that is the preferred plant for Monarchs and liked by other butterflies, too.
My recommendation for the perfect butterfly garden for Colorado? Butterfly bush (Buddleia), milkweed (Asclepias), zinnia, sunflower, aster, parsley, dill, verbena, cosmos and hollyhock. Whether you group them together, or intersperse them in your garden, you’ll have an excellent habitat for butterflies. The hollyhock, asclepias, verbena, and sunflower are quite drought tolerant, too. It seems to go without saying, but I’ll say it anyway: if you want to attract butterflies and hummingbirds to your garden, please do not use pesticides!
We found a great chart on the CSU website that lists common Colorado butterflies and their host and nectar plants. I’ve noticed that here the butterflies seem to love zinnias above almost every other flower. Swallowtails are one of the most beautiful butterflies and even their caterpillars are cute! I took this picture last summer in the nursery.
| Food used by common eastern Colorado butterflies and skippers. | |||
|
Butterfly |
Flight period |
Caterpillar food |
Common nectar plants, adult food |
| Black swallowtail (Papilio polyxenes) |
April-September | Dill, parsley, fennel, carrot | Butterfly weed, alfalfa, thistle |
| Checkered skipper (Pyrgus communis) |
April-October | Mallow, hollyhock | Verbena, dandelion, Canada thistle, aster |
| Checkered white (Pontia protodice) |
April-November | Tumble mustard | Alfafa, mustards, bee balm |
| Clouded sulfur (Colias philodice) |
April-November | Alfalfa, clover | Alfalfa, phlox, rabbitbrush, aster, marigold |
| Edwards fritillary (Speyeria edwardsii) |
June-September | Nuttall’s violet | Rabbitbrush, gaillardia, bee balm |
| European cabbage butterfly (Pieris rapae) |
April-October | Broccoli, cabbage (mustard family) | Many |
| Gorgone checkerspot (Charidryas gorgone) |
May-September | Sunflowers | White clover, dandelion, Canada thistle |
| Gray hairstreak (Strymon melinus) |
May-October | Many | Many |
| Hackberry butterfly (Asterocampa celtis) |
May-September | Hackberry | Rotting fruit, sap flows |
| Melissa blue (Lycaeides melissa) |
April-October | Wild licorice, alfalfa, etc. | Bee balm, sweet clover |
| Monarch (Danaus plexippus) |
June-October | Milkweed | Cosmos, Canada thistle, rabbitbrush, etc. |
| Mourning cloak (Nymphalis antiopa) |
February-November | Willow, aspen, cottonwood, elm | Rabbitbrush, milkweed, sap |
| Orange sulfur (Colias eurytheme) |
April-October | Alfalfa, vetch, pea | Alfalfa, marigold, zinnia |
| Painted Lady (Vanessa cardui) |
April-October | Thistle, hollyhock, sunflower | Grape hyacinth, cosmos, zinnia, alfalfa, many flowers |
| Silver-spotted skipper (Epargyreus clarus) |
May-July | Wild licorice, locust, etc. | Lilac, dogbane, zinnia, sweet pea, Canada thistle |
| Two-tailed swallowtail (Papilio multicaudatus) |
April-August | Green ash, chokecherry | Geranium, thistle, milkweed |
| Variegated fritillary (Euptoieta claudia) |
April-October | Various, including pansy | Rabbitbrush, Canada thistle |
| Weidemeyer’s admiral (Limentitis weidemeyerii) |
June-September | Willow, aspen, cottonwood | Sap flows, snowberry, dung |
| Western tiger swallowtail (Papilio rutulus) |
May-July | Willow, cottonwood, chokecherry | Zinnia, lilac, butterflybush, thistle, milkweed |
| Wood nymph (Cercyonis pegala) |
June-August | Grasses | Rabbitbrush, clematis, Canada thistle |
To read more about butterflies on the CSU site, go here http://www.ext.colostate.edu/pubs/insect/05504.html
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