Our story of this beautiful butterfly ought really to begin with that one of the most successful plants in the world. Now a plant is successful from its own point of view when it is able to multiply abundantly in many different sorts of situation and to spread easily over a large area. The plant I have in mind is the thistle, which from time immemorial has been one of the commonest neighbors of man. It is found over the whole habitable globe, as well as in many advantages in its struggle for life. The roots penetrate deeply into the soil; the thickened, spiny leaves are so protected by their juices and their spines that they are molested by very few enemies; the flower stalks and also clothed in a similar armature; and the great needs of flowers are surrounded with prickly involucres that generally prevent their being eaten by browsing animals or even by phytophagous insects. The brightly colored blossoms are abundantly provided with nectar and pollen and they attract great number s of bees, moth, and butterflies, in order to bring about cross-fertilization. But all of these advantages are of little significance so far as wide distribution is concerned, compared with the feathery seeds which are produced in such abundance and so generally scattered by the slightest breath of wind that the word thistle-down has come into general use to express a lightly moving object. These airy seeds have riding on the wings of the wind all over the surface of the earth for untold millions of years. Doubtless during severe storm they may be carried thousands of miles, and it is easy to think that one of them might readily, and it is easy to think that one of them might readily go half-way round the world before it found a resting place. Wherever such a seed alighted and found the condition of a moist soil and slight protection, it would be likely soon to spring into growth and to start anew the development of its ancient race. The thistle, however, has not been entirely unmolested during its eons of existence. There has been developing along with it one of the most beautiful of our butterflies which has received various scientific names and the common name of the Painted Lady Vanessa cardui , although it is often called the Thistle Butterfly. This butterfly, however, can scarcely be considered a troublesome enemy of its host plant, for it is seldom sufficiently abundant to injure the thistle appreciably. The relation between the two is rather suggestive of that mutual toleration by which two living things develop together with advantage a least to one and without serious disadvantage to the other. The universal distribution of the food plant has led to a like distribution of the butterfly.
Butterflies Worth Knowing , by Clarence M. Weed, 1992
A group exhibition “regional forecast,” Brew House SPACE 101,
Pittsburgh, PA