Emerging early in the spring the white and sulfur butterflies can be seen flying over meadows as they alternately flap and glide in the breeze, occasionally spiraling in pairs. These ever-present white, orange and yellow butterflies are always a pleasure to watch as they mesmerize the observer with their fascinating aerial displays.
White and sulfur butterflies have a wingspan that is about one inch and are one of the medium-sized butterflies. They belong to the Pieridae family in the order Lepidoptera, which is the moth and butterfly order. These beautiful insects are easily distinguished since they are the only butterflies that are solid white, yellow, or orange.
The spiraling flight of the white and sulfur butterflies is an instinctive behavior that can be observed during the mating season. It begins with two butterflies flying close together near the ground. Suddenly one will begin to circle around the other, which is immediately followed by both butterflies circling around each other as they rise into the sky-reaching heights of up to sixty feet.
Without warning one of the butterflies will drop from the sky like a dead weight falling all the way to the ground while the other will take several seconds to slowly drift down. This type of spiraling flight is very common among this species and over lush fields of vegetation many pairs of the white and sulfur butterflies can be seen performing this ritual at once during the spring and summer months. The pair will always be one male and one female.
In most cases the female has already mated and it is believed that she is using this behavior to get rid of a courting male so she can get back to the business of egg laying. The female is the first to rise in the spiral flight with the male following. Once the female has reached a certain height the male will give up his pursuit and drop straight down to the ground. The female then slowly glides to the ground allowing the male time to move along and find a receptive female.
When the mating ritual leads to consummation the female will spend a great amount of time laying her eggs. Each egg is laid singly on the leaves of a host plant. When doing this the female will fly lazily about over the vegetation without stopping to feed on the plant foods of her species. In some cases, she will just approach the plant and at other times she will light briefly for only a moment before moving on.
Once she discovers the right species of plant she will land on a leaf bending her abdomen down to touch the leaf. Looking at the leaf once the female has moved on, one can see a pinhead size dot of white that is her egg.
The eggs of these butterflies will hatch in about one week producing the larvae. White and sulfur butterflies in the adult stage will usually remain in areas where their larval food plants are in abundance. The larvae of the white butterflies eat cabbage, broccoli, wild mustards, and other plants from the mustard family. The sulfur butterfly larvae eat alfalfa, clover, wild senna, and plants from the bean family.
Since these are their choice food plants, both the adults and larvae can often be found in vegetable gardens. It takes two to three weeks for the larvae to mature during which they will go through four molts. To pupate the larvae attach themselves to plant stems, emerging in about ten days. Each year the white and sulfur butterflies produce three or more generations with the majority of these found in the South.