I am the orange sulphur butterfly! I can be found in all of the United States, except Alaska and Hawaii. I fly most of the summer, from May to October, in Nevada. When you see me flying, I will look yellow and fast! If you catch me resting with my wings open, I am orange with black edges, and a spot on each wing. It is easiest to find me in open sagebrush meadows, wet meadows, and areas where farmers are growing alfalfa as food for cattle. I usually avoid forests.
Why am I important?
Like many insects, orange sulphur caterpillars are important in controlling the populations of the plants they eat. In the late summer, they can even gather in large numbers in alfalfa fields, causing damage to plants before harvest. The adults are pollinators of many desert plants, helping them make seed by moving pollen between like flowers of host plants. Also like many insects, the caterpillars and adults are important food sources for many animals, including spiders, wasps and birds.
What do I eat?
As a caterpillar, I am pretty picky. I only eat the leaves of plants in the bean family, including clovers, lupines and alfalfa. As an adult, I visit the flowers of many plants found in open meadows.
What is my life cycle?
Like all moths and butterflies, I begin as an egg that hatches a few days after being laid.
My larval stage is a caterpillar, green in color with a white stripe on each side. I am very small when I am born, the size of the tip of a pencil! When I am big, I am over an inch long.
When I turn into a pupa, I am called a chrysalis. I stay totally still for six to eight days, turning into an adult butterfly, very different from the way I looked as a caterpillar.
As an adult, I fly around, visit flowers, and find places to lay eggs.
Egg and adult photos by Kevin Burls.
Caterpillar and chrysalis photos by Nicky Davis.
Orange Sulphur Butterfly Word Search
- Orange sulphur
- Colias eurytheme
- Alfalfa Caterpillar
- Host Plant
Follow the life cycle from egg to adult
The egg must hatch on the proper host plant, or it will not be able to develop into a butterfly.
Special thanks to Marcia Moffitt for the graphic design and formatting of the print version of this publication, which is available upon request, to Mark Rainey for the photos of the egg and chrysalis and to U.S. Fish and Wildlife Service Midwest Region for the photo of the adult.
This work is supported by Crop Protection and Pest Management Extension Implementation Program C-REEMS Grant Proposal Number: 2017-04410 GRANT # 12398398 “Nevada Extension Implementation Program 2017” from the USDA National Institute of Food and Agriculture.