Colias alexandra alexandra
Photo Life History: Colias alexandra alexandra
Habitat: Mountain Canyons
Host Plants: Astragalus beckwithii
Caring for Live Female Butterflies: Feed females regularly
How to Find Eggs: Check the ventral side of host leaves. Some eggs might be Colias philodice eriphyle.
How to Find Caterpillars in the Field: Look for Caterpillar Strip Patterns
Caterpillar setups: Open terrariums;
Larva to Pupa: Last instar larva constructs a cremaster and girdle.
How to Find Pupae in the Field:
Number of Broods per Year: 1-2
Overwintering Stage: Third Instar Larva
Overwintering Strategies: Alpine Overwintering Technique
Avoiding Diapause Techniques: Provide larvae with healthy host plant and expose to 24 hours of light. (Larvae will diapause if host plant dries out; simulating conditions in nature when caterpillars either hibernate or have another flight.)
Disease Prevention: Change out host plant and remove frass every three to four days.
Emergence: Emergence Container
Field Notes from Jacque Wolfe: "For large numbers of immatures of all Colias, it is best to get ova from females. The larvae of Colias eurytheme, Colias alexandra, and Colias philodice will not diapause if reared with a 24 hours photoperiod. It is best to use 24 hour photo period for all species of Colias. Constant light accelerates larval development and, with some individuals, or species prevents diapause. Colias are very hard to rear as they are highly prone to disease. The easiest and best way to rear all Colias is to use potted plants.
Colias larvae that always diapause will not leave drying plant in search of fresh food, but will just diapause on the plant. Potted plants stay fresh and the larvae will grow to their maximum diapausing instar. If only cut plant is available the containers must be designed so they can be placed in the sun for a few hours a day and then put in the lighted lab before sundown. Ultraviolet rays greatly reduce the chance of disease. Once a day, carefully remove the sleeve and check the plant for freshness and add water to the water bottle. When the plant freshness starts to decline transfer each larvae to the leaf of a fresh plant."