Binomial: Euphilotes battoides
Range: From Washington south to Baja California Norte and then west to Colorado and New Mexico.
Host Plants: Wild buckwheats (Eriogonum species). Caterpillars eat their flowers. Adults also favor Eriogonum nectar.
This is one of dozens of square-spotted blue (also known as buckwheat blue) caterpillars that we have seen this July and August. This species first appeared on our seacliff buckwheat (Eriogonum parvifolium) in 2022. We purposely planted it one of our coastal Los Angeles gardens to attract and support this and other insect species. While the green and pink jelly blobs (as my husband calls them) are well-camouflaged among the summer blooms, the movement of several Argentine ants helps to give away their position. The attending ants likely offer predator protection in exchange for the caterpillars’ sugary excretions.
Though we have yet to spot or photograph the adult butterflies, they emerge, fly and mate from mid-April to August. With a wingspan barely longer than half an inch, their patterns and colors are a treat for the sharp-eyed. The upperside of males is a metallic blue with dark borders while it’s brown on females. Both may have an orange band (also called an aurora) on the outer edge of their hindwings, though the marking is more often found on the females. The underside of each is off-white to gray with black, squarish spots. Another orange band can be found between bold and fused spots on the hindwing.
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Once our caterpillars pupate (about 30 days after hatching), they’ll overwinter in the leaf litter or soil beneath their nurse plants. For this reason we are sure to leave the leaves so that there will be square-spotted blue butterflies in our garden next year.