Ceraunus Blue – Hemiargus ceraunus

Ceraunus Blue butterflies are found in the southern United States.

Ceraunus Blue butterflies lay eggs on several woody legume plants. Females normally lay eggs on the blooms spikes of their host plants.

We often find them on Hairy Indigo (Indigofera hirsuta) and Creeping Indigo (Indigofera spicata). Caterpillars prefer to eat the bloom buds of the plants. Caterpillars blend well into the bloom spikes.

Male Ceraunus Blue butterflies have all blue on the top side of their wings while females have a smaller amount of blue.

Caterpillars are tended by ants. They extend glands that ‘call’ ants. The caterpillars excrete a sweet liquid that ants drink. Ants defend caterpillars against predators.

To locate caterpillars, simply pick bloom spikes from the host plants and place them in clear plastic containers. The next day, lift the container to see if frass (caterpillar excrement) is on the bottom of the container. If so, open the container and check the bloom spikes above the frass. Larvae are well camouflaged and are often difficult to see.