Capulin Volcano supports a wide variety of insects and particularly large populations of some that migrate to high elevations. However, mosquitoes are not a problem here, most likely because the volcano lacks permanent water sources for breeding sites.
Complete invertebrate surveys have not yet been conducted in the park, but lists are available for Union County, NM.
Convergent Lady Beetle (Hippodamia convergens) is named for the converging white lines on its thorax. They usually have 13 black dots on an orange elytra or shell.
Each summer at Capulin Volcano, a new generation of lady beetle participates in a wind-carried migration and takes up residence at the highest points of the volcano. After feeding all summer, they hibernate through the winter on the volcano. Surviving beetles then catch a warm current off the volcano in February to the south to reproduce. Since the wind carries the lady beetle in its migration, it has a hard time controlling its destination and may go to aphid-rich fields near the volcano or maybe to wheat fields in Texas.
During a lifespan of a few months, the females lay up to 500 eggs on leaves and twigs. The eggs hatch and the larvae gorge themselves on the aphids. After the larvae clear the area of aphids, they pupate. Since the larvae usually clean the area of their favorite food, aphids, the adults migrate back to Capulin Volcano to await the opportunity when they too can go back to these aphid-rich areas and lay their eggs.
False Cinch Bugs are less than 1/4 inch (1/2 cm) long, brownish gray, narrow bodied true bugs. While immature, they have inconspicuous red markings on their body. They feed on plants of the mustard family. As they reach maturity, they begin to cluster together in extremely high numbers in preparation for migration. They are a temporary nuisance but do little or no feeding while clustered. Wet winters result in greater mustard populations which will lead to larger populations of False Cinch Bugs.
These bugs are numerous at the top of the volcano. They are particularly attracted to light colors, especially white. While annoying, they do not bite.
Tent caterpillars are a noticeable presence, particularly in the crater and around the rim of the volcano. These caterpillars spin large webs around tree branches within which the larvae feed. At Capulin, these caterpillars seem to especially prefer the leaves of the chokecherry and oak shrubs. The caterpillars themselves are quite colorful with black stripes, blue sides with an orange stripe, black and white eye spots and orange-yellow hairs. The caterpillars pupate and become a small, less than two inch, brown moth.
North American butterflies in the genus Oeneis are commonly called "arctics" because they generally inhabit windy areas, often at high elevations. The Capulin subspecies of the Alberta arctic butterfly (Oeneis alberta capulensis) was discovered in 1970. It also inhabits other grassy volcanoes in the area. Originally found only on the north side of Capulin volcano at the rim, recent surveys have not located any specimens. Little is know about the subspecies distribution and biology in the park.