Hummingbird moths are a unique group of insects often mistaken for their avian namesakes. They are frequently seen darting among flowers with remarkable speed and precision, hovering while feeding from blossoms. A distinctive humming sound from their wings contributes to this common misidentification. This article details the life cycle and characteristics of the caterpillar that transforms into this fascinating creature.
Identifying the Hummingbird Moth Caterpillar
Hummingbird moth caterpillars have distinctive features. These larvae are plump and vary in color, appearing as yellowish-green, green, or brownish. A common characteristic is a harmless horn-like appendage at their rear. Some caterpillars also display black spots along their sides and pale lines down their back.
These caterpillars feed on specific host plants, useful for identification. They are often found on plants such as honeysuckle, hawthorn, snowberry, viburnum, dogbane, cherries, and plums. The most commonly encountered species in North America include the Hummingbird Clearwing (Hemaris thysbe) and the Snowberry Clearwing (Hemaris diffinis). For instance, the Hemaris thysbe caterpillar is typically yellowish-green with dark green and reddish-brown bands, possessing a white horn. The Hemaris diffinis larva can be green or brown, often with black spots and a bicolored horn.
The Transformation Journey
Once a hummingbird moth caterpillar reaches full size, it prepares for pupation. It often stops feeding and may change color, sometimes turning darker, before seeking a suitable location. The caterpillar then descends to the ground, spinning a loose silken cocoon. This cocoon is typically found among leaf litter or just beneath the soil surface, providing camouflage and protection.
The pupa is generally dark, oblong, and brownish. The duration of the pupal stage varies, typically lasting a couple of weeks, but it can extend depending on the climate and species. In colder regions, the pupa may overwinter, remaining in its cocoon throughout the winter months and emerging as an adult moth in the spring or early summer. Upon emergence, the adult hummingbird moth has a stout body, clear wings with reddish-brown borders, and a long proboscis for feeding on nectar. The clear wings result from scales that fall off after the moth’s first few flights.
Observing Hummingbird Moths in Nature
Observing hummingbird moths in their natural environment is fascinating. These day-flying insects are most active during bright sunshine, though they can also be seen at dusk and dawn. They are prevalent from spring through summer, with peak activity often noted in June and August.
To attract these pollinators, plant flowers known for their rich nectar and trumpet-shaped blooms. Popular choices include:
Bee balm
Phlox
Petunias
Honeysuckle
Verbena
Rudbeckia
Morning glory
Lilac
Lantana
Purple coneflower
When observing, avoid disturbing the insects or their habitat. Leaving leaf litter undisturbed in your garden can also provide shelter for pupating moths, supporting their life cycle.