Cicadas are present in Oregon, though the experience of encountering them differs significantly from regions known for massive periodical emergences. The state is primarily home to annual cicadas, which appear every year, but not in overwhelming, synchronized swarms. Unlike their periodical counterparts, annual cicadas do not emerge in numbers large enough to cause widespread, noticeable events.
Cicada Presence in Oregon
Oregon hosts around 30 cicada species, predominantly annual cicadas, sometimes called “dog-day cicadas.” These insects typically emerge during late summer, from July to August. Oregon’s cicadas are generally smaller and less loud than the periodical cicadas found in eastern and central U.S. states.
Most species belong to the genera Okanagana, Platypedia, and Neoplatypedia, with Okanagana being the most common. For instance, Okanagana oregona is a frequently encountered species. These annual cicadas are often camouflaged, appearing green or brown, blending with their arboreal habitats. Their size can vary, but adult annual cicadas are generally about 1.75 inches long, though some periodical species can be slightly smaller.
Distinguishing Sounds and Sightings
Oregon’s annual cicadas produce a continuous, often high-pitched buzzing or whining sound, generated by specialized structures called tymbals on the male’s abdomen. This sound can be loud, potentially reaching up to 100 decibels, comparable to a lawnmower. Not all Oregon cicadas create this typical buzzing; some species, like those in the Platypedia and Neoplatypedia genera, use their wings to produce clicking sounds to attract mates.
Cicada sounds are often confused with other summer insects, particularly crickets and katydids, which also produce loud calls. Crickets typically have more musical, lower-frequency songs and are heard at night. Katydids, often green and leaf-like, produce buzzy, raspy, or whiney sounds and are largely nocturnal singers. In contrast, cicadas are primarily active and vocal during daylight hours and at dusk, calling from trees and shrubs. Differentiating them involves noting the sound’s characteristic (continuous buzz vs. chirps or clicks), the time of day, and the insect’s appearance.
Understanding Cicada Life Cycles
The life cycle of an annual cicada, though termed “annual,” typically spans several years underground. After eggs hatch, tiny nymphs drop to the ground and burrow into the soil, feeding on fluids from plant roots. This underground nymph stage can last between two and five years for Oregon’s cicada species.
As they mature, nymphs undergo several developmental stages while feeding on tree roots. Once fully developed, the mature nymphs emerge from the ground, often climbing onto trees or other vertical objects. They then undergo a final molt, shedding their exoskeletons to transform into winged adults. The staggered emergence of individual nymphs, rather than a synchronized mass emergence, is why annual cicadas are seen every year, but not in overwhelming numbers. Adult cicadas live for only a few weeks, primarily to mate and lay eggs.