Jeff Holmquist/ University of California

Bugs are just one type of insect found in Yosemite.

From a bug’s eye view, Yosemite National Park is a good home for creeping, crawling, buzzing creatures to live, breed, and feed. They thrive here in high concentrations, outnumbering all other animals by the thousands. Insects are responsible, in part, for the overall biological diversity of the region’s native plants and wildlife.

From a human’s eye view, some bugs may be viewed as pests that might be parasitic, transmit disease, damage structures, or destroy agricultural produce. Humans do value insects, however, for the products, like honey and silk, they produce. Insectivores, those that feed on other insects, may seem especially useful to people. Yosemite’s dragonflies, for instance, eat mosquitoes that tend to bother hikers. (Mosquitoes, which breed near standing water including snow melt, are noticeable especially in spring.)

From a scientist’s perspective, insects are the most diverse group of animal on Earth with more than one million species–more than half of all living organisms–and 30,000 species residing in California. The important role of insects is clear to scientists. Bees, flies, and other insects function as pollinators; others, such as beetles, break down dead plant and animal matter; still others, such as mosquitoes, offer themselves as food for bats and other hungry creatures.

Photo by Jeff Holmquist

Ants are one of the dominant insects in Yosemite Valley.

Where are all these insects? Entomologists have found that lower and wetter sites have higher insect abundances than higher and drier sites. Insects and other arthropods found in a sample from a Yosemite meadow might include ants (often the most abundant group), as well as mites, beetles, leafhoppers, flies, spiders, wasps, bristletails, true bugs, grasshoppers, caddisflies, moths, butterflies, and lacewings.

One insect evades scientists statewide: the valley elderberry longhorn beetle, noted in Yosemite and the surrounding area, and listed as federally threatened. While new insect species, believed to exist nowhere else in the world, have been recently discovered in caves within Yosemite.

Insects, in summary, remain one of the most important animal classes for Yosemite’s scientists to better understand. Visitors, even those that do not naturally appreciate insects, can realize that the fragrant flowers they admire or the songbirds seen in quick flight might not be here if it weren’t for the thousands of insects supporting them. Insects serve as the base of the biological chain in terms of number and importance.

• View a recent scientific study on Yosemite's insects as affected by meadow trails and trampling.
• Black widow spiders: University of California’s Statewide Integrated Pest Management Program describes how to identify this native species.
• Learn about non-native insects referred to as forest pests that could threaten park resources and forest health if they find a home in Yosemite. Park managers work to prevent a pest outbreak from occurring.
• Fill out a Wildlife Observation Card to report wildlife sightings to the park. [37.83 kb PDF]