Insects & Terrestrial Invertebrates

Anise swallowtail butterfly resting on a tree

NPS photo

Golden Gate is teeming with insects, spiders, and other many-legged crawlers. Every habitat has its crew of characters, from bugs thriving in the tops of tall trees, to soil dwellers milling beneath the earth's surface. The sight of early morning dew on a spider web, or a bumble bee lumbering from flower to flower, or a centipede crawling through leaf litter can be an introduction to an entirely new world. Social insects such as ants, bees, and wasps are often introduced species from other parts of the world, but native representatives still thrive in the park. Grasshoppers jump in front of visitors in the grasslands, and beetles trek across the sand dunes. Even the fly, a creature we often think of as ugly, comes in a rainbow of colors and can be seen pollinating flower clusters in the spring. Bugs even show up in wetland areas, water striders gliding across a creek surface, or dragonflies and damselflies alighting on a sedge. There are as many insects to learn as the visitor has time to explore.

The most beautiful insects of the park are no doubt the butterflies. In late spring and early summer, the iridescent wing scales catch the visitor's eye as they move from flower to flower spreading pollen. Grassland wildflowers attract the majority of species, but butterflies abound in any of the park's ecosystems. At least 44 species of butterflies occur in the Marin Headlands, 30 in the Presidio, and 34 at Milagra Ridge, including species of skippers, swallowtails, hairstreaks, blues, ladies, admirals and crescents. Such high species diversity illustrates the importance of habitat fragments within largely developed landscapes. Learn how park staff are working with community partners to support healthy monarch butterfly and mission blue butterfly populations.