Top 20 Most Common Insects in San Luis Obispo

Sometimes greenish or reddish in color, the northern kelp crab is a vegetarian that enjoys eating kelp. This nocturnal feeder is commonly found around pier pilings and intertidal areas. The northern kelp crab switches its diet seasonally, turning to mussels and barnacles in winter when the kelp is less plentiful. A favorite food of the sea otter, it often meets its fate when this predator is nearby.

It is a large, brightly colored and active butterfly, rarely seen at rest; its wingspan is 8 - 10 cm, and its wings are yellow with black stripes, and it has blue and orange spots near its tail. It has the "tails" on the hindwings that are often found in swallowtails. The eggs are deep green, shiny, and spherical. Young caterpillars resemble bird droppings, and as they molt, they eventually turn bright green, with a pair of large yellow eyespots with black and blue pupils. The caterpillars molt five times, eventually reaching a length up to 5 cm before pupating.

The convergent lady beetle (Hippodamia convergens) is one of the most common lady beetles in North America, which is a great thing given that it is a common biological control agent of aphids. They lay a good chunk of eggs over a couple of months. If you have ever seen a small, black alligator-like insect, you may have seen one of its larva.

Chlosyne gabbii has a wingspan of about 3.5 - 4.5 cm. The upperside of the wings is checkered with bright orange-brown and black, while the underside of hindwing shows pearly-white spots.

The gray bird grasshopper (Schistocerca nitens) is a gray or brown grasshopper with jagged edges on its back legs. It can fly long distances, but it flies in a clumsy pattern low to the ground. It's often found among a variety of trees and shrubbery, and it will often fly in large groups toward lights during nighttime.

Red admiral (Vanessa atalanta) is a visually striking species of butterfly. Unusually territorial, males will compete for choice areas, and females will only mate with males that maintain their own territories. This butterfly is known for being particularly patient with human interactions, even to the point of perching on clothing or flesh.

Pagurus samuelis is a small hermit crab, at up to a total length of 40 mm (1.6 in) and a carapace width of up to 19 mm (0.75 in). The base colour of the exoskeleton is brown or green, but the antennae are red, and adults have bright blue bands near the tips of their legs. In smaller individuals, the bands may be white. The legs and carapace are covered in setae, and the rostrum at the front of the carapace is triangular.

Their appearance is quite similar to that of the western tiger swallowtail, except they are a white-cream color or very pale yellow. Some pale swallowtails also have differing amounts of red-orange patches on the wings just above the tail. Tiger stripes and borders are thicker than those of western tiger swallowtails. The wingspan is typically 9 - 11 cm .Caterpillars are plump green with a single yellow band behind the thorax. They have two eye-shaped spots on the upper thorax, which may help frighten predators. Like most swallowtails, they have a red wishbone-shaped organ called the osmeterium, which pops out from behind the head and releases a foul odor to warn off predators. Caterpillars turn brown just before the fifth moult. The pupa is brown and looks like a piece of bark.

The state insect of Montana, mourning cloak (Nymphalis antiopa) owes its name to a visual comparison with a girl who, disliking mourning, allows a few inches of color to show from under her mourning garb. Among the longest-lived butterflies, individuals may persist for as long as eleven to twelve months. It is a powerful flier, with vagrants often found many miles from the usual migration paths.

The yellow-faced bumble bee (Bombus vosnesenskii) is known for its mostly black body with a yellow face. Their population is not dropping, but continued expansion of urban human populations is causing some difficulty for this bee to make nests. But what it does find it tends to monopolize due to its early arrival in the season.