If you want to learn more about the insects and arachnids of our region, see our Reference section for species checklists, essays, books recommended by our staff, and other resources on our own site.

Dune Biodiversity of the Baja California Peninsula

Some of the longest stretches of undisturbed coast in North America are at risk of environmental degradation. Museum entomologists and scientists from Mexico are generating the first entomological inventory of the coastal dunes of the Peninsula of Baja California to provide data that will allow decision makers in Mexico to conserve and manage this precious resource. Learn more.

LepNet Digitization Project

Our Entomology Department is working on a multi-year project to digitize 150,000 specimens of Lepidoptera (butterflies and moths) from Southern California and Baja California, a known biodiversity hotspot. The important data associated with these specimens in our collection can be used to help inform important conservation activities. Learn more.

Checklist of Butterflies of San Diego County

Some of the species in this list are rare or are limited in their distribution. Those that are rare and are likely to be seen in limited capacity are marked with an asterisk(*). Species indigenous to San Diego County are bolded.Species with state or federal protection are bolded orange. Learn more.

Checklist of the Spiders of San Diego County

The following revised checklist, as probably with most regional checklists, is preliminary and hopefully will be useful for environmental management and planning as well as a starting point for further biological studies of the regional fauna. Citations refer to papers with descriptions, locality information, or nomenclatural notes. Learn more.

Checklist of the Spiders of Baja California

The following checklist is preliminary and hopefully will be useful for environmental management and planning as well as a starting point for further biological studies of the regional spider fauna. Citations refer to papers with locality information, descriptions, or nomenclatural notes. Learn more.


With over one million described species of insects and their relatives, it is impossible for one person to know them all. We use this blog to get our latest discoveries and poorly understood collections in front of the eyes of the internet! Create a login and you can use our image comment tool to add identification directly to images or add comments below each image. Learn more.

What We’re Up To

Three Ways to See Wildlife After Dark

Posted: September 29, 2022

Spotting animals in the wild is hard, but researchers from The Nat have a few easy tricks up their sleeves. Here are three things you can do to spot wildlife when it's most active—at night.   Read more.

Our first cohort of STEM apprentices reflect on their time with The Nat’s research department, sharing how they got here, what they learned, and where they’re going next.  Read more.

A recent court ruling blocked the proposed listing of four species of extremely rare bumblebees from being protected under the California Endangered Species Act. We have a few things to say about that. Read more.

The monarch butterfly is in severe decline. Recent studies show the Western Monarch population, which overwinters here in southern California, has decreased by 99% with less than 30,000 butterflies remaining. With such critically low numbers, now is the time to take action. Read on to learn how to support monarch butterflies right now. Read more.

The Top 10 Specimens of the 2010s

Posted: December 26, 2019

In the spirit of the decade-spanning top ten lists that abound in our collective news feeds, we asked our curators to nominate two to three of the best specimens that were collected or discovered in the 2010s. We got 17 nominations, and musuem staff and volunteers voted to narrow the list down to “The Top 10 Specimens of the 2010s.” Read more.