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Entomology (Study of Bugs)/Small red insects in Pasadena CA


Red Pasadena Insects
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Hello - I have attached a pic of some bugs I saw today on one of my potted plants in Pasadena CA.  The body of these insects are are around 1/4 inch long.  they are kind of slow-moving or motionless.  When I googled, they looked a lot like nymphs of milkweed assassin beetles, but apparently those are native to gulf states?

Hi Angela,

Thanks for the question. You have identified these little nymphs correctly; they are assassin bugs. Assassin bugs live all across North America, but prefer warmer climates. This includes southern CA. They are beneficial for gardens/plants because they are predators of other insects, but FYI they also can bite humans when they are adults so I wouldn't pick them up without gloves.


Entomology (Study of Bugs)

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Jessica Mellinger


I can answer questions about invertebrates native to California, including insects commonly found in homes. If you have an identification request, please attach a photo to your question.


I was involved in collection and identification of invertebrates for the United States Geological Survey, Biological Resources Division for six years. Also, I provided these same services intermittently for the UC Davis John Muir Institute of the Environment for many years. I have been a member of since 2009.

Department of the Interior: United States Geological Survey, Davis Field Station; University of California, Davis Aggie Alumni Association; UC Davis Center for Neuroscience; U.S. Department of Veteran's Affairs

I have two B.A.'s from the University of California, Davis and two Associate's degrees from Sacramento City College.

Awards and Honors
Special Thanks for Achieving Results award from the Department of the Interior

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