California has many insect species, but do you know which insects you see are native to California, or are introduced species? Do you know a “good insect” from a “bad insect”? To learn a little bit about native, introduced, good and bad insects, check out the pictures and see if you can tell “Which is Which.”

This website provides several ways to contact a state agency to identify your specimen. Look for the downloadable app to report suspect insects; an electronic form to fill out and send; a Hotline number (1-800-491-1899) to call; or a link to each county’s agricultural commissioner or extension offices.

Brown Stinkbug vs.
Brown Marmorated Stinkbug

NATIVE SPECIES: The Brown Stinkbug is one of several native pests that cause economic damage to crops and destroys garden produce.

INVASIVE SPECIES: The Brown Marmorated Stinkbug is an Asian species that first appeared in 1998, in Pennsylvania.

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Picture Wing Fly vs.
Mediterranean Fruit Fly

NATIVE SPECIES: The Picture Wing Fly is small to medium sized and is common, but not really noticeable. It causes no harm to our lives.

INVASIVE SPECIES: The Mediterranean Fruit Fly is a small, colorful fly and is very destructive to over 250 fruits. It has caused economic collapse wherever it has become established.

Argentine Ant vs. RIFA

INVASIVE SPECIES: The Argentine Ant has become a household nuisance and has the ability to spread quickly. It does not sting or bite humans, so is not a direct threat to humans.

INVASIVE SPECIES: The Red Imported Fire Ant (RIFA) is a pest and nuisance to agriculture, wilderness and urban areas. It has a nasty behavior of mass attack, with repeated stinging and biting of the intruder.

Which is Which: Asian longhorned beetle versus the banded alder borer

Banded Alder Borer vs. Asian Longhorned Beetle

NATIVE SPECIES: The banded alder borer, BAB for short, is an exotic looking beetle that is infrequently encountered from March to July in the Pacific Northwest. With their striking white/blue coloration, BAB adults are frequently mistaken for the Asian longhorned beetle.

INVASIVE SPECIES: The Asian longhorned beetle is a potentially dangerous exotic pest. The easiest way to distinguish these two species is to look at the segment directly behind the head. On the Asian Longhorn Beetle the area is entirely shiny black while on the BAB the area is white with a single, large black spot that occupies 60% or more of the segment.

Argentine Ant Image courtesy of Alex Wild Photography | Brown Stinkbug, Brown Marmorated Stinkbug, Mediterranean Fruit Fly, Picture Wing Fly and Red Imported Fire Ant Images courtesy of