What's That Bug? does not endorse extermination

Glow Worms!
I was walking through my front yard in the Santa Monica Mountains in Southern California last night and wondered why there was a glowing LED on the ground. Upon closer inspection I found two glow worms. One blinked out right away upon being disturbed, but the other kept right on glowing. I’ve lived in California for 33 years and have never seen any bioluminescence. This was an exciting first. Just thought I would share my find. All the best,

Hi Sean,
Though your image is a bit blurry, it is wonderful to see the glow as well as the Glowworms.

Update:  September 14, 2013  (From our personal email account)
Hello Daniel:
Hope all is well these last few days of summer….
Here’s a puzzle:  A colleague of mine said his coworker observed a firefly for an hour last night in his Woodland Hills backyard. Is that possible? Fireflies? I think of them as more midwestern…what could this have been?
Any thought would be appreciated…
Brenda Rees
Southern California Wildlife

Hi Brenda,
Thursday and Friday are very long work days for me.  Sorry for the delay.
This one has a confusing answer, and you didn’t explain exactly what the person saw.
We have several species in the Firefly family Lampyridae, but they are not bioluminescent.  To further confuse things, one has the common name California Glowworm, but Glowworms are in a different family.
We have Glowworms in the family Phengodidae as well.  They glow as larvae, and females are larviform are are supposed to glow.  Winged males do not
Hope that helps.  Would be nice to know exactly what the person saw.  If on the ground and glowing, I’m thinking Western Glowworm.

Hi Again Brenda,
We have been trying to clean up our California Glowworm and Firefly postings thanks to your email, because there were some inconsistencies.  We found this posting in our archives and it seems like a good place to add your email query.  Though it is commonly called a Pink Glowworm (according to Hogue in the Insects of the Los Angeles Basin), members of the genus
Microphotus are actually Fireflies in the family Lampyridae.  Though blurry, this image from our archives shows a nicely glowing individual.  Here is what Hogue writes:  “… the female of the Pink Glowworm … communicates her location to the male … by emitting a continuous uniform luminescent glow.  The adult male has the usual firefly beetle form, but the female is ‘larviform’ (wingless and elongate like the larva …).  The males are not seen as often as the females because they give light only when disturbed, and the light is weak and not used in communication.  The female is fairly common in late spring to early summer in the foothill canyons (a colony was reported from Griffith Park near the Greek Theater, in 1989).  Found at night by its glow and in the daytime under stones lying on leaf mold in grassy areas, the adult Pink Glowworm is easily recognized by the pink color of the flattened segments;  the terminal segments are yellowish.  The segments of the larvae of both male and female are blackish with pink margins.”  See BugGuide for additional information.

What's That Bug? does not endorse extermination
Location: Santa Monica Mountains, California

21 Responses to Pink Glowworms in Southern California

  1. Greg Olmsted says:

    My son and I saw what we thought were two small, but very bright, green LED’s in the leaves next to our driveway in Pilot Hill, CA, El Dorado county. I don’t have a photo to upload, but they’re definitely the pink glow worms that I saw on this site. I’m unclear on what they actually are. Are they indeed wingless female fireflys, or firefly larvae? I’ve never seen fireflys in California. In fact, I didn’t even know they existed here. Can you please tell me exactly what they are, and what they will develop into? I’m sure that looking for these glow worms will be a regualr pasttime in the spring and summer evenings this year.

    • bugman says:

      Both Glowworms in the family Phengodidae and the California Glowworm, which is actually a Firefly in the family Lampyridae, are found in California, however you will not be witnessing the type of nocturnal display that Fireflies or Lightning Bugs provide in more humid environments in the eastern portions of North America.

  2. Steve says:

    Just spotted the ‘pink gloworm’ 4-18-15 outside our home west of the Barona casino. I have seen similar glowing larvae like bugs that were a darker color in the mid 1980’s when I lived in Descanso Ca.
    Can’t say i’ve ever seen a glowing version of either in flight.

  3. Jack says:

    Just saw a pink glow worm (I think) in Laguna Niguel, Orange County California. Didn’t know those existed. Took a few pictures but not sure how to upload. Neat bug. She glowed even when disturbed but seemed pretty lethargic.

  4. Terry lindoerfer says:

    We saw three pink glow worms in several locations along side of the trail during an evening hike in Eaton Canyon Nature Center in Pasadena last night (6/5/15). Very exciting! I have lived and hiked here all my life and had never before noticed these little guys (well, girls I guess)

  5. Don says:

    Just saw a pink glow worm while camped out at the top of a mountain in the Trinity National Forest in Northern CA which led me to your website. As described by others it looked like an L.E.D. bulb in some pine needles. They’re up here too!

  6. Andy says:

    Last night I saw what looked like a tiny LED among some leaves. It turned out to be a pinkish worm or larvae about 3/8 of an inch long and very much like the one shown in the photo on this web page. In my 67 years I have never seen one of these and neither has my wife. We live in Mendocino County and thought we had seen just about everything that there is to see here.

  7. Angie Ferguson says:

    I just saw a tiny gloworm!It looked orange more than pink. One end was glowing pretty brightly. This was in Escondido, California-the northern part of San Diego. County. I have lived kn California 50 years and never have heard nor seen this.

  8. C Blackwell says:

    There is what I believe to be an entire colony of glow worms in the trees at the end of my street in Lake Forest, California. They are beautiful, and they make it look like a faded Christmas tree! I have never seen these, and I’m happy to have found your website to identify these glowing creatures.

  9. Karen says:

    I am in the Central Valley in Manteca. Last evening we were treated to a magnificent display of easily 100 or more glow worms on my backyard trees. Most were glowing a bright neon green. But some were a lovely ruby red. They had a strong, bright, steady glow for hours. They did not move about, they all stayed where they were. Amazingly, they were only on my trees and not on any of the neighbors’.
    I went back out to check on them about 10pm and a couple of them were blinking then went out a bit, but then came back. They were still there this morning.
    This is the first time I have seen anything like this. It was like having hung festive led lights in the trees -all decorated up for the Holidays!
    Had it not been so cold, I could of stayed and just stared at them for hours. What an unbelievable sight! So beautiful.

  10. Jim Voirol says:

    I have been observing glow worms in Ojai CA for the past twelve years. They are always along the same block-long stretch of road and always adjacent to the road in leaf litter or rock crevices. Saw ten last night 5-2-16. They seem to wait until 8:30pm to turn on their lights. Good hunting. I can’t help but smile when I see them.

  11. Jacque says:

    My husband called me outside to see what he thought was a broken florescent bulb. We put the light from a flashlight on the area and saw small (5/8 inch approx.) pinkish worms with glowing heads! Amazing! We are 65 years old and this is the first we have seen glow worms. I didn’t know if California had glow worms so I found this site. We are in Penn Valley, about 50 miles north of Sacramento. There were only 3 of them…pretty exciting find!

  12. Jim Voirol says:

    Have been observing glowworms for past month. Usually see 8-10 per night in same general location. We have made a glow worm perserve to protect them from mowing and weed whips.

  13. jon says:

    Just saw a bunch in two trees here in Ontario, very creepy.

  14. David Denner says:

    I found about 12 pinkish caterpillars that have greenish lights on one end when I pick it up it didn’t glow. So when I went to put it back I found that they only glow on one side. SO be careful when you walk. Dose anyone know why they are only in one spot in front of my barn? I looked all around and couldn’t find any. I live in Calaveras county

  15. Spencer says:

    Two pink gloworms here in Lompoc CA. 05/12/2020. Never have I seen these in 56 years in CA.

  16. Dave Zingg says:

    Thank you for sharing information on the pink gloworm. Just like several others, I’ve lived in my area for decades and had never noticed them until tonight. Found them near Santa Margarita in San Luis Obispo county.

  17. Jory Kahn says:

    Pacific Palisades, California, coastal Los Angeles, saw several after dusk in early June in the Temescal Canyon Park area. What a discovery! Never knew of these before. So fascinating.

  18. Shirley says:

    Last day of May saw three on an exposed rock in Griffith park. It is the second time I have seen them in the park. I saw one lone one a few years back.

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