My latest discovery on my knees along bottlewort trail is truly one of the most interesting insects of my lifetime! It is a California Pink Glowworm (Microphotus angustus), a member of the Firefly Beetle Family (Lampyridae). My ID was verified by iNaturalist & James Hogue at Cal State Northridge, coauthor of Introduction To California Beetles and Field Guide To Beetles Of California.

There are more than 350,000 species of beetles and they have complete metamorphosis: i.e. egg-larva-pupa-adult. The winged adult looks very different from the larval stage (although many adult beetles are flightless). The female of my latest insect is very different!!! Her adult stage looks just like the larval stage, except she is all pink with mature sex organs. Instead of a distinct winged adult form like most beetles with complete metamorphosis, she gradually changes into a pink larviform adult. In fact, I watched the black color of my larva slowly become replaced by pink! The technical word for this adult beetle is LARVIFORM and the technical name for this type of development is PAEDOGENESIS or PAEDOMORPHOSIS.

There are only a few beetle species on our planet that develop this way and my latest discovery is one of them. Some Internet sites state that this beetle is extremely rare, but James Hogue (personal communication, 2022) said they are fairly common in coastal areas of California. This is especially true if you crawl on your knees at night through vegetation & meadows. The fact that the adult glows in the dark to attract males certainly helps in spotting them!

I placed several larvae into moist containers in my photo room at my home. They appear to be larvae because of their black & pink coloration and anal prolegs. They apparently eat slugs & snails, but at the time of this writing, mine would not eat for some reason. Maybe they would like the snails stir-fried with seasoning. On 11 April 2022 I noticed they were motionless & appeared dead; however, their coloration was becoming more pinkish-orange. This may be an indication that they were gradually changing into an adult form that goes with the common name of "pink glowworm."

Larviform Female of European Glowworm (Lampyris noctiluca) Attribution: Wofl~commonswiki, CC BY-SA 2.0 DE , via Wikimedia Commons. Lampyris is a genus of beetles in the Lampyridae. In western Eurasia, they are the predominant members of this family and include the European common glowworm, which is the type species. They produce a continuous glow; the larvae and larviform females are among those organisms commonly called "glowworms." Image clearly shows that only the last 3 abdominal segments emit light. This attracts the smaller winged males like native glowworms (Microphotus angustus) in coastal sage scrub near Palomar College. I have yet to photograph our local species glowing.

My first experience with a glowworm was on Palomar Mountain many years ago. I was walking in a meadow and noticed what appeared to be a lighted cigarette butt dicarded by a careless smoker. To my surprise upon approaching it, I discovered that it was a glowing larva. On a field trip to the Napo River in Ecuador, a tributary of the Amazon, I was on a guided evening walk through the rainforest when we approached a small pond. To my astonishment, the distant shore had numerous lights that resembled a distant view of the San Diego coastline at night. It was bioluminence by hundreds of insects on the shoreline vegetation!

Bioluminescence is discussed in the marvelous book Introduction To California Beetles by James Hogue and Arthur Evans. "A precious few of California's beetles are capable of bioluminescence." The emission of light by an organism or population of organisms involves the oxidation of luciferin in the presence of ATP and the enzyme luciferase. If luciferase or ATP is lacking, the reaction will not occur. Luciferin is activated by ATP, enabling oxygen to attach to one of its carbon atoms, kicking out an electron into a higher orbit. The luciferin releases the oxygen and carbon together as carbon dioxide. As the electron drops back into its normal orbit, energy is released as a tiny flash of light. Multiply this activity by thousands of cells within the light-producing organs of glowworms and you have a visible light glow. Bioluminescence is nearly 100 percent efficient, with nearly all of the energy given off as light. By contrast, incandescent lightbulbs are only about 10 percent efficient, the remaining energy being lost as heat. It is truly remarkable that so many distantly related creatures have independently evolved this complex chemical reaction

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