Seeing the light

There’s a light at the end of the tunnel, I am beginning to see it!  And I don’t think it is the oncoming train (though that is always a possibility..).  I got some good news the other day and the train is slowly chugging down the tracks to more possibly good news.  Speaking of seeing the light, let’s talk about insects producing light: I present you with the railroad worm.  (You thought I was going to talk fireflies didn’t you?) 

These fascinating though poorly studied insects are in the family Phengodidae (fireflies are family Lampyridae), in eight different genera, and of course they are not worms but beetles.   So much entomologically awesome about these, I don’t know where to start!P. h.

Let’s start with the adults.  Males look like a fairly typical beetle with short, pointed elytra and long membranous wings.  They have crazy pectinate antennae that I have always thought are fascinatingly cool.  The females remain in a larviform state as adults.  One reference called it “lazy metamorphosis.  I kinda like that!

Next is their biology.  Most species of this genus are found in tropical areas of Central and

Nom nom, yummy milli’s!

South America and prefer moist soil.   They are most active at night and feast away on millipedes and other arthropods.  There isn’t too much published on these and I was curious if they have evolved some way to get past the defensive secretions that many
millipedes have.


Finally, the larvae and the adults produce light.  Cool right?  But even the egg stage is luminescent, though it takes about a month after being laid for that to happen.  Unlike fireflies, the females do not produce light to attract males.  It is thought to be more of a defensive action.  These insects are the only ones known to be able to bioluminesce a true red light.  The body luminesces a yellow-green color and the head,

NGS Picture ID:618649
Phrixothrix larvae

when threatened, glows red.  Hence, the common name that refers to the way a railcar looks when the window are lit and the engine at the front glows red.


Despite looking a bit like fireflies and both having bioluminescence “Branham and Wenzel (2001) not only hypothesize that phengodids and fireflies are not each others closest relatives, but that bioluminescence arose twice and was lost once in this lineage of beetles.” (from UF)


Pseudophengodes sp.  Love those antennae!

There you have it.  I hope you have seen the light and agree that these insects are totally entomologically awesome!  And why don’t you light up someone’s life by sharing this with them?  Brighten someone’s day and like it!  Shine a little brighter with the radiant entomological awesomeness on facebook!





Look at how fast they go!


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