Here are four anterior close-ups Pyractomena borealis. The telescoping head allows the larva to inject (via curved, hollow mandibles) a numbing agent into snails that have retreated inside their shells. The antennae and maxillae are also partially retractable. When a larva is done feeding on a snail (or slug or earthworm) it will de-slime all of these parts with the hooked, fingerlike projections of the holdfast organ (pygopod) located on the last abdominal segment. The head is also fully retractible (see previous post). These larvae are extremely active, so really hard to photograph.
Tag Archives: phylogeny
Pyractomena borealis (Lampyridae) exploring the surface of trees on a warm winter day in February. The third photograph shows how they can retract their head under the carapace like a turtle. At first I thought they might be foraging — they are highly predaceous, and hunt slugs and earthworms (in packs!) by first injecting them with paralytics. But they might have just been looking for a place to pupate, because it’s time for that. Adults will emerge sometime in early Spring to be the first fireflies in the area. The larvae are bioluminescent, too. The hypothesis about why the larvae glow is that it evolved first as an aposematic trait in larvae, warning mice and toads of the presence of lucibufagins, steroidal toxins in the hemolymph. It’s thought that the adult habit of using flashes is secondarily evolved, millions of years after the larvae evolved the ability to glow. The ability of larvae to glow even predates the origin of the Lampyridae, I gather. For more enlightening details, see Branham and Wezel (2003), Stanger-Hall et al. (2007), and Martin et al. 2017.
I finally put a few evolution-related images on a Shoppe page … just in case you need a geeky Christmas gift for somebody.
For giggles, I modified Charles Darwin’s tree of life sketch and sent it to a company that manufactures temporary tattoos. If you happen to be model quality and would like to help promote science, drop me a line and I can send you one. I think it’s good to have images like these show up during searches for “evolution” and “survival of the fittest” so that the public doesn’t just associate evolution with just old academics with questionable grooming (sadly, true).
I also dropped the image into Redbubble if you need a sticker or laptop case (for example). Here’s the original sketch, if you’re curious:
Nothing in religion makes sense except in the light of imagination.
I posted this graphic on Flickr in 2006, but thought I’d re-post here since I’d long ago stopped using Flickr. It shows how religions might have evolved from pre-existing religions, which in turn evolved from the early myths of our prehuman ancestors. If you are a religion buff, you are no doubt frothing at the mouth because of all the mistakes I’ve made … in my defense, it was just a quick sketch because I needed an “evolution of religions” slide for a talk and I couldn’t locate one on the internet thingy.
If you’re interested in the evolution of religions among primates, check this out:
McClenon, J. 1997. Shamanic healing, human evolution, and the origin of religion. Journal for the Scientific Study of Religion 36:345-354. JSTOR
By the way, my lead sentence is just a riffing on the phrase and article by Dobzhansky, “Nothing in biology makes sense except in the light of evolution.”