To give some brief backstory, I noticed what looked like an ant crawling up one of the walls in the family apartment yesterday. At least, I think it was an ant because it was hard to take a good picture, or get a good look at it. This got me interested in learning a little bit more about ants. Along with learning that the middle segment, the Alitrunk, is pinched towards the end to form the Petiole, ants also have three small eyes on the top of their heads! What other fascinating, or overlooked, facts are there about arthropods?
Scorpions are pretty interesting to me. The hyaline layer in the exoskeleton glows brilliant blue under a UV light. Even scorpion fossils that are millions of years old still have the hyaline layer.
“ A hyaline coating (cuticle) on the exoskeleton of a scorpion contains beta-carboline and 4-methyl, 7-hydroxycoumarin which absorb UV light and retransmit it as visible bluish-green light. Young scorpions and recently molted scorpions don’t glow until the cuticle hardens. These chemicals may help the exoskeleton become impermeable.
“According to scorpion expert Dr. Scott A. Stockwell, this could mean that the substance that causes fluorescence is a byproduct of the hardening process itself, or it might be secreted not long after the creature molts.
“Whatever its source, the glowing property is surprisingly long-lasting. When scorpions are preserved in alcohol, the liquid itself sometimes glows under UV light. And the hyaline layer is amazingly durable: It can survive millions of years, Stockwell says; it’s often found in scorpion fossils even when all other parts of the cuticle have vanished. What’s more, even fossilized hyaline fluoresces!”
OMG! Where to start. If I just think about moths, the fact that they can survive the Winter in any life stage. They can live with no head for days. They migrate, and eat just about anything. When they shed their skins (larvae, pupae) they also shed the lining of their spiracles. And those are only a few details about moths - other insects are just as fascinating, never mind the majority of the Arthropods which live in the sea. (BTW, I believe they are polypyletic though I have no data to back that up!). It is an incredibly diverse phylum, and deserves a lot of respect!
Just one word – beetles!
One out of every four animals on Earth Is a beetle.
“An inordinate fondness for beetles”.
All arthropods are amazing, but beetles are super amazing.
All Hymenoptera have this feature. I believe they are called ocelli, and I think the majority if not all insect orders possess them.
EDIT: I don’t think the last part is correct, but I do know Hymenoptera, Odonata, Diptera and Mantodea have them.
the process of metamorphosis generally is pretty incredible. Kinda like lego of the living world, where you break an organism down to it’s basic building blocks and then reconstruct it into something radically different!
I’ve learned recently that there are more wasps than beetles, and possibly more gall midges than either.
And to think that statistically metamorphosis actually might be the most common method of “growing up” in the animal world.
lol, yeah! I caught myself glancing at a mirror as I walked past it after writing that, and thinking "now, if only I could metamorphose some of this belly into striae…
^This is exactly how I feel about this topic! Lately I’ve spent a lot of my lunches sitting out by a manmade water structure that has been full of dragonfly larvae. They are fascinating!! And there is so little known about the larval forms of Arthropoda versus the adult forms (https://www.inaturalist.org/observations/63119859, and a cool video of the nymphs: https://www.kqed.org/science/1915435/a-baby-dragonflys-mouth-will-give-you-nightmares).
Also, just saw this observation the other day of fly cocoons made of sand: https://www.inaturalist.org/observations/68073190
Arthropods are amazing. The more I learn, the more realize I don’t know anything about them.
I was amazed when I found an ant-mimic spider, then I learned about ant-manipulating butterflies, then ant-mimic plant-hoppers and I have just heard about ant-mimic beetles!
Is there any more ant-mimic arthropods around?
I think that complete metamorphosis is one of the most amazing things that insects do. They are able to completely change their body structure, diet, and many other things about their physiology.
It is also amazing to see the sheer diversity of arthropods on Earth. For example, there are about 5,900 mammal species while there are at least 925,000 insects.
Wow!!! I loved that KQED video you linked. How very amazing about the eating mechanisms of odonata nymphs; “think of it as a fork, spoon, and plate all rolled into one.”
Too late. Once the insect reaches sexual maturity – called the imago – no further molting or metamorphosis occurs.
In answer to the original post: if you really want to have your mind blown about arthropods, try to find the books written at the turn of the 20th century by J. Henri Fabre, and since reprinted in translation.
Check out the Ant Mimics project - https://www.inaturalist.org/projects/ant-mimics. There are ant-mimic stick insects, wasps, assassin bugs and more!
Yikes, some of those ant mimics are astounding!
Any theories about why so many other species mimic spiders?
Are termites ant mimics?
Any which way, insects rule!
One of the creepiest interesting things about arthropods is that some species are “designed” to starve to death. The adults eclose without mouths, so that they will focus all their finite energy on mating, not on finding food.
Many ants possess stings or are very unpleasant tasting to predators, and a nest will produce many similar looking individuals that cover a wide area, so it makes sense to mimic them.
Aside from mimicking spiders in order to deter other things, there are also many myrmecophiles that live in ant nests. Some of these physically imitate ants while others are radically different and survive in the nest by chemical mimicry, since ants sense mainly by smell and touch/taste. There are many different ant associates including crickets and beetles.
There are also some very cool ant parasitoids. Instead of laying eggs on the ants directly like most parasitic wasps, they lay eggs on plants. The first instar larvae and mobile (a planidia) and finds a way to get picked up by an ant (exactly how this happens is still a little unclear). Then they get carried back to the nest where they detach and feed on the ant larvae, with the subsequent larval molts being a typical wasp grub.
A similar life cycle happens with blister beetle larvae (Meloidae), which parasitize bees. Sometimes you can see the planidia aggregating on flowers. A number of other parasites have strange life cycles, including obligate hyperparasitoids and twisted-winged parasites.