Mar 12, 2010

The First Instar

I had no idea that Madagascar hissing cockroaches ... issued their young like this. They're just spilling out of her!


I learned a new word today: instar. Arthropods such as insects must moult to grow. The phase between each moult, but prior to sexual maturity, is called an instar. So, can one of your experts confirm this: these wee roach nymphs can be said to not even be of the first instar yet, since they have yet to moult?

Hissers must be of at least the fourth instar before they can beginning hissing. I'll bet roach nymphs can't wait till that fourth moult. Such a milestone...

UPDATE: Joe has informed me that a new nymph is considered to be in its first instar. Furthermore, the final instar prior to sexual maturity is called the Penultimate Instar (great name for a rock band). When the first of my own brood reaches that gangly stage of puberty I'll accuse them of being in their penultimate instar and see what they have to say about that. Thanks, Joe.

Photo source: Matt Reinbold


11 comments:

Joe Lapp said...

It sounds like you hit upon a confusing definition. It's more accurate to say that an instar is a development stage of an arthropod. Instars are partitioned by molts. A newly hatched arthropod is in its first instar, even if it hasn't molted. After molting, it's in its next instar. The stage before the final instar is called the "penultimate" instar, and the final instar is called the "adult."

Interesting side note: Spiders molt after hatching from their eggs but before emerging from the egg sac. So the spiders that emerge from an egg sac are already in their second instar. Spiders in their first instar have yellow yolk sacs.

eyeawry said...

Awww. This makes me miss my hissers. They're so cute when they're tiny. With their wee beady eyes.

niner said...

I agree with eyeawry; the babies are kind of cute! I like the big ones too, but those still incite a little fear in me.

robin said...

They are so cute when tiny and white!

Anonymous said...

Joe hit the nail on the head. So far as I have understood it is a matter of the definitions being applied over a wider range, as in arthropods vs. Insects or Arachnids.

It's been a long time since I memorized that stuff though.

Those are some adorable lil' beebees flocking out of momma's abdomen. ;)

I wish my landlord's would let me have exoskeleton-ed pets. :(

Affectionately,

Arachnophile

Raging Wombat said...

Arachnophile, what your landlord doesn't know can't hurt him. Unless it's a particularly venomous exoskeletonized pet.

Jelo said...

Dude, this is a scene straight out of "Starship Troopers"...

Anonymous said...

Well since they look after my mammalian pets while I'm away, I'm afraid it would be hard to keep 'em secret. ;)

- Arachnophile

Curse Blogger and the chance to logging in. I can't recover my old Identity. I am hating on gmail at the moment

Anonymous said...

Sweet - something to add to my cockroach nightmares!
Yeah, I'll admit the babies are kinda cute as far as creepy-crawlies go, but it's the quantities that will haunt my dreams forever!

-Terri

Raging Wombat said...

Is it wrong of me to want to toss some into a pan with some olive oil, then add them to my pasta like pine nuts?

Anonymous said...

Creation of Allah, so beautiful <3