Relation arms - legs on insects

[BeBMan]

We all know they have six .....hmmm "extremities". But how exactly is the relation of arms and legs between those six?

Are all six legs? Or only four, while two are arms? Or balanced three - three? Or something else?

Who knows teh truth?

[Sandman]

Don't forget the wings which most insects have - making eight extremities.

[BeBMan]

Ah true - that should be considered. But that opens similar questions about arachnoids too....

[Immortal Wombat]

Insects have six legs.

[BeBMan]

I think its two legs, and four arms.

[VetLegion]

Two legs, two arms like everybody else. The other two are statistical error.

[Immortal Wombat]

It's six legs, just like humans have four legs.

[Mr. Harley]

And don't forget male spiders, some of which have six legs and then two modified legs that also serve as, umm, how to delicately put, sperm delivery organs. Which means....

[BeBMan]

....you mean they have quasi two dicks? Maybe those insects have just two legs and the rest serves a similar purpose.

Let's hope they don't get it twisted.

[Mr. Harley]

Yeah - but they leave the end of their appendage - finger? tip? - in the female along with the sperm. So they only have two "shots" you might say.

[VetLegion]

Wow, a plug. Once you visit, nobody else can

[Mr. Harley]

Yeah, but it had better be damn good sex.

[ajbera]

Those spider penis/limbs are called pedipalps, IIRC.

The relation of limbs between humans (and other animals) and insects isn't straightforward. Anything with 4 limbs (mammals, reptiles, birds) is straightforwards - 2 forelimbs, 2 aft limbs. Sometimes all the limbs are effectively legs, sometimes the forelimbs become wings (birds and bats). In seals the forelimbs are flippers, while the 2 aft limbs are fused into a "tail".

An ant uses all limbs as legs, whereas a mantis uses the specialized forelimbs as both legs and arms (mostly "arms".)

The families of the organisms in question are sufficiently divergent that they're not wholly analagous.

[Last Conformist]

The legs of insects aren't homologuous with the legs/arms of tetrapods (= amphibians, reptiles, mammals, and birds).

[Jaguar]

Yea, arthropods are fairly separate from most other animals we know. They're allowed to be their own category because it's such a huge group.

Centipedes/millipedes have lots of legs, insects have six, spiders have eight, and crustaceans vary. They're all part of the same phylum, the largest in the animal kingdom.

Almost all other animals basically have four limbs.