They are the same, in a hugely zoomed out grand view sense.
Shrimp Lobster Crab, Cockroach Spider and Grasshopper are all related, but for a common ancestor directly linking them all, you are going back mega millions of years.
But cockroach is of the insect branch of the family (which is very diverse), lobster is most definitely not.
Giant bugs though is kind of an all in the mind type of thing
Many people do eat insects, it was never put in their minds that it was some skeevy nasty thing, for other people it was.
During the last swarm emergence, there was talk in the local papers about whether the Cicadas are edible. One article warned that those who are allergic to shrimp are probably also allergic to cicadas.
So from an edibility standpoint, there may be less difference than taxonomy would indicate.
Not to speak for MichaelEmouse, but he did appear to be referring to “anatomy, behavior and niche” and not genetics. Obviously, decapod crustaceans are far removed genetically from hexapod insects. But convergent evolution can bring disparate species closer to each other ecologically.
Also obviously, lobsters live in the sea while cockroaches live on land, but it still might be worth wondering if lobsters are the cockroaches of the sea. Kind of like wondering what land predator most resembles the Great White Shark in behavior and niche.
Powers &8^]
You have spoken very well for me. A tyrannosaur, a tiger and a great white shark are obviously genetically different but have similarities.
For example, how similar are the nervous system of cockroaches and lobsters? What type of thing do they eat? What’s their brood size? Do they have similar eye/antenna ratio?
The antenna/eye ratio in lobsters is 2/1 and in cockroaches 1/1.
As for nervous systems, both lobsters and cockroaches have a venrtal nerve chord instead of dorsal as in chordates, but that is equally true for all other decapids and hexapods and in no way distinctive of lobsters and cockroaches.
A more likely water-based cockroach analogue is shrimp. Shrimp are also tiny scavengers who feed on effluent (i.e. poo), crumbs*, and garbage**.
*or the sea-going equivalent. Picture a shark feeding: bits of flesh get flung off and fall towards the seafloor. Any bit that falls off a meal is probably lost to that diner.
** stuff left behind by other animals: corpses, abandoned shell-casings, etc. (yes, you can actually fire a shotgun underwater :P).
I actually had this happen during wet seasons near Houston. It’s kind of unnerving to look down the hole in your lawn and see them menacingly waving tiny pincers at you. :eek:
Cockroaches are pretty distant. But the category of things that most would call “bugs” includes crustaceans. In particular, the pill bug/roly-poly/woodlouse is a crustacean. The giant isopod is closely related. The lobster is a couple more steps away (but shares the class Malacostraca).
