So, where exactly did the dead one stop moving? I hope the other one knocked it into the sea, if it died on the island. Have you even seen a decomposing caterpillar? It's disgusting.
But, wait: the island which the "Tokyo S.O.S." disc calls "Infant Island" looked much more lush that the Showa Infant Island. Perhaps the spreading pool of stinky larva guts revivified the island, forming a new layer of topsoil that wasn't hopelessly contaminated.
Ah, those wondrous gigantic insects. No wonder people worship them.

