This is one the odder corners of the Toho Studios mythos: the two tiny twin girls (the Peanuts) who summon Mothra to rescue mankind from some monster or other.
It's weird and cool that so many Japanese monsters are harmless creatures like moths, turtles (Gamera), lobsters (Ebirah), cuttlefish (Gezora), birds (Rodan). That would never fly in Hollywood. Some of the Japanese baseball teams have similarly gentle names: swallows, carp, blue waves.
There are so many Japanese monster movie clips on Youtube. It's bottomless.