This fly is known to transmit anthrax and other diseases. Though clever, these attempts at explaining the plagues naturalistically are really besides the point. In addition, since all nature is, in the view of the religious mind, directed by God, explaining these extreme phenomena as possible naturally does not preclude them from being divinely directed. Makkat Bechorot, the slaying of the first-born will be discussed in next week's posting. Frogs do not give birth directly to other frogs.
Frogs commonly croak to attract other frogs.
The Torah tells us that it is Siporah and Hashem who encounter each other by night in the lodging place, but Mosheh is not named at all. Nor are we allowed to see with clarity who is doing what to whom or why. Perhaps Siporah also saved him from death.