Apocalyptic Insect Plague

Is the sudden insect disaster and the spreading zombie virus a natural disaster or a man-made disaster? When the heroine and her best friend, who were originally doing insect taxonomy, were playing at home, the TV station suddenly reported a full report, and citizens were not allowed to go out and the doors and windows were closed. Where will the heroine and her best friend go? How much does the heroine's brother, who was working part-time, have to do with the insect plague? How will human beings survive on an earth where insect plagues are rampant and zombies are everywhere? Waiting for his words to come... Disclaimer: It has no special powers, it all relies on human efforts and technological development. The heroine becomes stronger in the later stage, the emotional drama is later, and the second female protagonist's emotional drama is earlier.