what will happen in food chain of ecosystem if all insects are killed
Answers
Without insects, all insectivores die… as do the animals that eat those animals, and vice versa. That's not a serious issue, however. The problem isn't the insects on the bottom of the food chain, but those at the very top… the detritivores. The insects that eat corpses and dung and rotting plant matter. Without these, waste piles up worldwide, water gets polluted, and diseases spread. Furthermore, without these detritivores to return nutrients from wastes to the soil, plus ants and termites and other soil critters to turn and aerate the ground, the soil loses its quality. Plants cannot grow, though that wouldn't matter much for the plants that are pollinated by insects which would die out in a generation, along with the animals that eat them, and the animals that eat those animals, etc. It would be a miserable world for humans: our civilization evolved in a world with Insects, and cannot exist without them.