How could eating insects help the environment?

Beneficial insects are a biological control for an organic garden or orchard. They are natural enemies of the garden pests. Injurious insects like aphids, mites, cutworms, and mealy bugs. Beneficial insects have been used in gardening since the late 1800's
Some of the most common beneficial insects are the spined soldier bug, lacewing, lady bug, nematodes, mason bee, parasitic gall-midges, mealy bug destroyer, minute pirate bug, and redworms.
Many perform valued services like pollination and pest control
Bees are beneficial as pollinators, facilitating propagation and fruit production for many plants. While some bees are predatory or parasitic, killing pest insects.

Think of beneficial insects like this simple story:
A Bird eats a insect. The bird uses the carbon from insect to make muscle tissue. This makes the bird stronger in order to survive. Once the bird dies, a fly will lay maggots on the bird, in which helps break down the bird's body. Carbon atoms will be released into the ground and be absorbed by a Apple tree. Humans and animals will consume the Apple.