All carbon in your body was once sequestered by plants.
As the total biomass of insects isn't growing, the carbon they consume is balanced by the carbon released by decomposition of (otherwise) unconsumed insects; the same applies for animals up the food chain - if at the end of 2019 the total weight of insects and animals in the Amazon is not larger than at the end of 1919, then zero carbon has been sequestered in these insects and animals over a hundred years.
The plants can't be net collecting carbon each year unless the Amazon contains more and more plant matter each year.