Benchmark 5D
The Living Environment: Interdependence of Life
Grades 3-5, page 116

Insects and various other organisms depend on dead plant and animal material for food.

The most closely related standard is at a higher level of sophistication.
 

NSES Content Standard C 
Life Science: Populations and ecosystems
Grades 5-8, page 157
Populations of organisms can be categorized by the function they serve in an ecosystem. Plants and some micro-organisms are producers--they make their own food. All animals, including humans, are consumers, which obtain food by eating other organisms. Decomposers, primarily bacteria and fungi, are consumers that use waste materials and dead organisms for food. Food webs identify the relationships among producers, consumers, and decomposers in an ecosystem.