do detrivores return eneregy to an ecosystem?

Based upon the definition of detrivores, I would say yes to that.

http://en.wikipedia.org/wiki/Category%3ADetritivores

Yes, from Wiki:

Detritivores are often eaten by consumers and therefore commonly play important roles as recyclers in ecosystem energy flow and biogeochemical cycles.

Yes, detrivores return energy to an ecosystem. Detrivores are a type of decomposer that obtain their energy by consuming dead organic matter, such as dead plants and animals. Through the process of decomposition, detrivores break down these organic materials into simpler forms, such as carbon dioxide, water, and mineral nutrients.

During this decomposition process, detrivores release and recycle chemical elements and energy back into the environment. These nutrients can then be absorbed by plants, which are then consumed by herbivores, and the energy flows up the food chain. This makes detrivores an important part of nutrient cycling and energy transfer within an ecosystem.

To understand how detrivores return energy to an ecosystem, you can conduct research on the specific types of detrivores in the ecosystem you are studying. You can also learn about the process of decomposition and how detrivores contribute to nutrient cycling. Scientific publications, textbooks, and online resources are great sources of information on this topic. Additionally, consulting with ecologists or biologists who specialize in ecosystem dynamics can provide valuable insights into the role of detrivores in energy flow.