- Bed bug droppings reveal a little bit about the bug.
- Sometimes a little information reveals a lot.
The common bed bug (Cimex lectularius) feeds exclusively on blood, and has complex systems in place to process each meal. The process that follows determines the consistency of the bed bug’s droppings.
Even while it is still feeding, the bed bug will begin to shed large droppings with high water content. For the next day or so, the droppings will be watery and soak into a porous substrate — such as a bedsheet — and appear similar to ink stains.
Having fed, the bed bug will digest its meal over the next few days, and its droppings will take on a thicker consistency, like pudding or tar. These droppings dry into round shiny spheres. As this happens, the bed bug shrinks into a flatter body shape.
If the bed bug can feed again, the process repeats, but if it finds no regular meal, it becomes flatter until it’s as thin as a flake. At this point, its droppings become fewer and are small, dry and granular — resembling the droppings of German cockroaches or coffee grounds.
In a healthy growing population, all these droppings can be found in bed bug habitats. When a single introduced bed bug is present, but hasn’t fed again, the only droppings found will represent a rough gauge of its feeding state.
It is important to make a thorough inspection of droppings, as evidence suggesting an introduced bed bug or a small group may be part of a larger group that lives on the other side of the bed.