What usually marks a true established larder beetle infestation, differentiating it from occasional sightings?

Answer

The consistent presence of larvae and their associated cast skins.

A true infestation requires a significant and consistent food source to sustain the damaging larval population, which is marked by the presence of these larvae and their associated cast skins, unlike occasional wandering adults.

What usually marks a true established larder beetle infestation, differentiating it from occasional sightings?
insectbitelarder beetle