What does capturing only adult cockroaches and large nymphs in a sticky trap suggest?

Capturing only adult cockroaches and large nymphs in a sticky trap suggests a new infestation moving in from a nearby infested site. When adult cockroaches and larger nymphs are found, it indicates that these are likely individuals that have migrated from an established population rather than arising from a local breeding cycle. This is particularly relevant since adults are typically the last stage to develop and can travel substantial distances in search of food and shelter.

The presence of nymphs in general may indicate some level of established habitation, but focusing solely on larger nymphs means that the establishment of a local brood is less likely. If a trap exclusively captures these life stages, it suggests that while there is some roach activity, it points more toward an influx of individuals rather than a self-sustaining population already developing in the area.

In the context of pest management, this information is critical as it helps inform the response strategy—targeting the nearby source of infestation may be necessary rather than simply addressing the current localized presence.