How Long Does it Take For A Bed Bug Infestation To Develop?

One of the most common asked questions are “How long have I had bed bugs?” and with good reason. This question of course has layers but to be quite simple it is all up to the bed bugs, let me explain. For large or long-term infestations, it becomes unrealistic to determine the age of the infestation by observation alone. Confounding factors such as feeding frequency and reintroduction and treatment attempts all come into play. It is always safe to say that they have been present for some time (months or years). Therefore, the age of small infestations can be gauged fairly well. For the first couple months, and that is likely sufficient in many cases.

A good guess, at normal room temperatures (72°F) combined ample feeding opportunity, bed bug nymphs require about a week for development of each instar between molts. Each molt leaves behind exuviae, the “shed skin.” In small infestations, these exuviae can be used to estimate a timeline. For instance this method is limited, but can be useful under the right circumstances. If on your mattress a fourth instar bug is found alone in a cluster along with some fecal spotting and three graduated exuviae, a reasonable guess would be that it has been using that harborage for at least two to three weeks.

Eggs take about 10 days to hatch at 72°F. If you find hatched eggs attached to furniture then that is a clear indicator that they’ve been there for at least that long. Newer eggs can be collected, and upon hatching provide an estimation of when they were laid.

Another good barometer of how long an infestation has been around is the number of adult bed bugs present. Generally it takes at least seven weeks for a bed bug to grow from an egg to an adult. There should be no new adults from eggs during that period. Therefore, if many adult bugs are present one can reasonably assume that the infestation has been there for more than seven weeks. The assumption here is that the infestation started from only a few bugs and there have not been additional introductions during that time. 

The bottom line is that while there isn’t a surefire way to determine the age of an infestation. However you can determine some limits. It requires careful inspection of the available evidence including fecal spotting, exoskelton, eggs and adult bugs. That is why it is ideal to call professionals who know what exactly to look for.



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