Can we ingest something that is (relatively) harmless to us that harms the bed bugs?
It seems can – though either you or I can do a bit more research to find out for sure, and in what quantities.
When bed bugs ingest reconstituted human blood that contains caffeine, it stunts their growth and decreases their reproduction rate.
See the articles below:
“An average mass percent increase of 163.90% (± 8.81%) was recorded for the control treatment. Bed bugs fed on 50 ppm caffeine showed an average mass percent increases of 104.62% (± 15.95%). A total of 264 (average 44.00 ± 2.45) eggs were produced by bed bugs in control and 81(average 13.5 ± 2.86) eggs produced by bed bugs fed on the highest caffeine concentration of adulterated blood. There were negative correlations between the caffeine concentrations vs the numbers of eggs produced and the average mass % increase of the bed bugs.”
Page 11 of the following article shows how much caffeine is in many different types of drinks:
Also findings show that when bed bugs ingest blood with alcohol in it, it also stunts their growth and decreases their reproduction rate.
See the article below.