Schon eine kurze Einwirkung von Insektiziden, die beim Verdampfen handelsüblicher Mückenschutzmittel verwendet werden, kann die Fähigkeit von Hummeln, den Weg zurück zum Nest zu finden, erheblich beeinträchtigen. Die Fähigkeit der Hummelarbeiter, mit Nahrung zum Nest zurückzukehren, ist für das Überleben der gesamten Kolonie von entscheidender Bedeutung.

Read the research article: [https://royalsocietypublishing.org/rsbl/article/22/4/20250749/481318/Volatilized-prallethrin-impairs-the-homing-ability](https://royalsocietypublishing.org/rsbl/article/22/4/20250749/481318/Volatilized-prallethrin-impairs-the-homing-ability)

More information from the press release:
The researchers studied the behavior of 167 buff-tailed bumblebees (Bombus terrestris). They were exposed to pyrethroid-based insecticide prallethrin for one, ten or twenty minutes with a repellent device meant for consumer use, after which the bumblebees were released a kilometers from their nest and their return was monitored for three days.

Of the bumblebees in the control group that were not exposed to prallethrin, 37% returned to the nest. The return percent of the bumblebees that were exposed to prallethrin for one minute did not differ from that of the control group. However, of the bees that were exposed for ten minutes, only 17% found their way back, and just 5% of the bumblebees that were exposed to the insecticide for twenty minutes returned to the nest. 

For those individuals that managed to return, the time taken to do so was not prolonged. Furthermore, laboratory tests showed that exposure did not increase bumblebee mortality, suggesting that the effect is specifically related to impaired navigation ability rather than direct toxicity.