A recent study published in Frontiers in Microbiology attracts researchers' attention because it reveals that some viruses might have the ability to monitor their surroundings and take action accordingly. T o be specific, viruses can sense the environment around themselves and their host and then decide whether or when to suspend their activities, spread infection, attack or kill the host cells, multiply, and burst out inside their hosts at any given time. T hi s finding is significant to uncover unknown interactions between viruses and their hosts and may have implications for the development of a new generation of antiviral drugs. Bacteriophages , or simply phages, are viruses that infect and harm bacteria. In this study, researchers look into a phage that can only infect the host when the bacterial cells have special appendages—pili and flagella that can help the bacteria move and mate. Specifically, this flagellotropic phage infects Caulobacter bacteria cells, which ha...