Octopuses Taste with Their Arms Using Microbial Signals, Study Finds
Octopuses have a unique way of tasting the world around them – through their arms. A recent study has revealed that these fascinating creatures rely on chemical cues from microbes to determine the quality of their prey and eggs. This sensory mechanism plays a crucial role in how octopuses make decisions about what to pursue and what to avoid.
Unlike humans, octopuses possess sensory receptors in their arms that allow them to “taste by touch”, enabling them to gather valuable information about their environment. This tactile tasting is essential for their survival, especially since they are opportunistic hunters that primarily forage at night in dimly lit areas.
Lead researcher Rebecka Sepela, a biochemist from Harvard University, explains, “If a microbial strain could activate a receptor, then it could generate a neural signal that tells the octopus: This is something I care about. The microbiome acts as a chemical translator, influencing the octopus’s behavior based on environmental cues.”
Exploring Microbial Signals in Octopus Behavior
The study involved isolating 295 different strains of bacteria from surfaces that are significant to wild-caught California two-spot octopuses. These surfaces included the shells of fiddler crabs and the egg casings of octopus offspring. By testing how octopus sensory receptors responded to each strain, the researchers identified key microbes that activated the octopuses’ receptors.
Living crabs’ shells were found to be relatively sterile, while decaying crabs’ shells teemed with bacteria. Similarly, octopus egg casings maintained by a mother octopus had a balanced microbial composition, whereas discarded egg casings exhibited bacterial overgrowth.
Decoding Chemical Language in Octopus Behavior
Further experiments involved presenting octopuses with egg mimics, some of which were marked with specific bacteria. The octopuses instinctively recognized the “bad eggs” and discarded them, highlighting their ability to discern microbial signals.
The study also identified the specific molecules that triggered octopus responses, emphasizing the importance of chemical communication in their sensory perception. Despite the aquatic environment, these molecules remain intact on surfaces, providing a constant source of information for the octopuses.
Implications for Microbiome Research
While the study focused on octopuses, the researchers believe that microbial signaling may play a broader role in various microbiomes, including our own. Harvard cell physiologist Nicholas Bellono notes, “Microbes are essential across life forms, influencing physiology and behavior. This study sheds light on the profound impact of microbial signals on organisms.”
This groundbreaking research, published in the journal Cell, underscores the intricate relationship between octopuses and microbial cues in guiding their complex behaviors.
