Mother pufferfish pass on non-toxic chemical to protect larvae
A study published in iScience shows that a chemical relative of tetrodotoxin helps offspring avoid being eaten by predators.
Researchers have discovered that mother pufferfish pass a nearly non-toxic chemical to their offspring to help them survive predators, according to a Times of India report. The study focused on the genus Takifugu, which is known for accumulating the potent neurotoxin tetrodotoxin (TTX).
The study, published in iScience, investigated 5,6,11-trideoxytetrodotoxin, or TDT. While TDT is a close relative of TTX, it has very little toxicity. Instead of killing predators, it appears to act as a warning signal that causes them to reject the prey.
To test this, researchers exposed grass pufferfish (Takifugu alboplumbeus) larvae to two predatory species: the nibbler (Girella punctata) and the Japanese flounder (Paralichthys olivaceus). The larvae were approximately one day old and had been administered specific compounds via their mothers before spawning.
The nibbler fish consistently rejected larvae containing TDT but ate those containing only TTX. Japanese flounders rejected larvae carrying either chemical. The researchers found that even predators with no prior contact with the toxins rejected the chemical-bearing larvae, suggesting an innate sensory response.
The findings suggest that while TTX provides a lethal defence, TDT offers an immediate rejection mechanism. This allows tiny larvae to escape before being swallowed. The researchers noted that TDT may also serve as a social signal, as pufferfish are attracted to the scent of the chemical.