Grasshoppers are a familiar sight in gardens and fields, recognized for their powerful jumping ability and often their vibrant colors. A common observation, however, is their tendency to release a dark liquid when handled or threatened. This behavior, while seemingly peculiar, is a natural and well-documented aspect of their biology, serving a specific purpose in their survival.
Identifying the Substance
The dark liquid grasshoppers emit is commonly known as “tobacco juice” due to its brownish or blackish appearance and sometimes thick consistency. Despite the nickname, it contains no actual tobacco.
This substance is primarily a mixture of the grasshopper’s digestive fluids, often containing enzymes, combined with partially digested plant matter. The exact composition can vary depending on the grasshopper’s recent diet.
It is not harmful to humans, though it may temporarily stain skin. The fluid can range in color, sometimes appearing more brown or even reddish, reflecting the plant material they consume.
The Purpose of Spitting
Grasshoppers primarily engage in this spitting behavior as a defense mechanism against predators. When threatened, it regurgitates this fluid from its mouth. The “tobacco juice” acts as a deterrent, making the grasshopper unpalatable or unpleasant to a potential attacker. This bitter, sometimes acidic, and foul-smelling substance can effectively discourage predators like birds, lizards, rodents, mantises, or spiders from consuming the insect.
Its unpleasant taste and odor signal to the predator that the grasshopper is not a desirable meal. This can cause the predator to release the grasshopper, allowing it to escape. The regurgitation can also serve as a physical barrier, coating the predator’s mouthparts or face with the sticky, distasteful liquid. This defensive action increases the grasshopper’s chances of survival when confronted.
How Grasshoppers Produce It
The production and expulsion of this fluid originate from the grasshopper’s digestive system. When under stress or threatened, the grasshopper can quickly force contents from its foregut or crop back out through its mouth. This process is a form of regurgitation, essentially a “vomiting” response.
It is an involuntary action triggered by the perception of danger. While some insects exhibit “reflex bleeding” (exuding hemolymph), the dark substance from grasshoppers comes from their digestive tract. This mechanism allows grasshoppers to rapidly deploy a chemical defense without requiring specialized glands for toxin production.