The Buzz About Cicada Noises: Why They "Scream" When You Touch Them
Ah, the cicada. For many Americans, the deafening chorus of these insects is a sure sign of summer. But what happens when you get a little too close for comfort? You might have experienced it yourself: you reach out, gently (or not so gently) pick one up, and suddenly, there's a loud, often startling noise. Many people describe this sound as a "scream" or a "buzzing shriek." So, why do cicadas make this racket when you pick them up?
The short answer is that they're not really screaming in distress, though it can certainly sound that way. The noise you hear is actually a defense mechanism, a way for the cicada to try and startle you or any other potential predator away. It's their way of saying, "Hey, back off!"
Understanding Cicada Anatomy and Sound Production
To truly understand why cicadas make this noise, we need to delve a bit into their biology. Cicadas are unique in that they are one of the few insects capable of producing such loud sounds. This ability is primarily found in the males of the species. The sound-producing organ in cicadas is called a tymbals. These are a pair of drum-like membranes located on the sides of the cicada's abdomen, just above the base of their wings.
Here's how it works:
- Tension and Release: The male cicada has special muscles that pull these tymbals taut, like tightening a drumhead.
- Buckling: When these muscles contract, they cause the tymbals to buckle inward, making a clicking sound.
- Resonance: The cicada then rapidly vibrates these tymbals. The hollow space within their abdomen acts as a resonant cavity, amplifying the sound dramatically. Think of it like cupping your hands around your mouth to make your voice louder – the cicada's abdomen does a similar job for its tymbals.
Why the Noise When Picked Up? It's a Startle Response
When you pick up a cicada, you are essentially triggering their predator-detection system. They perceive you as a threat, and their immediate reaction is to deploy their most effective defense: sound.
Here's a breakdown of the typical scenario:
- Perceived Threat: Your hand approaching and then making contact is a clear signal of danger to the cicada.
- Muscle Activation: In response to this perceived threat, the male cicada's muscles rapidly contract, causing the tymbals to vibrate intensely.
- Loud Amplification: The amplified buzzing or rattling sound is produced. This sudden, loud noise is intended to startle you, making you drop the cicada or retreat.
It's important to note that female cicadas do not produce this loud sound. They lack the tymbals and the associated muscles. The loud "singing" or "screaming" is solely the domain of the males, as it is primarily used to attract mates.
The Purpose of the "Scream"
The "scream" serves a few crucial purposes for the cicada:
- Deterrence: The primary goal is to deter predators. A loud, sudden noise can make a potential meal think twice, especially if it's a sound they're not familiar with or find alarming.
- Alarm Signal: While not a true "scream" of pain, it can also be interpreted as an alarm signal to other cicadas nearby, indicating the presence of a threat.
- Fight or Flight (Sound Edition): For the cicada, it's their version of "fight or flight." Since they can't run away very quickly on the ground, producing a loud noise is their best immediate defense.
It's also worth mentioning that the noise you hear when you pick up a cicada might be slightly different from their usual mating call. It's often more of a frantic, irregular buzzing or rattling sound, reflecting their heightened state of alarm.
Are They Hurt When You Pick Them Up?
Generally, no. Cicadas have a tough exoskeleton, and unless you are squeezing them with extreme force, picking them up rarely causes them physical harm. The noise is a reflex, a natural response to being handled. Think of it like a human flinching or yelping when surprised – it's an involuntary reaction.
However, it's always best to be gentle. If you're interested in observing a cicada, try to do so without disturbing them unnecessarily. If you do decide to pick one up, do so with care, holding them by their wings or body, and be prepared for that startling burst of sound.
A Note on Different Cicada Species
The sound and intensity of cicada noises can vary significantly depending on the species. Different species have different tymbal structures and abdominal resonance, leading to a wide range of sounds, from high-pitched whines to deep, rattling buzzes. The common annual cicadas and the periodical cicadas, famous for their mass emergences, both produce distinct sounds.
Conclusion
So, the next time a cicada lets out its distinctive "scream" when you pick it up, you'll know it's not out of pain or malice. It's a fascinating display of their biological defense mechanism, a loud and effective way to say, "Leave me alone!" It's a reminder of the intricate and sometimes surprising ways nature works.
Frequently Asked Questions About Cicada Noises
How do male cicadas make their loud sounds?
Male cicadas possess a unique anatomical feature called tymbals, which are drum-like membranes on their abdomen. By rapidly contracting muscles that pull these membranes taut and then releasing them, they create vibrations. Their hollow abdomen acts as a resonant chamber, amplifying these vibrations into the loud sounds we hear.
Why do only male cicadas make loud noises?
The loud sounds produced by cicadas are primarily for attracting mates. Only male cicadas have the specialized tymbals and muscles required to generate these noises. Female cicadas, lacking these organs, are generally silent in this regard.
Is the "scream" a sign of pain or distress?
While it sounds alarming, the "scream" or loud buzzing noise is not typically a sign of pain or distress. It is a defense mechanism triggered by being picked up or perceiving a threat. The cicada is trying to startle and deter potential predators away.
Why does the sound change when a cicada is picked up versus when it's just singing?
When a cicada is singing to attract a mate, the sound is usually more consistent and rhythmic. When it's picked up, the noise is often a more frantic, irregular buzzing or rattling. This is because the rapid vibration of the tymbals is a direct, immediate response to a perceived danger, rather than a sustained mating call.
