How does electricity move body parts in insects and I’m assuming other larger animals?



I recently found a moth fried to death in my outdoor electrical lamp, it found its way into a space with loose wiring. Upon unscrewing the lamp from the wall, this moth fell to the ground but wouldn’t stop flapping it’s wings for the better part of an hour. I’m curious about the energy consumption of each wing flap and how it could go on for so long without the energy dissipating from the clearly dead insect.

In: Biology

I mean our brains send electrical signals to our ligaments to move in a matter of nanoseconds, and when we die there is still somewhat of brain activity for a short duration of time.

Perhaps part of the mosquitos brain was still “alive” enough to react to electricity? It’s just like putting a coke can inside of a “dead” fish, some fishes jaws will clamp on it, it’s either a reflex or there is just enough juice left in the brain for it to enact that reflex

cells for motor function will clench / draw close together when electricity is sent through them. They even tenderize meat using electric shocks long after the animal has been butchered. They do not need to be alive for the electricity to activate the cells.

This may be a long one to truly go into some depth needed to make the majority of the whole system easier to understand, TLDR at the bottom.

As far as animals, particularly us, go, electrical signals trigger muscles to contract. That’s all muscles can do! They can only pull, not push. If it looks or feels like something is pushing, it’s actually just a muscle elsewhere pulling on a string called a tendon, wrapped over a pivot point like your elbow, which straightens it and makes your arm go straight as well.

The electrical signals are a bit different than what you may think of as “electricity”, but it is still electrical activity that is at play. Electricity in the walls is just a bunch of electrons zinging through a wire, hence “electricity ” however our bodies use Na+, a positively charged sodium ion to send the signals. It still moves by electrical forces though. I ask you to consider how the brain gets the Na+ ion all the way down to a muscle it wants to move:

Your brain wants to move your foot, so it releases an Na+ ion into the proper channel. It may be a different substance, but that’s not really important. The Na+ ion goes in the nervous system, and it sees a bunch of other Na+ ions where it enters. Positively charged particles hate each other, and will repel, so it pushes one or more Na+ ions out of the room. Those Na+ ions go to a different room, and in turn cause Na+ ions that were already there to GTFO. This chain reaction continues until it gets down to your foot. The muscle cells in your foot are big long strings, and I mean really long relative to a typical cell. They look like strings and are called muscle fibers. (Really, muscle fibers are like a rope woven out of many muscle cells, but as above so below) These muscle cells are capable of contracting when they see this Na+ ion, as they’re programmed to do. How they do that exactly, I am unsure, but maybe someone else can give a good explanation of it. When a bunch of them come together and form a muscle, it can produce some considerable force!

When all the Na+ ions are gone, and the nervous system chain they followed are all replenished with more Na+, the muscle relaxes and the brain is ready to fire another signal when needed.

Because it is an electrical process, actually being zapped by real “electricity”, as discussed earlier, causes these Na+ ions to go nuts and move anyway, triggering your muscles to contract.

Note 1. Na+ is simply sodium, not some variant of the element. Na+ is written with a plus to indicate it is positively charged, as a single Na atom typically is. We get it from table salt, which is NaCl, or one part sodium and one part chlorine. Salt helps retain water, but we also gotta split it to get the sodium ion alone.

Note 2. Electricity, as stated, causes your muscles to contract indefinitely, regardless of whether you want them to or not. For safety, if you suspect something might have some dangerous electrical current behind it, and you have NO choice but to touch it, touch it with the back of your hand so it doesn’t white knuckle grab it. People around you will have no choice but to tackle you or whack you with something real hard to get you off, endangering themselves as well.

Note 3. There are many compounds used to send signals through the nervous system. The nervous system is comprised of nerve cells which are all connected to each other and fire when they receive a signal, forming that chain I was talking about. They have no idea what they’re doing, they’re like bullets that just pop when they get whacked on the primer. When a bunch of nerve cells in your brain just start firing, mostly because for some health related reasons they are overly sensitive, you can have a seizure. The brain uses quite a few “neurotransmitters” while muscles typically use Na+.

Note 4. Is this the same for bugs or other animals?

Tldr; When the body dies, or really when the brain goes silent, it won’t send any signals to muscles anymore, so the energy lying around in the form of a particle known as ATP will pretty much stay there until it naturally deteriorates. When you zap a dead bug, it’ll trigger the muscle cells to move, and will do so as long as there’s energy available to make it happen.