Question: Are Shrimp and Cockroaches Related? Hmm…

The idea of a big fat cockroach topping off your fancy shrimp cocktail probably grosses you out.

And it should. Creepy crawly cockroaches anywhere near our food is definitely a big no-no. But you might be surprised to learn how closely related shrimp and cockroaches are!

All plants and animals are organized by scientists into separate groups based on the things they have in common. An easy example is how tigers and lions are very closely related, while cheetahs are basically cousins of them both. Your house cat Fluffy is related to all three, but more closely to a cheetah than a lion. They all eat meat, are mammals, and have quick reflexes and sharp teeth.

What about cockroaches? Do they have anything in common with shrimp?

As a matter of fact they do, and this is why it’s so important to understand how scientists group things. Cockroaches are insects. And shrimp are crustaceans. And while they both belong to their own groups (insects and crustaceans), they also share characteristics that group them together.

What are those characteristics?

Both insects and crustaceans have three part bodies, made up of a head, thorax, and abdomen.

Both have jointed legs.

And both have exoskeletons. An exoskeleton means that their bodies’ “bones” are on the outside instead of the inside (like yours). If you’ve ever eaten steamed shrimp, you probably know that they have a hard shell you have to take off first. This is the shrimp’s exoskeleton, and insects such as cockroaches have them too.

Creatures that share these characteristics belong to a group called Arthropods, which also include animals like spiders and centipedes. Scientists have found that insects and crustaceans have a particularly close evolutionary relationship, though. So close that they belong to a group all their own called Pancrustacea.

That means that shrimp, lobsters, and other crustaceans are related – very closely related – not only to cockroaches, but to all other insects, too.

Food for thought: If shrimp lived on land, would we change our opinion of them?

So what about the fact that people scream when they see a cockroach on the table, but not when they see a shrimp salad? Well, aside from the fact that in Thailand and some other Asian countries people do eat cockroaches as a delicacy, the ones here are dirty and sometimes carry disease.

So while the relationship is close, a shrimp is definitely not a cockroach. And though Pancrustacea sounds like the most delicious menu item ever, you’ll want to stay very choosy about the kind of Arthropod you eat.

Sure, house cockroaches are dirty, smelly, and not exactly the sort of creature you want to see on your kitchen counter.

But are they fast?

You bet they’re fast. Superhero fast. So fast that cockroaches are considered one of the fastest insects on the planet.

With lots of interest in the creatures, scientists couldn’t resist finding out exactly how fast they really are. So they began by testing cockroach’s “start-speed,” the time it takes to start moving from a dead stop.

For even the fastest of humans, start-speed doesn’t go much lower than about 110 milliseconds (about 1/10th of a second). But cockroaches went much faster, darting off at 8.2 milliseconds. Literally faster than the blink of an eye.

At top speed, they’re remarkably fast, and can cover 50 body lengths in a single second. For animals the size of humans that would be the equivalent of 200 miles an hour!

So how do cockroaches run that fast? The secret is in their legs. All six legs have three knees, 18 knees altogether. With so many joints, their movement has precision and accuracy, with very little wasted movement that could slow them down. Once they get up to speed, they rise on their hind legs and run as humans do, which helps them run even faster.

It’s those legs that help them react so fast too. Each leg has tiny hairs that can detect even the slightest movement of air. When you walk into a room, a cockroach can sense the air stirring… and off it goes!

They’re legs have another important feature. A hook-like structure that allows them to flip under ledges or scramble under tables at warp speed. The scientists studying these special ops-style stunts found that the acrobatics happen so fast, the cameras had to slowed down to super-slow speeds to track them all.

So it looks like when it comes to speed, the common house cockroach may not be so common after all!

Source: https://www.eurekalert.org/pub_releases/2012-06/uoc–sba060412.php

How long can a cockroach live without its head? A lot longer than you or I could, that’s for sure.

Of the many curious facts about this highly-studied creature, its ability to live without a head… for a while anyway… has got to be one of the creepiest.

But before outright telling you how long a cockroach can survive without a head, let’s look at the science behind why it’s possible at all. Because there’s something remarkable about a creature that can scoot across your kitchen floor, even when it’s missing its noggin.

A Headless Cockroach Isn’t Going to Bleed to Death From Its Wound

Even for major catastrophes like losing a head, cockroaches don’t bleed very much. Unlike humans, they have an open circulatory system: A system for distributing blood through their bodies that doesn’t depend on a closed network of arteries and veins. Their blood doesn’t pump under pressure like ours, but just sort of sloshes around, making its way into the cockroach’s tissues.

The great thing about this system – if you’re someday going to be headless – is that when a major wound occurs, blood doesn’t suddenly get forced out. For a cockroach that loses its head, the blood just clots at the neck. The cockroach will have a nasty scab for sure (where its head used to be), but it won’t die from loss of blood.

A Headless Cockroach Isn’t Going to Suffocate

Unlike humans, cockroaches don’t breath through a nose or their mouth. Instead they breathe through small holes in their bodies called spiracles that don’t need a brain to direct them. No nose, no mouth, and no need for a brain to regulate your breathing means that you can breathe all you want to without a head.

So that’s a second hurdle that won’t stop a cockroach. It won’t suffocate from its catastrophe.

A Headless Cockroach Can Get By Without a Brain

Cockroaches do in fact have brains. And they use them. It’s just that cockroaches don’t really need them that much.

In addition to brains, they have nerve tissues that control reflexes throughout their bodies, and these are distributed within each body segment. If a cockroach loses its head and brain, the nerve tissues (known as nerve tissue agglomerations) continue doing their job, providing the strange headless creature a fairly normal life. It can stand, react to touch, and move around.

In fact, aside from looking like something out of a horror movie or your worst nightmare, a headless cockroach behaves a lot any other cockroach. And it would continue its headless existence except for one thing…

A Headless Cockroach Can’t Eat or Drink

A headless cockroach isn’t going to die from bleeding and it’s not going to die from being unable to breathe. It’s also not going to die from the relatively minor event (for it) of losing its brain.

But it is going to die from being unable to eat. And well before that, it’s going to die from thirst. A headless cockroach has no mouth to drink with and will be dead from dehydration in less than a week.

Which brings the total day count from the moment it loses its head to the moment it loses its life to somewhere around 7 days or less. Not exactly a lot. But a lot more than you or I could manage to do.

Thought this was fun? You’re probably also wondering, “Are there cockroaches in chocolate?”

Sources:

http://www.bio.umass.edu/biology/kunkel/cockroach_faq.html
https://www.scientificamerican.com/article/can-a-cockroach-live-without-its-he/