Dear Bug Man

    Which insect between the house fly and the cockroach pose more of a threat in carrying and transmitting disease or do both?

E-Mail me back please I'm in desperation!   so there no mistakes,

 

Interesting question.... I would really like to know what you think the answer is, and why....

 

The real answer here is pretty easy, if you know a little about the animals themselves (if you are indeed doing a science fair project on them, and have researched how they eat, you should be able to figure this one out on your own!)

 

Even though cockroaches and flies often share similar habitats, and even eat similar types of foods - they are both scavengers - they have totally different ways of eating.

 

Cockroaches chew. Just like we do.

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Here, I just made up this poem when I said that:

 

Cockroaches chew
Just like we do

 

Flies sponge
And slop around in the grunge

 

Mosquitoes suck
That's our bad luck

 

Butterflies sip
They have a long tube for a lip

 

Grasshoppers chomp
At the end of a grassy romp

 

Spiders slurp
And then they probably burp

 

Every animal has to eat
But it's the way they eat that's really neat!

 

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okay, back to the answer now

 

The good thing about chewing is that you don't leave much behind. So, if cockroaches are going to spread diseases, they can only carry bacteria, fungi and other yucky stuff from one place to another, or they might... um.... well, poop it out. 

 

Either of those things could happen with cockroaches. But they pretty much don't. Cockroaches spend a lot of time cleaning themselves and, while they do poop all over the place (by the way, the science fair word for that is defecation or frass), they have never really been implicated in the transmission of any human illnesses - until very recently when large infestations of cockroaches have been shown to lead to an increase in childhood asthma.

 

Of course, flies can also transmit diseases through their frass and carry them from place to place. But - whoa - that's not all!

 

Flies are extremely mobile - and they visit some pretty yucky places. Most likely, cockroaches would visit all the same sorts of places, but they really don't move around as much. Flies can visit the garbage, some dog poop in the park across the street, the pie on your windowsill, and and out to ride horseback for a while. They can drag just about anything, from just about anywhere, to just about any place.

 

But it's even worse than that with flies. Flies do not chew their food. Their mouths are like sponges. Of course, if you're gonna eat some of a peanut butter and jelly sandwich, a sponge won't do the job -  unless you can make the sandwich good and mushy first. So a fly vomits digestive enzymes onto their food first - YUCK! This turns it into a savory mush that they can sponge up.  (Have you ever seen the movie The Fly with Jeff Goldblum and Geena Davis? Dunkin Donuts will never be the same. It's rated R and is pretty gruesome in some parts - don't even think about it if you're too young or squeamish - you'll have nightmares for years!)

 

This is the biggest problem with flies: They digest their food externally. They vomit digestive enzymes and turn their food to mush - and that's how they spread the most diseases. They can ingest (eat) a pathogen (something that makes you sick) of some sort, and then they spit it out on food you might eat. That is the only way they can eat.

There are even parasites that take advantage of this in flies - and in mosquitoes and ticks (which spit digestive enzymes into you when they feed). They coordinate their life cycles with those of  their hosts (the flies, ticks or mosquitoes) and the animals they come in contact with (us!) so they have their mass reproductions in good times for us when they can get plenty of nutrients.

 

Hope that helps your desperation!

 

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