We're Outnumbered

Dec 15, 2008

We’re outnumbered.

Plain as day. And they’re not going away.


The estimated ratio of insects to humans is 200 million to one, say Iowa State University entomologists Larry Pedigo and Marlin Rice in their newly published (sixth edition)  textbook, Entomology and Pest Management.  Rice is the 2009 president of the Entomological Society of America.


There's an average of 400 million insects per acre of land, they say.


400 million!


Per acre.


“The fact is, today’s human population is adrift in a sea of insects,” they write in their introduction.


Well, what about biomass? Surely we outweigh these critters?


No, we don't. The United States “is home to some 400 pounds of insect biomass per acre, compared with our 14 pounds of flesh and bone,” they write. “Another amazing statistic is that in the Brazilian Amazon, ants alone outweigh the total biomass of all vertebrates by four to one. Based solely on numbers and biomass, insects are the most successful animals on earth!”


There you go. The insects are the land owners; we are the tenants. “They are the chief consumers of plants; they are the major predators of plant eaters; they play a major role in decay of organic matter; and they serve as food for other kinds of animals,” Pedigo and Rice write.


Insects represent the good, the bad and the ugly.  


The good: they give us honey and pollinate our crops. They spin our silk. They serve as natural enemies of pests. They provide food for wildlife (not to mention food for some of us humans).  They are scavengers. They provide us with ideas for our art work.  They are  fodder for our horror movies.


And what scientist hasn't benefitted from the inheritance studies of the fruit fly, Drosophila melanogasta? What ecologist  hasn't studied water pollution by examining the mayfly population? Mayflies are the counterpart of canaries in the coal mine. 


The bad: they eat our food crops, forests and ornamental plants. They devour or spoil our stored grain. They chew holes in our clothing. They pester us. They annoy our animals, too.


The ugly: They can—and do—kill us. Think mosquitoes. Think malaria, West Nile virus, yellow fever, dengue, encephalitis and other vectorborne diseases.


But wait, there's more! Many more.  Scientists have described more than 900,000 species of insects but there could be seven times as many out there,  the authors point out. 

Ironically, despite the huge numbers of insects, many people don't know the meaning of the word,  entomology, the science of insects. They should.  Insects outnumber us and always will. They've lived on the earth longer than us (400 million years) and adapt to changes better than we do. Most are tiny.  Most can fly. And most reproduce like there's no tomorrow.  


"Based solely on numbers and biomass, insects are the most successful animals on earth," the authors claim.


You can't argue with that.


By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

THE BEES--Honey bees are the good insects. Here UC Davis bee breeder-geneticist Susan Cobey looks at a healthy frame of bees. (Photo by Kathy Keatley Garvey)

The Bees

THE APHIDS--Aphids are crop pests. Their reproductive capabilities are immense. (Photo by Kathy Keatley Garvey)

The Aphids

THE MOSQUITOES--Mosquitoes that transmit diseases, such as malaria and West Nile virus, can kill us. Entomology graduate student Tara Thiemann is studying Culex mosquitoes. Infected Culex mosquitoes can transmit West Nile virus. (Photo by Kathy Keatley Garvey)

The Mosquitoes