Insect Attack May Have Finished Off Dinosaurs

A "lone smoking gun" theory responsible for the extinction of dinosaurs around the K-T Boundary, which is the "the line between the Cretaceous and Tertiary Period about 65 million years ago" seems increasingly implausible. Popular consciousness still retains that a catastrophic event like giant asteroids impacting earth, or the fiery lava flow had eliminated dinosaurs. But studies show dinosaurs didn't die off this planet suddenly; it was a gradual process, even many thousand years after the K-T Boundary dinosaurs still roamed the earth.

George Poinar Jr. is a professor of zoology at Oregon State University, and he says, "There are serious problems with the sudden impact theories of dinosaur extinction, not the least of which is that dinosaurs declined and disappeared over a period of hundreds of thousands, or even millions of years. That time frame is just not consistent with the effects of an asteroid impact. But competition with insects, emerging new diseases and the spread of flowering plants over very long periods of time is perfectly compatible with everything we know about dinosaur extinction."

In recently published book What Bugged the Dinosaurs? Insects, Disease and Death in the Cretaceous, autor George Poinar and the co-author Roberta Poinar argues that "insects provide a plausible and effective explanation for the slow, inexorable decline and eventual extinction of dinosaurs over many thousands of years. This period is known as the famous "K-T Boundary," or the line between the Cretaceous and Tertiary Period about 65 million years ago. There is evidence that some catastrophic events, such as a major asteroid or lava flows, also occurred at this time -- but these provide no complete explanation for the gradual decline of dinosaur populations, and even how some dinosaurs survived for thousands of years after the K-T Boundary. Insects and disease, on the other hand, may have been a lot slower, but ultimately finished the job."

Here are more interesting observations by the authors:

In the Late Cretaceous, Poinar said, the world was covered with warm-temperate to tropical areas that swarmed with blood-sucking insects carrying leishmania, malaria, intestinal parasites, arboviruses and other pathogens, and caused repeated epidemics that slowly-but-surely wore down dinosaur populations. Ticks, mites, lice and biting flies would have tormented and weakened them.

"Smaller and separated populations of dinosaurs could have been repeatedly wiped out, just like when bird malaria was introduced into Hawaii, it killed off many of the honeycreepers," Poinar said. "After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases. But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them. Massive outbreaks causing death and localized extinctions would have occurred."

In similar fashion, the researchers suggest, insects would have played a major role in changing the nature of plant life on Earth -- the fundamental basis for all dinosaur life, whether herbivore, omnivore or carnivore. As the dinosaurs were declining, their traditional food items such as seed ferns, cycads, gingkoes and other gymnosperms were largely being displaced by flowering plants, which insects helped spread by their pollination activities. These plants would have spread to dominate the landscape. Also, insects could have spread plant diseases that destroyed large tracts of vegetation, and the insects could have been major competitors for the available plant food supply.

"Insects have exerted a tremendous impact on the entire ecology of the Earth, certainly shaping the evolution and causing the extinction of terrestrial organisms," the authors wrote in their book. "The largest of the land animals, the dinosaurs, would have been locked in a life-or-death struggle with them for survival."

Now that's some food for thoughts, especially when looking or swatting an insect of any kind, just ponder for a moment or a two: perhaps humans are now in a "life-or-death struggle with" insects "for survival", just as dinosaurs were 65 millions years before, without human beings aware of this epic battle when their minds are occupied with flashy but super-shallow "threats". Nature is indeed kind, but can be unforgiving for the boisterous fools!

Link to this must read article:
Insect Attack May Have Finished Off Dinosaurs