07 January 2008

Were the dinosaurs laid low by insects?

A huge meteorite around 65m years ago is believed to have caused massive global climate change that led to the extinction of the dinosaurs. However, according to a new theory they may have in fact been pushed to extinction by insects .


According to a new hypothesis by entomologists George and Roberta Poinar the later part of the dinosaurs' era saw an explosion in insect diversity and in the process dealt a double whammy to the reptiles - they spread disease and contributed to a transformation of vegetation which the plant-eating reptiles failed to adapt to.


"We can't say for certain that insects are the smoking gun, but we believe they were an extremely significant force in the decline of the dinosaurs," said Poinar. "Our research with amber shows that there were evolving, disease-carrying vectors in the Cretaceous period, and that at least some of the pathogens they carried infected reptiles. This clearly fills in some gaps regarding dinosaur extinctions."


In the gut of one biting insect preserved in amber - fossilised tree sap - from that era, the team has found the pathogen that causes the parasitic disease leishmaniasis, and in another they found a type of malaria parasite that infects birds and lizards. By inspecting fossilised dinosaur faeces, the team also found parasitic microbes that are carried by insects.


In addition to spreading disease, insects were busy pollinating flowering plants. These gradually took over from seed ferns, cycads and gingkoes. If herbivorous dinosaurs could not adapt to this new diet they would have gone hungry.


Poinar believes that the most popular theory for the dinosaurs' demise - that a meteorite impact changed the global climate - falls short because the extinction took too long. "Other geologic and catastrophic events certainly played a role. But by themselves, such events do not explain a process that in reality took a very, very long time, perhaps millions of years. Insects and diseases do provide that explanation."


I have no idea whatsoever if Poinar’s hypothesis holds water but it does sound intriguing

7 comments:

david mcmahon said...

I saw this story a few hours ago and it sure raised my eyebrows too!!

jams o donnell said...

I agree it is definitely an eyebrow raiser. It would be interesting to see what they have to say

Roger B. said...

Hmm... interesting, but it doesn't explain why a lot of sea creatures were wiped out around the same time.

Steve Bates said...

I'd say the theory has a few bugs in it...

jams o donnell said...

Ah good point Roger. I forgot about that!

Lol, you couldn't resist that one could you Steve!

SnoopyTheGoon said...

Well, that is another theory in the long line.

I say dinos just became bored with procreation...

jams o donnell said...

Flesh it out and you have a book there Snoopy!