In the past giant dragon flies possessed wingspans of seventy centimeters, as they exposed to optimal levels of oxygen in the atmosphere. Neo-age experiments confirm that dragon flies attain enormous sizes if exposed to favorable hyperoxic conditions.

The challenging aspect of the study is in understanding why certain insects grow in favorable atmospheric conditions compared to other groups.

Use of fossilized insects could assist in adapting favorable oxygen levels in the past, to modern insects in the present. Researchers suspect that hollow tracheal tubes are responsible for the changes in the insects.

The secrets to why these changes happened may be in the hollow tracheal tubes insects use to breathe. Getting a better handle on those changes in modern insects could make it possible to use fossilized insects as proxies for ancient oxygen levels.

“Our main interest is in how paleo-oxygen levels would have influenced the evolution of insects,” said John VandenBrooks of Arizona State University in Tempe. In order to confirm the same, they exposed different groups of insects at varying oxygen conditions. , Dragonflies, Grasshoppers, Cockroaches, Beetles, Meal worms and other insects were used in the experiment to trace out the effect of the atmospheric conditions on them.

A comparative study between dragonflies and cockroaches indicated that, cockroaches grew slower. The findings also revealed that 10 out of 12 insect groups when exposed to lower oxygen conditions, decreased in size. The responses were different for each group of insects, when placed in an oxygen enriched atmosphere. The findings of this study will be announced at the annual meeting of the Geological Society of America in Denver in November 01, 2010.

“The dragonflies were the most challenging of the insects to raise,” said VandenBrooks because, among other things, there is no such thing as dragonfly chow. As juveniles they need to hunt live prey and in fact undergraduate students Elyse Muñoz and Michael Weed working with Dr. VandenBrooks had to resort to hand feeding the dragonflies daily.

“Dragonflies are notoriously difficult to rear,” said VandenBrooks. “We are one of the only groups to successfully rear them to adulthood under laboratory conditions.”