By Kristina Charania
Photos courtesy of PAMR
After extensive time spent amongst the rocky deposits of Driftwood Canyon Provincial Park, the Okanagan Highlands, and areas of Washington, SFU palaeontologist Dr. Bruce Archibald has unearthed the oldest assemblage of ancient green lacewing insects known to date.
“The insects were finely preserved in such exquisite detail. It really surprised us,” says Archibald. “Some of their soft bodied tissues are clear to see – internal organs at times, too.”
Belonging to the scientific family Chrysopidae, green lacewings is the second largest family of the order Neuroptera. The insects are common garden insects that have large wingspans, golden compound eyes, and bright green bodies.
“They’re regular insects that you’d see around a light at night,” says Archibald. “Organic gardeners really like them for pest control, too. They’re predators and eat plant pests like aphids.”
Dr. Archibald, alongside partner Vladimir Makarkin from the Russian Academy of Sciences, have collected a series of 24 green lacewing fossils from various fossil beds and museums. Although the green lacewings in southern BC and Washington were previously discussed by other palaeontologists, they had not named any particular species in their research — only the insects’ existence in these areas was noted.
Out of the 24 fossil series, at least six genera and 10 new species were present: six of the new species were named, and three of the six genera were newly discovered. The female reproductive spermatheca organ, spermathecal ducts, and trichosor-like structures — thickened wing margins with several hair growths – were observed for the first time in any Chrysopidae fossil. An article further detailing the newlydiscovered insect species has recently been published in the Journal of Palaeontology.
In total, there are currently over 1,200 species of green lacewings worldwide excluding the high latitudes that they cannot inhabit. When the green lacewing fossils formed during the Eocene Epoch, Western Canada was dominated by cooler temperatures year round — less than Vancouver’s average annual temperature at present. This encouraged high levels of insect biodiversity at the time.
Archibald spoke to The Peak and described that the fossils’ formation took place nearly 49–53 million years ago. “There was a lot of uplift in southern BC going into Washington at that time, so many highlands and volcanoes were being formed,” he said. “In this region, there was also a series of lakes that filled up with sediment — different insects and plants from the surrounding forests wound up being trapped in the bottom layer of the mud, and this sediment became the shale that these fossils were found in.”
The classification and examination of these fossilized insects play key roles in larger-scale studies like those conducted by Archibald and other scientists.
Alongside SFU Paleoecology professor Dr. Rolf Mathewes, Archibald is looking at the past diversity of his group of green lacewings and the reasons why a different group within the same family of insects has now become more diverse.
“Green lacewings usually fly in the evening or at night, and they’re vulnerable to predators like bats. Some of the green lacewings have bat ears that can detect bat cries,” Archibald stated. “We’re interested in looking at the relationship between the evolution of bats and the changes in groups of green lacewings relative to their ability to avoid predation.”
By understanding the evolutionary pattern of green lacewings through such studies, researchers can better understand broader aspects of general evolution.
Examining the green lacewings’ climatic preferences relative to large scale climate change over the last 50 million years, will also contribute to better comprehension of broad-scale evolution and patterns of biodiversity.
“In understanding how communities change relative to a transforming climate, we can understand the future better,” Archibald said. “We’re obviously going through a period of great climate change, so it’s best to know all that we can about these patterns.”
