As the sun rose and set in the skies of long-ago Egypt, it rolled across the horizon courtesy of the sun god Khepri, a scarab.
The humble dung beetle, the ancients believed, was responsible for the transition from day to night. In the era of modern astronomy, it seems a stretch.
To Egyptians who watched the beetles roll manure balls into holes and then saw hatchlings emerge from the earth, however, the insect was an apt symbol for cycles of nature, said entomologist Michael Wall.
So important was the beetle to Egyptian belief that it formed a part of King Tut's throne name, and was one of the most distinctive motifs in the culture's religious art.
"For the Egyptians, it's scarabs, scarabs, scarabs," Wall said.
Wall, curator of entomology and vice president of research for the San Diego Natural History Museum, described the role of insects in religion during a recent lecture. He explained how biblical plagues and Egyptian iconography can be traced to human encounters with creepy crawlies.
The discussion shed light on the scarabs that adorn the artifacts of the museum's exhibit "The Discovery of King Tut." It also explored how insects alternately served up blessings and curses to cultures throughout the world.
"What the Egyptians were specifically interested in were the dung beetles, which were focused on vertebrate dung," Wall said.
That is to say, they roll balls of poop across the ground. In those dung dwellings, they mate and lay eggs. Pupae hatch and pop up as the next generation of beetles.
"The Egyptian god Khepri is in charge of the transit of the sun," Wall said. "The sun crosses the sky, goes into the underworld and rises again."
Just like dung beetles. Sort of.
"There's this kind of ashes to ashes feel to it," Wall said. "What goes into the Earth comes out of the Earth."
To Egyptians, at any rate, the similarities between dung beetles and the sun's cycle were striking enough that the boy king Tutankhamun incorporated the scarab god into his throne name, Nebkheperure. Throughout the museum's King Tut exhibit, the image of the scarab appears in hieroglyphics of Tut's name, and as elaborately wrought ornamentation on a gilded throne, tomb and chariot.
In addition, "heart scarabs," beetle-shaped ornaments placed on the chests of mummies, protected the dead during judgment in the afterlife.
"Why a scarab?" Wall asked. "It comes back to this cycle of metamorphosis and rebirth. The ideas is that the scarab is going to help you with the transition from life to death."
Other invertebrates played a role in Egyptian lore as well. The scorpion goddess Selket stands watch over a portion of Tut's tomb, and served as patron to a line of Egyptian scorpion kings, Wall said. Fierce and fickle, she could save you from a scorpion's sting or sic it on you instead.
The dual role of insects is present in biblical verse as well. Three of the biblical plagues describe mass infestations of grasshoppers, gnats or lice, and flies, Wall said.
Certain species of grasshoppers, also known as locusts, can form swarms 40 miles wide, which devour all crops in their wake he said. They're so devastating to the region's food supply that the United Nations has a team that tracks and controls them, he said. So they could have easily appeared to be a symbol of divine wrath.
On the other hand, he noted, the biblical manna that saved the Israelites on their trek across the desert may have been a beneficial insect product — either a species of scale insect or its edible excrement — Wall said.
In other cultures ranging from Native Americans to African Bushmen, insects appear as deities, tricksters, demons and creators. In many cases, the ancient stories mirror bug behavior in nature.
"I look at all these mythical or religious stories that involve insects and what I see are good natural historians," Wall said. "They clearly were observing the insects doing their business, and then morphed that into things that helped them make sense of their world."
To learn more about "The Discovery of King Tut" exhibit, visit sdnhm.org/kingtut.