A new species of parasite wasp was found, and it was named after the ancient Egyptian God of evil and chaos, Set. It is also known as the “crypt-keeper” since it forces other parasites to create a hole for them to escape. Once the hole is big enough, they eat their host and escape through its head.

The new parasite wasp was found by Dr. Scott P. Egan, from Rice University, in 2015. This new species of parasite can manipulate the gall wasps, which are another type of parasite that infests live oaks. It was discovered in Florida; however, it can be found all over the southeast United States.

The new parasite wasp was found by Dr. Scott P. Egan, from Rice University, in 2015. Image credit: Ryan Ridenbaugh and Miles Zhang / New Scientist
The new parasite wasp was found by Dr. Scott P. Egan, from Rice University, in 2015. Image credit: Ryan Ridenbaugh and Miles Zhang / New Scientist

The parasite of another parasite

In 2015, Scott Egan noticed while walking in Florida Beach, some oak trees with distinctive swelling on their branches. He could tell that they were made by gall wasp – or Basettia pallida – which is a parasite that puts eggs in plants. The larvae manipulate oak trees to create chambers with nutritious tissues in which they can grow within. Once they become adults, they chew the tree, creating a hole to escape and fly away.

Egan, who is an expert on gall wasps, took off some branches to his lab. When he was analyzing them alongside Kelly Weinersmith, a parasitologist at the Rice University, they found out that not all the orange gall wasps make it out of their crypts, some of them had their heads stuck in the holes. They also saw that the crypts where the wasps were stuck had another companion, a second wasp that was half the size of the gall wasps. These little blue-like wasps were eating, in every case, the orange wasps.

Image credit: Andrew Forbes / University of Iowa / Popular Science
Image credit: Andrew Forbes / University of Iowa / Popular Science

Those were an entirely new species of wasps, and given its behavior, the scientists called them the “crypt-keeper wasps.” However, the formal name is Eudorus set, after Set the Ancient Egyptian god of evil, who killed his brother, and then cut him into small pieces he scattered all over the world. According to Egyptian mythology, Set could control evil animals such as serpents.

“Set was the god of chaos and evil, and he was said to control other evil beings,” says Weinersmith. “He also locked his brother Osiris in a crypt for him to die. It kind of blew our minds how many cool connections we could find.”

The new wasps belong to a genus of 77 species approximately. They measure from 1.2 to 2.3 mm in length. When analyzed under a microscope, they appear as one of the most colorful insects. They are shiny metallic combined with olive green, turquoise, and iridescent blue. Their color also depends on the age of the wasp. They can be found across the US. Golf Coast, including sites in Georgia, Florida, Mississippi, Louisiana, and Texas.

The crypt keeper wasps escape through the head of the gall wasps

The recently discovered wasps are a perfect example of hyperparasite, a parasite whose host is another parasite. Hyper-parasites are not that uncommon as one might think, especially when it comes to wasps. Many species lay the eggs in the bodies of other insects. As well, some hyperparasites can be parasitized by other hyperparasites.

Furthermore, these tiny parasites can also control the behavior of their host. This is not that common, though some fungi can turn ants into zombies, or hairworms that force crickets to jump into the water. Beyond that, the crypt-keeper wasps are just one of the few hypermanipulators, which are parasites that manipulate the behavior of parasites that are manipulative themselves.

Once the crypt-keeper wasps find a tree with a gall wasp’s egg inside, it lays the egg, and this larva manipulates the gall wasps to escape by making a hole. When the hole is big enough for the crypt-keeper wasps, it forces the orange one to stop while it is being eaten by the first. Through all this process the crypt-keeper wasp grows and feeds inside of the gall wasp. When it is an adult, it eats the other wasp leaving parts of exoskeleton behind, and it finally escapes through the head of its no longer existing crypt mate.

The discovery is published in the open access journal ZooKeys

The way the crypt-keeper wasp forces its host to make a hole, the scientists don’t know yet. They don’t know either how do the wasps get the egg into the other wasp, and how does it make later to stop the gall wasps from widening the hole, as soon as it is big enough for the head but not for the body of the host to escape.

According to David Hughes from Pennsylvania State University, the crypt-keeper must secrete some kind of mind-addling chemical. As well, he said that he might eat the host to the point when it can make an escape hole that is not that big.

“This is the type of science I love; it leaves us hungrily asking more questions,” said David Hughes, who is an expert on manipulative parasites.

Source: The Atlantic