A new species of gall wasp discovered in Houston, whose life cycle involves spending 11 months of the year encased in protective “crypts,” has been named after a pub.

Neuroterus valhalla, which is only a millimeter long, honors ‘Valhalla,’ the Rice University graduate student pub outside of which it was found in a live oak.

“It would have been a missed opportunity not to call it something related to Rice or Valhalla,” said biologist Pedro Brandão-Dias, who first collected the wasp in 2018.

According to the researchers, N. valhalla is the first insect species to be described along with the publication of its fully sequenced genome.

The study was led from the lab of Rice University evolutionary biologist Scott Egan, who, over the course of eight years, discovered as many new species of gall wasps as N. valhalla or its predators.

“At Rice, we emphasize learning by doing,” Professor Egan said.

‘In my lab, undergraduate and graduate students share the experiential learning process by studying biologically diverse ecosystems in the live oak trees just outside our front door.

Armed with a little patience and a magnifying glass, the discoveries are endless.

According to the researchers, there are more than 1,000 different species of gall wasps, all of which have a life cycle that involves tricking their host tree into feeding and protecting their young.

When they lay their eggs, they do so in conjunction with a special chemical cocktail that causes the tree to form a “crypt” or “gall” around the egg, serving both to house the egg and to provide a food source for the larvae. when they hatch.

‘Once they emerge, they only live three or four days. They do not eat. Their sole purpose is to mate and lay eggs,” Brandão-Dias said of the tiny wasps.

The galls take various forms, some forming on the undersides of leaves, some inside branches, and others on tree blossoms, the latter of which is where the biology student collected specimens of N. valhalla for first time in the spring of 2018.

Mr. Brandão-Dias and his colleagues had been collecting oak catkins while searching for an entirely different species of gall wasp known to make the flowers at home, but DNA analysis revealed they had managed to catch more than expected.

“They lay their eggs in the catkins that are developing,” Brandão-Dias said.

‘They develop into galls on the flowers, and then they emerge. And that happens in March. But the flowers are a unique thing each year, and when they emerge, there are no more flowers for them to lay eggs.

“So they have to lay eggs in a different tissue.”

In fact, many gallers lay their eggs every two years and not necessarily in the same kinds of places each time, which is why it took nearly four years for the researchers to feel comfortable publishing their description of N. valhalla as a new species.

As Professor Egan explained, it is unprecedented for alternate generations of cockerels to be confused with entirely different species, making genetic testing of specimens at different parts of their life cycle essential.

In addition to this, the team had to find out where N. valhalla laid its eggs in March, if not in the flowers.

The stroke of luck came in 2019, when during a trip to Florida, biologist Kelly Weinersmith of the University of Iowa and her colleagues found the ‘missing’ generation of N. valhalla in galls on the branch joints of a species of oak. I live from Florida.

‘To confirm where they went after leaving the flowers, I did an experiment where we offered the wasps a bunch of different tissues from the tree and watched them,’ explained Mr Brandão-Dias.

This experiment, conducted in a Petri dish, allowed the researchers to see where N. valhalla went after emerging from the galls on Rice, and to catch them in the act of laying their eggs elsewhere.

However, this process was made more challenging due to the coronavirus pandemic.

We’d go out together and collect the gills and catkin tissues for behavior tests in petri dishes, but [undergraduate student Camila Vinson, who lived on the Rice campus] I had to go to the lab every day to see if any errors had come up,” Brandão-Dias said.

Based on Dr. Weinersmith’s observations and laboratory tests, the researchers were able to return to the live oak trees on the Rice campus where they had found the first generation of wasps, to find missing galls from the other generation.

According to Mr. Brandão-Dias, the generation of N. valhalla that hatches in live oak catkins mature from eggs to fully formed adults in about 2 to 3 weeks, but their successors spend 11 months growing inside the branches.

‘They have to come out at the exact time the tree blooms. If they come out at the wrong time and there are no flowers around, they can’t lay their eggs and they just die,” explained the biologist.

At present, it is unclear exactly how N. valhalla manages to coordinate its appearance with the flowering of the trees, which can vary from year to year.

Researchers are now eagerly awaiting to see how last year’s winter storm in February, which brought record cold temperatures to Houston and delayed the blooming of oak trees, might have affected the insects.

“The day the frostbite happened, I asked Pedro, ‘Is this going to mess up when they come out or even their ability to reproduce?'” Ms Vinson recalled.

The biologist is tackling this question as part of her senior thesis, which explores more broadly how climate change might be affecting such specialized insects.

‘Our gall wasps live on live oaks from the southern United States to Mexico: environments [that] they’re not used to the kind of temperatures we had last February,’ said Ms. Vinson.

‘That kind of frost will probably happen more and more frequently with climate change. The big question is: will these populations be in danger or can they adapt quickly?

The full results of the study were published in the journal Systematic Entomology.