Surprise! Sixteen tiny wasp species found masquerading as one_sierra rutile jobs     DATE: 2022-06-27 18:40:41


Surprise! Sixteen tiny wasp species found masquerading as one

The new discovery hints at other hidden insect diversity waiting to be uncovered

Scientists recently discovered that one supposed species of parasitic wasp, Ormyrus labotus, is 16 or more genetically distinct species. At least from the outside, however, they all look the same.

Sofia Sheikh

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By Lindsey Konkel Neabore

You might think that discovering a new animal species requires traveling to a remote part of the globe. Perhaps you’d have to look high in the treetops of a rainforest. Or maybe deep in an ocean trench. Not so. One group of scientists recently discovered at least 16 new wasp species. Many had been hiding within view of the scientists’ windows at the University of Iowa.

For more than 160 years, scientists thought that all of North America’s Ormyrus labotuswasps were one species. Just a few millimeters (tenths of an inch) long, these critters do look pretty much the same. Only their behavior hinted at potential differences.

These wasps are parasitoids (PAIR-ih-sih-toyds). That means they are parasites that prey on other parasites. O. labotuswasps lay their eggs in abnormal growths — called galls — on oak trees. Other parasitic wasps created those galls to protect their own young. Once the predator’s eggs inside these galls hatch, those young will begin feeding on the prey species. More than 65 different oak species and parts of those trees can host galls that O. labotusparasitizes.

Many hundreds of different wasp species make galls. Some of the galls in which O. labotusputs its eggs are hard. Other galls are squishy. Some are fuzzy. Others not. The galls in which O. labotusfinds prey may be on a branch, a stem or a leaf. Some invaded galls develop in spring. Others emerge only in summer.

a composite of two photos, on the left an oak gall on a branch, on the right an oak gall on the underside of a leaf. The left gall looks fluffier and more yellow. The right gall has spiky red tufts.
Oak galls can have different characteristics depending where on a tree they grow.Anna Ward

“It was confusing and surprising to find one species that was so good at parasitizing so many different [gall-wasp] hosts,” says Sofia Sheikh. Such generalists are rare. Most parasitic wasps lay their eggs to dine on one very particular host. Sheikh and her colleagues wondered: “How can one parasite successfully attack dozens of hosts that are all so different?”

To find out, these researchers gathered galls from oak trees across the country. Some were right around their university campus in Iowa City. Carefully, they logged what type of gall it was, where it was found and when.

Back at the lab, the researchers collected the O. labotuswasps that emerged from these galls and looked at them under a microscope. This was similar to how naturalists in the 1840s first identified the wasps. But Sheikh’s team also had modern tools to inspect the insects’ genetic material. They used these tools to decode one particular gene in the wasps’ DNA. Then, they looked for differences in that gene from one insect to the next.

And they found distinctly different versions of the gene. The researchers used these data — combined with those on the type of gall from which the wasps emerged — to group O. labotusinto some 16 to 18 different species.

“What’s really cool,” says Alex Smith, “is how this shows that Darwinian discovery could be happening in backyards and at schools all over North America.” Smith is a biologist in Ontario, Canada who did not take part in the new study. He works at the University of Guelph. By Darwinian discovery, he refers to the finding of many new species, just as naturalists in Charles Darwin’s era did during the 1800s. They regularly turned up new species of animals and plants.

The Iowa team shared its wasp discovery February 16 in Insect Systematics and Diversity.

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Uncovering “cryptic” species

“We used multiple lines of evidence” to uncover the new species, says Sheikh. Researchers call this an integrativeapproach. It can help scientists quickly unveil so-called cryptic species — ones that may have been hidden because they looked identical to another.

This is important for a couple of reasons, Sheikh says. For instance, O. labotuswasps could be used to destroy other parasitic insects that damage oak trees. But to do that, scientists can’t bring in just any O. labotuswasps. They’ll need to find which specific ones attack and dine on the target pest.

Uncovering new parasitoid species also can help scientists understand how parasites evolve. It might even reveal how vulnerable these creatures are to extinction. Parasites with many types of prey tend to be resilient. If they lose one host, they can turn to another species. But what if parasites thought to be such generalists are, in fact, quite specialized — as the O. labotuswasps seem to be? These “specialist” parasites could be more likely to die out when they lose their particular host species.

Sorting out the species of O. labotuswasps is one step toward uncovering the full diversity of life on Earth, notes Smith, at the University of Guelph. “Studies like this one help us better understand the cast of characters whose planet we share.”

For now, Sheikh says, the 16 new wasp species haven’t been given new names. So awkward as it is, they’re all still being called O. labotus.

Power Words

More About Power Words

behavior: The way something, often a person or other organism, acts towards others, or conducts itself.

biologist: A scientist involved in the study of living things.

colleague: Someone who works with another; a co-worker or team member.

diversity: A broad spectrum of similar items, ideas or people. In a social context, it may refer to a diversity of experiences and cultural backgrounds. (in biology) A range of different life forms.

DNA: (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

ecology:  A branch of biology that deals with the relations of organisms to one another and to their physical surroundings. A scientist who works in this field is called an ecologist.

evolve: (adj. evolving) To change gradually over generations, or a long period of time. In living organisms, such an evolution usually involves random changes to genes that will then be passed along to an individual’s offspring. These can lead to new traits, such as altered coloration, new susceptibility to disease or protection from it, or different shaped features (such as legs, antennae, toes or internal organs).

extinction: The permanent loss of a species, family or larger group of organisms.

gall: (in plants) An abnormal growth, often caused by insects, fungi or other plant pests.

gene: (adj. genetic) A segment of DNA that codes, or holds instructions, for a cell’s production of a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

genetic: Having to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

host: (in biology and medicine) The organism (or environment) in which some other thing resides. Humans may be a temporary host for food-poisoning germs or other infective agents. (v.) The act of providing a home or environment for something.

insect: A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.

microscope: An instrument used to view objects, like bacteria, or the single cells of plants or animals, that are too small to be visible to the unaided eye.

naturalist: A biologist who works in the field (such as in forests, swamps or tundra) and studies the interconnections between wildlife that make up local ecosystems.

parasite: An organism that gets benefits from another species, called a host, but doesn’t provide that host any benefits. Classic examples of parasites include ticks, fleas and tapeworms.

prey: (n.) Animal species eaten by others. (v.) To attack and eat another species.

rainforest: Dense forest rich in biodiversity found in tropical areas with consistent heavy rainfall.

resilient: (n. resilience) To be able to recover fairly quickly from obstacles or difficult conditions.

species: A group of similar organisms capable of producing offspring that can survive and reproduce.

systematics: The field of biology that studies evolutionary relationships among living things. People who work in this field create “family trees” that show which creatures descended from common ancestors. The same people often practice “taxonomy,” naming new species or other groupings that they identify. People who work in this field are known as systematists.

tool: An object that a person or other animal makes or obtains and then uses to carry out some purpose such as reaching food, defending itself or grooming.

trait: A characteristic feature of something. (in genetics) A quality or characteristic that can be inherited.


Journal:​ ​​S.I. Sheikh et al.​ ​Ormyrus labotus (Hymenoptera: Ormyridae): Another generalist that should not be a generalist is not a generalist.​ ​​Insect Systematics and Diversity.​ ​​Vol. 6, February 16,  2022. doi:​ ​10.1093/isd/ixac001.