Hidden diversity: When one wasp species is actually 16 wasp species
Advanced genetic techniques reveal several look-alike parasitoid wasps previously grouped as one species

Date:
February 16, 2022
Source:
Entomological Society of America
Summary:
Some undiscovered species are hiding right under our noses. Ormyrus
labotus, a tiny parasitoid wasp known to science since 1843,
has long been considered a generalist with more than 65 host
species. But a new study suggests wasps currently called Ormyrus
labotus are actually at least 16 different species, identical in
appearance but genetically distinct.



FULL STORY ==========================================================================
A common refrain among biologists holds that the majority of Earth's
plant and animal species remain undiscovered. While many of those species inhabit narrow or hard-to-reach ranges, others may in fact be hiding
right under our noses.


==========================================================================
Take Ormyrus labotus, a tiny parasitoid wasp known to science since
1843. It has long been considered a generalist, laying its eggs in more
than 65 different species of other insects. But a new study published
today in Insect Systematics and Diversity suggests that the wasps
currently called Ormyrus labotus are actually at least 16 different
species, identical in appearance but genetically distinct.

It's not unusual, especially with advancing genetic techniques, to
discover "cryptic" species within one known insect species, but the
number of those found within Ormyrus labotus underlines the importance of seeking out the world's "hidden diversity," says Andrew Forbes, Ph.D., associate professor of biology at the University of Iowa and senior
author of the study.

"We know so much from ecology about how important even the smallest
species can be to an ecosystem," he says, "such that uncovering this
hidden diversity - - and, maybe more importantly, understanding the
biology of each species - - becomes a critical component of conservation
and maintenance of ecosystem health." Intriguing Insects That Emerge
From Oak Galls Parasitoid wasps lay their eggs on or in other insects and arthropods, and they commonly specialize in parasitizing a small number of
host species, or even just one. Meanwhile, a wide variety of insects lay
their eggs on plants where their larvae hatch and then induce the plant
to form a protective structure called a "gall" around the larvae. Wasps
in the genus Ormyrus parasitize these gall-forming insects.



==========================================================================
For a separate research project between 2015 and 2019, Sofia Sheikh
and Anna Ward, both graduate students in Forbes' lab, collected galls
formed on oak trees and observed the insects that emerged. They noticed
that wasps emerging from a large diversity of gall types all matched the description of Ormyrus labotus, and this got the researchers wondering.

"It seemed highly unusual for one parasitoid species to be able to exploit
such a wide and dynamic set of hosts," says Sheikh, a master's student
at the time in Forbes' lab (now a Ph.D. student at the University of
Chicago) and lead author on the new study.

To test whether the wasps they collected were all truly one species
or instead a band of look-alikes, Sheikh, Ward, and Forbes extracted
DNA samples from each of the wasp specimens that emerged from the oak
galls and analyzed the degree of genetic variation between them, with assistance from collaborators at Rice University and the U.S. Department
of Agriculture. Then they combined this genetic analysis with data on
the wasps' physical attributes and ecological factors -- e.g., which
type of oak galls they emerged from, at what time of year, and so on --
to place the wasps in groups of likely separate species.

The final result? The collected wasps that originally appeared to be
Ormyrus labotus instead comprise at least 16 distinct species, and
possibly as many as 18.

The Hunt for Cryptic Species In their review of other research, the
team found several other studies that had uncovered cryptic species
within purported generalist species but none that had found so many at
once. And it's possible more distinct species that would otherwise match
O. labotus remain to be found, the researchers say, because the original collection of oak-gall specimens that Sheikh and Ward conducted wasn't
designed to encompass all known O. labotus hosts.

For now, Ormyrus labotus will remain a "species complex," with these
newly delineated species known to exist but not yet formally described
and named.

Forbes says his lab "only dabbles" in formal taxonomy, but all specimens
from the study have been preserved and are available for other researchers
who want to conduct a taxonomic revision of the Ormyrus genus. "If
someone wants to take a crack at naming these species of Ormyrus, we're
ready to help however we can," he says.

Until then, the current findings underscore the importance of fundamental biodiversity research and its potential implications. For example, if O.

labotus were ever enlisted for control of an invasive oak-galling pest,
it would be critical to know which species within the complex targeted
that specific pest species -- and the same dynamic applies in the use of
any parasitoid wasp species for biological control. Meanwhile, failing to differentiate specialists from generalists hinders scientists' ability
to understand actual generalist insects and what enables them to target
a variety of hosts, the researchers note.

Sheikh says she sees parasitoid wasps as "emblems of weird -- i.e.,
interesting -- biology" and is intrigued by their specialization
strategies. "More so than any specific number of potential new species,
I am excited about how this study and many others are revealing a plethora
of cryptic diversity," she says.

"This, to me, suggests that we still have a lot to
learn about the processes that structure species
interactions with each other and their environments." ========================================================================== Story Source: Materials provided by
Entomological_Society_of_America. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Sofia I Sheikh, Anna K G Ward, Y Miles Zhang, Charles K Davis, Linyi
Zhang, Scott P Egan, Andrew A Forbes. Ormyrus labotus (Hymenoptera:
Ormyridae): Another Generalist That Should not be a Generalist is
not a Generalist. Insect Systematics and Diversity, 2022; 6 (1)
DOI: 10.1093/ isd/ixac001 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220216103041.htm

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