Rise of termite clone queendoms offers clue to curb invasions
Preventing a homeowner headache

Date:
January 28, 2022
Source:
University of Sydney
Summary:
The scientists who discovered all-female termite colonies have now
ascertained how they came to exist. In doing so, they revealed
how these powerful females potentially threaten other termites,
as well as homeowners.



FULL STORY ==========================================================================
Four years ago, entomologists at the University of Sydney discovered
the existence of all-female, forest-dwelling drywood termite colonies
in Japan.

Now, they have determined how they evolved, and the implications of insect 'girl power' for established termite species (hint: they're bad).


========================================================================== Their new research shows all-female colonies of drywood termites
(Glyptotermes nakajimai) developed through unwitting human-assisted hybridisation some time in the last century. Females from one lineage
mated with males from another, as one lineage was unknowingly moved
from a smaller island to mainland Japan, likely via boat. Their hybrid offspring are more genetically diverse, and likely to be more robust.

In addition to stronger offspring, the all-female colonies can clone
themselves and do not require a male to procreate, resulting in double
the amount of breeding. According to the researchers, this is bad news
for the incumbent, non-hybrid species, which can be outcompeted by its
hybrid relatives.

It's also potentially bad news for property owners. Drywood termites,
as their name suggests, do not require moist conditions to burrow into
and eat wooden beams, walls, floors or furniture, and are commonly
moved around the world by trade, opening the door to hybridisation
events. Once an infestation occurs, it can be difficult to eradicate, potentially leading to structural damage to a building, or even collapse.

Professor Nathan Lo, who led the study with University of Sydney
Postdoctoral Fellow Toshihisa Yashiro, said his findings have implications
for biosecurity: "Our study highlights the importance of making sure
termites from overseas are not permitted to establish themselves. If
they were to hybridise with local termites, it might lead to even nastier lineages of termites for homeowners to deal with." 'Really weird'males
Aside from discerning how the female colonies evolved, the researchers
also studied several drywood termitecolonies with males and females,
which contained a quirk: the sperm of males consisted of either 15 Y
or 15 X chromosomes, out of a total of 17. In most species, including
humans, male sperm have only a single Y or X chromosome (out of 23,
in the case of humans).



========================================================================== "It's really weird," said Professor Lo, who posits that this occurred
out of necessity.

"Termite offspring can inherit nests from their parents, saving them the trouble of venturing into the dangers of the outside world, burrowing
into wood, and creating their own nests. The problem with nest inheritance
is that it results in a lot of inbreeding -- sisters mate with brothers,
and offspring may even mate with parents.

"As a solution, male termites probably evolved to have multiple Y
chromosomes, making them harbour more genetic diversity than females. So,
even if a sister and brother mate, they can produce viable offspring."
The researchers say that this chromosomal pattern is found in some other organisms, including plants and huntsman spiders, but not usually to
the extremes found in drywood termites.

About the study The results have been published in the high-impact
journal Proceedings of the National Academy of Sciences. Termites were collected and preserved by Dr Yashiro prior to undertaking his fellowship
in Professor Lo's lab in Sydney, and DNA was analysed in Australia using nuclear SNP and mitochondrial markers.

Chromosome analyses were performed using DNA stains and fluorescence microscopy.

========================================================================== Story Source: Materials provided by University_of_Sydney. Note: Content
may be edited for style and length.


========================================================================== Related Multimedia:
* Images_of_termites ========================================================================== Journal Reference:
1. Toshihisa Yashiro, Yi-Kai Tea, Cara Van Der Wal, Tomonari Nozaki,
Nobuaki
Mizumoto, Simon Hellemans, Kenji Matsuura, Nathan Lo. Enhanced
heterozygosity from male meiotic chromosome chains is superseded
by hybrid female asexuality in termites. Proceedings of the
National Academy of Sciences, 2021; 118 (51): e2009533118 DOI:
10.1073/pnas.2009533118 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220128085808.htm

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