University Of Memphis: University Of Memphis Biological Sciences Faculty Published In High-Profile Journal Proceedings Of The National A ...

Press release from the University of Memphis:

June 1, 2021

Combining species and population-genetic approaches, the research team demonstrated
that weevils colonized the Antarctic islands from Africa at least 50 million years
ago and repeatedly dispersed among islands—despite being flightless—likely using seabirds
to travel long distances over open ocean, and often against prevailing ocean currents.
As the climate cooled over the last ~20 million years, weevil diversification accelerated,
resulting in an unusual diversity of living weevil species for such an inhospitable
region—36 species of Ectemnorhinini are known from the Antarctic. Some species of
Ectemnorhinini evolved the ability to feed on “lower” (non-seed bearing) plants, which
dominate the polar habitats that now prevail in the region. One unusual weevil species
lives only in the marine littoral zone and is currently undergoing further speciation.
Yet other species retain the more common weevil habit of feeding on flowering plants
(angiosperms). Unexpectedly, Ectemnorhinini weevils diversified in synchrony with
many other denizens of the Southern Ocean, including penguins, limpets and some fishes.
This suggests that diversification driven by climate-cooling may be a general biodiversity
paradigm underlying much of the region’s present biodiversity and should be sought
broadly as an explanation for the unexpected diversity of some groups of Antarctic
organisms.

McKenna and Shin, along with their colleague Dr. Rolf Oberprieler (CSIRO, Australia),
helped reconstruct the weevil family tree and timing and patterns of weevil diversification
using large-scale DNA data, as part of the NSF-DEB funded 1,000 Weevils Phylogeny
and Evolution Project. Adams contributed his expertise in data analysis to resolving
the geographic origins of Ectemnorhini. The University of Memphis team worked closely
with other colleagues worldwide, including Dr. Steven Chown at Monash University (Australia),
a specialist on Ectemnorhinini weevils and the Antarctic (project PI and past President
of the Scientific Committee on Antarctic Research), and Dr. Helena Baird, the paper’s
lead author, who conducted a large fraction of the laboratory, field and analytical
work for the study (Baird is a postdoc in the Chown lab), along with several other
colleagues from Australia or France.           

According to McKenna, “This work involved the most comprehensive analyses of DNA data
to uncover the geographic and evolutionary origins of a group of Antarctic insects
and is notable for having illuminated the remarkable antiquity of Antarctic weevil
biodiversity, its geographic origins, and its responses and apparent resilience to
climate cooling over millennia.” The research reported in their paper “Fifty million
years of beetle evolution along the Antarctic Polar Front” was funded in-part by the
Swiss Polar Institute and Ferring Pharmaceuticals through the Antarctic Circumnavigation
Expedition, by École Polytechnique Fédérale de Lausanne, France, and by the U.S. National
Science Foundation.

For more information on this published work and research, contact McKenna at dmckenna@memphis.edu.

This press release was produced by the University of Memphis. The views expressed here are the author’s own.