Corrie S. Moreau talks with
ScienceWatch.com and answers a few questions about
this month's Emerging Research Fronts paper in the field of
Social Sciences, general. The author has also sent along
images of her work.
Article: Phylogeny of the ants: Diversification in the
age of angiosperms
Author: Moreau, CS;Bell, CD;Vila, R;Archibald,
Journal: SCIENCE, 312 (5770): 101-104 APR 7 2006
Addresses: Harvard Univ, Museum Comparat Zool, 26 Oxford St,
Cambridge, MA 02138 USA.
Harvard Univ, Museum Comparat Zool, Cambridge, MA 02138
Florida State Univ, Sch Computat Sci, Dirac Sci Lib 150R,
Tallahassee, FL 32306 USA.
Dr. Corrie Moreau on Magnetic Island,
Queensland, Australia. Photo by J. Moreau
Why do you think your paper is highly
Ants occupy almost every terrestrial niche on the planet, so understanding
how they came to this ecological dominance and the time frames involved is
an intriguing question. The results of our 2006 research published in the
journal "Science" suggest that ants are considerably older than
had been appreciated based on the fossil record alone, having originated
140-168 million years ago, but also that the rise of the angiosperms or
flowering plants likely had a marked effect on the diversification of the
I believe our paper is highly cited due in part to our finding of a
correlation of the diversification of the ants and rise of the flowering
plants and the large amount of DNA data and molecular clock techniques we
utilized in our research.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
My colleagues and I produced the first large-scale molecular phylogeny of
the ants based on DNA from 6 genes for each of 139 of the 288 described
genera. This well-resolved phylogeny reinforced some previous hypotheses
about the morphological evolution of the ants, but we also were able to
demonstrate that the modification or reduction of the stinger happened
twice independently within the ants.
In addition, we used a "molecular clock," calibrated with 43 fossils
distributed throughout the ant family tree, to date key events in the
evolution of ants, providing a well-supported estimate for the age of
modern lineages. Although ants are older than hypothesized, their
diversification appears to closely track the rise of the angiosperms. Our
data suggest that these insects, now dominant in terrestrial ecosystems
worldwide, flourished with the rise of flowering plants.
Would you summarize the significance of your paper
in layman's terms?
Our research sheds light on three main points in the evolution of the ants:
1) We reconstructed the first large-scale phylogeny or family tree for ants
based on DNA; 2) Using the extensive ant fossil record, which goes back
100–125 million years, we were able to provide an age of
140–168 million years ago for the modern ants and a timeline for
their evolution; and 3) Using the resulting family tree and timeline for
ant evolution, we were able to explain patterns of their diversification
and suggest that ants were able to capitalize on the ecological
opportunities provided by flowering plants and the herbivorous insects that
co-evolved with them.
An ant of the genus
These plants provided ants with new habitats, both in the forest canopy and
in the more complex leaf litter on the forest floor, and the herbivorous
insects that evolved alongside flowering plants provided food for ants,
allowing them to diversify into the over 14,000 species known today.
How did you become involved in this research and
were any particular problems encountered along the way?
My Ph.D. thesis was on the evolution of the ants and the natural
progression for my interests was to take on this large project to really
delve into this topic. By coupling my passion for ant biology, molecular
phylogenetics, and evolutionary biology, I was able to address these
questions in a significantly more rigorous way than I would have been able
to using a single tool alone.
Where do you see your research leading in the
Although I have many interests in evolutionary biology, several projects I
have been involved with recently have me really excited.
First, we are just beginning to understand the wealth of bacteria
associated with ants and how these mutualisms may have helped ants
diversify and take advantage of novel food resources and ecological niches.
Some recently published research by my colleagues and I (PNAS 106:
21236-41) suggest that multiple independent associations between
Rhizobiales bacteria and herbivorous ants provide strong evidence
that symbiotic bacteria have facilitated the evolution of nectar and
exudate-feeding life histories in ants and their radiation into otherwise
inhospitable rainforest canopy habitats, providing a novel instance of
innovation through symbiosis.
Second, I have been conducting research on ants in the lowland rainforests
of Queensland, Australia to determine how past (and potentially future)
climate changes have affected the ants and other organisms. My preliminary
findings suggest that past drying events did indeed significantly impact
the lower elevation species and that some of the known genetic barriers to
populations of vertebrates appear to be even older than previously thought
and that these barriers have affected invertebrate species, including ants.
In addition, some ant species were more impacted than others, due to their
ability to climatically buffer during these fluctuations. It appears that
species that live in the soil and rotten logs may have been able to buffer
themselves from the long period of drying events by digging further into
the soil where moisture likely remained higher.
Species that are always associated with the leaves of the plants in the
rainforest (such as those species that build their nests between leaves and
live in the canopy) were very hard hit and likely suffered severe
extinction events. This has implications not only for understanding the
past history of these species, but also how they will likely respond to
future changes in their ecosystems due to habitat destruction and global
Lastly, the wave of genomic tools that are becoming available, even for
non-model organisms, makes this an exciting time to be involved in
evolutionary biology. Genomics provides us with the power to unlock many
interesting mysteries in biology and I am personally looking forward to
seeing what we learn.
Do you foresee any social or political
implications for your research?
Although all research in biodiversity, ecology, and evolution furthers our
understanding of the natural world, it is really the potential for direct
conservation implications that makes much of our research likely to have
social or political implications.
Through understanding the factors that affect the distributions, densities,
or genetic diversity of species and how they change through time, we can
study how past, current, and potentially future events impact species.
In my own research in Australia's rainforests, it appears that past
climatic drying events had profound impacts on ant species diversity, which
has implications for current and future deforestation and climate change
Through careful scientific investigation and advocacy for governmental
policy, we can potentially help protect the planet's biodiversity by
identifying factors that may lead to the loss of biological and genetic
diversity, which could eventually lead to species extinction.
Corrie S. Moreau, Ph.D.
Field Museum of Natural History
Department of Zoology
Chicago, IL, USA
KEYWORDS: RDNA SEQUENCES; FORMICIDAE; HYMENOPTERA; ORIGIN; BEETLES.