College of Liberal Arts

University of Mississippi

Ecosystem Function of Ants

One of the big advantages to collecting and studying ants is that they are much less likely than vertebrates to land on any endangered species list. More importantly, scientists can use them as “surrogates” for other species that might.

Click here to find out more!“You can sample them easily and get lots of them,” said Brice Noonan, a University of Mississippi biologist. “Also, the things we observe in ants aren’t only applicable to ants. We can apply them to other organisms that are more difficult to sample.”

Noonan, assistant professor of biology at UM, is collaborating with entomologist Brian Fisher of the California Academy of Sciences, and Philip Ward, professor of entomology at the University of California-Davis, to study the ants of the Southwest Indian Ocean islands and adjacent portions of east Africa.

These islands are known for their exceptional biological diversity and high concentrations of endemic species. As land masses fragmented and islands formed over time, isolating the habitat, unique examples of flora and fauna evolved. Yet the area, particularly the insects of the region, has been poorly studied.

The goal of the research is to obtain data about the region’s evolution and biodiversity, information that could prove especially valuable for conservation efforts. “For example, if we are interested in where a park might be placed, we can go in and explore the biodiversity in the area using ants,” Noonan said.

“We might not be able to get an adequate sample of frogs and snakes,” he added. “But if we see a particular pattern with ants in a certain patch, and if that pattern is repeated across different lineages of ants, it would be reasonable to assume it likely applies to other organisms that live in these places.”

Ants offer a diversified selection of life histories, which makes their experiences relevant to other groups of animals, he said. For example, some ant colonies are ruled by queens with wings, meaning they can fly and disperse across the landscape. Others are led by queens without wings, who cannot easily change locations.

“The ones that can disperse readily (fly) might have similarities to other things that can move, such as birds,” Noonan said. “The ones who can’t may exhibit patterns representative of organisms that have difficulty dispersing, like amphibians, which can’t swim across the ocean. Because of this diversity, different groups of ants may provide insight into the evolution of different groups of organisms.”

Ants of this region are the perfect study subjects to better understand the process of evolution, the finer points of biogeography, and to explore the effects of global climate change, Noonan said.

 

“With the aid of novel DNA sequencing technologies, and recently developed analyses that elucidate the impact of climate on these organisms, we are uniquely poised to answer some of the more pressing questions in evolutionary and conservation biology,” he said.  “With a DNA-derived concept of species diversity, we can then use ecological modeling analyses to understand what factors influence distributions, use this to understand the impacts of past climate changes, and make predictions of the impacts of climate change in the next 100 years.”

Noonan’s work is funded by a $178,333 grant from the National Science Foundation, while Fisher is receiving $1,908,517 and Ward, $276,489, each of the grants spread over five years. The awards are part of the American Recovery and Reinvestment Act of 2009. Among other things, the money will help employ and train “the next generation of scientists,” Noonan said.

For example, the grant has enabled Stuart Nielson, a graduate student who works with Noonan, to receive training critical to his academic development, Noonan said. “With these funds, Stuart is developing novel genetic markers for ants with which he is exploring their evolution,” Noonan said. “These recently developed methods will greatly benefit him in his own research, and make him more competitive for academic employment in the future.”

Also, the researchers are developing new methods for specimen collection and preservation, and have generated an online resource of information they have accumulated, www.antweb.org.  “Up until now, if you were a scientist who wanted to study a particular ant, you would have visit a museum,” Noonan said.

“Brian [Fisher] is creating images for antweb.org in all dimensions, all posted online,” he continued. “This will free museums and researchers from having to move specimens about, and facilitate research, saving resources in terms of money and time.”

Fisher’s goal is to disseminate their results broadly, and in real time.  Among other things, he has been writing a blog about his field work, at http://scientistatwork.blogs.nytimes.com/author/brian-fisher/.

“Scientists must also be advocates,” Fisher said.  “We need to communicate why biodiversity research is relevant and important to everyone, not just the few scientists who read our academic articles.”

Overall all, the project uses Madagascar and nearby islands as a model system to explore species evolution.  “The current research would not be possible without the past ten years of intense inventory work across all biogeographic region in Madagascar,” Fisher said.

“Why is this research relevant?” he added.  “It is through this type of research that we will understand how to measure the biological scope and societal costs of climate change, species invasions, natural disasters, the spread of disease vectors, and agricultural pests, and other environmental concerns.”

Fisher built the Madagascar Biodiversity Center, located in the National Zoo in Antananarivo, to house the project and promote the study of entomology. The center will also be the hub for applying project results to local issues in Madagascar, Fisher said.

Ward’s part of the research focuses on the broader patterns of diversity, looking at specific genera of ants and exploring the ‘when’ and ‘where’ of their evolutionary history.  “Where did they originate and how did they reach their present distribution and species diversity?” Ward said.

In Madagascar, one of the islands under study, there are 400 known species of ants, and probably at least 1,000 in total, Noonan said. The other islands of the region are even less understood.

“So there is much we don’t know,” he said.  “We’re using genetic methods to examine populations on the southwest Indian Ocean islands to see if they are the same as those on the African mainland and Madagascar. Do they move back and forth? Or are there unique species on these islands? “

The researchers estimate that more than 95 percent of the ant species in the region “are found nowhere else on the planet,” Noonan said.

“This is pretty consistent for most animals found in this region, other than birds and bats,” Noonan said.  “Madagascar has been geographically isolated from other land masses for at least 80 million years, and has had a tremendous amount of time on its own for these species to diversify. There really has been little opportunity for species to leave and colonize in other parts of the world.”

Thus, Ward added, “the key to understanding their evolutionary origin is to discover where are the closest relatives of the Madagascar species? Do they occur in other southern Indian Ocean islands, in east Africa or farther afield? And how much time has elapsed since they last shared a common ancestor? Answers to these questions will give us insight into how and when Madagascar and other islands were colonized.”

Another unique trait of ants is that they are important ecosystem engineers; that is, they do much to keep an ecosystem in proper balance.

“Worldwide, the mass of ants exceeds the total mass of all vertebrates,” Noonan said.  “They do so much. They farm fungi and disperse seeds, process soil and work leaf litter, and process it.  They break things down and move things around. There are seeds with specific ‘handles’ on them for ants to disperse them, and their movement of soil plays an enormous role in plant community structure and establishment. The role of ants in ecosystem function cannot be overstated.

“They aren’t only something simple we can sample that can serve as a proxy,” he added.  “They are a very important component of the ecosystem. If you were to take them out, and leave everything else, the system would not function properly.”

from US News & World Report