Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Which came first, the moth or the cactus?

15.08.2007
Studies of desert duo show there's more to life than predator eats prey

It's not a good idea to put all your eggs in one basket… unless you're a senita moth.

Found in the parched Sonoran desert of southern Arizona and northern Mexico, the senita moth depends on a single plant species -- the senita cactus -- both for its food and for a place to lay eggs. The senita cactus is equally dependent upon the moth, the only species that pollinates its flowers. Senita cacti and senita moths have a rare, mutually dependent relationship, one of only three known dependencies in which an insect actively pollinates flowers for the purpose of assuring a food resource for its offspring.

"Mutualistic relationships like this present a problem for ecological theory," said Rice University ecologist Nat Holland, who co-discovered the senita moth-senita cactus mutualism in 1995 and has studied it ever since.

The problem is that the moths lay their eggs inside the cacti's flowers immediately after pollination, and when the eggs hatch the moth larvae eat the fruit, destroying the flowers' chances to produce seeds. Historic theory predicts extreme ecological instability for this relationship; as moth populations increase, more flowers are destroyed, fewer new cacti appear, and the spiral continues until both species disappear.

Yet that hasn't happened, and Holland, assistant professor of ecology and evolutionary biology, spends several months each year observing moths and cacti in the Mexican desert to document why.

Holland, whose lab is just a few steps down the hall from his Houston office, jokes that his "real" lab is 1,500 miles away. He's studied senita at several locations in the Sonoran Desert, including the Organ Pipe Cactus National Monument in southern Arizona. But his primary site for more than a decade is a desolate, 30-acre patch of desert straddling three ranches near Bahia de Kino on the Gulf of California. Holland said he and his students sometimes go weeks without seeing other people at the sites, with the exception of a cowboy on horseback here and there.

There isn't much to see on the long drives to and from Houston either, but Holland said hours of solitude provide a valuable time for thinking and synthesizing what he's learned in the desert. That's important because his ultimate goal reaches far beyond the Sonoran Desert to a fundamental rethinking of ecological theory for such mutualistic interactions.

"I develop theoretical models, equations that attempt to explain mutualistic relationships like the one between the moth and the cactus, and I take those models into the field and examine them empirically to find out how well they predict what really happens," Holland said.

Traditional theory of such mutualistic interactions leads to predictions of unbounded population growth or instability and eventual doom due to one species overexploiting another. These predictions clearly don't square with what Holland and his students see happening in the Sonoran Desert, where both species thrive. Holland's models differ from traditional theory, suggesting that one mutualist may exert some control over the other's population increases, such that neither unbounded growth nor overexploitation ensue.

"I have always been interested in the community ecology of mutualism -- the larger puzzle -- and this moth-cactus relationship is just one piece of that," Holland said. "When we discovered the relationship in 1995, I immediately thought of using it to look at the bigger picture. But in aiming to do that, I wound up spending a decade working on the population ecology of mutualisms, a prerequisite for then understanding this larger puzzle."

Having made some progress on the population ecology of mutualism, some of Holland's current work, which is slated for publication later this year, returns to his earlier interests in community ecology. "We want to understand how the structure of mutualistic communities influences their stability and dynamics, both of individual species and of whole networks of species." The results suggest that the structures of mutualistic communities compliment those of predator-prey food webs, a finding that presents the tantalizing possibility of developing an overarching scheme that incorporates elements of both.

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>