Navigation Links
Which came first, the moth or the cactus?
Date:8/13/2007

HOUSTON, Aug. 13, 2007 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.


'/>"/>
Contact: Jade Boyd
jadeboyd@rice.edu
713-348-6778
Rice University
Source:Eurekalert

Related biology news :

1. Identification of specific genes predicts which patients will respond to Hepatitis C treatment
2. Overbearing colored light may reveal a second mechanism by which birds interpret magnetic signals
3. Bacteria which sense the Earths magnetic field
4. Researchers discover which organs in Antarctic fish produce antifreeze
5. First-ever genomic test predicts which lung cancer patients need chemotherapy to live
6. Researchers discover key mechanism by which lethal viruses Ebola and Marburg cause disease
7. Newts which regrow their hearts
8. Reminding doctors which antibiotics to prescribe cuts C. difficile infection rates
9. Killing the messenger RNA -- But which one?
10. Scientists discover stage at which an embryonic cell is fated to become a stem cell
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/10/2017)... 2017 Research and Markets has ... Medicine - Scientific and Commercial Aspects" to their offering. ... ... integrated with therapy for selection of treatment as well for ... prevention of disease in modern medicine. Biochip/microarray technologies and next ...
(Date:2/8/2017)... YORK , Feb. 7, 2017 Report Highlights ... The ... should reach $11.4 billion by 2021, growing at a compound ... Includes - An overview of the global markets for synthetic ... 2015, estimates for 2016, and projections of compound annual growth ...
(Date:2/7/2017)... Ind. , Feb. 7, 2017 Zimmer ... leader in musculoskeletal healthcare, will present at the LEERINK ... New York Palace Hotel on Wednesday, February 15, 2017 ... live webcast of the presentation can be accessed at ... replay following the conference via Zimmer Biomet,s Investor Relations ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... , Feb. 23, 2017  Seattle,s upscale Capitol Hill ... a strange place for a head lice treatment salon to ... between a Tuscan restaurant and a French bistro on E ... perfect. "We aren,t just any old lice clinic, we pride ... feel comfortable, and release some of the stigma associated with ...
(Date:2/23/2017)... ... 2017 , ... Today, researchers can fast-track sample collection and ... other biomarkers or SNPs of interest) using one, easy-to-collect saliva sample. With the ... between insulin and other relevant biomarkers can be extensively studied through a non-invasive ...
(Date:2/23/2017)... USA, and CARDIFF, UK (PRWEB) , ... February ... ... international society for optics and photonics , have been named Fellows of the ... significant scientific and technical contributions in the multidisciplinary fields of optics, photonics, and ...
(Date:2/22/2017)... CINCINNATI , Feb. 22, 2017 Scientists ... drives inflammation and organ damage in Gaucher and maybe ... fewer risks and lower costs than current therapies. ... Children,s Hospital Medical Center , which also included investigators ... , report their data Feb. 22. The study ...
Breaking Biology Technology: