Leaf-cutting ants, one of a few groups of social insects to cultivate crops, have harvested plant material to fertilize their underground fungal gardens for ~50 million years.
New results from the Smithsonian show that both the ants and their fungal crop actively combat fungi coming into the nest inside leaves, thus ensuring the health of their mutualism.
"When you look at a healthy tropical plant, you think you're seeing just one organism, but each leaf can have dozens of fungal species growing inside, some of which may protect the plant by excluding pathogens," explains Sunshine Van Bael, post-doctoral fellow at the Smithsonian Tropical Research Institute. The fungi growing inside leaves without causing disease to the plant are called endophytes: endo-, inside, and –phyte, plant.
"We knew that leaf cutter ants practice phenomenal garden hygiene. But we wondered if the fungi in leaves might make them less attractive to ants, and thereby protect the plant from leaf cutter ant invasion. Also, since most leaves in nature have endophytic fungi, we wondered how the ants' leaf preparation process might affect the passage of endophytes into the nest."
Van Bael and colleagues used laboratory colonies of one leaf cutter ant species, Atta colombica, to test the ants' response to leaves from a tropical vine, Merremia umbellata, in which they had experimentally manipulated the densities of one fungal endophyte species, Glomerella cingulata, in order to present the ants with leaves containing either high or low levels of fungus. They also pitted 32 additional endophytic fungal strains against cultures of the garden cultivar in Petri plates to find out if they would restrict each others' growth.
Ants cut leaves that contained both high or low levels of fungi, but they took longer to cut leaves from the high endophyte treatment. Moreover, the leaf preparation process by the ants significantly lowered the amount of fungi in leaf pieces before they were placed into the fungal garden. The Petri plate experiment also showed that the garden fungus reduced the growth rate for 28 of the 32 endophytic fungal strains that were tested, with a stronger effect for more rapidly growing endophyte strains. This suggests that, apart from the hygiene practiced by the ants, the garden itself can compete with incoming microbes.
"Fungi in the leaves were not welcome in the leaf cutter ants' garden," concluded Van Bael.
Their work is published online in the Proceedings of the Royal Society B.
STRI, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.
Researchers discover natural product that could lead to new class of commercial herbicide
16.07.2018 | UCLA Samueli School of Engineering
Advance warning system via cell phone app: Avoiding extreme weather damage in agriculture
12.07.2018 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences