“Molecular sponge” could replace the pesticides used to control ants

It’s a dilemma – leaf cutter ants do a lot of damage to tropical plants, but applying pesticides to these plants is harmful to the environment. Scientists have developed a possible solution in the form of a high-tech material that uses an odor to catch ants.

Like other social insects, leaf cutter ants emit chemicals known as alarm pheromones when they detect a threat. Other ants instinctively follow the scent of these pheromones to their source so they can defend their colony.

In the past, such pheromones were built into ant traps. However, because the chemicals evaporate relatively quickly, these traps quickly become ineffective.

Under the direction of Prof. Andrew Burrows, researchers from the University of Bath, UK, went in search of a trap material that would keep the pheromones longer. Ultimately, they had the greatest success with so-called metal-organic frameworks (MOFs) – porous materials that consist of a series of positively charged metal ions surrounded by organic “linker” molecules.

The team started with computer simulations to see how alarm pheromone molecules would move around in the pores of different types of MOFs. Specifically, the researchers were looking for a material that could absorb large quantities of the chemicals and release them again over a long period of time.

They eventually developed a “molecular sponge” MOF that releases the pheromones over several months, as opposed to the usual several days. Colleagues from the University of Sussex tested the material in ant traps on a eucalyptus plantation in Brazil, where it successfully attracted leaf cutter ants.

“Our proof-of-principle study shows that these materials effectively release the pheromone and the insects respond normally,” says Burrows. “This system could reduce the amount of pesticides that are sprayed on a crop and could be particularly useful for high-quality crops in small areas.”

An article about the study was recently published in the journal Dalton Transactions.

Source: Bath University

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