A new study has shed light on the dietary preferences of ants, one of the most abundant and diverse groups of insects in the world.
The researchers found that ants are hungry for sugar and oil, especially in the high mountains of the tropics, where food resources are scarce and unpredictable.
The study, published in the journal Global Ecology and Biogeography, involved an international team of scientists from six countries, led by researchers from the Biology Center of the Czech Academy of Sciences (CAS).
They conducted a unique field experiment on three tropical high mountains, each on a different continent: Mt. Wilhelm in Papua New Guinea in Oceania, Kilimanjaro in Africa, and the South American Cordillera.
These mountains are home to some of the last virgin forests in the world and host a rich diversity of ant species, many of which are still unknown to science.
How the experiment was done
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The researchers offered the ants different food sources, from the foothills to the tops of the mountains.
They placed more than 2,300 vials, each containing a solution with one of six nutrients: sugar, salt, olive oil, amino acid, honey, and water.
They then recorded which vials were visited by ants, and identified the ant species using DNA barcoding.
The experiment revealed that ants preferred sugar and oil over other nutrients, regardless of the mountain or the elevation.
Sugar and oil are rich sources of energy and essential fatty acids, which are vital for the survival and reproduction of insects.
The researchers also found that ants were more selective in their food choices at higher elevations, where the climate is colder and the vegetation is sparser.
The study provides new insights into the ecology and evolution of ants and their role as "ecosystem engineers" in tropical forests.
Ants are important for the functioning of ecosystems, as they perform various services such as pollination, seed dispersal, soil aeration, decomposition, and pest control.
Understanding their dietary needs and preferences can help predict how they will respond to environmental changes, such as global warming, deforestation, and land use.
The study also highlights the need for more research and conservation efforts in the tropical high mountains, which are among the most threatened and understudied habitats in the world.
The researchers discovered more than 100 new species of ants during their fieldwork, which shows how much biodiversity is still waiting to be explored and protected.
The study was funded by the Czech Science Foundation, the German Research Foundation, the Swiss National Science Foundation, the National Geographic Society, the Slovak Research and Development Agency, and the Slovak Academy of Sciences.
Previous studies have focused on specific regions, such as the Australian Wet Tropics, the Middle American rainforest, and the Himalayas.
These studies have also found that ants show a mid-elevation peak in species richness and that different sampling methods and subcommunities may reveal different patterns.
The study by the CAS team adds to the existing knowledge by showing that ants have consistent preferences for sugar and oil across different continents and elevations and that these preferences are influenced by the seasonal moisture stability of the habitats.
The study also suggests that ants may have different evolutionary histories and adaptations to the high mountain environments, which may explain the high level of endemism and diversity in these regions.
