Australian ants prepared for 'Insect Armageddon'

Date:  July 16, 2019

Source:  La Trobe University

La Trobe University researchers have uncovered an exception to the global phenomenon known as 'Insect Armageddon' in the largest study of Australian insect populations conducted to date.

Researchers studied ants in the Simpson Desert for 22 years and found that local changes in climate, such as long-term increases in rainfall, combined with human efforts to restore ecosystems, may have led to increased numbers of species -- rather than the declines which might be expected in such unpredictable conditions.

Lead researcher, Associate Professor Heloise Gibb, said annual rainfall in the north Australian desert varied from 79 to 570 millimetres.

"While this unpredictability in rainfall is expected in hot climates, this is the first time we've been able to understand how insects respond to such large inconsistencies in their environment," Associate Professor Gibb said.

"For many species, this unpredictability -- exacerbated by climate change -- would equate to increasingly difficult conditions for their survival.

"What we've found, however, in contrast to warnings of a long-term decline in insects, is that species that already like it hot may do better where it also becomes wetter."

Associate Professor Gibb said researchers discovered a boom in the population of aggressive sugar-feeding ants with every rapid increase in rainfall.

"Water is the driving factor for this species' survival," Associate Professor Gibb said.

"These tyrant ants, as we would call them, are able to adjust their time of activity so they're active only when above-ground conditions are suitable.

"While the average temperature of their environment may be increasing, their flexibility in tough environments enables them to survive until the next big rainfall."

Researchers found the increase in ant populations reflected the change in resources available to them.

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