Ants in Australia's semi-arid areas routinely carry seeds half their size over distances of 50 metres, and in some cases hundreds of metres, new research has found.
The study, published in a recent issue of Oecologica, showed ants in these environments carried seeds much further than they did elsewhere.
"To put it mildly, we were flabbergasted when we saw this," said co-author Dr Jonathan Majer, an entomologist affiliated with Curtin University.
Previous research has found that, on average, ants do not disperse seeds very far from parent plants - on average just 2.24 metres.
This has led to the idea that if ants are involved in dispersal, a plant is much more likely to evolve into a greater number of species because there is little genetic mixing of plants over long distances, Dr Majer said.
However, he said the seed dispersing behaviour of ants in semi-arid and arid areas has been understudied.
Dr Majer and his colleagues studied dispersal of seeds from the native Acacia karina tree by two species of ants - Iridomyrmex agilis and Melophorus turneri perthensis - in an area 400 kilometres north-east of the Australian city of Perth.
"One way you can study this is to sit and watch, but this is extremely difficult to do and it's not very reliable," Dr Majer said.
Instead, the researchers used genetic markers in the seeds and compared these to genetic markers to plants in the area.
"In this way we could find out which plants the seeds came from," Dr Majer said.
To ensure the ants were actually dispersing the seeds, the researchers sampled seeds from conspicuous "rubbish dumps" or middens on top of their nests.
"You get volcanoes of sand around the hole and you find the seeds in there," Dr Majer said.
"The ants usually remove the oil body of the seed, and these particular species aren't interested in eating the rest of the seed."
Using genetic markers the researchers were able to plot the movement of the seeds from parent trees to ant nests.
The researchers were astonished to find that the average distance seeds were carried was between 40 and 79 metres, with the maximum between 417 and 423 metres.
This is a "major feat" given the ants are only four or five millimetres long, Dr Majer said.
The researchers said water could not have dispersed the seeds over such long distances, since most of the seeds were found uphill from the parent plant.
"We do think the ants are involved - even in the long distance dispersal events," Dr Majer said.
Article first appeared on ABC Science.