Natures wonders: ants use fungus to trap large insects (Introduction)

by David Turell , Wednesday, April 25, 2018, 01:08 (2403 days ago) @ David Turell

Much like a torture rack iti sbuilt on trees with multiple holes:

https://www.newscientist.com/article/2167060-ants-build-a-medieval-torture-rack-to-catc...

"These ants have transformed the characteristic ant zeal for teamwork into something macabre. Azteca brevis ants build and set a trap not unlike a medieval torture device, which is used to cooperatively capture and rip apart insect prey.

"Lead author Markus Schmidt first came across Azteca brevis ants in Costa Rica’s Piedras Blancas National Park in 1999. He saw the ants constructing unusual, porous nests on tree trunks. But he could not find any research explaining what these structures were for.

"After months of observations and experiments in the rainforest, Schmidt and his colleague Alain Dejean of the University of Toulouse in France discovered that A. brevis ants were engaging in an ingenious ambush hunting strategy.

"The millimetres-long ants build a network of galleries and tunnels, reinforced with fungus, in the tree trunk. The end result is a Swiss cheese-like contraption, dotted with holes just wide enough for a worker ant’s head. Schmidt calls it a “carton nest”.

"The ants lurk in the holes, jaws agape, waiting for a large grasshopper or leafcutter ant (Atta spp.) to step onto the trap. When one does, an ant will clamp onto a leg and start pulling. At this point, the victim is doomed.

“'By trying to set itself free, the Atta ant would then step in yet another hole where the same process was repeated, until the legs and antennae of the Atta were all fixed and the intruder was spread-eagled on the carton nest,” says Schmidt.

"After pinning the insect down, the A. brevis ants carve it up on the spot. The trap allows workers to efficiently kill insects nearly fifty times heavier than themselves.

"Dejean has also seen an unrelated ant species (Allomerus decemarticulatus) in French Guiana using a similar hunting method. This suggests that the strategy has evolved at least twice, independently.

“'[The trap] is quite unique and so far limited to the very specific lifestyle and ecological niche of these two arboreal ants,” says Schmidt.

"Farmers in Costa Rica are increasingly using fungicide in the ants’ native range. This may imperil the species by killing the fungus used to reinforce the trap tunnels and galleries."

Comment: Ants continue to amaze.I can't imagine this developed step wise. The design is intricate. Each ant's actions must be automatic as shown in other previously reported studies. Saltation?